Research On The Process Optimization Of The Jinan Second Wastewater Treatment Plant By Using Activated Sludge Mathematical Model

The Second Wastewater Treatment Plant in Jinan City, which is invested by China Everbright Water Investment Limited, is a large wastewater treatment plant that is operated in TOT model. It adopted DE oxidation ditch process, with a certain degree of nitrogen and phosphorus removal capabilities. The treated water quality is up to the second level of national emission standards while the indicators except the total nitrogen can meet the demands of urban sewage treatment plant pollutant emission standards (GB 18918-2002) for a B standard. However, in order to coordinate South-to-North Water Transfer Project, the emission standards alongside Little Qsing River is to increase gradually. So the effluent quality of the Second Wastewater Treatment Plant in Jinan City will also be further improved to achieve an A emission standard.To solve the above problem, we comprehensively evaluated the current running condition of sewage plant, through surveyed the situation of equipment operation, water quality, water flow, and the degradation ability of activated sludge. According to the survey process operating parameters, we built an activated sludge model of the current treatment process for the Second Wastewater Treatment Plant in Jinan City without adding any infrastructure or extending measurement of bio-pool.In order to increase the efficiency of nitrogen and phosphorus removal in wastewater treatment plant, the DE oxidation ditch process was retrofitted, making sure it can meet an emission standard. In this study, we majorly considered three kinds of process modification, the A2/O process, MLE process and Bardenpho Technology. The operating simulation of three processes was analyzed by mathematical model, and taking into account 12 kinds of different operating conditions, including 10℃,20℃,30℃, and different water flow. Simulation results showed that:(1) In the current water quantity and water quality situation, without changing the original bio-pool facilities, only to change the treatment process or the operation mode, the water quality of wastewater treatment plant can not fully meet the an A emission standard. TP removal can not satisfy A or B emission standard in all conditions of process simulation programs. (2) If wastewater treatment plant adopt the conventional A2/O, or MLE process, the water quality index except TP can meet A emission standard, in the case of water inflow more evenly; and the removal of SS, TN was impact by the water quantity. The water quality except TP of 4 Bardenpho process can meet A emission standard, only in the high-temperature conditions. (3) The key factors which made the wastewater not meet emission standard is the low removal of TP.The study will provide technical proofs for the long-term process upgrading and renovation project of the Second Wastewater Treatment Plant in Jinan City. The sewage plant effluent quality will be able to meet the new emission standards through process optimization or model simulation. Additionally, it may lower operating costs or increase the handling volume.