The impact of pH on anaerobic phosphorus release from sludge

Impact of pH on anaerobic phosphorus release from sludge was investigated. The results showed: 1) that there are two ways of phosphorus release during phosphorus release of sludge, and anaerobic phosphorus release of microorganism is primary while pH value is higher than 6.5, and phosphorus release from chemical dissolution dominate as pH value is less than 6.5, 2) that PAOs growth is resisted, and GAOs growth is inevidently influenced, under the condition of low pH, and PAOs gradually dominate with pH increase, 3) that the concentration of SCOD increased with pH increase, and the content of phosphorus released by dissolution increased with pH decrease at the range of pH less than 6.5, and the content of phosphorus released by microorganism increased firstly, then decreased, and became the most at pH 7.5, with pH in crease at the range of pH higher than 6.5.