{"text_format":"1","workbook":"xlsx","n_sheets":12,"sheets":["Cover","Notes","Introduction","1) a) Source","1) b) Pathway","1) c) Receptors","2) Site Hazard Rating","3) Likelihood","4) Site Risk and Classification","5) Standard Containment Designs","Sheet1","Risk Scoring"],"not_rendered":{"charts":0,"images":22,"macros":1,"external_links":1,"defined_names":56,"comments":4,"pivot_tables":0},"unopened":[],"bounds":{"document_bytes":16777216,"sheet_cells":100000,"rows_first":2000,"rows_last":500,"rows_between":2000,"halvings":0,"cell_chars":16384,"cell_head_chars":4096},"cells_cut":0,"cells_raw":0,"read":"whole","date_system":"1900"}

{"sheet":"Cover","index":0,"n_rows":57,"n_cols":6,"rows_kept":57,"cut":false,"hidden":false,"merged":[]}
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[null,"JOB TITLE",null,null,null,"Ellesmere Port IED Application"]
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[null,"JOB NUMBER",null,null,null,331002023]
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[null,"MADE BY",null,null,null,"Elizabeth Wilson"]
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[null,"CHECKED BY",null,null,null,"Joshua Parsons"]
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[null,"DATE",null,null,null,"2022-09-14"]
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[null,"Description of spreadsheet",null,null,null,"This spreadsheet provides a secondary containment risk assessment for Ellesmere Port Sludge Treatment Centre (STC) using the Anaerobic Digestion and Biogas Association (ADBA) secondary containment risk assessment tool. "]
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[null,"Sheet Number prefix",null,null,null,""]
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[null,"Member/Location",null,null,null,""]
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[null,"Drawing Reference",null,null,null,""]
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[null,"Filename",null,null,null,"Ellesmere Port ADBA"]
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[null,"CONTENTS OF SPREADSHEET"]
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[null,"Sheet",null,"Description"]
[null,"Cover"]
[null,"Notes"]
[null,"Introduction",null,"Introduction to the ADBA Tool"]
[null,"1 a) Source",null,"The inventory of materials for Ellesmere STC is provided in the worksheet 1a) Source "]
[null,"1 b) Pathway",null,"The Pathway information for Ellesmere Port STC is provided in the worksheet 1) b) Pathway "]
[null,"1 c) Receptors",null,"The Receptor information for Ellesmere Port STC is provided in the worksheet 1) c) Receptor."]
[null,"2) Site Hazard Rating",null,"The Site Hazard Rating is displayed in the worksheet 2) Site Hazard Rating"]
[null,"3) Likelihood",null,"The likelihood of loss of primary containment and the associated mitigation."]
[null,"4) Site Risk and Classification",null,"The Site Hazard Rating and Classification is in this worksheet"]
[null,"5) Standard Containment Design",null,"The Standard Containment Design is in this worksheet"]
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[null,"AUTHORISATION OF LATEST VERSION"]
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[null,"Type and method of check",null,null,null,"Review of method, inputs and assumptions"]
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[null,"Signatures & dates:",null,null,"Made by "," Elizabeth Wilson"]
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[null,null,null,null,"Checked ","Joshua Parsons"]
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[null,null,null,null,"Reviewed","Jeremy Cork"]
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[null,"REVISIONS",null,null,"Current Revision ","V1"]
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[null,"Rev.","Date","Made by","Checked"," Description"]
[null,"V1","2022-09-13","EW","JP","Checked"]
[null,"V1","2022-09-14","EW","JC","Reviewed"]

{"sheet":"Notes","index":1,"n_rows":62,"n_cols":3,"rows_kept":62,"cut":false,"hidden":false,"merged":[[39,1,39,2],[46,1,46,2],[52,1,52,2],[61,1,61,2],[1,1,1,2],[3,1,5,2],[6,1,6,2],[7,1,9,2],[15,1,15,2],[19,1,19,2]]}
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[null,"(1) Purpose of spreadsheet"]
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[null,"This spreadsheet outlines the information and data utilised, as well as the assumptions applied to undertake a secondary containment risk assessment for Ellesmere Port Sludge Treatment Centre (STC) based on the using the Anaerobic Digestion and Biogas Association (ADBA) secondary containment risk assessment tool and associated guidance. The ADBA risk assessment is based on CIRIA 736  Containment systems for the prevention of pollution: Secondary, tertiary and other measures for industrial and commercial premises. "]
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[null,"(2) Key Assumptions"]
[null,"Any assumptions are outlined in the spreadsheet."]
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[null,"(3) Basis of calculations"]
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[null,"ADBA Risk Assessment tool."]
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[null,"(4) References"]
[null,"All references are outlined in the spreadsheet."]
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[null,"(5) Special features"]
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[null,null,"Input Cell"]
[null,null,"Key Outputs"]
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[null,"(6) Holds or items that require Clarification"]
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[null,"(7) Summary"]
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[null,"Best Practice Guide"]

{"sheet":"Introduction","index":2,"n_rows":75,"n_cols":9,"rows_kept":75,"cut":false,"hidden":false,"merged":[]}
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[null,null,null,null,null,null,null,"Although this tool works as a standalone tool, we recommend you read this first:","ADBA CIRIA736 Bund Classification Assessment"]
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[null,"There are 5 steps to follow:"]
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[null,"1)","Identify the hazard posed to the environment by the inventory of materials held on the site and the location of the site"]
[null,null,"a. Categorise the source"]
[null,null,"b. Identify the pathways"]
[null,null,"c. Identify the receptor"]
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[null,"2)","The Site Hazard Rating is derived by this tool from the combination of the hazards assessed above"]
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[null,"3)","Calculate the likelihood of a loss of primary containment event occurring"]
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[null,"4)","The combination of the Site Hazard Rating and the likelihood of a loss of containment occuring gives the site risk rating and required secondary containment classification"]
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[null,"5)","From the class of containment needed, identify suitable designs from the 'Standard Containment Designs' sheet"]
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[null,"Additional Guidance"]
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[null,"The worksheets in this spreadsheet are protected to prevent inadvertant damage to the tool.  To remove the protection, the password is CIRIA736"]

{"sheet":"1) a) Source","index":3,"n_rows":47,"n_cols":15,"rows_kept":47,"cut":false,"hidden":false,"merged":[[33,1,33,3],[3,12,3,14],[5,12,6,12]]}
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[]
[null,"Material","Material","Total Enclosed Quantity","units","Storage","Flammability","Corrosive","Ecotoxicity (based on LD and quantity)","Environmental hazard rating ","Justification",null,"Risk quantification"]
[null,"Feedstock",null,null,null,null,null,null,null,null,null,null,"Material","Volume (m3)","Environmental Hazard Rating"]
[null,null,null,null,null,null,null,null,null,null,null,null,"Wet Sludge","0-99","Low"]
[null,"Imported raw sludge liquid","Liquid",660,"m3","Raw Sludge Tanks x4 (associated screens, feed well) and associated pipework. ","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. ",null,null,"100-999","Medium"]
[null,"Raw sludge liquors ","Liquid","10 - 100","m3","Supernatant Well (buried and lidded)","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,null,null,null,null,null,null,null,"Feedstock Overall Rating","H","Any material with a \"High\" rating means the overall rating is High."]
[null,"Process"]
[null,"Thickened sludge tanks","Liquid",2640,"m3","Thickened sludge tanks x3  (fully buried, covered reinforced concrete tanks surrounded by impermeable surfacing) and associated pipework","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Digesting Sludge (dewatered / thickened sludge)","Liquid",360,"m3","Thermophilic digester tanks x3  (above ground steel tanks) and associated pipework","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Digested Sludge","Liquid",10200,"m3","Mesophilic Digesters x3 (partially buried reinforced concrete tanks with fixed roofs) and associated pipework","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Digested Sludge","Liquid",880,"m3","Digested sludge overflow tank (buried reinforced concrete tank) and associated pipework","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Digested Sludge","Liquid",2200,"m3","Post digestion tank (above ground glass fused to steel constructed tank)","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Digested Sludge","Liquid",30,"m3","Digested sludge buffer tank  (above ground glass fused to steel constructed tank)","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Digested  Sludge Liquors (centrate)","Liquid",40,"m3","Centrate buffer tank (above ground glass fused to steel constructed tank) ","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Digested  Sludge Liquors (centrate)","Liquid",1200,"m3","Centrate tank (above ground glass fused to steel constructed tank) and Associated Pipework","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Raw sludge ","Liquid",469,"m3","Unfinished Surplus Activated Sludge (SAS) tank (above ground glass fused to steel constructed tank) and associated pipework","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Dewatered / thickened sludge","Solid ",834,"m3","Thickened SAS Tank (above ground tank glass fused to steel constructed tank)","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Raw sludge","Liquid","10 - 100","m3","Consolidation wet well (partially buried reinforced concrete tank)","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,"Digested sludge","Liquid",880,"m3","Digester overflow tank (buried reinforced concrete tank)","Not flammable","No","Low","H","Permitted waste types (wet sludge) are non-hazardous, however include substances which exhibit a high source hazard and have an unfavourable influence on the oxygen balance (CIRIA Guidance, Appendix A2).  This would result in an Environmental Hazard rating of High. "]
[null,null,null,null,null,null,null,null,"Process Overall Rating","H","Any material with a \"High\" rating means the overall rating is High."]
