Case Study in Meat Processing
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1. Case study or built example
Case study
2. Industry Sector
Meat production
3. Industrial application
Cleaner production assessment was carried out in a Danish abattoir. 1.1 million pigs are processed every year. They are delivered in trucks, each containing 50 – 60 pigs. After unloading the trucks are cleaned and disinfected in certain areas. The number of cleaned trucks is around 75 per day.
4. Planning and organisation
The costs of water used for cleaning processes and the disposal of wastewater were too high. Therefore it was required to find options for reduce water consumption and pollution without impairing products quality. A team consisting of a technical engineer, an external consultant and a foreman was formed and it was decided to focus on the pig reception and the holding areas.
The job of the team consisted of these working steps:
- 1. Inspection of areas
- 2. Measurement of water consumption
- 3. Assessment of working procedure
- 4. Development of a list of possible strategies
5. Pre- Assessment
The first step was to describe various processes taking place in the reception and in the holding areas. Furthermore truck drivers were observed during their cleaning procedure.
Following points were noted:
- 1. Sawdust is used as bedding in trucks
- 2. Truck drivers remove bedding and manure with water coming out of hoses with 10 mm nozzles.
- 3. The waste is washed to drains, very little is collected.
- 4. Afterwards the drivers clean the trucks with cold water.
This way of working causes various problems:
- High consumption of water;
- Running hoses;
- Manure and sawdust cause high organic load in the effluent.
6. Assessment
The consumption of water was measured by measuring the needed time for filling a container with a known volume.
Collected data:
- Water consumption: 17 liter per pig and 950 liter per truck;
- Pressure of water: ~12 bar;
- Quantity of organic load in the effluent was not measured.
The next step was to identify different CP strategies:
- Use water at a higher pressure than 12 bar;
- To install smaller noozles;
- To remove bedding with scrapers before washing with water;
- To reduce sawdust bedding in trucks;
- To train employees to reduce losses in general:
7. Evaluation and feasibility studies
- Technical evaluation
It was decided to increase water pressure from 12 up to 18 bars and to substitute trigger controlled jet spray guns for 10 mm nozzles. Also the construction of a new area was planned where the trucks could park and the cleaning process could take place. After dry collection of bedding and manure the waste could be scraped directly into an automatic solid waste remove system.
- Economic evaluation
The investment costs of changing from nozzles to jets were comparatively low and for the implementation of dry collection in the cleaning process even no investment costs were required. The total costs including new equipment and its installation were calculated to be US$ 5000.
- Environmental evaluation
A reduction of 50% of water consumption was awaited and a similar reduction also in organic load of effluent.
8. Implementation and continuation
Following options were implanted:
- Bedding and manure are collected in a dry way in separate areas and then scraped into a solid waste storage container. The waste is composed and later used as fertiliser.
- The hoses were equipped with trigger- controlled spray guns and the water pressure was increased from 12 to 18 bars.
- Drivers were instructed in use of new equipment and made aware of the importance of saving water.
- A monitoring program was installed and documented the improvements for evaluating new cleaning operations.
9. Results
- Water consumption: 5.6 L per pig; it is a reduction of 67%;
- BOD: 13 g per pig;
- Solid organic waste: 1.4 kg per pig;
- Annual saving (US$2 per KL including costs of water and charge for disposal of wastewater): US$~24.000;
- Costs for transporting manure and bedding and pressuring water were not evaluated.
Reference: Cleaner Production Assessment in Meat Processing; prepared by COWI Denmark for UNEP (United States Environment Programs) and Danish Environmental Protection Agency, 2000 Denmark
