全流程分析揭示同步化学除磷对倒置AAO工艺的潜在影响

UNCOVERING THE POTENTIAL IMPACT OF SIMULTANEOUS CHEMICAL PHOSPHORUS REMOVAL ON AN INVERTED AAO SYSTEM BY WHOLE PROCESS DIAGNOSIS METHOD

为了积极响应《关于推进污水处理减污降碳协同增效的实施意见》,全面推进城镇污水处理行业的减污降碳,对无锡市某同步化学除磷污水处理厂开展全流程分析,诊断除磷药剂聚合氯化铝铁(PAFC)投加对工艺稳定性的影响,探究倒置AAO工艺节药方式。该厂采用缺氧/厌氧/好氧(倒置AAO)工艺,处理规模达15万m^(3)/d,长期通过投加PAFC保障出水水质稳定。全流程分析发现,该厂一期工艺PAFC药耗逐年增加,尽管实现了TP的高效去除(98%),但残留的PAFC大量回流至厌氧段,导致磷酸盐提前去除,恶化活性污泥(AS)吸磷能力,吸磷速率仅为0.44 mg P/(g SS·h)。因此,进一步开展了一期工艺PAFC药耗调节实验,以期逐步恢复AS吸磷能力。结果表明,将PAFC投加量控制在0.027~0.053 kg/m^(3)即可实现磷酸盐的稳定去除,同时保障污泥沉降性能,而较高投加量的PAFC(≥0.077 kg/m^(3))将快速去除磷酸盐,并明显抑制好氧吸磷过程。

In order to respond to the Implementation Opinions on Promoting Synergy and Efficiency Enhancement of Wastewater Treatment for Pollution and Carbon Reduction,and comprehensively promote the reduction of pollution and carbon emissions in the urban wastewater treatment industry,a whole process analysis was conducted on a simultaneous chemical phosphorus removal WWTP in Wuxi,to diagnose the impact of phosphorus removal agent dosage on process stability,and explore the agent-saving method of the inverted AAO process.This WWTP adopts an Anoxic/Anaerobic/Aerobic(inverted AAO)process,with a treatment capacity of 150000 m^(3)/d.The stable effluent quality is ensured through the long-term addition of PAFC.Through the whole process analysis,it was found that the PAFC consumption in the phase I project of the WWTP has been increasing year by year.Although the efficient removal of TP(98%)has been achieved,a large amount of residual PAFC flows back to the anaerobic section,leading to early removal of phosphorus and deterioration of the phosphorus absorption capacity of activated sludge(AS).The phosphorus absorption rate was only 0.44 mg P/(g SS·h).Therefore,this study further conducted the PAFC dosage regulation experiment in the Phase I project to gradually restore the phosphorus absorption capacity of AS.The results showed that a controlled PAFC dosage at 0.027 kg/m^(3) to 0.053 kg/m^(3) can help achieve stable removal of phosphorus while ensuring sludge settling performance.However,PAFC with a higher dosage(0.077 kg/m^(3) above)will quickly remove phosphorus and significantly inhibit the aerobic phosphorus absorption process.