[null,"Additives and site chemicals"]
[null,"Liquid polyelectrolyte – thickening plant","Liquid","1 - 10","m3","GBT Poly Storage Tank (fibreglass / plastic tank bunded as per UU asset standards","Not flammable","No",null,"M","Material stored  internally within  buildings (GBT building)  and on impermeable surfacing. Low ecotoxicity for the quantities stored."]
[null,"Liquid polyelectrolyte – thickening plant","Solid","1 - 10","m3","GBT Poly Storage Tank (fibreglass / plastic tank)","Not flammable","No",null,"M","Material (powder) stored  internally within  buildings (GBT building)  and on impermeable surfacing. Low ecotoxicity for the quantities stored"]
[null,"Make up polyelectrolyte ","Solid","1 - 10","m3","GBT Poly Mixing Tank (fibreglass / plastic tank)","Not flammable","No",null,"M","Low ecotoxicity for the quantities stored."]
[null,"Liquid polyelectrolyte – centrifuge","Liquid","1 - 10","m3","Centrifuge Poly Storage Tanks (fibreglass/ plastic tanks bunded as per UU asset standards)","Not flammable","No",null,"M","Material stored  internally within  buildings (Centrifuge Building) and on impermeable surfacing. Low ecotoxicity for the quantities stored"]
[null,"Powder polyelectrolyte –  centrifuge","Solid","1 - 10","m3","Centrifuge Poly Storage Tanks (fibreglass/ plastic tanks bunded)","Not flammable","No",null,"M","Material (powder) stored  internally within  buildings (Centrifuge Building)  and on impermeable surfacing. Low ecotoxicity for the quantities stored"]
[null,"Make up polyelectrolyte ","Solid","1 - 10","m3","Centrifuge Poly Make up Tank (fibreglass / plastic tank)","Not flammable","No",null,"M","Low ecotoxicity for the quantities stored."]
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[null,null,null,null,null,null,null,null,"Chemicals Overall Rating","M","The overall source assessment for additives and site chemicals is  considered to be Medium. "]
[null,"Fire fighting agents and cooling water spillages"]
[null,"Fire Fighting Agents harmful in their own right or contaminated by inventory","Liquid",null,null,null,"Not flammable","No","Low","L","Low in the example in the ADBA Tool."]
[null,"Fire fighting and cooling water contaminated by inventory",null,null,null,null,"Not flammable","No","Low","L","Low in the example in the ADBA Tool."]
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[null,null,null,null,null,null,null,null,"Spillages Overall Rating","L","All the hazards are \"Low\" therefore the overall rating is low"]
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[]
[null,null,null,null,null,null,null,null,"Sources Overall Hazard Rating",{"$f":"IF(OR(J9=\"H\",J23=\"H\",J39=\"H\"),\"H\",IF(OR(,J33=\"M\"=\"M\"),\"M\",\"L\"))","v":"H"}]
[]
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["H"]
["M"]
["L"]

{"sheet":"1) b) Pathway","index":4,"n_rows":102,"n_cols":15,"rows_kept":102,"cut":false,"hidden":false,"merged":[]}
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[null,null,null,null,null,null,null,"Postcode","CH2 4HZ"]
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[null,"Pathway - the route from primary containment to receptor",null,null,null,"Environmental hazard rating ","Notes","Source","Description","Link","Image","Source","Description","Source","Source"]
[null,"Site layout and drainage"]
[null,"If any of the site inventory has a runoff time of a few minutes…",null,null,null,null,"N/A  - Run-off time is an estimate of how long it would take to flow to the nearest receptor."]
[null,"If any of the site inventory has a runoff time of a few hours.…",null,null,null,"H","It is assumed the site inventory has a runoff time of a few hours due to the form of sludge and the distance to the receptors. 2D modelling has been completed for the site that identifies sludge would leave the site in the event of failure of the Post Digestion Tank and Mesophilic Digester. 2D modelling for the failure of the centrate tank doesn't show sludge leaving the site.  Realistically, the physical property of sludge is slow flowing suspension and relatively immobile. Notwithstanding  the limitations of the modelling software. "]
[null,"If any of the site inventory has a runoff time of a few days…",null,null,null,null,"N/A  - Run-off time is an estimate of how long it would take to flow to the nearest receptor."]
[null,"If any of the site inventory has a runoff time of a few weeks…",null,null,null,null,"N/A  - Run-off time is an estimate of how long it would take to flow to the nearest receptor."]
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[null,"Topography, geology and hydrology"]
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[null,"Made ground (artificial ground)",null,null,null,"M","A medium environmental hazard rating has been selected for geology due to made ground exhibiting variable thickness across the site (Stantec, 2022). Made Ground (Artificial Deposit) is reported to be present across the site and is generally described as firm gravelly sandy clay with assorted lithologies of gravel including brick and low to medium cobble content.  Made ground was reported to be overlying superficial drift deposits (Tidal Flat Deposits), comprising bands of sand, gravel and peat, overlying clay (Glacial Till). ","BGS geoviewer","Made ground  (artificial deposit)  on record shown as per image.","http://mapapps2.bgs.ac.uk/geoindex/home.html",null,"Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1"," Made Ground (Artificial Deposit) is reported to be present across the site at a variable thickness of 0.2 to 5.7 m.  Made ground is generally described as firm gravelly sandy clay with assorted lithologies of gravel including brick and low to medium cobble content.","C2V+ (2018) Ellesmere Port WwTW  Ground Investigation Report, Document No. 80040560-01-C2V-ELLES-99-RP-G-01\n\n[included as a source to Stantec 2022]","BAM Ritchies (2014 & 2015). Factual Geotechnical Report on a Ground Investigation, 4882 & 5653 Ellesmere Port WwTW\n\n\n[included as a source to Stantec 2022]"]
[null,"Superficial deposits - Secondary A Undifferentiated Aquifer",null,null,null,"M","Superficial deposits on site include Glacial Till in the west and Tidal Flat Deposits and then Glacial Deposits in the east.  BAM Ritchies (2014 and 2015) also identifies peat in the east and south of the site.  \n\nSuperficial deposits, with the exception of peat, are designated as a Secondary Undifferentiated Aquifer therefore a Medium Environmental Hazard Rating has been selected.","BGS geoviewer","Till, Devensian Diamicton overly the site as per the image. ","http://mapapps2.bgs.ac.uk/geoindex/home.html",null,"Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1","Made ground is underlaid by Glacial Till ranges in thickness from 25.8 to 31.8 m with a base of -19.6 to -29 mAOD and is described as firm to very stiff brown occasionally grey variably sandy gravelly clay with low to medium cobble content.\n\nBGS Logs provide additional data from 13 boreholes on site confirming that superficial deposits on site include Glacial Till in the west and Tidal Flat Deposits and then Glacial Deposits in the east.  Tidal Flat Deposits comprise bands of sand, gravel and peat, overlying clay (Glacial Till).\n\nBAM Ritchies (2014 and 2015) recorded around 2 m of Peat underlying the Made Ground in the east and south of the Site which is underlain by around 0.2 – 1.6 m of silt/sand/clay before the thick Glacial Till unit is encountered.\n\nThe overlying Glacial Till and Tidal Flat Deposits are designated as Secondary Undifferentiated aquifer by the EA, which is used to designate lithologies “in cases where it has not been possible to attribute either category A or B to a rock type. In most cases, this means that the layer in question has previously been designated as both minor and non-aquifer in different locations due to the variable characteristics of the rock type.\"","C2V+ (2018) Ellesmere Port WwTW  Ground Investigation Report, Document No. 80040560-01-C2V-ELLES-99-RP-G-01\n\n[included as a source to Stantec 2022]","BAM Ritchies (2014 & 2015). Factual Geotechnical Report on a Ground Investigation, 4882 & 5653 Ellesmere Port WwTW\n\n\n[included as a source to Stantec 2022]"]
