There is a sewage lifting pump house, including five submersible sewage pumps, q = 1375m3 /hr, H= 15m, N=80KW, of which four are standby. The water regulation in the pump house is one submersible sewage pump for 5 minutes, and the number of pumps is automatically controlled according to the liquid level in the pump house. Another electric hoist is provided with a lifting weight of 3T and a lifting height of 12m. During maintenance, lift the water pump to the maintenance platform. Fine grid chamber and aerated grit chamber are jointly built. There are three fine-grid channels with a width of 1.3m in the fine-grid room. Three rotating solid-liquid separators are respectively set, with a grid spacing of 5mm and an inclination angle of 60. The fine grid is cleaned regularly by the liquid level switch and time relay in front of the grid, and the fine grid intercepts the grid slag and is discharged into the slag hopper by the screw conveyor through the grid discharge funnel. Sewage enters the aerated grit chamber in the water distribution area after passing through the fine grid.
The aerated grit chamber consists of two compartments, each with a width of 3.8m, an effective water depth of 3.05m, a total water passing area of 17.72 m2, a length of 2 1.7m, a horizontal flow rate of 0.08m/s, a sewage retention time of 4.5min and a scum area of 63m2. Grease and scum are scraped to two scum chambers at the water inlet end of the pool by the skimming scraper on the sand suction machine, and then sent to the slag bucket outside the pool by two screw conveyors respectively. The aerated grit chamber adopts perforated pipe coarse bubble aeration, and the aeration amount is 0.22 cubic meters/cubic meter of sewage. It is equipped with two low-noise roots blowers, one for use and one for standby. The capacity of a single blower is 2 1.5m 3/min, the boosting pressure is 58.8KPa, and the motor power is 37KW. A bridge-type sand suction scraper with a span of 8.0m is equipped with two sand suction pumps, Q=54 m3 /hr, H=2m, N= 1.4KW, N=0.55KW, which are used for scraping slag, lifting rake and driving device. The gravel at the bottom of the pool is pumped by the sand suction pump to the sand collection pool at the edge of the pool, and then flows to the sand-water separator by itself. One set of separator for sand distribution water plant outside the pool, with capacity of 20 ~ 27L/s, n = 0.75 kW. Both the fine grid room and the aerated grit chamber are reinforced concrete structures, and the blower room of the aerated grit chamber is built at the lower part of the fine grid room with a clearance height of 3.5m This project adopts SBR process with intermittent water inflow and low pollutant load, and the front end of the main reaction tank is provided with a high-load anaerobic selection area and a contact mixing area. Sewage influent and internal reflux mixed liquid are mixed in anaerobic zone. Under anaerobic conditions, microorganisms release phosphorus accumulating bacteria, while high pollutant load and low dissolved oxygen can inhibit the growth of filamentous bacteria and prevent sludge from expanding during precipitation. After that, the contact mixing zone was set up, which made the SBR reactor not only in an ideal state of plug flow in time series, but also in space. The whole system also has good phosphorus and nitrogen removal function, low sludge output, high oxygen transfer driving force and good precipitation and separation effect.
Sewage enters SBR bio-tank after passing through the water distribution well, and there are 4 groups of bio-tanks, 2 in each group, and each bio-tank runs periodically. Each cycle includes four stages: aeration, precipitation, decantation and idleness. In the process of aeration and precipitation, water enters, and the process of decanting is the process of effluent, and the excess sludge is removed in the process of idleness.
The typical cycle is about 4 hours, and the running status of two biological pools in each group is as follows:
Table 3- 1 min Water inflow, aeration and sedimentation of biological pond 0 ~ 6061~1~180181~ 240a. Sludge discharge and water aeration, each biological pool is 53. 1m long, 23m wide, with a maximum water depth of 5.7m, a minimum water depth of 3.95m and a pool depth of 6.2m The total effective area is 9568m2 and the maximum effective total volume is 54537m3. The total hydraulic retention time is 8.4 hours, the sludge age is 15 days, the reflux ratio of mixed liquid is 18%, the average sludge load is 0.083kgBOD5/kgMLSS.d, the dissolved oxygen in the aeration tank ranges from 0.5 to 2.0 mg/L, and the bottom of the tank is evenly distributed with φ 90 mm, and L =/kloc-0. Two floating barrel decanters are installed at the water outlet end of each pond, totaling 16, and the water output of each pond is 387 L/s, and each pond outlet is equipped with two submersible sewage pumps, 1 for mixed liquor reflux and 1 for removing excess sludge. The flow rate of single pump is 44l/s, the head of reflux pump is 6m, the motor power is 8. 1kw, the head of residual sludge pump is 12m, and the motor power is12.2kw. Each reaction tank is equipped with inlet control valve (electric eccentric plug valve), air control valve (electric butterfly valve) and outlet control valve (electric butterfly valve).
