Comparison of anaerobic phosphorus release from activated sludge with three carbon sources

Abstract

Three carbon sources, namely sodium acetate, sewage and effluent, were used to simulate the process of phosphorus release in an actual sewage treatment plant, in order to explore the phosphorus release performance of the sludge, the relationship between phosphorus release and chemical oxygen demand (COD) in sewage, and the stability of phosphorus-rich sludge. The results showed that the type and concentration of carbon sources had significant effects on the rate of phosphorus release, reaction equilibrium time and phosphorus release amount. When sodium acetate was used as the carbon source, the phosphorus release rate reached 12.54 mg P (g VSS·h)−1, and tended to be stable at 4.0 hours. The phosphorus release amount in the first 2.5 hours accounted for 36.88% of the total phosphorus in the sludge. When sewage was used as the carbon source, the phosphorus release rate did not reach equilibrium even at 5.0 hours, and the phosphorus release amount increased by 1.0 mg L−1 for every 10.5 mg L−1 increase sewage COD within a certain range. When effluent was used as the carbon source, the visual phosphorus release amount was only 0.83 mg L−1 after standing for 24 hours and the actual phosphorus release amount was 17.98 mg L−1. These conclusions can provide technical support for the optimization of phosphorus removal in sewage treatment plants. HIGHLIGHTS The effect of anaerobic phosphorus release from activated sludge with three carbon sources was compared.; A formula was obtained by linear regression for the correlation between COD concentration and phosphorus release amount.; A phosphorus load contribution of 8.38% to the influent was due to the sludge treatment process.; Parameters obtained in the experiments can be used to optimize sewage treatment plant performance.;

Keywords

• activated sludge
• anaerobic phosphorus release
• carbon sources