[null,"Bedrock - Principal Aquifer",null,null,null,"M","The site is underlaid by  the Wilmslow Sandstone Formation overlying the Chester Formation, both of the Sherwood Sandstone Group.  The bedrock Sherwood Sandstone is designated as a Principal Aquifer.  The closest fault is located along the western boundary of the Site trending north northwest to south southeast with another fault running parallel 1.5 km to the east; a further fault branching off to join the two together, to the north and south of the site.  A Medium Environmental Hazard Rating has been selected.\n","BGS geoviewer","Wilmslow sandstone formation - sandstone","https://magic.defra.gov.uk/MagicMap.aspx",null,"Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1","The regional bedrock geology for the site is dominated by the Wilmslow Sandstone Formation overlying the Chester Formation, both of the Sherwood Sandstone Group.   The closest fault is located along the western boundary of the Site trending north northwest to south southeast with another fault running parallel 1.5 km to the east of the site with a further fault branching off to join the two together to the north and south of the site. \n\nThe bedrock Sherwood Sandstone is designated as a Principal aquifer.  Principal aquifers are classified as “geology of high intergranular and/or fracture permeability, usually providing a high level of water storage and may support water supply/river base flow on a strategic scale.”\n","C2V+ (2018) Ellesmere Port WwTW  Ground Investigation Report, Document No. 80040560-01-C2V-ELLES-99-RP-G-01\n\n[included as a source to Stantec 2022]","BAM Ritchies (2014 & 2015). Factual Geotechnical Report on a Ground Investigation, 4882 & 5653 Ellesmere Port WwTW\n\n\n[included as a source to Stantec 2022]"]
[null,"Drainage ditch",null,null,null,"H","An unnamed ditch is located along the south-eastern boundary of the site.  \n\nThe ditch will transport any contaminants that enter the drain through surface water runoff, groundwater flow and other potential receptors downstream, i.e. River Gowy.  A High Environmental Hazard Rating has been selected.","Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1"]
[null,"Shropshire Union Canal",null,null,null,"L","The Shropshire Union Canal runs along the western boundary of the site on an embankment at a slightly higher elevation than the Site (c. 10 mAOD).\n\nThe canal will transport any contaminants that enter the canal through surface water runoff.\n\nA low risk has been selected due to the 2D Modelling not identifying sludge reaching the canal in the event of a failure, due to proximity from the site. ","Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1"]
[null,"Mill Brook",null,null,null,"H","Mill Brook runs through the centre of the site and flows in a north-westerly direction.  The nearest sludge storage asset on the Site is located c. 30 m away from the Brook (SAS tanks), however the thickened SAS pipeline and GBT filtrate return pipeline both run directly above the Brook.  The Brook merges with the River Gowy approximately 1 km north of the site.\n\nMill Brook will transport any contaminants that enter the Brook through surface water runoff, groundwater flow to other potential receptors downstream, i.e. River Gowy. \n\nA high  risk has been selected as the 2D modelling for Ellesmere Port STC identifies sludge does leave the site.","Catchment Data Explorer (CDE)","Mill Brook is categorised as 'moderate' with regard to Ecological, Physio-chemical quality elements and supporting elements (surface water).  \n\nDiffuse sources, largely from agriculture and trade/industry discharges, are reasons for the waterbody failing to meet the  'good' ecological status.","Stanney Mill Brook | Catchment Data Explorer | Catchment Data Explorer"]
[null,"River Gowy",null,null,null,"H","The River Gowy is a tributary of the River Mersey and flows northwards c. 550 m east of the site; it discharges to the River Mersey approximately 3 km north of the site. This waterbody, in 2022,  has an overall WFD classification of 'Moderate', with an ecological status of 'Moderate' and  a chemical status of 'Fail' (although previous years were reported to be 'good'.  \n\nThe River Gowy will transport any potential contaminants that enter the river through surface water runoff, groundwater flow and other potential receptors downstream. A high  risk has been selected as the 2D modelling for the site  identifying sludge leaving the site and reaching Mill Brook in the event of a failure.","Catchment Data Explorer (CDE)","Diffuse sources, largely from agriculture and trade/industry discharges, are reasons for the waterbody failing to meet the  'good' ecological status.","Gowy and tribs (Source to Milton Brook) | Catchment Data Explorer | Catchment Data Explorer"]
[null,"Mitigation - do these apply?"]
[null,"Some secondary and tertiary containment system is present (see Likelihood assessment)"]
[null,"Spills will be contained within the hard surfaced and drained areas and returned to the WwTW for treatment. \n"]
[null,"2D modelling for the site identifies routes to river or watercourse (Mill Brook reaching River Gowy), mitigations have been applied and  mitigation modelling confirms containment. \n"]
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[null,null,null,null,"Path & Mitigation Overall Rating","M","Justification: \n\n - There is good secondary containment for chemicals.\n - Modelling identifies a catastrophic spill  (failure of all tank installation areas) would leave the site via a potential route through Mill Brook in certain circumstances (see above). However, the majority of the sludge would be contained within hard surfaced and drained areas and returned to the WwTw for treatment. 2D Modelling software cannot  model these features and due to its limitations. Mitigation measures have been proposed in the modelling report to allow for effective containment of spills on site (see likelihood).\n- There is in excess of 25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and hence will act as a vertical barrier for transport to the principal aquifer bedrock below. "]
[null,"Climatic conditions"]
[null,"Annual rainfall < 1000 mm",null,729,null,"L"," - The annual rainfall is less than 1,000 mm","Met  Office","UK climate averages","https://www.metoffice.gov.uk/research/climate/maps-and-data/uk-climate-averages/gcqzwq04e"]
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[null,"Fire Fighting Water"]
[null,"Flammable materials normally present on site in large quantities",null,null,null,"L"," - There is limited flammable materials on the site that would combust over long periods and would require significant volumes of fire fighting water. \n - The key flammable material is the biogas, which is contained within the double contained storage gas bag. Use and transfer of biogas is controlled via the site SCADA system, which included low and high pressure monitoring that would shut off any gas flows in the event of gas release, such as in a fire.\n- Controls are in place in accordance with DSEAR.  A hazardous areas risk classification has been undertaken in accordance with DSEAR. Equipment is adequately rated in accordance with the zoning classification.\n - If firefighting was needed on the site, the drainage system returns surface water to treatment within the WwTW.\n - Firefighting water is therefore not  considered to be a pathway risk. "]
[null,"Fire fighting and cooling water contaminated by inventory",null,null,null,"L"]
[null,"Location"]
[null,"Flooding",null,null,null,"M"," - A medium environmental hazard rating has been selected as the majority of the site is classed as Flood Zone 2.","EA Flood Map for Planning","The site is mostly classified as a Flood Zone 2 (medium risk of flooding)","Flood risk information for this location - Flood map for planning - GOV.UK (flood-map-for-planning.service.gov.uk)",null,"Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1","The Site is located within a designated flood plain area (Flood Zone 2) along with the surrounding land to the north, east and south (Flood Zone 3)."]
