Influence of mechanical methods for separating phases on the efficient removal of heavy metals and phosphates from activated sludge after its detoxification
This paper describes the effect of mechanical methods for separating phases (centrifugation, filtration, settling) on the efficient removal of heavy metals and phosphates from the solid phase of activated sludge after its detoxification. The research showed the variegated effect of heavy metal removal from the solid phase. The removal rates for all these methods were as follows: chromium - 4%, copper - 5.2% and manganese - 3-11%. The lowest removal rate was observed in nickel. The removal rate of phosphates was 23-27% during the settling process, 18-24% during filtration and about 8% of the total content during centrifugation. The high-degree phosphate removal can hardly be achieved using mechanical methods. The most likely explanation is the formation of an anaerobic zone in the activated sludge mixed with the materials and the duration of phase separation. Settling and filtration processes can be considered more efficient in terms of residual concentrations of heavy metals and phosphates in the activated sludge. The obtained data can be used to improve methods for eliminating past environmental damages.