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Clarification of phosphorus fractions and phosphorus release enhancement mechanism related to pH during waste activated sludge treatment
- He, Zhang-Wei, Liu, Wen-Zong, Wang, Ling, Tang, Cong-Cong, Guo, Ze-Chong, Yang, Chun-Xue, Wang, Ai-Jie
- Bioresource technology 2016 v.222 pp. 217-225
- activated sludge, inorganic phosphorus, molybdates, apatite, pH, rock phosphate
- This study aimed to clarify phosphorus (P) fractions in waste activated sludge (WAS) and explore release performance and enhancement mechanism of different P species related to pH. Results showed that inorganic P (IP) was the major P fraction in raw sludge (87.86% of total solid P), and non-apatite inorganic P (NAIP), the most labile P forms, occupied 81.30% of IP, suggesting that WAS could be selected as potential substitution of phosphate rock. The optimized acid and alkaline conditions were pH=4 and pH=12 for molybdate reactive P accumulation, increased by 311.20mg/L and 479.18mg/L compared to raw sludge, which were 3.80 and 5.84 times higher than that of control, respectively. The mechanism study demonstrated that high pH promoted NAIP release, and apatite P was sensitive to low pH. Moreover, the releasable and recoverable P depended on both fractions of different P species in sludge and pH adjustment for sludge treatment.