HU De-xiu,ZHANG Cong,ZHANG Yan.Phosphorus Release from Sludge Enhanced by Ultrasound and Optimization of Phosphorus Recovery by Magnesium Ammonium Phosphate Method[J].China Water & Wastewater,2020,36(15 15):65-72.
Phosphorus Release from Sludge Enhanced by Ultrasound and Optimization of Phosphorus Recovery by Magnesium Ammonium Phosphate Method
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第36卷
Number:
15 15
Page:
65-72
Column:
Date of publication:
2020-08-01
- Keywords:
- excess sludge; ultrasound; magnesium ammonium phosphate (MAP); phosphorus release; phosphorus recovery
- Abstract:
- In order to improve phosphorus release and recovery from sludge, ultrasound was applied to enhance phosphorous release from sludge treated by EDTA and anaerobic digestion, and then the phosphate in the supernatant was recovered by MgNH4PO4·6H2O (MAP) crystallization. Effect of ultrasound on phosphorus release was investigated, and the optimal ultrasonic operational parameters were determined. A quadratic polynomial model of phosphorus recovery by MAP method was constructed by response surface method (RSM) and its applicability was verified. The application of ultrasound could significantly strengthen phosphorus release of anaerobic digested sludge. The optimal ultrasonic operational parameters were as follows: sound energy density of 1.0 W/mL and ultrasonic time of 40 min. Under the optimal parameters, 60% of TP could be released to the liquid phase, and TP and PO3-4-P concentrations were 1.6 times and 1.4 times higher than those obtained by non-ultrasonic treatment. The increase of TP in supernatant after ultrasound was positively correlated with the decrease of MLSS and MLVSS, and 1 mg MLSS released 0.010 1 mg TP into the liquid. The optimal conditions of phosphorus recovery were as follows:nMg/nP=2, pH value of 9 and stirring time of 21 min, and the phosphorus recovery rate was 89.29%. The main component of the recovered crystals was magnesium ammonium phosphate with a purity of 77.56%, and the yield of obtained crystals increased by 30% compared to that without ultrasound.
Last Update:
2020-08-01