Reduction of Water Consumption in Meat and Fish Processing  

In most parts of the world, the cost of water is increasing as supplies of fresh water become scarcer, and as the true environmental costs of its supply are taken into consideration. Water is therefore becoming an increasingly valuable commodity and its efficient use is becoming more important. Strategies for reducing water consumption can involve technological solutions or equipment upgrade. However, reviewing cleaning procedures and operator practices can make some of the most significant gains. Adopting dry cleaning practices, using spray nozzles on process lines and hoses, and reusing water use for non-critical cleaning applications can also reduce water consumption. Other water minimization options include countercurrent rinsing systems where clean water is used for final rinsing and then reused for initial cleaning processes, dry transport conveyers and the use of dry pre-cleaning techniques (Environment Canada, 1994a). Technologies that improve product yield also reduce solid and liquid waste.

Key pollution prevention strategies for reducing water consumption are listed below:

• Teach employees how to and why it is important for them to conserve water, provide appropriate tools (scrapers, squeegees, wet/dry vacs) to facilitate water conservation;
• Know how much water is used in facility operations; installing meters will provide area specific usage to help prioritize pollution efforts.
• Install low-volume high-pressure nozzles on all hoses; consider making hoses less available to employees to increase dry clean-up efforts;
• Dry cleaning of trucks prior to washing with water;
• Use of automatically operated scalding chambers rather than scalding tanks for the dehairing of pigs;
• Use of offal transport systems that avoid or minimize the use of water;
• Use of dry dumping techniques for the processing of cattle paunches and pig stomachs that avoid or minimize the use of water, instead of wet dumping techniques;
• Reuse of relatively clean wastewaters from cooling systems, vacuum pumps, etc. for washing livestock if possible;
• Reuse of final rinse waters from paunch and casings washing for other non-critical cleaning steps in the casings department;
• Reuse of wastewaters from the slaughter floor, carcass washing, viscera tables and handwash basins for the washing of inedible products if possible;
• Reuse of the final rinse from cleaning operations for the initial rinse on the following day;
• Use of dry cleaning techniques to pre-clean process areas and floors before washing with water;
• Use of high pressure rather than high volume for cleaning surfaces;
• Use of automatic control systems to operate the flow of water in handwash stations and knife sterilizers.

Reduction of Wastewater Generation in Meat and Fish Processing  

The efficient recovery and segregation of blood is a significant way to reduce pollutant loading in meat processing wastewater. An efficient blood removal system will have a 40 percent lower polluting load than one that allows blood to flow to the effluent (Nielsen, 1989). Other opportunities for reducing the pollutant load of wastewaters are: the removal and recovery of solids from the wastewater stream by screening; the use of biodegradable detergents and sanitizers; the collection of paunch manure and intestinal contents without the use of water; and the provision of receptacles to catch hair and meat trimmings. Additionally, biological treatment of wastewater will reduce organic load and to some extent nutrients. Strategies for reducing the pollutant load of abattoir effluent principally focus on excluding blood, fat, manure and scraps of meat from the effluent stream. This means capturing materials before they enter drains and by using dry cleaning methods. 

In fish processing, capturing skins, scales and gut material as solid streams and collecting blood before cleaning significantly reduces wastewater loads. A Canadian fish processing operation is reported to have replaced its manual salmon gutting lines with semiautomatic vacuum suction lines. This resulted in a reduction of its water consumption of almost 90 to 95 percent (Environment Canada, 1994a). However, such systems are capital and energy intensive (UNEP, 1998).

Pollution prevention opportunities include: 

• Maximizing the segregation for blood by designing suitable blood collection facilities and allowing sufficient time for bleeding;
• Sweeping up solid materials for use as inedible byproducts, instead of washing them down the drain;
• Fitting drains with screens and/or traps to prevent solid materials from entering the effluent system;
• Using offal transport systems that avoid or minimize the use of water;
• Using water sprays with sufficient pressure for carcass washing to avoid removing fat from the animal surface;
• Using dry cleaning techniques to pre-clean process areas and floors before washing with water;
• Segregating high-strength effluent streams, such as rendering effluent and wastewaters from paunch washing, and treating them separately;
• Ensuring that the most appropriate form and amounts of food-grade chemicals are used in facility cleaning activities, and train employees on proper use (mixing, storage, handling, application).

Energy Conservation in Meat and Fish Processing  

Energy is an area where substantial savings can be made almost immediately with no capital investment, mostly through simple housekeeping efforts. Additional savings can be made through the use of more energy-efficient equipment and heat recovery systems.  Keeping energy costs to a minimum will improve the organization's profits and help to save precious natural resources. Keeping energy use records and routinely reviewing the utility bills will provide a good idea of how much energy is used and potentially how much money can be saved.

Pollution prevention options include: 

• Training employees to be aware of energy conservation and to keep lights/equipment off when not in use;
• Implementing switch-off programs and installing sensors to turn-off or power-down lights and equipment when not in use;
• Improving insulation on heating or cooling systems and pipe work;
• Insulating and covering scald tanks to prevent heat loss;
• Recovering waste heat from effluent streams, vents, exhausts and compressors;
• Recovering evaporative energy in the rendering process using multi-effect evaporators;
• Maintaining a leak-free compressed air system;
• Installing more efficient equipment;
• Improving maintenance to maximize energy efficiency of equipment;
• Maintaining optimal combustion efficiencies on boilers;
• Eliminating steam leaks; and
• Being aware of demand charges. Meet with the service provider on electrical purchasing and discounted rates.

In addition to reducing a plant?s demand for energy, opportunities exist for using more environmentally benign sources of energy. Opportunities include replacing fuel or coal with cleaner fuels, such as natural gas, purchasing electricity produced from renewable sources, or cogeneration of electricity and heat on-site. For some plants it may also be feasible to recover methane from the anaerobic digestion of high-strength effluent streams to supplement fuel supplies.   

Meat and Fish Processing Pollution Prevention Checklists  

The following checklists summarize P2 opportunities for meat and fish/seafood processing operations.  Most of the opportunities identified are simple techniques that can result in major environmental and economical returns for processors. 

Meat Processing P2 Checklist

UNEP 2000

Fish/Seafood Processing P2 Checklist

 UNEP 2000