新型MBBR用于类地表Ⅳ类水排放标准升级改造工程

Application of New MBBR in WWTP Upgrading to Meet Class Ⅳ Surface Water Standard

为进一步改善河湖水环境质量及恢复水体功能,我国部分省市已经要求污水处理厂出水水质达到类地表Ⅳ类水标准,为此亟需建立适用于类Ⅳ水升级改造的标准技术,为实际工程提供指导。北方某污水厂面临提标、扩容、无扩建用地等问题,采用Bardenpho-MBBR工艺对原A2/O-MBBR工艺进行了升级改造,在未新增扩建池容的基础上,通过增加填料膜面积及池内功能区重新划分,以类地表Ⅳ类水为出水标准,处理水量从9×104m3/d提升至11×104m3/d。实际运行表明,出水COD、氨氮、TN均值分别为21.58、0.54、8.04 mg/L,去除率均值分别为94.3%、99.3%、89.7%,抗冲击负荷能力强,可稳定达到类地表Ⅳ类水标准;节能降耗作用显著,MBBR区采用无动力混合技术,改造后可节约10%的电耗;同步硝化反硝化及内源反硝化的存在使得药剂费用节约1 440万元/a;MBBR工艺升级改造具有可持续性,通过新增悬浮填料膜面积数量及重划内部功能分区,即可在原改造工艺基础上进行平滑升级;MBBR工艺与Bardenpho工艺相结合,可突破常规工艺对TN去除的限制,非常适用于进水TN高且出水要求高的升级改造工程或新建工程。

For the purpose of improving water quality of rivers and lakes and recovering the func- tion of water body, class Ⅳ surface water standard was taken as requirement for effluent quality of wastewater treatment plants in some provinces and cities in China. Since the effluent of the existing treat- ment processes could not meet the class Ⅳ surface water standard, it is urgent to develop the upgrading wastewater treatment technologies so that the practical guidance could be provided for the wastewater treatment projects. In a northern municipal wastewater treatment plant, both the quality and quantity of treated water had to be improved under the condition of no more area for new treatment facilities construc- tion. With regard to this requirement, the modified Bardenpho - MBBR combined process was adopted to take the place of the previous A2/O - MBBR combined process. The dual-purpose of improving water quality and enlarging treatment capacity without no more space was achieved by increasing the biofilm attaching area of suspended carriers and redistributing reaction sections of the treatment tank. The treatment capacity was increased from 90 000 m3/d to 110 000 m3/d and the effluent quality was improved from the first level A criteria to the class 1V of surface water standard. The result indicated that effluent quality of Bardenpho - MBBR process could meet class IV surface water standard stability. The average COD, NH4 - N, TN of the effluent were 21.58 mg/L, 0. 54 mg/L, 8.04 mg/L and the relevant average removal efficiencies were 94.3%, 99.3%, 89.7%, respectively. Besides the good performance above, the energy-saving and cost-reducing were evident in the upgrading and reconstruction projects. The unpowered mixing technology without power consumption was used in the MBBR section, so the power consumption of the whole project could be saved by 10%. Due to the good performance of the SND and the endogenous denitrification, about 1.44 × 107 yuan could be saved in the dosage cost. The MBBR process usage as upgrading technology had advantage of sustainability, and the effluent quality and treatment ca- pacity could be improved via addition of suspended carrier attaching area and redistribution the pollutant removal functional section in the whole tank. The combination of MBBR and Bardenpho could break through the limitation of conventional treatment process for TN removal. It was proven to be appropriate for renovation or new construction projects under the condition that influent TN was relatively high and re- quirement of effluent quality was stringent.