In China, with development of industries, for EPT (sewage treatment plant) in industrial parks, the sewage quality generally is complicated. Because it contains not only a variety of industrial waste water, but also a part of domestic sewage, so pollutants are diversified and the composition is complicated, thus water quality changes greatly. Especially for some industrial wastewater, such as: concrete waste water, chemical sludge, paper slurry, printing and dyeing effluent ect., they will increase the difficulty of treatment. Sewage treatment plants generally adopt A/O process (Anoxic/Oxic), and can also choose auxiliary methods, say, oxidation ditch, SBR, hydrolysis aerobic method and so on. The final formed sludge will be dehydrated by a chamber membrane filter press to achieve zero pollution.
The specific treatment processes are as follows. The raw water flows into the grit tank after being treated by a mechanical grid to remove large solid and impurities. Then the supernatant enters into the conditioning tank, and directly mixed with chemicals in the coagulation tank and then enters the sedimentation tank to separate the mud and water. After that, the effluent enters the next process for A/O treatment. Finally, the sludge at the bottom of the sedimentation tanks flows into the thickening tank for concentration, and sedimented sludge will be pumped into a sludge filter press to recycle water. After the above treatment, the final effluent quality will be generally better than national discharging standard. This A/O combined technology not only can reduce the biochemical treatment, but also have good denitrification performance and COD removal effects.