The operation of the biological pool is controlled by time, and the air volume of the blower is adjusted according to the dissolved oxygen concentration in the pool.
The biological pool adopts one-time water distribution, and the head loss of sewage passing through the inlet control valve is large, so the difference of head loss along the way caused by different pipeline lengths can be ignored, and the water distribution is basically uniform. Sewage is disinfected with liquid chlorine before leaving the factory. The maximum chlorine dosage standard is 8mg/L, and the maximum chlorine dosage is 44 kg/hr; The average chlorine dosage is 4 mg/L, and the average chlorine dosage is 400 kg/day ... The storage capacity of liquid chlorine is 15 days, and the chlorine dosage is controlled by the flow ratio. The chlorination room has a building area of 250m2, including chlorine warehouse, chlorination room and duty room. Two vacuum chlorinators with chlorine dosing capacity of 57kg/hr, 1 standby, an automatic pressure switching device, a chlorine leakage detection and alarm device, 12 chlorine bottles with filling capacity of 1000kg, and two 2T digital platforms. A set of electric gourds.
The plane size of the contact tank is 30.0× 15.0m, the effective water depth is 4.0m at high flow rate, the sewage retention time is 19.6min, and the general retention time of flow rate is 26min. The effluent from the contact pool flows into the Yellow River through the fourth drainage ditch and the main ditch of Yinxin, and continues to contact and disinfect in the drainage ditch.
After the grit chamber and the contact chamber, the inflow and outflow of sewage are detected by electromagnetic flowmeter and open channel ultrasonic flowmeter respectively. The amount of excess sludge is 13.0t/d, and the solid load of the concentration tank is 31kg/㎡ d.
The water content of the remaining sludge in the biological pool is 99.6%, and the water content of the concentrated sludge is 97%. The amount of sludge before concentration is 3250 m3 /d, and after concentration is 433 m3/d ... There are two concentration tanks with the diameter of 16m * *, and each concentration tank has a centrally driven sludge scraper; Each tank is equipped with a sludge lifting pump station and a concentration tank, with the sludge lifting pump Q = 40m3/hr, H = 7m and N = 2.4kW. ..
The concentration tank continuously discharges sludge. In order to cooperate with the intermittent operation of sludge dehydrator, a homogenization tank is set behind the concentration tank. The diameter of homogenization tank is 6.5m, the effective depth around it is 5.4m, and the regulated volume is 1.43 m3, which can store the surplus sludge for 7.3 hours. The homogenizing tank is equipped with a low-speed submersible agitator with a power of 2.8KW. The plane size of the dewatering room is 3 1.0× 16.0m, and the height is 5.30m There are three belt filter presses used alternately. The width of the filter belt is 2.0m, the motor power is 2.2KW, the processing capacity of a single filter is about 9 ~ 12m3 /hr, and it works 16 ~ 12h every day. Before sludge dewatering, polymer flocculant polyacrylamide was added with the dosage of 3 ~ 5kg/kgds and the dosage of flocculant was 52 kg/hr. A set of automatic dosing device with the dosage of 5kg/hr and three dosing pump were set up. There are four sludge dosing pump in the dewatering room, each with Q = 12m3 /hr and H=20m, of which three are used for 1 standby. There is a washing water pressurizing pump station outside the sludge dewatering room, and the washing water comes from the effluent of the biological pool. When the dehydrator works, the washing pump works at the same time. After mechanical dehydration, the water content of sludge is reduced to 76 ~ 80%, and the volume is 65 ~ 54 cubic meters/day. The dehydrated mud cake is sent to the sludge dump by screw conveyor for loading. * * Set up three screw conveyors with conveying length of 1 1m and installation angle of 240.