Independent Appraisal of Odour Situation – Butchers Pet Care Ltd

Appraisal of Odour Situation – Butchers Pet Care Ltd Restricted – Commercial

AEA/ ED47395/Final

Title / Appraisal of odour situation – Butchers Pet Care Ltd
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File reference / ED47395/3.3
Reference number / AEA/ED47395/Final

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Author / Name / Dr Nigel Gibson and Dr Mike Holland
Approved by / Name / Dr Alan Collings
Signature /
Date / 28thAugust 2007

Executive summary

AEA Energy & Environment1

Appraisal of Odour Situation – Butchers Pet Care Ltd Restricted – Commercial

AEA/ ED47395/Final

Background and objectives

Butchers Pet Care (BPC) has submitted plans to relocate their production facility from an existing site in Crick to a new location at CotonPark near Rugby. Historical odour problems associated with the operation of the Crick site have caused significant concern about the potential impact of the new development on businesses and residents in and around CotonPark.

This report provides an independent review of the odour impact assessment carried out by ADAS that accompanied BPC’s planning application. The objectives agreed by the Coton Park Residents’ Association and BPCfor this report are as follows:

Carry out a critical review of the odour emission information contained in the ADAS report;

Review the selection procedures carried out by ADAS to determine the most appropriate odour control system; and

Provide a commentary on the odour assessment technique adopted by ADAS and the modelling results provided in their reports.

The work programme did not include new measurement or further detailed modelling of odour in connection with either the Crick or CotonPark sites.

Odour assessment and modelling

To permit the development of the BPC site in CotonPark, the local planning authority must be convinced that the development will not harm the amenity of people in the surrounding area. BPC’s assessment of the proposed development relies on an odour survey of their existing Crick siteto estimate the odour emission rate for the pet food manufacturing process. Results of the odour survey have then been used as input data for a dispersion modelling study. This concludes that the proposed development will not cause an exceedance of a PPC related odour assessment criterion of 1.5 ouE/m3 as a 98th%ile of 1 hour averages[A]. However, subsequent data provided by ADAS show that the difference between predicted concentration and the assessment criterion may be less than initially stated. This is particularly important as we question below whether the criterion of 1.5 ouE/m3 is sufficiently precautionary, given local circumstances.

To ensure that the entire assessment procedure is fit for purpose BPC need to demonstrate:

Firstly, that data on the odour emission rate reflect the worst case situation. The ADAS measurements were for a single product line, taken over a 2 day period in November when it seems likely that fresh materials were bring used (rather than, e.g., material stored over a weekend). It is clearly possible that more odour would be generated from other products made under hotter summer conditions using material that had been stored. We question, therefore, whether the odour emission rate represents a worst case.

Secondly, BPC need to demonstrate that dispersion modelling has been carried out using the correct design parameters (e.g. extraction flow rates). This review suggests that the modelling carried out by ADAS may be based on a higher than expected effective stack height which would bias towards underestimation of ground level concentrations.

Thirdly, that adequate attention has been given to possible variations in emission and dispersion. To illustrate, sensitivity runs could address the effects of running the plant at reduced flow rates (e.g. at weekends when only the waste plant is running, affecting plume rise characteristics), and the impact of variation in the temperature difference between extracted and ambient air. The omission of such sensitivity runs naturally creates uncertainty as to whether the results from the modelling work show that the proposed approach for managing odour is adequate.

Next,BPC need to demonstrate that the impact assessment has taken into account all receptors including both businesses and residential properties. The local area has undergone significant recent development (post-dating the maps used by ADAS). To ensure odour does not cause a problem at CotonPark it is concluded here that a more precautionary approach should be considered for the modelling. This would reduce the assessment criterion by 0.5ouE/m3 to account for the proximity of houses and businesses and by 0.5 ouE/m3 to account for the likely high sensitivity of the population to any odour from the site. On this basis the assessment criterion falls from 1.5 ouE/m3 to 0.5 ouE/m3. Higher resolution mapping would also be useful, particularly for consideration of potential effects of the plant on local businesses that use air conditioning.

Finally, it is necessary to demonstrate that the impact assessment has had due regard to peak to mean factors that may give rise to elevated concentrations for short periods of time. Again, this has not yet been considered. Information presented in this reportindicates that elevated concentrations will occur over the full range of atmospheric stability classes (stable, neutral and unstable) and are not restricted to highly unstable situation as suggested by ADAS.

These points would be of limited importance had the modelling shown that odour was estimated to be far below concentrations likely to cause concern. However, this is not the case and so we conclude that the analysis does not adequately demonstrate a sufficient level of protection to people in the area around the proposed plant.

