Red meat processing results in the production of a range of solid wastes.
The primary environmental concern with waste solids from meat processing plants regards the miscellaneous solids that must be sent to landfill.
Possible environmental impacts are soil or water contamination, atmospheric pollution and greenhouse gas emissions.
Disposal of solid waste is often related with high costs, which gives abattoirs an incentive to reduce solid waste production.
The majority of waste solids (85%) generated are organic in nature and are recycled by:
- Rendering - Meat scraps and bones
- The rendering process simultaneously dries the material and separates the fat from the bone and protein. A rendering process yields a fat commodity and a protein meal.
- Composting - Paunch solids
- Paunch manure is partially digested ruminant feed taken from the rumens of slaughtered cattle. It can be turned into compost
- Land rehabilitation – Sludge
- In some cases nutrient rich sludge can be used for rehabilitation of degraded land, such as mine sites.
In order to reduce the environmental impact of solid waste Meat & Livestock Australia and the Australian Meat Processor Corporation are supporting the meat processing industry to:
- Reduce production of solid waste, by:
- monitoring of waste produced
- the improvement of processing and packaging procedures
- the consideration of the lifecycle of a new purchase
- the improvement of cleaning methods
- Recover energy from waste, through the:
- co-combustion of waste products, such as paunch waste and sludge, in boilers
- pyrolysis of sludge or paunch waste
- dewatering of waste streams
- Develop new value added products, such as:
- pet food
The processing industry is focussed on ensuring that nothing goes to waste and that the whole carcase is utilised. There is a strong profit driver behind this motive, which ensures maximised carcase utilisation.
- 10% of the carcase value is derived from offal and co-products and sustainability as a business depends on finding a market or disposition for every product and waste stream
- Offal is a valued component in many traditional national cuisines and is captured and exported wherever possible. That which cannot be exported finds value in pet food and rendered products.
- All meat that can be harvested is sold into the food value chain, providing meals for consumers in the form of whole muscle or mince.
- Excess fat is trimmed and turned into tallow which primarily goes to soap manufacture, cooking, biofuel and other industries as diverse as textiles, glues, lubricants and paints.
- Blood and bones are processed through rendering into dry powders which can be used in petfood, poultry feed and fertiliser applications or to bone chips which are then processed to produce gelatin for photographic, food or pharmaceutical uses.
- Blood also can be fractionated to plasma, albumin, globulin and haemoglobin which are highly valued proteins for nutritional and functional applications in the food and nutraceutical areas.
- Dried proteins can also be used in bioplastic manufacture.
- Hides are processed to collagen or to leather and even the hair on the hides is captured for use in fertilisers.
- Manure recovered from holding pens and partially digested straw paunch contents also find their way to uses as fertiliser components. Paunch material can also be dried and used as biofuel in boilers in the processing plants.
- Energy is recycled where possible either as heat or as electricity generated through effluent treatment.
- Sheep and lambskins provide fleece for wool manufacture and lanolin for cosmetics.
- Bile is collected for use in chemical manufacture and gallstones are collected for use in traditional Chinese medicine.
- Even eyeballs and lenses are collected and processed for industrial or research chemical purposes.
Major research is underway to improve abattoir waste management practises and reduce disposal costs. Some projects include: