化学强化除磷自控系统优化试验研究

Optimization of auto-control system for chemical enhanced phosphorus removal

针对当前化学强化除磷自控系统的短板,并结合疫情防控常态化背景下污水厂消毒设施的改造升级,从3个方面开展了对化学强化除磷自控系统的优化试验研究:一是将投药点后移至深度处理滤池与接触消毒池之间;二是用当前可快速在线测定的正磷酸盐(OP)替代总磷(TP)作为自控参数,建立总磷与正磷酸盐的相关关系;三是基于化学除磷效率与投药量之间的半经验关系,建立CEPRM模型算法,以取代PLC控制器传统的PID算法。结果表明,优化后污水厂出水总磷稳定达到《城镇污水处理厂污染物排放标准》(GB 18919—2002)一级A标准,化学除磷投药量明显降低,隔膜计量泵可适时稳定调频变速,整个除磷自控系统鲁棒性好。

In view of the disadvantages of the current auto-control system for chemical enhanced phosphorus removal and the disinfection facilities upgrading of the sewage plant in regularized epidemic prevention and control,the optimization study of the auto-control system for chemical enhanced phosphorus removal was carried out from three aspects.Firstly,the dosing point was moved back to the point between the advanced treatment filter and the contact disinfection tank.Secondly,orthophosphate was replaced total phosphorus as the key parameter of auto-control system,which can be determined quickly,and the relationship between total phosphorus and orthophosphate was established.Thirdly,the traditional PID algorithm of PLC controller was replaced by the CEPRM model algorithm,which based on the semi empirical relationship between efficiency and dosage of chemical phosphorus removal.The test results showed that the effluent total phosphorus could reach standard A of first-level of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18919—2002)by optimization of sewage treatment plant.The reagents dosage of chemical phosphorus removal decreased significantly.Diaphragm metering pump could adjust speed stably through frequency control technique in time,and the optimized auto-control system for chemical enhanced phosphorus removal had good robustness and the feasibility.