[null,"Site is connected to a Wastewater Treatment Works",null,null,null,"L"," - The WwTW is designed with capacity to treat peaks in flow and loads including from surface water drainage input from the site.  \n - In the event of a catastrophic failure on site, the SCADA system would manage the Wastewater treatment process to contain any additional load within the system, where possible.  In addition high level and treatment alarms would alert site operators, who would start the emergency procedures in line with the site accident protocols in the site EMS and shut down/divert processes that risk the  WwTW discharge consent. \n - The potential risk of releases via the WwTW is considered to be low. \n"]
[null,null,null,null,"Site Considerations  Overall Rating","M"]
[]
[]
[null,null,null,null,"Pathway Overall Hazard Rating","M"]
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[]
["H"]
["M"]
["L"]

{"sheet":"1) c) Receptors","index":5,"n_rows":100,"n_cols":20,"rows_kept":100,"cut":false,"hidden":false,"merged":[]}
[]
[null,null,null,null,null,null,null,null,null,null,null,"Postcode","CH2 4HZ"]
[]
[null,"Receptors","Within","units",null,null,null,null,null,"Environmental hazard rating ","Notes","Source","Description","Link","Image","Source","Description","Source","Description","Source"]
[null,"Watercourses and bodies"]
[]
[null,"Drainage ditch (overland flow)","<50","m",null,null,null,null,null,"M","An unnamed ditch is located along the south-eastern boundary of the site; its water level is linked to rainfall.  Therefore, a Medium Environmental Hazard Rating has been selected.","Google Earth (2022)",null,null,null,"Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1"]
[null,"Shropshire Union Canal","<50","m",null,null,null,null,null,"M","The Shropshire Union Canal runs along the western boundary of the site on an embankment at a slightly higher elevation than the Site (c. 10 mAOD).\n\nThe canal will transport any contaminants that enter the canal through surface water runoff. A Medium Environmental Hazard Rating has been selected.","Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1"]
[null,"River Gowy",1000,"m",null,null,null,null,null,"H","The River Gowy is a tributary of the River Mersey and flows northwards c. 550 m east of the site; it discharges to the River Mersey approximately 3 km to the north.  In 2022, this waterbody has an overall WFD classification of 'Moderate', with an ecological status of 'Moderate' and a chemical status of 'Fail' (although previous years were reported to be 'good'.  \n\nThe River Gowy will transport any potential contaminants that enter the river through surface water runoff, groundwater flow and other potential receptors, downstream. The wider area falls within a Nitrate Vulnerable Zone.  A High Environmental Hazard Rating has been selected.","Drinking Water Safeguard Zones and NVZs","Surface Water S630 - Stanney Mill Brook NVZ","Check for Drinking Water Safeguard Zones and NVZs (data.gov.uk)",null,"Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1"]
[null,"Mill Brook","<50","m",null,null,null,null,null,"H","Mill Brook runs through the centre of the site and flows in a north-westerly direction.  The nearest sludge storage asset on the Site is located c. 30 m away from the Brook (SAS tanks), however the thickened SAS pipeline and GBT filtrate return pipeline both run directly above the Brook.  The Brook merges with the River Gowy approximately 1 km north of the site.\n\nMill Brook will transport any contaminants that enter it through surface water runoff and groundwater flow, to other potential receptors downstream, i.e. River Gowy. The wider area falls within a Nitrate Vulnerable Zone. A High Environmental Hazard Rating has been selected.","Drinking Water Safeguard Zones and NVZs","Surface Water S630 - Stanney Mill Brook NVZ","Check for Drinking Water Safeguard Zones and NVZs (data.gov.uk)"]
[null,"Superficial deposits - Secondary A Undifferentiated Aquifer","Beneath site",null,null,null,null,null,null,"M","Superficial deposits on site include Glacial Till in the west and Tidal Flat Deposits, followed by Glacial Deposits in the east.  BAM Ritchies (2014 and 2015) also identifies peat in the east and south of the site.  \n\nSuperficial deposits, with the exception of peat, are designated as a Secondary Undifferentiated Aquifer, therefore a Medium Environmental Hazard Rating has been selected.\n","BGS geoviewer","Till, Devensian Diamicton overly the site as per the image. ","http://mapapps2.bgs.ac.uk/geoindex/home.html",null,"Stantec (2022) Environmental Quantitative Risk Assessment at Ellesmere Port Wastewater Treatment Works, Report Reference 331001867R1"]
[null,"Bedrock - Principal Aquifer","Beneath site",null,null,null,null,null,null,"M","The site is underlaid by  the Wilmslow Sandstone Formation overlying the Chester Formation, both of the Sherwood Sandstone Group.  The Sherwood Sandstone bedrock is designated as a Principal Aquifer.  The closest fault is located along the western boundary of the Site trending north northwest to south southeast with another fault running parallel 1.5 km to the east of the site with a further fault branching off to join the two together to the north and south of the site.  A Medium Environmental Hazard Rating has been selected.","BGS geoviewer","Wilmslow sandstone formation - sandstone","https://magic.defra.gov.uk/MagicMap.aspx",null,null,null,null,null,"Stantec (2021) - Lundwood STF\nEnvironmental Permit Site Condition Report"]
[null,"Abstraction","N/A","m",null,null,null,null,null,"L","There are no active surface water abstraction licences within 500 m.  ","Magic map Source Protection Zones merged (England)","Magic map: No SPZs","Magic Map Application (defra.gov.uk)"]
[null,"Mersey Estuary (Ramsar, SPA)",2550,"m",null,null,null,null,null,"H","The Mersey Estuary is a Ramsar and Special Protected Area (SPA); it is located approximately 2.55 km from the site. It status relate to the aquatic environment, therefore a Medium Environmental Hazard Rating has been selected.","Magic Map Stautory Designations",null,"Magic Map Application (defra.gov.uk)"]
[null,"WwTWs",50,"m",null,null,null,null,null,"L","The WwTWs activities incompass a significant number of assets over a large surface area.  Direct impact on site actvities/operations are extremely unlikely as sludge would not accumulate to a depth where there was risk of disruption to electrical equipment (i.e. control cabinets) or other assets. "]
[null,null,null,null,null,null,null,null,"Water Overall Rating","H","Justification: River Gowy and Mill Brook have a High Environmental Hazard Rating. Mill Brook is located in close proximity to the site and has the potential to carry contaminants through to River Gowy (Ramsar, SPA)."]
[null,"Habitation"]
[null,"Commercial / industrial",275,"m",null,null,null,null,null,"L","Commercial / industrial properties are located to the north west of the site, the closest being located approximately 275 m to the north west.  Commercial properties largely comprise the Designer Outlet, Cheshire Oaks and surrounding industrial land uses.\n\n","Google Earth (2022)"]
[null,"Industrial - Gas Storage",130,"m",null,null,null,null,null,"L","Industrial land uses, including Avanti Gas (including gas storage assets) is located approximately 130 m north east of the site.","Google Earth (2022)"]
[null,"Highway; A5117","<50","m",null,null,null,null,null,"L","A5117 located along the northern boundary of the site, running east to west.  ","Google Earth (2022)"]
[null,"Farm (and associated dwelling)",275,"m",null,null,null,null,null,"L","A farm is located approximately 275 m south west of the site.","Google Earth (2022)"]
[null,"Residential dwellings",500,"m",null,null,null,null,null,"L","The closest residential properties are located within Stoak, a small village located approximately 500 m south of the site.","Google Earth (2022)"]
[]
[null,null,null,null,null,null,null,null,"Habitation Overall Rating","L","Justification: All the receptors are Low Environmental Hazard Rating"]
[null,"Other"]
[null,null,null,null,null,null,null,null,null,null,null," "]
[]
[]
[null,null,null,null,null,null,null,null,"Receptors Overall Hazard Rating","M",null,"  "," "]
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[]
[]
["H"]
["M"]
["L"]

{"sheet":"2) Site Hazard Rating","index":6,"n_rows":106,"n_cols":5,"rows_kept":106,"cut":false,"hidden":false,"merged":[[12,1,12,3],[3,1,3,4]]}
[]
[]
[]
[null,"Calculated hazard ratings:"]
[null,"Source","Pathway","Receptor","Site Hazard Rating"]
[null,{"$f":"'1) a) Source'!J42","v":"H"},{"$f":"'1) b) Pathway'!F41","v":"M"},{"$f":"'1) c) Receptors'!J29","v":"M"},{"$f":"IF(E106<6,\"Low\",IF(E106<10,\"Medium\",\"High\"))","v":"High"}]
[]
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[]
[]
[]
[]
[null,"Possible Combination",null,null,"Site Hazard Rating"]
[null,"L","L","L","Low"]
[null,"M","M","L","Low"]
[null,"H","L","L","Low"]
[null,"M","M","M","Medium"]
[null,"H","M","L","Medium"]
[null,"H","H","L","Medium"]
[null,"H","M","M","High"]
[null,"H","H","M","High"]
[null,"H","H","H","High"]
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[null,"Rating lookup table"]
[null,"L",1]
[null,"M",2]
[null,"H",3]
[]
[null,"This assessment score"]
[null,{"$f":"VLOOKUP(B6,B101:C103,2,FALSE)","v":3},{"$f":"VLOOKUP(C6,B101:C103,2,FALSE)","v":2},{"$f":"VLOOKUP(D6,B101:C103,2,FALSE)","v":2},{"$f":"B106*C106*D106","v":12}]

{"sheet":"3) Likelihood","index":7,"n_rows":264,"n_cols":9,"rows_kept":264,"cut":false,"hidden":false,"merged":[[126,4,138,4],[126,3,138,3],[126,5,138,5],[22,4,34,4],[35,4,47,4],[48,4,60,4],[61,4,73,4],[74,4,86,4],[74,5,86,5],[61,5,73,5],[48,5,60,5],[35,5,47,5],[22,5,34,5],[100,3,112,3],[113,3,125,3],[113,5,125,5],[100,5,112,5],[87,5,99,5],[87,4,99,4],[100,4,112,4],[113,4,125,4],[152,5,164,5],[126,1,138,1],[22,1,34,1],[35,1,47,1],[48,1,60,1],[61,1,73,1],[74,1,86,1],[87,1,99,1],[100,1,112,1],[113,1,125,1],[22,3,34,3],[35,3,47,3],[48,3,60,3],[61,3,73,3],[74,3,86,3],[87,3,99,3],[191,3,203,3],[204,1,216,1],[204,3,216,3],[204,4,216,4],[204,5,216,5],[191,1,203,1],[191,4,203,4],[191,5,203,5],[20,6,20,7],[178,1,190,1],[178,3,190,3],[178,4,190,4],[178,5,190,5],[165,1,177,1],[165,3,177,3],[165,4,177,4],[165,5,177,5],[139,1,151,1],[139,3,151,3],[139,4,151,4],[139,5,151,5],[152,1,164,1],[152,3,164,3],[152,4,164,4]]}
[]
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[null,"Rational for the assessment of likelihood "]
[null,"Identification of risks is based on the individual sources of potentially polluting material (sludge tanks, etc.) and on the general site risk identified in the CIRIA guidance"]
[null,"Assessment of the unmitigated risk of emissions from each source is based on the potential for failure of any containment measures provided. "]
[null,"This considers the primary, secondary and tertiary containment associate with each source and the potential breach of these containment measures."]
