Enhanced phosphorus biological removal from wastewater-effect of microorganism acclimatization with different ratios of short-chain fatty acids mixture

摘要

Two activated sludge was acclimatized respectively with a lower and a higher ratio of propionic/acetic acid wastewater(i.e.biomass A and biomass P),and the effect of biomass acclimatization on enhanced phosphorus biological removal from acetic acid enriched wastewater was investigated.Due to biomass P having a higher biomass polyphosphate content,less glycogen degradation,and probably greater phosphorus accumulating organisms(PAO)fraction,it exhibited a greater phosphorus release(1.18mmol versus 0.94mmol)and PHB accumulation(2.66 mrnol-C versus 2.54 mmol-C)than biomass A per gram mixed liquor volatile suspended solids(MLVSS)in anaerobic phase.During the aerobic stage,it took up much higher phosphorus(1.54mmol/g-MLVSS versus 1.17mmol/g-MLVSS)but degraded slightly less PHA(3.67mmol-C/g-MLVSS against 3.73mmol-C/g-MLVSS)than biomass A.Further studies revealed that since biomass P consumed less energy for the aerobic glycogen synthesis and cell growth,its lower PHA degradation did not result in a lower phosphorus uptake.Thus,the biomass acclimatized with a higher propionic/acetic acid wastewater displayed a much greater PHA utilization efficiency for phosphorus uptake(0.42 mol-phosphorus/mol-C-PHA versus 0.31 mol-phosphorus/mol-C-PHA)and a much higher phosphorus removal efficiency than with a lower one(95.76% against 65.75%).