The purpose of treatment process selection is based on the amount of sewage, sewage water quality and environmental capacity, in consideration of the economic conditions and management level of the premise, the selection of safe, reliable, advanced technology, energy saving, low operating costs, investment, occupies an area of less, easy to operate and manage the mature process. According to the water quality, water quantity and treatment requirements of this project, in order to realize the purpose of obtaining the best effluent effect with the lowest construction cost and operation cost, we recommend adopting the internationally advanced Bailock sewage treatment process which has good effect on sewage treatment. Bailek process originated in Germany, it is in the conventional activated sludge process and aeration oxidation ponds developed on the basis of a new process, which uses a low sludge load, high sludge age design, through the non-fixed floating mobile aeration system for oxygen supply, due to the mobile aeration system of the oxygenation characteristics, in the biochemical tank can produce multiple anoxic and aerobic areas, so the process has a good nitrogen removal and phosphorus removal, the main features of this new process are as follows The main features of this new process are as follows: 1. Floating aeration delayed activated sludge process, long sludge sludge age, full oxidation of organic matter, to meet the most stringent sewage treatment discharge requirements, reliable effluent, shock load resistance; multi-stage A/O aeration process, nitrogen removal and phosphorus removal is very high efficiency. Compared with the traditional oxidation ditch, A/A/O and SBR process, the project investment is low, covers an area of less, and the operation and management is simple. 2, floating microporous aeration system produces bubbles in the water residence time is 3 times that of the traditional fixed way, thus the oxygen transfer efficiency is high, and the power consumption is low. At the same time floating aeration system is simple to operate, no fixed installation, easy maintenance (no need to empty the pool), can effectively reduce labor costs. 3, set up in front of the aeration pool biological selection pool, can use microbial selection growth law, inhibit the growth of filamentous bacterium, while providing the anaerobic environment for the release of phosphorus by the bacteria polyphosphorus, to strengthen the effect of biochemical phosphorus removal. 4, the use of dissolved oxygen on-line control system, economically regulate blower Output air volume, can greatly save the aeration power costs. 5, pool body civil construction flexibility, combined arrangement, covers an area of small, compact, according to local conditions, can be used in a variety of slopes such as concrete, gravel, soil pools, seepage panels, various types of civil construction construction, civil construction investment is extremely economical. Sewage treatment project is a technically complex, large investment, strong policy infrastructure projects. Although there is no obvious economic benefits, but the environmental benefits and long-term social benefits are immeasurable. Based on this feature, even though the developed countries for the development and construction of sewage treatment engineering projects, are very important. But also must consider how to reduce the cost of infrastructure investment and operation, research to simplify the sewage treatment process, less land occupation, power saving, easy to manage and improve the treatment effect of new breakthroughs. Bailock process is to do this, it is with the traditional secondary biochemical treatment and the current oxidation ditch, SBR process comparison, the process is simple, strong applicability, excellent effluent water quality. There are obvious advantages from the analysis of construction investment, floor space, operation cost, etc. 2.2 Process Program Design 2.2.1 Sewage Treatment Process Flow Sewage Coarse grating pumping station Fine grating Process Desanding Metering Drainage Pelletizing Pool Contact Pool Outlet Discharge Sewage is introduced from the south side of the plant into the plant, through the coarse grating to the intake pump room, lifted by the pump and then entered into the fine grating, Process Desanding and Pelletizing Pool for physical and biochemical treatment, and the final effluent is treated in a physical and biochemical manner, and the final effluent is treated in a physical and biochemical manner. And biochemical treatment, the final effluent by the beach river discharge or reuse. 1. coarse grating main function: retain sewage in the larger floating and suspended matter, to prevent the clogging of the pumping unit, reduce the subsequent treatment of the processing load of the building, and make it run normally structure type: underground steel mixed straight wall parallel channel design parameters: design flow Qmax = 3300m3 / h flow rate V = 0.8m/s channel width B = 1400mm channel number 2 channels. 1400mm channel number 2 main equipment: rotary grating machine and supporting slag conveyor system equipment type: high chain plane grating, conveying system selection of shaftless screw conveyor design parameters: grating e = 20mm grating width B = 1200 mm over the grating flow rate v = 0.9m/s over the grating loss of h = 200mm motor power N = 1.5KW control: according to the grating before and after the liquid level difference control Clearing and conveying action equipment sets: two grating machine, each other as a backup, with a set of slag conveyor. 