Sarval Rendering Plant, Nuneaton

Closes 18 Sep 2023

Opened 20 Sep 2022


We are sorry to hear that residents are experiencing problems with odour from this site. Please be assured we are working with the operator to resolve these issues. We have created this page in response to an increase in reports and we aim to keep residents updated on our regulation of the site. This page will be updated monthly.

Site background

Sarval (Hartshill) Limited operate the animal by-product rendering plant on Mancetter Road in Hartshill. This was formerly known as De Mulder & Sons Limited. The company take animal by-products from the meat processing industry and produce processed animal proteins for pet food products and high-grade fats such as tallow to be made into biofuel. The rendering process generates odorous exhaust gases that need to be abated to prevent nuisance.

The Environment Agency (EA) regulates this site under an Environment Permit, which was issued in 2006. This permit controls emissions from the site into the environment, it includes maintenance, management, and amenity conditions.

A copy of the Environmental Permit for the site can be viewed here, however please be aware that this information is not immediately available with a licence for use. Please contact us if you want to know if, and under what conditions, we would be able to license you.

Latest update

Following the significant odour incident that occurred in August 2022, the EA have commenced a formal investigation of the circumstances which led up to the incident and the impact caused.

The Environmental Permit was breached. The company have received a copy of our Compliance Assessment Report (CAR) and we are now in the appeal period before this can be published on our public register and shared on this page.

We continue to press the company for improvements to the facility to avoid a repetition of the incident and reduce odour emissions from the plant.

We are working with our professional health partners to review impacts from the odours from the facility and ensure the safety of the community.

We are meeting regularly with Marcus Jones MP and Councillor's Margaret Bell and Marli Parker as your community representatives, to provide them with the latest information.

We understand that reporting incidents is time consuming and frustrating, however the information that you provide is invaluable for us to understand the impact that the plant is having on the community and investigate and take action. Please continue to report incidents to us using our hotline number 0800 807060.

Frequently asked questions (FAQs)

We have produced an FAQ document for the site, which you can read here, alternatively you can use th drop downs below. This document will be added to and updated if we received further queries that are not already included. Please read through this page and refer to this FAQ document in the first instance if you have any questions.

For any concerns regarding the operational life of the site, hours of operation and traffic movements to and from the site, please contact North Warwickshire Borough Council at:

More Information

The company take animal by-products from the meat processing industry and produce meat and bone meals for pet food manufactures, and high-grade tallow to be made into biofuel. The rendering process generates malodourous exhaust gases that need to be abated to prevent nuisance. This is done is several ways:
• Concentrated gases from the rendering process are ducted via a water scrubber to a gas-fired Regenerative Thermal Oxidiser. This destroys malodourous compounds at an efficiency of 99.7%.
• Three scrubbing towers are used to treat malodourous air with sulphuric acid, caustic liquor, and sodium hypochlorite.
• The factory buildings are maintained under negative pressure with the air directed to the steam boilers, acid scrubber, activated carbon filter and a final biofilter.
• Condensed water vapour is pre-treated at an effluent treatment plant before discharge to sewer.

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Certain specific activities, that could be harmful to the environment, need an environmental permit to operate. A permit gives the holder permission to carry out certain types of activities at a specific location. The permit sets conditions which will protect the environment and people’s health. If we grant a permit, we carry out periodic inspections to check compliance with the permit. We review permit conditions and can change them at any time. We may take enforcement action if we consider that the permit holder has breached one or more conditions of their permit.
We must decide whether to grant or refuse an environmental permit under the Environmental Permitting (England and Wales) Regulations 2010. We will only grant a permit if the operator applying has shown that the proposed facility meets the requirements of UK and European laws in how it will be designed and run. We will not grant a permit if we believe it is likely to cause significant pollution to the environment or harm people’s health.

More Information

Report all incidents to our 24-hour hotline on 0800 807060.
This line operates 24 hours a day, 7 days a week. The below link includes a section on how to “Report an Environmental Incident” which provides additional information for members of the public on reporting any concerns.