Consideration of BAT for odour control at the CotonPark site

The overall design of the CotonPark facility shows improvements for odour management compared to the existing site at Crick, for example by containing operations within a single building and simplifying on-site treatment of liquid effluents. However, the main technique for odour management at the CotonPark site is simply to collect process air within the manufacturing plant and pass it to atmosphere via a stack of at least 30 m. This approach is reliant on dilution to reduce the concentration of odour to an acceptable level by the time that it reaches sensitive receptors. It has been concluded by ADAS, working on behalf of BPC, that active abatement of odour at the site, for example using scrubbers, is not possible because of the large volume of air that would need to be treated. This report concludes that there is potential for a significant reduction in the volume of air extracted through improved design of the extraction hoods above the cooking lines that are likely to generate the highest quantity of odour at the CotonPark site. Reducing the volume of air would, in turn, increase the potential for adopting systems such as scrubbers for actively removing odour from the captured gases.

Further questions are raised here in association with the storage of waste. For example, whether temperature control in the waste storage area is adequate to prevent significant generation of odour, given the volume and temperature of material entering the waste area, and whether the sludge storage tank is to be emptied by pumping or sucking under vacuum. The nature of the sludge will result in the generation of components with strong odour when it is kept under anaerobic conditions.

It is therefore concluded that the BAT assessment requires further work, with particular consideration given to reducing the volume of gas collected at those parts of the system that generate the most odour.

Other issues

Specific assessment of the effects of odour releases from the proposed BPC plant on airquality within surrounding buildings, particularly those that use air conditioning, has not beenundertaken in this review, as it would be necessary to have information on pollutantconcentrations at specific locations and heights relevant to air intake. These are not provided in the ADAS reports.

Table of contents

1Introduction

2Pet food manufacture

2.1Products

2.2The process

3Emission inventory

3.1Raw materials handling and storage

3.2Manufacturing

3.3Production Wastes

4Impact of the process

4.1Experience at the existing operation at Crick

4.2Predictions for BPC manufacturing at Coton Park

4.3BAT assessment

4.4Other related issues

5Conclusions

5.1Current odour control situation at the Crick plant

5.2Situation for the proposed new plant at Coton Park

5.3Odour assessment for the Coton Park plant

Annex 1: Run 10 – Results provided by Steve Smith

Acknowledgements

We wish to thank the following:

Angela Murphy of Butcher’s Pet Care for providing a tour of the site, and discussing odour related issues at the current and planned site.

Steve Smith and Steve Peirson of ADAS for providing modelling and other data relevant to their odour assessments of the Crick and CotonPark sites.

AEA Energy & Environment1

Appraisal of Odour Situation – Butchers Pet Care Ltd Restricted – Commercial

AEA/ ED47395/Final

1Introduction

Butchers Pet Care (BPC) has submitted plans to relocate their production facility from their existing location in Crick, to a new site at CotonPark near Rugby. Due to historical odour problems associated with the operation of the Crick site there is significant concern about the impact on businesses and residents were the development to be permitted. Within the planning process BPC need to demonstrate that amenity will be safeguarded. This has been considered in a series of reports prepared by ADAS.

This report provides an independent review of the odour impact assessment that accompanied the planning application. The objectives agreed for this report by the Coton Park Residents Association (CPRA) and BPCare as follows:

Carry out a critical review of the odour emission information contained in the report, paying particular attention to:

  • The extent of the odour assessment;
  • The range of products produced by the current and proposed site; and
  • The type of process involved in pet food production and how this may influence the odour emissions from the site.

Review the selection procedures carried out by ADAS to determine the most appropriate odour control system for this site paying particular attention to:

  • The design of the process equipment to determine whether every reasonable effort has been made to adequately contain all potential odour sources;
  • The nature of the emitted gas stream (e.g. temperature, moisture etc.); and
  • The selection process that led ADAS to select a strategy based on the principles of dilution and dispersion rather than end-of-pipe abatement.

Provide a commentary on the odour assessment technique adopted by ADAS and the modelling results provided in their reports. The aim here is to determine whether odour assessment of the current facility provides a realistic illustration for the proposed plant, and whether the principles of PPS 23 have been adopted for the proposed plant, to ensure that the design specifications for the odour control system has adequate safeguards to prevent loss of amenity to local residents

The following documents are key to this review, though others provided with the planning application have also been considered:

