Assessment On The Operation And Technologic Renovation Scheme For The Municipal Sewage Treatment Plant Of Chongzhou City

The water resource is a crucial natural resource on the earth, and it is also the most important resources to sustain the survival and development of the human beings. In order to reuse the water, the waste water treatment is a purification process of separating pollutants from the water by using various methods. In nowdays, more and more advanced technology has been applied into engineering applications, such as activated sludge, oxidation ditch, A/O and A2/P.The municipal sewage treatment plant (MSTP) of Chongzhou is located in Chongyang Town, Chongzhou City, and Northwest of Sichuan Province. The ultimate design capacity is4×104m3/d of the wastewater treatment(2x104m3/d for the first stage project). The core technique applied in this case is A2/C(Modified from Carrousel2000), and the quality of final effluent can reach the National Standard (GB18918—2002) Level1Grade B.With the growing environmental pressure, China has launched a serious of acts to strict and regulate the pollution enterprises. According to the 《The eleventh Five-Years planning---The volume of state environmental protection》, Sichuan Province locally issued the 《Notice on strengthen the management of aquatic environment functional classification for surface waters in Sichuan Province》 that regulated all the newly constructed wastewater treatment plant adjacent to the key watershed must followed the national standard of 《Discharge standard of pollutants for municipal sewage treatment plant》 Level1Grade A. However, the main stream of Minjiang River was included in the area of key drainage basin. So the wastewater treatment plant was on the utmost urgency that upgraded and improved the first stage project.This thesis is discussed a case on the oxidation ditch process in the1st stage project of MWTP of Chongzhou City. It was analyzed the problems of the current procedure from the process, technological and economic aspects, and which was shown as follows:①Flow rate is very slow to cause the sedimentation of sludge, short hydraulic retention time and fluctuation of denitrification effect.②High SS content to cause the variation of second sedimentation tank.③Water moisture contents of the sludge dewatering section are too high that resulted in the reducing of sludge dewatering capacity.Several renovation scheme and experiments have been also proposed practically and economically in this thesis:Adjust the oxidation ditch flow rate from0.1m/s increased to0.3m/s; Set additional fiber turntable filters to further filter the SS sewage; Using the pump to transport the sludge to sludge storage tank replaced gravity sinking process. And the results are appreciable to meet with the requirement under the national standard regulations.Finally, the results after renovating are shown as shown as below:①The flow rate should be higher than0.3m/s in the Carrousel2000oxidation ditch or that could resulted in sludge deposition.②Change the pressure transport pathway in place to gravity can transport the remain sludge and biological treatment controllably and effectively.③Add a fiber rotary-filter to filtrate the SS to ensure the effluent reach the national standard for wastewater discharge.