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Calls to our incident hotline are answered by a team providing a service for customers reporting environmental incidents across the whole of England. The advisers taking the call may not be familiar with the location of the incident being raised.
We get many types of incidents reported to us and, so that our team collect all the information required to assess the risk of harm to people and the environment, they will ask all callers a set of questions tailored to the type of incident being reported. These are usually;
• What is the name of the site where the odour is coming from?
• What is the site location/ street name or postcode of area where was odour detected?
• What are the weather conditions? For example, wind direction and strength)
• Can you describe the odour?
• Can you rate the odour from 0 to 6? (See odour intensity scale above)
• What time was the odour first noticed today or has it been present for a few days?
• Is the odour getting inside the house or building?
• Are the windows and doors being kept closed?
• How is the odour affecting you? (e.g., cannot use garden, cancelled events, feel unwell)
Reports received via the hotline number are assessed by our incident team immediately and if this is categorised as significant or a flurry of incidents are reported, these are passed to a local duty officer within 30 minutes. We always request that reports are made via the incident line and not directly to a site officer. This ensures they are picked up when a site officer is on leave or out of the office. Incidents passed directly to an officer are also not recorded on our National Incident Recording System as they bypass the logging process.
Reports can also be passed to us by email, but please be aware that these may take slightly longer to review. This may result in us not having all the available information to assess the full scale of the incident at the actual time of the issue.
Our incident team email address is. If you use the email to notify us of an issue, please provide the answers to the above questions and your name, address and contact details.

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Our call centre call handlers are not able to provide you with information about the site you are concerned about, as their role is to collect information and get it to the right people inside our organisation.
We do not routinely provide feedback on action taken on incidents on an individual basis. This is to prioritise our regulatory activities which protect the environment. This does not mean that your report has gone unheard or unaddressed. We take all reports of environmental pollution seriously and the report is combined with other reports and intelligence to determine our response. By managing our responses in this way, we can ensure that the incidents which pose the greatest risk to the environment are prioritised.
We have put this web page together to help provide feedback to the community and we are regularly meeting with your elected representatives to keep them up to date.

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We encourage members of the community to report issues directly to the Company. This informs the Company that they are causing an impact and allows them to instigate an immediate investigation to stop the problem occurring.
The operator is informed about all incident reports that we receive. We do not release any personal information and therefore the operator cannot identify members of the community. The operator is expected to respond to complaints regarding odour in accordance with the Odour Management Plan for the site, and to advise us of any resulting changes to their operations.

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We do not attend the site as a result of every incident reported to us, however we do use this information to help us focus our checks on times of the day and locations when residents have reported concerns. The frequency of these checks will be variable depending on local weather conditions and we focus on times when there is the greater potential for odour off site.
We will carry out unplanned inspections as a direct result of incident reports, alongside some planned odour checks, inspections, and audits of the site.
We assess odour at several locations around the exterior of the plant to assess if this is likely to be causing pollution to people living in and using amenities in the area.

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Recent company investments and improvements to August 2022 include the following:
• Bio Bed – this is a treatment process by which the gas from the hoppers, crushing area, external balance tank, tallow storage facility and pre-evaporation room is bubbled through wood chippings containing bacteria to remove the compounds causing odours. The company has had one for some time and has recently completed works to construct and bring a second Bio Bed on-line. The previous Bio Bed (1) has now been switched off and will be cleaned and maintained for future use. Both Bio Bed’s were checked by our officers on 15 June and no mal-odours were noted around the beds or the emissions points.
• No.3 Scrubbing Tower is a single stage scrubber (sodium hypochlorite and sodium hydroxide) which treats air from the drying and pressing area, the tallow filter room and the external tallow tanks. Works to refurbish this tower were completed in December 2021 and this is fully operational.
• High intensity odours can also be treated in the PASCF (Pre-Acid Scrubber and Carbon Filter) System. This provides an additional back up of 10,000m3/hr of treatment capacity. The system is independent from the steam raising process and therefore is a failsafe to treat odours at periods when there is low steam demand, or the boilers are not incinerating odours. The media in the carbon filter has recently been replaced to keep this facility in good working order.
• A new weather station has been installed which also records weather conditions for any future interrogation.
• Whilst the site is busy, the company confirm that it is not operating near or at capacity.
The company have updated and implemented their complaints process to ensure that any calls are immediately escalated and investigated.

