Commissioning And Operation Of CAST In Shuozhou Municipal Wasterwater Tratment Plant

Along with the constant development of China's economy and people's awareness of environment, sewage treatment has been brought up on the agenda. So as infrastructure, urban sewage treatment plant must be coordinated is modern city. The process in city sewage treatment plant is complex; the electrical and mechanical equipments are many; the running debugging requirements are high; in particular the training and management of activated sludge in the activated sludge treatment process should be carried out in accordance with certain procedures. So debugging process relate to the normal operation of a sewage treatment plant and full play of its benefits.This paper takes the Shuozhou Sewage Factory CAST as example and studies of the debugging in the sewage plant. Activated sludge debugging is the most important and the most crucial step. For general urban sewage, any of the cultivation methods can cultivate the activated sludge normally. But different methods request different culture time, handling capacity and training costs are also different. In practice, one or several kind of training methods should be selected according to the specific circumstances of treatment plants. In May 13, 2007, Shuozhou Sewage Factory begins activated sludge train. According to the local water volume and water quality, suitable training method (full load continuous culture) are selected. After more than two months, except ammonia all the other indicators have reached the water effluent design requirements.The respective removal rates of COD, BOD₅,SS, NH₃-N, phosphate were 90%, 86.5%, 91.2%, 11%, 74%. Against the issue of ammonia, the factory analyzes the reason theoretically and practically, and timely adjusts the parameters to resolve the issue so that the effluent ammonia can meet the requirements. In addition, in the debugging process various indicators such as SV30, microbiological examination, MLSS, MLVSS were monitored in order to judge the sludge quality.This study from May 2007 to January 2008 experienced the lowest outdoor temperature in the winter and in aeration tank the water temperature reached the lowest point since it had been operated in the winter. Because the water temperature is in 10℃which is not high enough to change the morphological and physiological characteristics of microbe, sewage plant could go through the winter smoothly and the effluent quality would meet effluent standards. In Shuozhou wastewater treatment plant, through the debugging process of CAST technology, all structures and equipments operated stably and all the effluent indicators reached " sewage discharge standards" GB8978-1996 ,Grade I, standard . In the operating process of CAST technology, we need to pay special attention to equipment maintenance and management. Due to the high automation degree of the technology, simple artificial operation, more necessary materials and equipment, complex operation management, higher quality requirements of the matching , a higher level of equipment maintenance is needed.According to the actual debugging problems, this paper theoretically and practically studies the CAST technology and its operation mode, and put forward rational proposals, which provides management information for managers of newly-built and imminently built water treatment plants.