[null,"The likelihood of failure is quantified, based on the guidelines provided in CIRIA 736 and United Utilities experience of containment failures on their sites. "]
[null,"Basing the quantification of containment failure on United Utilities experience on their own sites therefore accounts for the United Utilities design specification, making the assessment relevant to the designs. ",null,"The identification of the likelihood of the loss of containment ad subsequent release of contaminants "]
[null,"The mitigation applied to the risks considers the operational and maintenance procedures, including regular inspecting and testing of containment measures.  "]
[null,"Based on the regular inspecting and testing of containment measures it is considered that the potential for catastrophic failures would be identified prior to failure and either decommissioned and replaced (for example tanks) or repairs (e.g. pipelines)"]
[]
[]
[]
[]
[]
[null,"Risk ","Description of Risk","UNMITIGATED LIKELIHOOD \n","Mitigation applied","MITIGATED LIKELIHOOD",null,"L","Site Overall Likelihood"]
[null,"Raw Sludge Tanks (x4)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank;\n - tank overflow; or\n - tank leaks.","Containment:\n - Concrete tank construction.  Tank is self contained / has lid.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- 2 tanks are partially submerged (1.2m below ground) and 2 are fully submerged covered tanks to 1.5m depth\n- Submersion (full or partial) acts to protect the tanks from the risk of impact\n\n- Run-off from sludge areas (surrounding partially submerged tanks) returned to head of works. \n- There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Partially submerged tanks are surrounded by impermeable hardstanding which drains to the head of works, which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - Tanks visually inspected on a regular basis \n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater (in the case of fully submerged tanks), or across the surface of the site. If the latter occurs then UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment. \n","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tanks are constructed from reinforced concrete and are maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage around pipe flanges, particularly the inlet pipework connection and connection to screens as these are below ground. Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact - only two tanks are partially above ground, with the other two fully submerged. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - the pipework is not routed along areas of potential flammable atmosphere.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed after geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime are in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - two tanks are completely submerged and are therefore not at risk of lightning strike.  Partially submerged tanks are sited lower relative to other structures within the works, therefore unlikely to be struck by lightning.  Likelihood of emissions due to lightning is considered to be low"]
[null,"Thickened Sludge Tanks 2,640 m3 total (3x tanks)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank;\n - tank overflow; or\n - tank leaks.","Containment:\n - Concrete tank construction.  Tank is self contained / has lid.\n- All pipelines, valves and screens are made from steel.\n- Frost and accident protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- Tanks are fully submerged covered tanks to 7m depth\n- Submersion acts to protect the tanks from the risk of impact\n- Run-off from sludge areas returned to head of works. \n- There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below.","M","- Tanks are surrounded by impermeable hardstanding which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tanks are constructed from reinforced concrete and are maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Pipework associated with the tank is below ground. Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact - Tanks are fully submerged. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion -  the pipework is not routed along areas of potential flammable atmosphere.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed after geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - tanks are completely submerged and are therefore not at risk of lightning strike.  Likelihood of emissions due to lightning is therefore considered to be low"]
[null,"Supernatant Well (10 - 100 m3)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank;\n - tank overflow; or\n - tank leaks.","Containment:\n - Concrete tank construction.  Tank is self contained / has lid.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- Tanks are fully submerged covered tanks\n- Submersion acts to protect the tanks from the risk of impact\n- Run-off from sludge areas returned to head of works. \n-There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Tank is surrounded by impermeable hardstanding which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tank is constructed from reinforced concrete and is maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Pipework associated with the tank is below ground. Associated pumps are above ground and are visually inspected on a regular basis for leaks.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact - Tank is fully submerged. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - the tank is vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed after geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - tank is completely submerged and are therefore not at risk of lightning strike.  Likelihood of emissions due to lightning is therefore considered to be low"]
[null,"Mesophilic Digesters\n10,200 m3 total capacity (3x units with 1,922 m3 individual capacity) / Thermophilic Digester (3x units with 360 m3 total capacity) \n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank;\n - tank overflow; or\n - tank leaks.\n","Containment:\n - Mesophilic Digesters are partially buried, fixed roof digesters constructed from concrete.  Thermophilic Digesters are above ground and constructed from steel.  All digesters have lids.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Digesters are located on impermeable surfacing.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- Partial submersion of Mesophilic Digesters protects against the risk of impact\n- Run-off from sludge areas returned to head of works. \n-There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Tanks are located on impermeable surfacing which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tanks are constructed from reinforced concrete and are maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Pipework associated with the tank is both above and below ground. Above ground pipework is visually inspected on a regular basis for leaks.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact - Mesophilic Digesters are partially buried. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - the tanks are low relative to other structures within the area therefore unlikely to be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Digested Sludge Overflow Tank (880 m3 total capacity)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank;\n - tank overflow; or\n - tank leaks.","Containment:\n - Tank is buried to 7m depth and constructed from concrete.  Tank is self contained / has lid.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- Submersion of tank protects against the risk of impact\n- Run-off from sludge areas returned to head of works. \n- There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M"," - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tank is constructed from reinforced concrete and is maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Where above ground, pipework is visually inspected on a regular basis for leaks.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact - Tank is fully submerged. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - tank is completely submerged and are therefore not at risk of lightning strike.  Likelihood of emissions due to lightning is therefore considered to be low"]
[null,"Post Digestion Tank (2,200 m3 total capacity)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank;\n - tank overflow; or\n - tank leaks.","Containment:\n - Tank is constructed from glass fused to steel and is self contained / lidded.\n- Tank is located on impermeable surfacing.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n-There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M"," - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tanks are constructed from glass fused with steel and is maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Pipework associated with the tank is below ground.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact - Pipework associated with the tank is buried. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - the tanks are low relative to other structures within the area therefore unlikely to be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Digested Sludge Buffer Tank (30 m3 total capacity)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank;\n - tank overflow; or\n - tank leaks.\n","Containment:\n - Tank is constructed from glass fused to steel and is self contained / lidded.\n- Tank is located on impermeable surfacing.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Tanks are located on impermeable surfacing which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tanks are constructed from glass fused with steel and is maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Pipework associated with the tank is below ground.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact - Pipework from the digested buffer tank to the centrifuge is buried. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - the tanks are low relative to other structures within the area therefore unlikely to be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Centrate Buffer Tank (40 m3 total capacity)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank\n - tank overflow or\n - tank leaks.","Containment:\n - Tank is constructed from glass fused to steel and is self contained / lidded.\n- Tank is located on impermeable surfacing.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Tanks are located on impermeable surfacing which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tanks are constructed from glass fused with steel and is maintained to UU specifications.  Tank is surrounded by impermeable surfacing. Low volumes stored would result in liquids from a catastrophic failure flowing to the inlet works. Therefore, the risk of catastrophic tank failure is considered to be low."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Pipework associated with the tank is visually inspected on a regular basis.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact -Associated pipework is protected by kerbing/bollards etc to reduce the likelihood of impact. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - the tanks are low relative to other structures within the area therefore unlikely to be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Centrate Tank (1,200 m3 total capacity)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank\n - tank overflow or\n - tank leaks.","Containment:\n - Tank is constructed from glass fused to steel and is self contained / lidded.\n- Tank is located on impermeable surfacing.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n-There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below.  ","M","- Tanks are located on impermeable surfacing which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tanks are constructed from glass fused with steel and is maintained to UU specifications.  