Meat processing wastewater treatment. Rational use of raw materials and energy resources is a major problem of today. It is closely related to the protection of environment and, in particular, the protection and conservation of water resources.
In the 1980s the big meat processing complexes treated their wastewater mainly by mechanical methods. Now a significant number of small and medium enterprises release their practically untreated wastewater into the municipal sewers or into natural waterways.
Such waste dumping into the urban sewers raises the problem of cleaning wastewater with high content of organic pollutants. These pollutants can not be eliminated by aerobic biological oxidation.
The main difficulty of treating this wastewater is its instability in volume and composition. This instability is caused, first of all, by the different raw animal materials (supplied meat is semi-finished or it is cattle for slaughter and subsequent processing), which, in turn, affects the stages of meat production, and consequently affects the wastewater. Secondly, the instability is caused by a range of products, including quantitative and qualitative composition of the ingredients in meat products. Thirdly, it is affected by the chemical composition of detergents which are used in compliance with sanitary and hygienic conditions in the workplace. Fourthly, the wastewater depends on seasonal fluctuations of demand for meat products in the market.
Traditional wastewater treatment by grease traps, sediment tanks and flotators does not always provide the necessary quality of wastewater treatment. Improving the treatment by using various filtering materials like flexible polyurethane, polystyrene and others, does not always give the expected results, besides, the filter material loses its properties after working for some time in the filtration-regeneration cycles and must be recycled, otherwise it may cause a negative impact on the environment.
High pH of wastewater (11,6-12,4) is unfavorable, and moreover, it is disastrous to the development of microorganisms, making biological methods unsuitable for cleaning such wastewater.
Furthermore, this wastewater is characterized by intense unpleasant odor, which requires prompt deodorizing and special anaerobic biological treatment to separate biogas.
The biogas contains hydrogen sulfide, which is a product of biochemical conversion of proteins. Also, the anaerobic wastewater treatment for meat processing plants takes longer than aerobic.
Wastewater treatment by electrochemical methods requires special equipment and skilled personnel, making it unavailable for small companies