2. lifting pump room main function: lifting sewage, to meet the hydraulic requirements of the subsequent treatment facilities structure type: underground steel mixed rectangular submersible pumping station design parameters: the design flow rate of Qmax = 3300m3 / h catchment basin volume V = 400m3 number of pools: 1 main equipment: submersible pumps equipment type: anti-clogging With automatic coupling system equipment parameters: flow Q=700m3/h head H=11m power N=55KW control mode: according to the level of the catchment basin control operation equipment sets: 6 sets (1 set of standby) pumping station structure form of underground, the pumping station of the plane dimensions of 8.3 × 11.8m, the total height of 5.8m.3. 3.fine grating main function: to further remove the sewage of the fine suspended matter, fine fiber, reduce the biological treatment load Fine fiber, reduce the biological treatment load structure type: elevated steel mixed straight wall parallel channel design parameters: design flow Qmax = 3300m3 / h over the grating flow rate V = 1.0m / S channel width B = 1240mm channel number: two main equipment: grating machine and supporting slag conveying system equipment type: rotary fine grating, both conveying, dewatering design parameters: over the grating flow Qmax = 3300m3 / h, the pump room plane size 8.3 × 11.8m, height 5.8m. = 3300m3/h grating b = 6mm grating loss Δh = 300mm grating width B = 1200mm motor power N = 2.2KW control mode: according to the grating before and after the level difference between the control of the clearing and conveying action equipment sets: two fine grating, one with a backup 4. process of desanding traditional desanding process occupies a large area, high investment, and has a negative impact on the biological phosphorus removal. Bio-phosphorus removal is negatively affected. Bio-phosphorus removal process adopts the international popular rotary fine grating to remove sand and other impurities larger than 1mm in the sewage at one time, which has the advantages of simple process, convenient operation and low operation cost. At the same time, the suspended aeration method of Bailac makes up for the influence of fine sand sedimentation. Main equipment: rotating fine grating and screw press equipment type: NOVA fine grating, both conveying, pressing function design parameters: over the grating flow Qmax = 3300m3 / h drum grating diameter d = 900mm drum grating length L = 2500mm grating width b = 1mm equipment sets: rotating fine grating three, two with a spare 5. measuring well in order to improve the efficiency of the sewage treatment plant and the operation management level, the accumulation of technical information. In order to improve the working efficiency of sewage treatment plant and operation and management level, accumulate technical information to summarize the operation experience, and correctly grasp the amount of treated sewage and power consumption, reflecting the operating costs, set up after the fine grating measuring well, the design selection of electromagnetic flowmeter, the information will be input into the computer, you can always understand, record the amount of water treated in the biochemical reaction pool. 6. Bailake pool Bailake pool according to the design of 66,000m3/d, according to the 80,000m3/d calibration. This design adopts 2 parallel processes. This design adopts 2 parallel process lines. (1) biological selection pool main function: water quality and water quality adjustment, while mixing, anaerobic treatment effect, can inhibit the growth of filamentous bacteria to prevent sludge expansion. At the same time has the role of hydrolysis acidification, both biological phosphorus removal and decolorization, to create conditions for water reuse. Structure type: reinforced concrete design parameters: hydraulic retention time HRT = 3.8hr pool depth: H = 5.5m total volume: V = 3300m3 number: 1 main equipment: 2 sets of submersible mixer equipment type: high-speed mixing submersible mixing device equipment parameters: speed: n = 960rpm power: N = 9KW control: run by the programmable control system control or manual control Equipment sets: 2 sets (2) biochemical reactor main function: in aerobic environment, using microorganisms to degrade BOD and COD, and can effectively remove nitrogen and phosphorus through the wave oxidation process structure type: semi-aboveground earth dam rectangular pool body, slurry masonry slope, geotextile seepage control design parameters: volumetric loading Nv = 0.3kgBOD/(m3-d) sludge concentration MLSS = 4500mg/l sludge age: θ = 30 days sludge reflux ratio R = 100% hydraulic retention time HRT = 1.1d pool depth: H = 5m total volume: V = 72600m3 pool number: two joint construction of the main equipment: aeration equipment (floating aeration pipe) equipment parameters: air flow rate Q = 12m3/branch.h oxygen transfer efficiency E = 25% of the effective length of the equipment L = 2000mm Number of sets: two sets, 30 aeration chain (3) integrated clarifier main function: vertical separation of activated sludge in the effluent, sludge in the concentration of the return flow to the biological selection tank structure type: reinforced concrete design parameters: surface load q = 0.75m/h total volume V = 5800m3 main equipment: 1 set of floating sludge extraction system, 1 set of sludge power system type of equipment: submersible sludge pump equipment Number of sets: 2 sets (1 standby) Equipment parameters: flow Q = 300m3/h head: H = 10m Power: N = 18.5KW pool number: 2 (4) stabilization tank: design residence time of 2.4hr, pool total volume of 3050m3, the minimum depth of 5 meters. Main equipment: floating aeration tube 1 