近年来，随着城市排水管网的逐步完善，雨污分流制度的逐步实施，污染物浓度显著提高，由此导致很多老旧大型城市污水处理厂处于超负荷运行状态。针对济南市某大型污水处理厂的连续监测与调研，从进水水质、运行工艺条件以及各个单元的处理效果分析该厂污水处理工艺的运行稳定性、污水处理效果，研究了投加铁盐活性污泥法驯化常规活性污泥法，处理高浓度城市污水，提高生物脱氮除磷效率的方法，并在该污水处理厂运行中开展了应用研究。针对该大型污水处理厂近年来进水水质与运行效果分析，冬季月份进水COD、NH3-N、SS等指标平均高出设计值40%以上，同时还伴随着进水黑臭现象，色度较深，气味较大。在进水水质大幅波动的条件下，通过适当降低进水量的方法，科学调控污水处理厂运行参数，使出水水质中COD、TN、NH3-N、TP浓度分别控制在8.0~39.0mg/L、5.0~15.0 mg/L、0.20~7.20mg/L 、0.10~0.43 mg/L的范围内。但是，长期进水水质过高导致污泥负荷偏高，再加上偶有偷排废水的混入，工艺设备单元运行长期处于处于超负荷，使运营成本增加，部分设施和设备相继出现严重影响生产的问题。通过小试反应器实验研究了投加铁盐对活性污泥工艺运行过程的影响，结果表明，在投加铁盐活性污泥在污泥含铁量5%（占污泥有机质干重）时，对COD、TN、TP的去除效果达到最优，稳定运行条件下比对照反应器的COD、TN、TP去除率分别提高5.9%，10.1%和4.5%，硝化活性和反硝化活性分别提高17.9%和15.7%，对污泥沉降性影响较小。含铁量5%的活性污泥在Zn2+、Cu2+浓度都不超过20mg/L时、油类浓度浓度不超过120mg/L时，比普通活性污泥对COD的去除有一定优势。采用投加铁盐活性污泥法驯化常规活性污泥法，使得该污水厂在进水负荷较高的情况下依然能够实现出水水质的稳定达标，出水COD、TN、TP、NH3-N、SS平均去除率分别达到94.0%、77.3%、95.5%、96.5%、98.4%。将投加药品确定为30%浓度的三氯化铁溶液，该厂药剂吨水成本大大降低，吨水成本药耗控制在0.0170元/吨以下，显著低于上一年度吨水药耗0.0210元/吨。
During recent years, with the gradual improvement of urban drainage network and the gradual implementation of rain and sewage separation systems, the load of pollutants in wastewater increased significantly. Some of the existing wastewater treatment plant which ran at higher load conditions than its designed capacity, could not operate stably and the effluent was not able to meet the standard. After continuous monitoring and investigation in one typical large scale wastewater treatment plant in Jinan, the operation sustainability and treatment effects were analyzed based on the study of influent quality, operation process conditions and treatment results in each units. The process of activated sludge with iron dosage was studied and applied in the plant to acclimate the traditional activated sludge, treat high-loading wastewater and enhance the efficiency of nitrogen and phosphorus removal.The influent quality and operation results in the plant during recent years were analyzed. COD, ammonia nitrogen and SS were higher than designed capacity in winter season, with the phenomenon of smelly black influent. In the condition of drastic fluctuation of influent quality, the influent quantity was reduced and th operation parameters in the plant were adjusted, in order to control the concentration of COD, TN, Ammonia-N and TP in the range of 8.0~39.0 mg/L, 5.0~15.0 mg/L, 0.20~7.20 mg/L and 0.10~0.43 mg/L, separately. However, the process equipment were overloaded with high sludge loading in the long-term operation, due to the high influent concentration and the mixture of illegal wastewater discharges. The operational costs were thus increased and some equipment and facilities were faced with serious problems.Based on the batch experiment, the impact of iron dosage on activated sludge process operation was studied. When the iron content reached 5% in the activated sludge, the optimal removal of COD, TN and TP was achieved, with removal efficiency increased by 5.9%, 10.1% and 4.5% compared with control. At the same time, nitrification and denitrification activity were increased by 17.9% and 15.7%, while the impact of iron dosage on sludge settling property was neglectable. Iron dosage also improved COD removal ability of activated sludge when wastewater containing heavy metals (Zn2+/Cu2+ concentration≤20mg/L, Oil concentration≤120mg/L) was treated.The process of activated sludge with iron dosage to acclimate the traditional activated sludge ensured the stable effluent quality to meet the discharge standard, when the influent load was relatively high, achieving the average COD/TN/TP/ NH3-N/SS removal efficiency of 94.0%, 77.3%, 95.5%, 96.5%and 98.4%, separately. When 30% FeCl3 was applid as added agent, the cost of dosage per ton of treated wastewater was reduced significantly, with the average cost of 0.0170 yuan/ton, lower than 0.0210 yuan/ton in the last year.