Tank is surrounded by impermeable surfacing. Low volumes stored would result in liquids from a catastrophic failure flowing to the inlet works. Therefore, the risk of catastrophic tank failure is considered to be low."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Pipework associated with the tank is visually inspected on a regular basis.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the import tank. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact -Pipework from the centrate buffer tank to the centrate tank is above ground. Above ground pipework is protected by kerbing/bollards etc to reduce the likelihood of impact. Pipework from centrate tank to head of works is wholly buried. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - the tank is similar height relative to other structures within the area therefore unlikely to be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Unthickened Surplus Activated Sludge (SAS) tank (469 m3 total capacity)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank\n - tank overflow or\n - tank leaks.","Containment: \n - Tank is constructed from glass fused to steel and is self contained / lidded.\n- Tank is located on impermeable surfacing.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Tanks are located on impermeable surfacing which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - Minor to moderate spills will be cleaned up before there has been sufficient time for infiltration into the ground. \n - In the event of loss of contaminants it is possible that sludge could flow across paved areas to grassed /stones areas into Mill Brook or into groundwater via faults in hard-standing or in areas of soft-standing. In this event, UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  The tank was constructed in 2021 and is constructed from glass fused with steel; tanks are maintained to UU specifications.  Tank is surrounded by impermeable surfacing. Based on the CIRIA risk criteria for steel tanks, the risk is therefore considered medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage - Pipework associated with the tank is both above and below ground. Above ground pipework is visually inspected on a regular basis for leaks.  Leaks would be contained by the impermeable surfacing. Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the plant items. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is low"]
[null,null,"- Impact - SAS to unthickened SAS pipework is partially buried and the unthickened SAS to RDT's is above ground. The tank and associated pipework is protected by kerbing between the tank and site access roads.  Likelihood of emissions due to impacts low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - the tanks are high relative to other structures within the area therefore could be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Thickened SAS tank\n(834 m3 total capacity)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank\n - tank overflow or\n - tank leaks.","Containment: \n - Tank is constructed from glass fused to steel and is self contained / lidded.\n- Tank is located on impermeable surfacing.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Tanks are located on impermeable surfacing which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - Minor to moderate spills will be cleaned up before there has been sufficient time for infiltration into the ground. \n - In the event of loss of contaminants it is possible that sludge could flow across paved areas to grassed /stones areas into Mill Brook or into groundwater via faults in hard-standing or in areas of soft-standing. In this event, UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  The tank was constructed in 2021 and is constructed from glass fused with steel; tanks are maintained to UU specifications.  Tank is surrounded by impermeable surfacing. Based on the CIRIA risk criteria for steel tanks, the risk is therefore considered medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage - Pipework associated with the tank is both above and below ground. Above ground pipework is visually inspected on a regular basis for leaks.  Leaks would be contained by the impermeable surfacing. Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the plant items. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is low"]
[null,null,"- Impact - RDT's to the thickened SAS tank is above ground and thickened SAS tank to thickened sludge tank is partially buried. The tank and associated pipework is protected by kerbing between the tank and site access roads.  Likelihood of emissions due to impacts low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - the tanks are high relative to other structures within the are therefore could be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Consolidation wet well\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank\n - tank overflow or\n - tank leaks.","Containment:\n - Concrete tank construction.  Tank is self contained / has lid.\n- All pipelines, valves and screens are made from steel.\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- Partially submersed acts to protect the tanks from the risk of impact\n- Run-off from sludge areas (surrounding partially submerged tanks) returned to head of works. \n- There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Tanks are located on impermeable surfacing which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater via faults in hard-standing or in areas of soft-standing. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic pipe failure - Tank is constructed from reinforced concrete and is maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Where above ground, pipework is visually inspected on a regular basis for leaks.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker Operators are trained to operate the tanks. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is considered to be low"]
[null,null,"- Impact - Tank is partially submerged. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The pipework was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike -  tank is partially submerged and low height compared to surrounding structures, therefore is unlikely to be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Digester overflow tank\n(880 m3 total capacity)\n\nSpillage of non hazardous sludge: \n - catastrophic failure of tank\n - tank overflow or\n - tank leaks.","Containment:\n- Concrete tank construction. Tank is self contained / has lid.\n- The tank is surrounded by impermeable hardstanding which drains to the head of works which would return spills for treatment\n- Frost and accidental protection where practical for pipework (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Physical property of sludge is slow flowing suspension and relatively immobile. This limits the risk of sludge flowing to off-site receptors and facilitates clean-up if a spill was to happen. \n- Tanks are fully submerged, covered tanks to 7m depth\n- Submersion acts to protect the tanks from the risk of impact\n-There is in excess of  25 m of low permeability Glacial Till which is assumed to have low hydraulic conductivity due to the high clay content found in the site investigation boreholes as detailed in BAM Ritchies (2014 and 2015) and will act as a vertical barrier for transport to the principal aquifer bedrock below. ","M","- Tank is partially surrounded by impermeable hardstanding which drains to the head of works which would return spills for treatment. Roads and turning areas should also be impermeable concrete.\n - TCM checks are conducted regularly. \n - Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n - Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n - The EMS contains procedures for visual inspections and actions to be taken in the event of tank failures.\n - In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Additional mitigation measures to reduce the impact from loss of containment events e.g. kerbing, containment walls, sacrificial areas, are detailed in Ellesmere Port Sludge Treatment Centre Secondary Containment Modelling Assessment.","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic tank failure -  Tank is constructed from reinforced concrete and is maintained to UU specifications.  Therefore, the risk of catastrophic tank failure is considered to be medium."]
[null,null," - Tank overflow or leaks - Due to level monitors and the interlock on feed pumps, the risk of overflow is considered to be low. The high-level overflow also drains into the site drainage system and is then returned to the head of the works. "]
[null,null," - Potential for minor leakage Where above ground, pipework is visually inspected on a regular basis for leaks.  Emission due to leaks is therefore considered medium."]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is considered to be low"]
[null,null,"- Abuse -all site staff and tanker operators are trained to practice standard operating practices for sludge importing. No risk of overflow, due to level monitors and the interlock on feed pumps. Likelihood of emissions due to abuse is low"]
[null,null,"- Impact - Tank is fully submerged. Likelihood of emissions due to impacts is considered to be low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"- Fire, explosion - assets are vented so flammable gasses would not build up in the tank.  Likelihood of emissions due to fire or explosion is considered to be low"]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The tank was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - Ageing / deterioration were considered at the point of design. Visual inspections and maintenance regime in place to identify any potential defects caused by ageing.  Likelihood of emissions due to age is considered to be low"]
[null,null,"- Lightning strike - tanks are completely submerged and are therefore not at risk of lightning strike.  Likelihood of emissions due to lightning is therefore considered to be low"]
[null,"Pipework associated with tanks above ground\n\n - Spillage of non hazardous sludge: catastrophic failure and leaks from pipework.","Containment: \n- All pipelines, valves and screens are made from steel\n- Most pipework above ground is over impermeable surfacing that falls to the site drainage. \n- Frost and accidental protection where practical (all pipes 150 mm and below should have lagging and trace heating)\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.\n- Straight runs and sweeping bends rather than curves.","M","- Above ground pipework visually inspected frequently. \n- TCM checks are conducted regularly\n- Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n- Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n- The EMS contains procedures for visual inspections and actions to be taken in the event of pipework failures.\n- In the event of overflow of contaminants it is possible that sludge could flow directly into groundwater or Mill Brook. In this event UU will react with an emergency spill response and clean up the area that has been contaminated. \n- Existing site drainage pipes and manholes are regularly inspected and maintained. This will ensure that all minor or catastrophic sludge spills draining to the existing site drainage network has a low risk of entering the soil store through cracks or defects.  \n- A programme of leak detection improvements, which for Ellesmere Port includes the installation of flow meters and interlock connection of various high level alarms to feed pumps.  In the majority of cases for pipework the only option available was the installation of network/PLC linked flow meters at appropriate locations (upstream and downstream of each pipe run) to allow for real time indication of any issues, triggering a rapid intervention at site level by operations. ","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic pipe failure -  As a result of a schedule of non-destructive testing the potential for catastrophic failure is considered low."]
