Study On Small-town Domestic Sewage Treatment By MST Technology

In China, there are a large number of small towns widely distributed in the wholecountry. So, only small or medium sewage treatment plants are suitable for the smalltowns. The sewage treatment construction in small towns is still in its infancy in ourcountry. In this situation, in the construction of small-town sewage treatment plants, it isshort of appropriate norms and standards, applicable technology and equipment.An integrated device named MST wastewater treatment technology emerged. It meetsall aspects of requirements of small-town sewage treatment. The integrated reactor is adevice that can realize the different physical, chemical and biological treatmentprocesses completed in one reactor. Suspended packing biofilm and airlift bio-contactoxidation has been selected as the primary technical process of the two correspondingmodules inside the integrated reactor respectively. The appropriate parameters weredetermined through experiment, the removal efficiency of each pollutant can beachieved, and the process principles, anti-impact loads were also analyzed. In this way,we can provide designing and running parameters for projects in the future.The results show that80.56%of COD,72.3%of NH3-N,49.39%of TN and95.22%of SS can be removed by the co-working modules under the conditions of air/waterration of10.0and17.1of each module and the hydraulic loading of2.88m3/(m3·d) and4.61m3/(m3·d) of each module. The treated water can be used as urban recycled water.The integrated reactor doesn’t have the problem of sludge bulking, and the sludgeproduction is small, that makes the device can remain stable when the quality of theincoming sewage changes dramatically.To make the integrated device can be used more extensively, a chemical phosphorusremoval process is added to it. FeSO4was chosen as the flocculant. The result showsthat when the FeSO4/TP ration was about4.5, the concentration of TP in effluent can becontrolled below0.5mg/L. Using the MST integrated device with chemical phosphorusremoval process to treat small-town sewage, we can find out that it not only has theability of conventional urban sewage treatment plant, but also has a lot of advantagescompared to the traditional sewage treatment process. With the suspended fillerbiological carrier and airlift reactor, the removal of SS is outstanding and stable so that asecondary sedimentation tank would be not necessary, and the device can be very smalland has a strong resistance to impact load at the same time. The integrated device is composed by modules, it simplified the traditional contactoxidation process. This new sewage treatment device is small footprint, low investment,simple to installation and easy to operate and manage, and these features make theintegration technology perfectly for small-town sewage treatment.