More Information

We use an assessment process designed to provide as much information as possible. The 'FIDOR' acronym - Frequency, Intensity, Duration, Offensiveness and Receptor Sensitivity - is a useful reminder of some factors that will influence the degree of odour pollution.
We record odour intensity on a scale of 0 to 6 as follows:
0 – No odour
1 – Very faint odour (need to inhale into the wind to smell anything)
2 – Faint odour (you can detect an odour when you inhale normally)
3 – Distinct odour (there is clearly an odour in the air as you leave your car or enter the area)
4 – Strong odour (a bearable odour but strong, you could stay in the area for some time)
5 – Very strong odour (unpleasantly strong, you will want to leave the area quickly)
6 – Extremely strong odour (likely to cause nausea and a strong need to remove yourself from the odour immediately)
This is the same scale that we ask you to use to report odours to us via our hotline. Environmental Permit conditions require an EA officer to make a judgement about whether odour beyond the site boundary is considered to be pollution and whether the operator is using all appropriate measures to limit and control odours.

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Odour sensitivity describes how sensitive a person is to a particular smell. If you are highly sensitive to an odour you can detect it when it is present at lower concentrations in the air than someone who has a low sensitivity. Sensitivity to odour annoyance is slightly different because it describes how easily someone is offended by a particular smell.
How easily annoyed a person is by a smell also varies widely. A lack of annoyance may be because an individual is less sensitive to a smell, for the reasons given above, but it may also be related to where they are and what they are doing when they experience it. This is important when it comes to the difference between experiencing smells in or around your home, compared to experiencing them as part of your work. You are much more likely to be offended by a smell if it disturbs your home and leisure time than if it impacts on you in your workplace or away from home.
Odours can also remind people of past experiences, both good and bad. This is due to how smell is processed in your brain. Because of this, if you associate a smell with a bad memory, it may have the effect of upsetting you or annoying you more easily. These differences in sensitivity and annoyance are perfectly normal. It is important for all those involved in managing and reporting odour to be aware of why differences might occur and to be cautious before dismissing other people's points of view.

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Sniff testing is the name given to the assessment of smells using the human nose. Some people are surprised that the human nose is used rather than monitoring equipment. There are several reasons for this. The odour condition in environmental permits require odour pollution to be “perceived by an authorised officer” which means that it is necessary for an officer to smell the odour themselves.
The human nose is still the best means we have for detecting the full range of gases that cause odour. The concentrations at which these odorous gases are present in outdoor (ambient) air is usually very low beyond site boundaries (even if the smell is intense), and few pieces of equipment are sensitive enough to pick up the full range of these gases, when compared to the nose.
In addition, sniff testing is physically versatile and allows us to assess odour at most locations without worrying about external power, weather conditions, terrain etc. Monitoring equipment is used in specific situations where additional data is needed if access is available. This is particularly useful when specific gases need to be monitored such as the odorous gas hydrogen sulphide.

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Information about how we score permit breaches is set out in guidance available here: Waste operations and installations: assessing and scoring environmental permit compliance - GOV.UK ( We have formal descriptions of each category within our Compliance Classification Scheme ("CCS") guidance which enables scoring to be consistent.
The 4 categories that our officers use to score permit breaches are:
• CCS 1 – a non-compliance which could have a major impact on human health, quality of life or the environment
• CCS 2 – a non-compliance which could have a significant impact on human health, quality of life or the environment
• CCS 3 – a non-compliance which could have a minor impact on human health, quality of life or the environment
• CCS 4 – a non-compliance which has no potential environmental impact. CCS4 is often used for administrative errors.

