Wastewater treatment process with nitrogen and phosphorus removal function is still the focus of future development
The discharge standard for pollutants of urban sewage treatment plant (GB18918-2002) has clear requirements for nitrogen and phosphorus in the effluent. Therefore, the existing urban sewage treatment plant needs to be rebuilt, and facilities should be added to remove nitrogen and phosphorus pollutants in the sewage, so as to meet the national discharge standard. The new sewage treatment plant must be constructed according to the standard GB18918-2002.
At present, the research on the mechanism, influencing factors and process of biological nitrogen and phosphorus removal from sewage has become a hot spot, and some new processes and reform processes have been put forward. Such as MSBR, inverted A2 / O, uct, etc., and actively introduce new technology from abroad. For nitrogen and phosphorus removal process, the future development requirements are not only limited to high nitrogen and phosphorus removal rate, but also require stable and reliable treatment effect, flexible process control and adjustment, and saving investment and operation costs. At present, biological phosphorus and nitrogen removal technology is developing towards this simple, efficient and economic direction.
High efficiency, low input, low operation cost, mature and reliable sewage treatment process is the preferred process of sewage treatment plant in the future
China is a developing country with a relatively backward level of economic development. In the face of increasingly serious environmental pollution in China, the country is stepping up efforts to carry out sewage treatment. The fundamental measure to solve the urban sewage pollution is to build a secondary urban sewage treatment plant with biological treatment as the main process.
However, the construction of a large number of secondary urban sewage treatment plants requires a lot of investment and high operating costs, which is a heavy burden for China. At present, the construction of sewage treatment plants in China is difficult to carry out due to the lack of funds. Some of the completed sewage treatment plants have been unable to operate normally due to high operating costs or lack of professional operation management personnel. Therefore, the research on high efficiency, low investment, low operating cost, mature and reliable sewage treatment process is a key research party in the future. Xiang.
Study on the technology of sewage treatment plant in small town
The development of small towns is the only way in the process of urbanization in China, and it is the strategic choice of urbanization with Chinese characteristics. From 1978 to 2000, the number of towns in China increased from 2178 to 20312. At present, there are nearly 48000 small towns of various scales and natures. If we only pay attention to the construction of sewage treatment projects in large and medium-sized cities, but ignore the sewage treatment in such a large number of small towns, then the sewage treatment in China can not achieve the intended goal.
And for the small town sewage treatment is facing a series of problems: the characteristics of small town sewage is different from the big city; the small town capital shortage; the lack of operation and management personnel. Therefore, the sewage treatment process in small towns should be a process with low capital construction investment, low operation cost, relatively easy operation management and high operation reliability. At present, the research direction of the process suitable for small town sewage treatment plant is: select the process suitable for small town sewage treatment plant from the existing process, and develop a new process suitable for small town sewage treatment plant.
Study on sewage treatment process with low sludge production and stable sludge
At present, the treatment of sludge produced by sewage treatment plants is also a key and difficult point in China's sewage treatment industry. In 2003, the total sewage treatment capacity of China's urban sewage plants was about 95.9562 × 108 / A, the average solid content of urban sewage was 0.02%, the wet sludge output was 965.562 × 104t / A, and the composition of sludge is very complex, containing a variety of harmful and toxic components, so the output is large and If sludge containing a lot of toxic and harmful substances is discharged into the environment without effective treatment, it will bring great damage to the environment.
At present, the current situation of sludge treatment and disposal in China is not optimistic: according to statistics, only 25.68% of the urban sewage treatment plants that have been built and operated in China have been treated by sludge thickening, digestion and drying dehydration, 55.70% of the sewage plants that do not have sludge stabilization treatment, and 48.65% of the sewage plants that do not have sludge drying and dehydration treatment.
This shows that more than 70% of the sewage plants in our country do not have complete sludge treatment process, and an effective way to solve this problem is: the sewage treatment plant adopts a sewage treatment process with low sludge production and stable sludge to control the copyright of the engineering network, so that the sludge production can be reduced at the source, and the stable residual sludge can be obtained, so as to reduce the sludge production. It lightens the burden of subsequent sludge treatment.
At present, some processes in our country can achieve this, such as biological contact oxidation process, BIOLAK process, hydrolysis aerobic process, etc., but the systematic research on sewage treatment process with low sludge production and stable sludge has not yet begun.