MBBR-A2O/MBR处理农村生活污水动力学研究

采用MBBR-A2O/MBR(又称BCO-MBR)工艺,对水质特征呈现低碳源高氮磷、水质波动大和日变化系数大等特点的农村生活污水进行研究。对比MBBR-A2O/MBR工艺在5种不同水力停留时间下的(0.42 d、0.50 d、0.75 d、1.25 d、1.50 d)运行状况,挑选出最佳的水力停留时间,并利用Lawrence-McCarty模型构建该工艺的污染物降解动力学方程。结果表明,随着水力停留时间(HRT)的延长,MBBR-A2O/MBR工艺对污染物的去除效果逐渐提升。当HRT为1.25d,CODCr、NH3H、TN、TP平均进水质量浓度分别280.67mg/L、36.88 mg/L、50.59 mg/L、2.51 mg/L时,平均出水质量浓度分别为34.33 mg/L、3.19 mg/L、5.13 mg/L、0.63 mg/L,平均去除率分别可达87.86%、89.92%、89.85%、74.95%。CODCr、NH3H、TN出水质量浓度在城镇污水排放标准一级A限值以下,TP出水质量浓度达到一级B标准,因此确定最佳的HRT为1.25 d。污染物降解动力学计算所得模拟值与实际出水质量浓度测量值拟合度良好,其中CODCr模拟值与平均测量值一致性最高,相对误差在0.02~0.14,NH3H与TN的相对误差分别在0.19~0.60和0.1~0.33。这表明污染物降解动力学方程可以较好地模拟工艺出水的污染物质量浓度。CODCr降解动力学方程常数为Vmax=0.19 d-1,KS=82.97 mg/L;NH3H降解动力学方程常数为Vmax=0.02d-1,KS=8.49 mg/L;TN降解动力学方程常数为Vmax=0.024 d-1,KS=8.10 mg/L。研究的动力学常数与传统活性污泥法动力学常数相比,KS较高,而Vmax较低,导致Vmax较低的主要原因可能是测定的污泥质量浓度高于实际有效的质量浓度。研究对利用MBBR-A2O/MBR工艺处理农村生活污水和传统活性污泥工艺提标改造具有一定的应用参考价值。

Dynamics of the MBBR-A2O/MBR for treating the rural domestic sewage

This paper intends to introduce the MBBR-A2O/MBR(also known as BCO-MBR) process for its practical adoption to the domestic sewage removal in the rural areas.The reason for our introduction can be stated as follows:low carbon source,high nitrogen and phosphorus,high fluctuation of the water quality and greater daily variation coefficient are all favorable for the domestic sewage removal.For instance,as compared with the operational conditions of MBBR-A2O/MBR process under the 5 different hydraulic residence hours (0.42 d,0.50 d,0.75 d,1.25 d,1.50 d),the best hours for the hydraulic residence can be chosen in accordance with the kinetic equation of the pollutant degradation of MBBR-A2O/MBR process based on the LawrenceMc Carty model.The results of our testing practice show that with the extension of HRT,the removal processing effect on the pollutants can be improved gradually.Say,when HRT was 1.25 d,the average influential concentration rate of CODCr,NH3-H,TNand TP can be illustrated as 280.67 mg/L,36.88 mg/L,50.59mg/L and 2.51 mg/L,correspondingly and respectively.And,the average effluent concentration rates can be shown as 34.33mg/L,3.19 mg/L,5.13 mg/L and 0.63 mg/L,with the average removal rates being 87.86%,89.92%,89.85% and 74.95%,respectively.As to the effluent concentration rates of CODCr,the methods of NH3-H and TN have been found below the limit of Class A of urban sewage discharge standard with the effluent concentration rates of TP noticed by Class B,that is,the best HRT being determined for 1.25 d.And,in comparison,the simulated duties calculated by the pollutant degradation kinetics prove to be well fit for the measured ones of the actual effluent concentration,of which the CODCrsimulation results prove to be highly consistent with the average measurement ones,while the relative errors prove to be between 0.02-0.14,with the NH3-H and TN being between 0.19-0.60 and 0.1-0.33,correspondingly.And,furthermore,the kinetic equation of the pollutant degradation can better simulate the pollutant concentration rate in the processing effluent.On the other side,the equation constant of the CODCr degradation kinetics has been found equal to Vmax=0.19 d-1 and KS=82.97 mg/L.Aside from it,the kinetics equation constant of the NH3-H degradation has also been worked out at Vmax=0.02 d-1,KS=8.49 mg/L,correspondingly,with the TN degradation constant of the kinetic equation being Vmax=0.024 d-1and KS=8.10 mg/L.Thus,it can be seen that,in comparison with the traditional activated sludge process,the KS value is higher but the Vmax value tends to be lower.The main reason for the Vmaxvalue being low may account for the result that the measured sludge concentration rate is being higher than the effective actual concentration disclosed.Thus,it can be seen that the study results we have determined turns to be with higher application reference value for MBBR-A2O/MBR process in treating the rural domestic sewage and the traditional process upgrading with the activated sludge.