[null,null," - Leaks from over ground pipework -   Due to regular checks for leaks, it is considered that there is a low likelihood of significant leakage. Secondary containment is in place for all above ground pipework. Any leaks would be contained by the site drainage except those crossing over Mill Brook. The potential for emission is therefore considered low.  "]
[null,null,"- Catastrophic failure of pipe joints and flanges - Any sudden loss of pressure related to a catastrophic pipe failure would be identified by the site SCADA system resulting all pumping being stopped and an alarm on the site SCADA system, therefore reducing any emissions. Likelihood of emissions due to catastrophic pipe failure is considered low. "]
[null,null,"- Shortcomings or failure in operational control system: The site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. The risk of emission of sludge is considered low"]
[null,null,"- Abuse -all site staff and tanker operators are trained to practice standard operating practices for sludge importing. Likelihood of emissions due to abuse is low"]
[null,null,"- Impact -  The pipework is located safely away from site road.  Likelihood of emissions due to impacts low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"-Fire, explosion -  The risk of Fire and explosion in sludge containing pipework is medium as sludge is not flammable and pipework is designed to prevent build up of flammable gases within it. The pipework is not routed along areas of potential flammable atmosphere."]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The pipework was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - The pipework are regularly monitored to check for leakages and material failure. Likelihood of emissions due to age in low"]
[null,null,"- Lightning strike - the pipework is low relative to other structures within the area therefore unlikely to be struck by lightning.  Likelihood of emissions due to lightning is low"]
[null,"Pipework below ground associated with tanks\n\n - Spillage of non hazardous sludge: catastrophic failure and leaks from pipework.","Containment: \n- All pipelines, valves and screens are made from steel.\n- Isolation valves are present at each end of pipe sections. This allows the isolation of leaking or failed pipe sections and limits the volume released.","M","- TCM checks are conducted regularly\n- Ellesmere Port STC is either manned, or when not, monitored by the Integrated Control Centre (ICC) on a 24/7 basis using SCADA and critical process alarms. A significant spill would be identified quickly, and the spill management procedure initiated, ensuring a rapid clean up.  SCADA controls would also, via a number of surrogate metrics, such as level monitoring, transfer, pump and valve status, provide rapid process control indications of certain loss of containment scenarios. \n- United Utilities has a fleet of sludge tankers across their region which form part of the operational response to sludge spills to be utilised rapidly in the event of a spill at Ellesmere Port STC.\n- Dependant on the age of the asset non-destructive testing (NDT) is carried out every 10, 5, 2 years and yearly on all tanks and associated ancillary assets. The risk of catastrophic failure will therefore be identified before failure occurs. \n- The EMS contains procedures for visual inspections and actions to be taken in the event of pipework failures.\n- In the event of overflow of contaminants it is possible that sludge could seep directly into groundwater . In this event UU will react with an emergency spill response and clean up the area that has been contaminated.\n- Existing site drainage pipes and manholes are regularly inspected and maintained. This will ensure that all minor or catastrophic sludge spills draining to the existing site drainage network has a low risk of entering the soil store through cracks or defects.  \n- A programme of leak detection improvements, which for Ellesmere Port includes the installation of flow meters and interlock connection of various high level alarms to feed pumps.  In the majority of cases for pipework the only option available was the installation of network/PLC linked flow meters at appropriate locations (upstream and downstream of each pipe run) to allow for real time indication of any issues, triggering a rapid intervention at site level by operations.  ","L"]
[null,null,"Failure risks and Mitigation Measures:"]
[null,null," - Catastrophic pipe failure -  As a result of a schedule of non-destructive testing the potential for catastrophic failure is considered low."]
[null,null," - Leaks from underground pipework would be emitted to ground. There is no secondary containment in place. The risk of emission due to leaks is therefore considered to be medium. "]
[null,null,"- Catastrophic failure of pipe joints and flanges - Any sudden loss of pressure related to a catastrophic pipe failure would be identified by the site SCADA system resulting all pumping being stopped and an alarm on the site SCADA system, therefore reducing any emissions. Likelihood of emissions due to catastrophic pipe failure is considered low. "]
[null,null,"-Shortcomings or failure in operational control system: the site is maintained inline with a proactive maintenance schedule and the EMS to ensure ongoing operation of all plant items. Operators are trained in the running of plant items. Likelihood of emissions due to operational failure is low"]
[null,null,"- Abuse -all site staff and tanker operators are trained to practice standard operating practices for sludge importing. Likelihood of emissions due to abuse is low"]
[null,null,"- Impact -  The pipework is located below ground and therefore the likelihood of emissions due to impacts is low"]
[null,null,"- Vandalism, etc. -the STC and WwTW are within a fenced and gated site, with access to the site controlled and CCTV system operational.  Likelihood of emissions due to vandalism is considered to be low"]
[null,null,"-Fire, explosion -  The risk of Fire and explosion in sludge containing pipework is medium as sludge is not flammable and pipework is designed to prevent build up of flammable gases within it. The pipework is not routed along areas of potential flammable atmosphere."]
[null,null,"- Geological factors - There has been no evidence of wider geotechnical issues during the time the WwTW has been operational on the site.  The pipework was designed with geotechnical input parameters.  Likelihood of emissions due to geological issues is low"]
[null,null,"- Ageing - The pipework are regularly monitored to check for leakages and material failure. Likelihood of emissions due to age in low"]
[null,null,"- Lightning strike - pipework is completely submerged and are therefore not at risk of lightning strike.  Likelihood of emissions due to lightning is therefore considered to be low"]
[]
[]
[]
[null,"Risk","Examples of mitigation options","Reduction in likelihood","Detail of measures"]
[null,1,"Operational Failures"]
[null,null,"The team will carry out periodic design reviews and a comprehensive HAZOP involving all the designers (process, civil, drainage, electrical) to ensure primary containment failure risk is very low. In addition operator training will be strengthened with detailed standard operating procedures.",-2,"(Taken from consultant's HAZOP report, for example)"]
[null,null,"Maintenance programme in place",-1]
[null,null,"Audit process in place",-1]
[]
[null,2,"Shortfalls in design"]
[null,null,"Plant control will be assessed at the HAZOP stage",-2]
[null,null,"No outlets below normal liquid level",-1]
[]
[null,3,"Structural failure – materials, components, detailing, corrosion or when exposed to heat and flame"]
[null,null,"Pre-cast concrete tank",-2]
[null,null,"Tank design has no history of failure",-1]
[null,null,"Tank failure risk assessment completed?",-1]
[null,null,"Steel valves",-1]
[null,null,"Structures will be built to British Standards with contractors that work under ISO9000",-1]
[]
[null,4,"Abuse – inappropriate change of use or other misuse"]
[null,null,"Change control procedure in place with sign off from competent personnel in applicable disciplines",-2]
[]
[null,5,"Vehicle impact"]
[null,null,"Armco crash barriers around tank",-2]
[null,null,"Tanks in bund not accessible by vehicles",-2]
[null,null,"Restricted vehicular access to site",-1]
[]
[null,6,"Vandalism, terrorism, force majeure etc"]
[null,null,"lockable valves on outlets (that are locked when not in use by procedure)",-1]
[null,null,"automatic and manual shut off valves",-1]
[null,null,"The site will include fencing where access is open to public",-1]
[null,null,"Passive CCTV system",-1]
[null,null,"Monitored CCTV with motion detection and warning signs",-2]
[]
[null,7,"Fire or explosion"]
[null,null,"DSEAR assessment completed",-2]
[null,null,"Control of ignition sources on site",-1]
[]
[null,8,"Geological factors -subsidence etc"]
[null,null,"Site investigations will be provided to the civil contractor for the design of the foundations",-1]
[]
[null,9,"Ageing or deteriorating assets/sub-components."]