  • BPC – “Production and operation statement” (R07-0814);
  • ADAS – “Odour emission estimates and dispersion modelling to assess the odour impact of the proposed Butcher’s Pet Care Ltd production plant at Coton Park, Rugby” (February 2007)[B];
  • ADAS – “Odour emission estimates and dispersion modelling to assess the odour impact of the Butcher’s pet care Ltd production plant at Crick” (March 2006);
  • BPC – “Response to Planning & Environmental Health Queries on Air Quality & Odour raised in e-mail dated 22nd June 2007”;
  • Guidance for the Food and Drink Sector (IPPC S6-10) and Secretary of State's Guidance for Pet Food Manufacturing Involving the Processing of Raw Animal Material (PG6/24a)
  • Integrated Pollution Prevention and Control Reference Document on Best Available Techniques in the Slaughterhouses and Animal By-products Industries (May 2005) and Integrated Pollution Prevention and Control Reference Document on Best Available Techniques in the Food, Drink and Milk Industries (January 2006)

The project team undertook a tour of the Crick plant, led by Angela Murphy (Site General Manager). This provided opportunity for close inspection of inputs and process.

2Pet food manufacture

2.1Products

According to the BPC website ( the Company produces a range of canned products:

All-meat loaf in jelly

  • Chicken, ham and rice
  • Lamb, rice and peas
  • Tripe
  • Tripe and chicken
  • Tripe and beef

All- meat chunks in jelly

  • Chicken and tripe
  • Lamb and kidney
  • Beef and liver

All-meat chunks in gravy

  • Chicken
  • Ham and pea
  • Beef and vegetable
  • Lamb and mint
  • Turkey and cranberry

Other products are manufactured by BPC in pouch or sachet format.

The bulk of the ingredients (ca. 90%) used are broadly the same whatever product is manufactured. The variation between the different product types is contained in the remaining 10% of ingredients, which includes flavour components.

At Crick there are three production lines covering the following in a variety of flavours:

Canned meatloaf;

Canned meaty chunks in jelly or gravy; and

Meaty chunks in jelly or gravy produced in small disposable trays providing single servings.

2.2The process

2.2.1Raw materials

Raw materials used within the pet food process meet all applicable legislation according to information provided by BPC in their planning submissions. These raw materials include:

Fresh & frozen offal (Category 3 animal by-products slaughtered fit for human consumption). This is delivered in refrigerated vehicles contained in dolavs (plastic 500 litre pallecons) and on shrouded pallets (frozen materials). These are off loaded via sealed docks and stored in chilled store (+2ºC) or cold store (-25ºC).

During the site visit it was evident that the raw materials used include liver, tripe, lung and bone from lamb, pork and beef processing, and neck and feet from chicken processing.

Dry ingredients – e.g. powders and dehydrated products are delivered on wrapped pallets and off loaded into a warehouse at ambient temperature.

Oils, chemicals and salt for water softeners for boilers are transported by authorised companies, delivered in drums. All are stored in appropriately bunded rooms or tanks.

2.2.2Manufacture

The manufacture of pet food by BPC at Crick involves the following steps:

Incoming meat ingredients are ground, mixed & blended with other dry ingredients to form a meaty paste;

Some of the paste is extruded and pre-steamed in excess of 90 °C to reform the raw materials into chunks[this stage does not apply to the canned ‘loaf’ products];

Additional material such as vegetable may be added if required for a specific product;

Cans are then filled with the meaty paste (for the canned meatloaf) or meaty chunks with jelly or gravy, and sealed;

Cans are then cooked by batch steam sterilisation under pressure at around 130°C; and

The final stage of manufacture is the downstream processing of cans (cooling, labelling, packing and palletising prior to storing in the warehouse until dispatch).

The same processes would be followed at the proposed plant.

Other processes and equipment include steam generation via boilers for cooking, refrigeration equipment for chillers and cold store, and air compressors for pneumatic machinery. The Crick plant uses heavy fuel oil for the boilers. The proposed plant would use natural gas instead, which has lower emissions of all pollutants, though in neither case should fuel combustion generate odour.

The Crick plant includes a full treatment system for liquid effluents. This level of treatment is required because the treated effluent is discharged to a local stream. In contrast, the proposed site would have a considerably simpler system whereby the trade effluent would be pre-treated through a dissolved air floatation plant to remove oils and suspended solids only prior to discharge to the sewer. The company providing water and sewerage services to the site will clearly need to be satisfied that the effluent sent to sewer can be effectively treated in its wastewater treatment works and will not cause problems in the sewerage system.

2.2.3Production wastes

Waste offal (raw) is stored in a bulk trailer and transported off site to an approved rendering plant. The trailer at Crick is kept in the open air and taken away once or twice a week. The trailer at the proposed plant would instead be housed in a chilled enclosed bay, and taken away on a similar schedule.

Damaged canned product is transported off site for separation, recycling (metal) and biogas digestion of the meat contents.

Wet sludge from the effluent Dissolved Air Flotation (DAF) plant will be stored in sealed tanks and tankered off-site for biogas digestion.