低碳氮比进水AAO污水处理厂低碳运行

为探明低碳氮比进水条件下AAO污水处理厂的碳排放特征,提出可行的低碳运行策略,基于排放因子法对7座低碳氮比进水AAO污水处理厂(分为AAO组和AAO-MBR组)运行1a产生的碳排放进行核算与评价,对具有显著低碳表现的污水处理厂开展全流程分析剖析其碳减排途径。结果表明,电耗和N₂O排放是主要碳排放来源,分别贡献49.43%和25.75%的碳排放。AAO-MBR组以间接碳排放为主,电耗碳排放占至约60%,而AAO组生物作用导致的直接碳排放占主导。AAO组平均吨水比碳排放显著低于AAO-MBR组(0.47和0.79kgCO_2eq/m³),更具低碳运行潜力。7座污水处理厂中,WWTP7各项比碳排放评价指标均为最低,意味着其最具低碳运行能力。充分利用进水碳源,多路径协同脱氮除磷同时精准控制溶解氧浓度避免过曝气是其大幅削减能耗和物耗,实现碳减排的关键路径。

Research on low-carbon operation mode in AAO-based wastewater treatment plants with low C/N influent

In order to clarify the carbon emission characteristics of wastewater treatment plants (WWTPs) with low C/N influent and to propose feasible low-carbon operation strategies, seven AAO-based WWTPs (divided into AAO-based WWTPs and AAO-MBR-based WWTPs) were operated for one year, and the carbon emissions based on the emission factor method were calculated and evaluated. In addition, according to the whole process analysis method, the carbon emission reduction pathways of WWTPs with significant low-carbon operation characteristics were subsequently analyzed. The results show that electricity consumption and nitrous oxide emissions are the main sources of carbon emissions, contributing 49.43% and 25.75% of carbon emissions on average, respectively. AAO-MBR-based WWTP is dominated by indirect carbon emissions, and electricity consumption accounts for about 60% of carbon emissions, while the direct carbon emissions caused by the microbial activity in AAO-based WWTP dominate. The average specific carbon emission of AAO-based WWTP was significantly lower than that of the AAO-MBR-based WWTP group (0.47 and 0.79kg CO_2eq/m³), which presents remarkable low-carbon operation potential. Among the seven WWTPs, all the specific carbon emission evaluation indicators of WWTP7are the lowest, indicating that WWTP7has the highest potential for low-carbon operation. Furthermore, the study found that making full use of the influent carbon source, multi-path synergistic nitrogen and phosphorus removal, and precise control of dissolved oxygen to avoid over-aeration are the key points to greatly reduce energy consumption and achieve carbon emission reduction.