Impact Analysis Of Seasonal And Process On Polutant Removal And Costs Of Wastewater Treatment Plant

Wastewater treatment efficiency is affected by many interacted factors. It is significant to analyze and summarize the change rule of wastewater treatment plants influent characteristics. The government has invested huge funds in municipal wastewater treatment projects in order to protect environment and benefit the people. Hence, it is necessary to manage, run the plants correctly and make sure the effluent achieve the discharge standard. However, the water characteristics (e.g. quality, quantity and temperature etc.) would strongly vary with the seasonal changes and could have a great impact on the operational condition of the plants. This research is aimed to optimize plants operation, increase treatment efficiency and decrease treatment cost.The analyzed operation data in this research came from a local wastewater treatment plant. First, the impacts of seasonal changes on removal performance of different contaminants and running costs (power consumptions, sludge disposal costs and additives costs) were discussed respectively. Then, the effects of different treatment processes on treating performance and running cost were discussed through comparing three kinds of commonly used biochemical treatment processes. This research could promote the existing plants to cut the cost with a good running performance via adjusting the treatment parameters according to the seasonal changes, and make guidance for the upcoming project on the treatment processes selections.Results showed that the seasonal changes affect the influent characteristics and lead series changes of controlled parameters (e.g. temperature). The water quantity varied with seasonal changes remarkably. The maximum and minimum quantities were appeared in July and April respectively. However, most influent characteristics (e.g. COD, SS, Total-P, etc) were not obviously changed with the cycle of the seasons except NH3-N. Three kinds of the operational costs were affected by seasonal changes. They are power consumption, additives cost and sludge disposal cost. Data showed that the power consumption and additives costs of per ton wastewater were at a low level in summer. But due to the quantity in summer was much larger than that in other seasons, the total operational costs of electric, additives and sludge disposal were not low. Besides, the power consumption in winter was high as well.Effluent from the three kinds of biochemical treatment processes could reach the discharge standard. A/O process had a slightly better performance on COD and BOD removal efficiency compared with the other two processes. Considering Total-N and NH3-N removal, A/O process with the advantage of good denitrification performance, has an obviously higher Total-N removal efficiency than that of others. Taking power consumption into account, the power consumption of per ton wastewater and per kilogram removed COD of BAF process were0.2kW-h and0.82kW-h respectively, which were lower than that of A/O and CAST processes. Results indicated that biofilm process has a positive advantage in power consumption compared with the activated sludge process. As for the sludge disposal cost, with the same condition of good sludge activity and treatment performance, the A/O process with longer SRT has a lower sludge yield and hence save more sludge disposal cost.During the operational management process of wastewater treatment plant, the operational cost could be reduced and the treatment performance could be improved through optimization treatment processes and sludge disposal methods, controlling electric equipments’operation, comparison, selection and replacement of the materials etc.