[Fate of matrix-bound phosphine during acidification with anaerobic bacteria]

Matrix-bound phosphine of anaerobic granular sludge was studied during methanogenic and acidogenic stage of anaerobic reactors. Results showed that at methanogenic stage, the concentration of matrix-bound phosphine of anaerobic sludge decreased as the height of reactor increased. But during acidogenic stage, matrix-bound phosphine disappeared when pH of the solution declined to 4-5. Further anaerobic static experiments showed that increased acidification and lower pH value promoted the decrease of matrix-bound phosphine. After cultivation with 2 000 mg x L(-1) glucose synthetic wastewater for two days, the matrix-bound phosphine fell from 1.76 ng x kg(-1) to 0.09 ng x kg(-1); At the same time, the highest disappearing rate of phosphine was reached 0.84 ng x (kg x d)(-1). While the glucose synthetic wastewater was 400 mg x L(-1), the disappearing rate of phosphine was only 0.27 ng x (kg x d)(-1). With further cultivation under acidogenic stage, the phosphine decreasing rate slowed down.