1. Adopt advanced, reasonable, mature and reliable technological process.
2. Actively select new technologies, new processes, new equipment and new materials to ensure the content and advancement of Engineering technology.
3. Ensure low energy consumption and low cost operation to ensure operation safety and stability.
4. Combining with the long-term planning of enterprises, rational layout and land saving should be achieved.
5. Fully listen to the opinions of construction units to ensure user satisfaction.
(1) Pretreatment process
The pretreatment structure is realized by grille, regulating pool and other process units. On the one hand, the water quality and quantity are regulated homogeneously and equally. On the other hand, the large granular pollutants and S S in raw water are removed to ensure the normal operation of the follow-up treatment units and the stable attainment of the effluent index.
(2) Dissolved air flotation process
Dissolved air flotation makes use of the different solubility of water under different pressures to produce micro-bubbles in water under pressurized or negative pressures, instead of the traditional air-entraining equipment to air-entraining process in water.The working principle of dissolved air flotation is that air from air compressor to air tank is brought into the dissolved air tank through jet device and forced dissolved in water at 0.35 Mpa pressure. Dissolved water is sent to the floating tank. Under the condition of sudden release, the air dissolved in the water precipitates, forming a large number of micro-bubbles, contacting sufficiently with the suspended matter in the sewage pumped and flocculated after adding medicine, and adsorbing in the flocculated suspended matter in the process of slow rise, so that its density drops and floats to the surface, from removing SS and COD, and demulsifying the residual oil stains in the water.
(3) Biochemical treatment process
A2/O (Anaerobic-anaerobic, Anoxic-anoxic and Oxic-aerobic) processes are commonly used for phosphorus and nitrogen removal in municipal wastewater treatment plants, and have mature operation experience. Based on the traditional A/O phosphorus removal process, an anaerobic zone was added, which has the function of simultaneous nitrogen and phosphorus removal. Membrane separation device replaces the secondary clarifier in conventional bioreactor, thus achieving high efficiency of solid-liquid separation. AAO process has the following
In this process, BOD5, SS and various forms of nitrogen and phosphorus will be removed one by one. In the activated sludge of A2/O biological denitrification and phosphorus removal system, the microflora is mainly composed of nitrifying bacteria, denitrifying bacteria and phosphorus accumulating bacteria. In the aerobic stage, nitrifying bacteria ammoniate the inflow of ammonia nitrogen and organic nitrogen into nitrate through biological nitrification; in the anoxic stage, denitrifying bacteria convert the nitrate brought back by internal reflux into nitrogen into atmosphere through biological denitrification, so as to achieve the purpose of denitrification; in the anaerobic stage, phosphorus-accumulating bacteria release phosphorus and absorb low-grade fatty acids. The easily degradable organic matter; in the aerobic section, the phosphorus accumulating bacteria absorb excessive phosphorus and remove phosphorus through the discharge of excess sludge.
Discharge Standards for Pollutants from Urban Sewage Treatment Plants (GB 18918-2002)
1. The aim of simultaneous removal of BOD5, nitrogen and phosphorus can be achieved by alternating anaerobic, anoxic and aerobic operation.
2. This kind of filamentous bacteria is not easy to grow and reproduce, and there is basically no problem of sludge bulking.
3. The total hydraulic retention time is less than that of other similar processes.
4. No additional carbon source is needed. Anaerobic and anoxic sections only need to be stirred at medium and low speed, and the operation cost is low.