Abstract
The meat processing produces solid, liquid and gaseous wastes from stockyards, abattoirs and packing plants contain blood, fats, protein, gut contents, heavy metals, antibodies, hormones and other substances. Solid and liquid wastes can lead to an impairment or disruption of water eco-functionality and a preponderance of disease-causing organisms. In developing nations, many abattoirs dispose of their waste directly into streams or rivers and also use water from the same source to wash slaughtered meat. Most solid, liquid and gaseous wastes are released into the immediate environs of the abattoir. This chapter is a literature review of the impact of untreated slaughterhouse wastewater on water quality in selected areas of Southern Africa. The review shows that abattoir activities significantly reduced the physical, chemical and microbiological quality of water bodies. Although an improvement of the water quality was observed downstream, this was a result of self-purification and dilution effects.
TopBackground
Meat processing, slaughtering and processing remain critical in ensuring that consumers receive a hygienically safe product. Production processes for meat products have been shown to have a significant impact on the environment, accounting for between 15% and 24% of greenhouse gas emissions (Mittal, 2006). Abattoirs are an important industry in Africa’s domestic meat supply and export industry, as well as employment opportunities to many communities. Abattoir effluent is known to degrade the quality of receiving water bodies. Waste from abattoirs changes the microbiological and physico-chemical water quality parameters such as pH, temperature, electrical conductivity, salinity, turbidity, total dissolved solids (TDS), total suspended solids (TSS), dissolved oxygen (DO) and coliforms (GDARD, 2009). The effluent characteristics of the abattoir are nutrients and biologically active constituents which pose a considerable challenge for water resources management particularly the delivery of essential water, sanitation services and environmental protection. Nitrates are very high in the abattoir wastewater especially at the evisceration and slaughter step where the urine and undigested stomach content concentrated in nitrate was mixed in wastewater streams (Mittal, 2004). This is because wastewater streams for these processes consist of mixed intestinal contents and blood with a high content of nitrates. This chapter focuses on the environmental effects of meat processing in general. In particular, it highlights how meat processing contributes to changes in water quality.