[null,null,"Ageing/deterioration factored into plant design",-1]
[]
[null,10,"Lightning strike"]
[null,null,"Catenary or multiple lightning conductors supplied by specialists",-1]

{"sheet":"4) Site Risk and Classification","index":8,"n_rows":31,"n_cols":11,"rows_kept":31,"cut":false,"hidden":false,"merged":[]}
[]
[]
[]
[]
["Activity","Site Hazard Rating","Likelihood","Overall Site Risk Rating","Indicated Class of Secondary Containment Required"]
["Site - overall summary score",{"$f":"'2) Site Hazard Rating'!E6","v":"High"},"Low",{"$f":"IF(D31<3,\"Low\",IF(D31<5,\"Medium\",\"High\"))","v":"Medium"},{"$f":"IF(D6=\"Low\",\"Class 1\",IF(D6=\"Medium\", \"Class 2\",\"Class 3\"))","v":"Class 2"}]
["Raw sludge tanks","High","Low","Medium",{"$f":"IF(D7=\"Low\",\"Class 1\",IF(D7=\"Medium\", \"Class 2\",\"Class 3\"))","v":"Class 2"}]
["Thickened sludge tanks","High","Low","Medium","Class 2"]
["Supernatant well","High","Low","Medium","Class 2"]
["Mesophilic digesters / thermophilic digesters","High","Low","Medium","Class 2",null,null,null,null,null," "]
["Digested sludge overflow tank","High","Low","Medium","Class 2"]
["Post digestion tank","High","Low","Medium","Class 2"]
["Digested sludge buffer tank","High","Low","Medium","Class 2"]
["Centrate buffer tank","High","Low","Medium","Class 2"]
["Centrate tank","High","Low","Medium","Class 2"]
["Unthickened SAS tank","High","Low","Medium","Class 2"]
["Thickened SAS tank","High","Low","Medium","Class 2"]
["Consolidation wet well","High","Low","Medium","Class 2"]
["Digester overflow tank","High","Low","Medium","Class 2"]
["Pipework above ground","High","Low","Medium","Class 2"]
["Pipework below ground","High","Low","Medium","Class 2"]
[]
[]
[]
[]
["Rating lookup table"]
["Low",1]
["Medium",2]
["High",3]
[]
[{"$f":"VLOOKUP(B6,A27:B29,2,FALSE)","v":3},{"$f":"VLOOKUP(C6,A27:B29,2,FALSE)","v":1},null,{"$f":"A31*B31","v":3}]

{"sheet":"5) Standard Containment Designs","index":9,"n_rows":129,"n_cols":8,"rows_kept":129,"cut":false,"hidden":false,"merged":[]}
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[null,null,null,null,null,null,null,{"$f":"IF('4) Site Risk and Classification'!$E$6=\"Class 1\", \"Your site needs a design based on this diagram\",\"\")","v":""}]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[null,null,null,null,null,null,null,{"$f":"IF('4) Site Risk and Classification'!$E$6=\"Class 3\", \"Your site needs a design based on this diagram\",\"\")","v":""}]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[]
[null,"# ","Material ","When used ","How ","Why "]
[]
[]
[null,"A ","Clay ","If plentiful on site ","1m thick, sheepsfoot roller etc. ","Low cost & effective. "]
[]
[]
[null,"B ","Stabilised soil ","If soil tested and is suitable ","Sample and test to determine amount of lime, cement and depth. ","Low cost & effective when no clay on site. "]
[]
[]
[null,"C ","Bentonite matting ","If A or B not suitable ","Prepare sub, roll out and cover. ","Moderate cost. Quick & easy to lay. Tolerant of damage. "]
[]
[]
[null,"D ","Landfill liner type foil ","If A, B or C not suitable ","Prepare sub, roll out, weld and cover. "]
[]
[]
[null,"E ","Concrete ","Small areas only ","Shutter, place mesh and pour fibre reinforced.","Only if A, B, C or D not suitable. "]

{"sheet":"Sheet1","index":10,"n_rows":46,"n_cols":13,"rows_kept":46,"cut":false,"hidden":true,"merged":[]}
[]
[]
[null,null,1,null,2,null,3,null,4,null,5,null,6]
[null,null,"Ag Man",null,"Ag Man & PGC",null,"Ag Man & FW",null,"PGC & FW",null,"FW",null,"Indus & commercial inc green waste"]
[null,"Approx size typical plant +/- 50 %","150 kW",null,"500 kW",null,"1 MW",null,"1 MW",null,"1.5 MW",null,"> 2MW"]
[1,"Source"]
[null,"Farm yard manure","L"]
[null,"Slurry","L"]
[null,"Energy Crops","L"]
[null,"Energy Crop silage","M"]
[null,"Energy crop silage effluent","H"]
[null,"Food waste","-"]
[null,"Green waste","-"]
[]
[null,"Digestate","L",null,"L",null,"M",null,"M",null,"H"]
[null,"Based on vol and aquatic pollutant results"]
[]
[null,"Separated digestate solids","L"]
[null,"Separated digestate liquid","L"]
[]
[null,"Rainwater or surface water runoff contaminated by inventory","L"]
[]
[null,"Fire Fighting Agents harmful in their own right or contaminated by inventory","N/A"]
[]
[null,"Fire fighting and cooling water contaminated by inventory","N/A"]
[]
[2,"Pathway"]
[null,"Site layout and drainage"]
[]
[null,"Topography, geology and hydrology"]
[]
[null,"Climatic conditions"]
[]
[3,"Receptors"]
[null,"Groundwater","See groundwater sheet (similar to amaya's inventory sheet)"]
[]
[null,"Surface water"]
[]
[null,"Local Water Quality"]
[]
[null,"Protected areas"]
[]
[null,"Overall site hazard rating"]
[]
[]
[4,"Liklihood"]

{"sheet":"Risk Scoring","index":11,"n_rows":17,"n_cols":20,"rows_kept":17,"cut":false,"hidden":true,"merged":[[1,17,4,17],[7,11,7,14]]}
[null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,"Risk Rating"]
[null,"Rating",null,"Likelihood",null,null,"Consequence","incident level",null,null,null,{"$f":"L6*$P$2","v":4},{"$f":"M6*$P$2","v":8},{"$f":"N6*$P$2","v":12},{"$f":"O6*$P$2","v":16},4,"H","Consequence",null,"High"]
[null,"Very low",null,1,"up to 10%",null,1,"Category 4",null,null,null,{"$f":"L6*$P$3","v":3},{"$f":"M6*$P$3","v":6},{"$f":"N6*$P$3","v":9},{"$f":"O6*$P$3","v":12},3,"M",null,null,"Medium High"]
[null,"Low",null,2,"up to 20%",null,2,"Category 3",null,null,null,{"$f":"L6*$P$4","v":2},{"$f":"M6*$P$4","v":4},{"$f":"N6*$P$4","v":6},{"$f":"O6*$P$4","v":8},2,"L",null,null,"Medium Low"]
[null,"Medium",null,3,"up to 50%",null,3,"Category 2",null,null,null,{"$f":"L6*$P$5","v":1},{"$f":"M6*$P$5","v":2},{"$f":"N6*$P$5","v":3},{"$f":"O6*$P$5","v":4},1,"VL",null,null,"Low"]
[null,"High",null,4,"up to 70%",null,4,"Category 1",null,null,null,1,2,3,4]
[null,null,null,null,null,null,null,null,null,null,null,"VL","L","M","H"]
[null,null,null,null,null,null,null,null,null,null,null,"Likelihood"]
[]
[]
[null,"Category 1 – major, serious, persistent and/or extensive impact or effect"]
[null,"on the environment, people and/or property "]
[null,"Category 2 – significant impact or effect on the environment, people"]
[null,"and/or property "]
[null,"Category 3 – minor or minimal impact or effect on the environment, people"]
[null,"and/or property "]
[null,"Category 4 – substantiated incident with no impact."]