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An operator will not be in breach of the odour condition in their environmental permit when they cause odour pollution beyond the site boundary, provided they are using all appropriate measures. However, even if the operator is using all appropriate measures but we consider the residual odour is at such a level that it is unreasonable, it will be necessary for the operator to take further measures to reduce odour pollution, or risk having to reduce or cease operations if appropriate. Where the residual odour pollution is, or is likely to be, unacceptable we will work closely with operators to require them find solutions.
Repeated substantiated odour breaches may result in escalation, particularly when no improvement plan is proposed by the operator. We have a range of regulatory powers that we can use, including taking legal action. We require any site that we regulate to be well run and managed, and not cause harm to the environment or human health. If we agree an action plan with the operator to address the problem, this does not mean we have ruled out taking enforcement action. Our focus will always be to ensure any issues are resolved as quickly as possible. Any enforcement response we take will be in accordance with our published Enforcement and Sanctions guidance which you can find on our website. See link below.

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Incidents are classified using our nationally consistent Common Incident Classification Scheme (CICS). For EA purposes, an incident is:
● a specific event or occurrence
● brought to our attention
● within our areas of responsibility
● and which may have an environmental and/or operational impact
All incidents reported to us are recorded on our National Incident Reporting System (NIRS) and assigned a unique report number.
An incident with category 2 impact has a significant impact or effect on the environment, people and/or property, or on our operations. A category 2 odour Incident has a significant effect on the human senses and a significant impact on amenity value.
Significant effect on human senses:
• Odour offensive and persistent enough to cause significant effect on human senses.
• Odour that is intense and offensive to human senses, persistent or extensive enough that it leads to a noticeable change in behaviour of those exposed e.g., more than ten complaints during one week where people have to shelter (windows and doors closed)
• A widespread effect e.g., complaints are received from some of the local community e.g., more than twenty complaints within one week (not necessarily sheltering)
• An ongoing odour issue, which for a reasonable proportion of the time, is of a significant intensity or extent. Abnormal odour which leads to noticeable adverse impact on local businesses. Significant effect on amenity value:
• Odour resulting in a significant adverse effect on an amenity or recreation area (such as a park) or preventing reasonable use of a domestic area, such as a garden or allotment.
• Odour that is intense, offensive, persistent, or extensive enough that it prevents or restricts some of the local population’s use of a public or private amenity or recreation area.

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A complaint is any expression of dissatisfaction made against the Environment Agency, a member of our staff or anyone working on our behalf. We can receive complaints verbally or in writing by any member of staff, at any time, while on Environment Agency business. We do not tolerate abusive, threatening, or hostile behaviour, verbally or in correspondence.
If you require further details concerning the EA’s complaints procedure and service commitment standards, more information is available on our website at:
Both FOI and EIR requests are requests for recorded information. An EIR applies to requests for environmental information and an FOI applies to all other recorded information that we hold.
Please send complaints, enquiries and FOI/EIR’s to our enquiries team at We aim to response to all requests within 20 working days from the date it is received.
Odour reports about the site

We have received a total of 134 odour notifications between 1 January and 31 August 2022

In August we received 91 reports regarding odours from the site.

Over the Winter and up to Easter there had been very few odour complaints regarding the operation of the company. Since Easter complaints have been intermittent, averaging around 10 reports per month until the incidence from 8 to 18 August.

Over the month of August we saw a sharp rise in incidents reported to us that were centred around the weekend of 13/14 August.

Reports of odour near Sarval rendering plant in August 2022

More graphs and maps of the incident reports can be seen here.

Regulation of the site

On 5 May, 15 June and 20 June 2022, we conducted odour assessments in and around the site. On 5 May and 15 June no offensive odours were detected by our officers, however on 20 June some odour was detected near the site boundary.

On 15 June we met with the site management to discuss the next phase of improvements and investments at the site. These included modelling the emissions from the plant and reviewing if alterations to the chimney height and operating temperatures would help to dissipate odours away from Hartshill. We also discussed odour generation from the Effluent Treatment Plant (ETP) and plans to reduce surface aeration and cover tanks to reduce odours.  

