毕业论文关键词：SBR废水处理、脱氮、除磷

Abstract In recent years China's sewage treatment industry although has made great progress, but there are still sewage treatment plant design standard is low, the equipment and technology backward. Sewage treatment process and other process similar, in a certain temperature, pressure, flow, level, etc. craft conditions. Sewage treatment of many variable factors, water, concentration, temperature, air volume and microbiological status of mechanical operation and system control will influence the efficiency of sewage treatment and function, so as soon as possible to establish a higher degree of automation of the sewage treatment plant and efficient operation has become the current urgent task.

With the continuous improvement of the social and economic rapid development and people's life, urban sewage and industrial wastewater emissions are increasing, the shortage problem of water pollution and water resources is more and more outstanding. In order to realize the water resources sustainable utilization and there is a need for people to pay attention to the protection of water resources, but also the need to strengthen the governance of water pollution.

In recent years, due to the accumulation of nitrogen and phosphorus in water, resulting in the phenomenon of water eutrophication. The amounts of nitrogen and phosphorus into the water, causing the large number of algae growth, leading to eutrophication. Eutrophication, water quality will deteriorate gradually, water resources use value will be greatly reduced. Therefore, control of nitrogen discharged into the water body, the amount of phosphorus and other plant nutrients for the improvement of eutrophication and water environment pollution has very important significance.

Nitrogen and phosphorus are the microorganisms in the process of growth and reproduction of necessary nutrients, but if the excessive amounts of nitrogen and phosphorus in water, causing great harm. Because the process of nitrogen is discharged into the water, it will accelerate the water eutrophication, deterioration of water quality, reduce water use and can be dangerous to human health.

Compared to SBR process and the traditional sewage treatment process and their different place is, SBR technology used in time pision mode of operation to replace the traditional dynamic precipitation way. His main characteristic is to run orderly and intermittent operation of the same, SBR process technology is the core of SBR reactor, the reaction tank set and mean, primary sedimentation, biological degradation, sedimentation and other functions in a pool, and no sludge return system. In SBR reactor, an aeration tank and sedimentation tank combined, is a biochemical reaction and slurry separation process in a reaction tank. Waste water batch entry into the SBR reaction pool, in accordance with the time sequence, followed by the reaction period, precipitation, drainage, idle period and other basic process, even if the completion of a running cycle.

SBR process through anaerobic, aerobic, three stages of hypoxia time reasonable configuration alternate operation to achieve carbon, nitrogen, phosphorus removal, with the advantages of process is simple, stable treatment effect, small occupation area, and strong resistance to impact load etc.. So in the urban sewage, agricultural products processing wastewater, brewery wastewater, chemical wastewater, printing and dyeing wastewater, papermaking wastewater, garbage dumps exudate obtained the development and application of. But in the actual treatment of urban domestic sewage, often appeared to take off the nitrogen effect is good when phosphorus removal effect is very poor and phosphorus removal effect is good when nitrogen removal efficiency and poor situation.

In full of classic SBR process, it is difficult to achieve satisfactory removal effect, improve his operation and reasonable control of operating conditions can significantly improve the removal efficiency of [10]. By mixing water, the water filling period in need of mixing, so that you can maintain anaerobic environment, so phosphorus accumulating bacteria can use water in sufficient amounts of organic substrate phosphorus release, but also for the aeration stage phosphorus uptake reaction provides good conditions. Precipitation and drainage stage caused by hypoxic environment will lead to phosphorus release, in order to avoid phosphorus released in advance, the mixed liquid precipitation and sludge discharge operation. Which can make poly phosphate bacteria in the form of excess sludge timely excluded, so as to improve the phosphorus removal effect. And the selection of reasonable drainage and drainage rate can effectively reduce effluent SS concentration which can improve the treatment efficiency of total phosphorus [11]. According to the mode of operation and control of operating conditions, the system can get more than 90% of the phosphorus removal efficiency [12].