Coagulation Treatment of Effluent From Milk-processing Enterprises with Waste FeSO4

As the world's population grows, the problem of food shortages becomes global, and, for human survival, it is necessary to significantly increase food production, which may increase environmental pollution. This paper has theoretically and practically substantiated the expediency of coagulation treatment of wastewater from milk-processing enterprises. The coagulant proposed to use is a multi-tonnage waste from industrial enterprises, specifically technical ferrous sulfate. It is shown that it is advisable to use the dairy effluent imitations based on milk powder for experimental studies. The potentiometric titration of dairy effluent imitations has established the presence of two points (pH=4.2 and 8.3), which characterize the boundaries of the buffering capacity of solutions. The expediency of carrying out the process of coagulation of dairy effluents in a weakly alkaline environment at pH≥8.3 has been substantiated, and, for the starting effluent to reach such a pH value, a 10-% suspension of Са(ОН)2 should be used. The effectiveness of reagent treatment of dairy effluents has been experimentally confirmed, subject to the alternate introduction of a coagulant (technical FeSO4) and flocculant (polyacrylamide) in the quantities of 120 and 40 mg/dm3, respectively; the degree of clarification of dairy effluents is 90 % while the residual COC value is 76 mgO2/dm3. It has been shown that when ultrasound was applied, it was possible to significantly reduce the interaction time and the amount of Са(ОН)2 suspension necessary to achieve pH≥8.3. Thus, there are grounds to assert the prospects for devising highly effective technology for the coagulation treatment of wastewater from milk-processing enterprises; the results and conclusions reported here about the technological feasibility of using technical FeSO4 as a coagulant could be practically applied for other technologies of coagulation wastewater treatment, provided that its pH value is brought to 8.3