We carried out a full audit of the odour abatement system on 14 July 2022. Actions arising from this are listed in the section below.  

On 29 July, 12 August, 17 August we conducted off-site odour assessments. Offensive odours were detected and the site was identified as the source. On 12 and 17 August the odour was at a level likely to cause pollution and the incident has been categorised as a Category 2 incident ‘significant incident’ in accordance with our National Incident Categorisation Scheme. From 10 August 2022 weather conditions were extremely hot and were combined with a prevailing wind towards Hartshill village, which worsened the conditions.

On 17 August we inspected the site to identify the cause of the odour emissions and it was found that the ETP was not operating as expected. The company provided us with a 6-point plan to resolve the issues. The company were already removing 300 tonnes/week of effluent by tanker from the site to reduce loading on the tanks and reducing their inputs of raw materials into the site. The steps in the plan reflect changes needed to several of the tanks including installation of new parts, such as cooling and aeration and a new tank that will offer more resilience to climate conditions. The latter is a significant investment and expected to be commissioned in Spring/Summer 2023.

On 17 August we carried out an unplanned check of odour in the vicinity of the site, no offensive odours were detected off site.

Update on health

The community also reported health impacts from the odour i.e. nausea, headaches and vomiting, which our regulatory team referred to the UK Health Security Agency (UKHSA). UKHSA have consulted with health professionals at the Local Authority and the Centre for Radiation, Chemical and Environmental Hazards (CRCE) who provided the following advice;

'The human nose is very sensitive to odours, and many substances that are perceived as odorous are usually present at levels below which there is a known health effect. Odours can cause nuisance, possibly leading to stress and anxiety. Some people may experience symptoms such as nausea, headaches or dizziness, as a reaction to odours even when the substances that cause those smells are themselves not harmful to health.'

UKHSA are continuing to meet and investigate the health concerns that have been reported. They are monitoring the situation and are in correspondence with Councillor Bell regarding the health of the local community.

Actions and next steps

We continue to make regular odour checks in the area and inspections of the site.

We continue to investigate the circumstances leading up to the significant incident in August and odour emissions from the plant.  

The company are regularly updating us to demonstrate progress with their action plan and actions from our compliance inspections.

We met with Marcus Jones MP, Hartshill Ward Councillor’s Margaret Bell and Marli Parker and company representatives on Friday 16 September to discuss the issues and plans. Further meetings will be arranged to review the situation.  

Actions from the odour abatement audit on 14 July 2022

Review of the operation of the Regenerative Thermal Oxidiser (RTO):

  • Options for improved stack dispersion should be explored in conjunction with an impact assessment in terms of atmospheric dispersion modelling of the exhaust plume. To submit a brief outline of the planned actions with prospective timescales to the EA by 31 October 2022
  • We have recommended that the company carry out emission monitoring related to the emissions to air from the RTO for oxides of Nitrogen, Oxides of Sulphur, Carbon Monoxide and volatile organic compounds by 31 October 2022

Review of the Effluent Treatment Plant (ETP):

  • Provide a progress update on the installation of the cooling system in the aeration tank as stated in the 6-point plan of ETP improvement which was discussed on 17 August 2022 – by 31 October 2022

Review of the Biofilters:

  • Submit a report of odour abatement efficiency of recently commissioned biofilter-2 including chemical composition, conducted by an independent consultant by 30 November 2022. The odour sampling and analysis should be undertaken using UKAS accredited procedures.

Actions from the incident investigation audit on 17 August 2022

A report was issued to the company on 2 September 2022. This is currently within the appeal period (28 days). If no appeal is made by the company to the contents of the report, the information can be shared in the October community update.  

Report and incident 

We want to hear from you if you have an environmental incident or concern to report, including any odour concerns.

To do this, call our free 24-hour incident hotline on 0800 80 70 60.

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Please contact us at if you have any further enquiries


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