air flow: Q = 12m3 / branch. h, oxygen transfer efficiency E = 25%, the effective length of L = 2000mm, the number of pools: two 5. blower room blower room is to ensure that the aeration system is working properly key facilities, calculated to meet the normal operation of the aeration system, set up six sets of automatic adjustment of the air supply of the special blower, 4 with 2 spare. Each centrifugal blower design flow Q = 6800m3 / h, the design of the maximum wind pressure P = 58.8kPa, power N = 160kW. blower is the highest energy consumption of sewage treatment plant equipment, accounting for the plant's energy consumption of 65% or so, to reduce its energy consumption to reduce the cost of sewage treatment plant operation is very critical to the design of the blower from the blower air flow adjustment to reduce energy consumption. Bailac comprehensive pool pool with dissolved oxygen detector, the blower can be based on changes in dissolved oxygen, can automatically adjust the amount of gas supply, this measure can save energy consumption of more than 10%. The inlet air pipe of each blower is equipped with mufflers and elastic joints, and the outlet air pipe of each blower is equipped with check valves, safety valves, gate valves elastic joints, outlet mufflers, pressure switches and so on. The blower and outlet air pipe are equipped with manometer electric valve and flow meter, thermometer and so on. The air inlet pipe is equipped with an air filter, which has a dust removal efficiency of 99% for dusts larger than 1um. The blower room is equipped with lifting facilities to facilitate equipment maintenance, and installed with roof ventilation facilities. Blower room plane size of 21 × 7.2m, 5.5m high.6. Chlorine dioxide generator city sewage after secondary treatment, the water quality has been improved, the bacterial content has been substantially reduced, but its absolute value is still considerable, and there is a possibility of pathogenic bacteria. According to the requirements of the health epidemic prevention, environmental protection and other supervisory departments, sewage treatment plant effluent needs to be disinfected, the project uses chlorine dioxide disinfection. Chlorine dioxide is a broad-spectrum disinfectant, which has a high killing effect on pathogenic microorganisms in water, including viruses, bud pack, heterotrophic bacteria in the distribution network, sulfate, reducing bacteria and fungi. Chlorine dioxide has a strong oxidizing effect, so it has a good decolorization effect disinfection room design operation according to the uninterrupted operation throughout the year to consider. When chlorine dioxide is used for water disinfection, its dosage is 0.1 to 1.3mg/L; for deodorization, its dosage is 0.6 to 1.3mg/L, the project is considered by 1.0mg/L. The amount of chlorine dioxide is designed to be 6.0mg/L, and the amount of chlorine dioxide is considered by 1.0mg/L. Design plus chlorine dioxide according to 66,000m3 / d water intake considerations, plus the amount of chlorine dioxide 66kg / d, designed to use sodium chlorite and hydrochloric acid or sulfuric acid synthesis chlorine dioxide generator two. Single capacity of 3kg / h, supporting all ancillary equipment, and has a double probe alarm, in order to prevent accidents, but also set up two sets of leakage chlorine absorption device 7. contact pool this project using chlorine dioxide disinfection, disinfection contact time of 0.5hr. In order to ensure that the contact time of chlorine dioxide disinfection, contact with the pool of hydraulic retention time according to the 0.5hr design. Plane size of 30m × 17m, 1, the effective water depth of 4.8m, 0.5m high. reinforced concrete structure. 2.2.2 sludge treatment process design sludge sludge storage tank sludge dewatering machine harmless treatment of sludge cake transportation 1. sludge circulation sludge circulation function is to clarify the discharge of the pool of reflux sludge pumped to the biological selection of pools and the residual activated sludge is pumped to the sludge storage tank. The return sludge is lifted by the clarifier sludge pump and then flows into the bio-selective tank. The residual sludge pump adopts 4 sets of submersible sewage pumps, 2 with 2 standby, the main selection of pump parameters are: single flow Q = 45m3/h, head 10m, power 2.2kW.2. Thickening sludge storage tank system sludge yield 1.03kgDS/kgBOD5, the amount of dry sludge discharged into the 7600kg/d, with a water content of 99.2%, the volume of its calculation for the 950m3/d. Sludge thickening The working time of the dewatering machine is 24 hours, and the sludge storage tank is considered as 3 hours, with the dimensions of L×B×H=8.0m×5.0m×3.5m, and the effective water depth is 3 m. The reinforced concrete structure. The sludge storage tank is equipped with a submersible mixer to prevent phosphorus in sludge from anaerobic precipitation, and a shorter storage time is adopted.3. Dewatering machine roomIn the case of biological phosphorus removal technology adopted in ZC City Wastewater Treatment Plant, in order to avoid re-releasing phosphorus in residual sludge with high phosphorus content in anaerobic conditions, the sludge thickening adopts mechanical thickening. The water content of the residual sludge discharged from the Parachem biochemical system is 99.2%. After the sludge is mechanically thickened, its water content is 95% on average, and then after mechanical dewatering, the water content can be reduced to about 75-80%. In this program design we use mechanical thickener and centrifugal dewatering machine. *** choose 3 sets (two with a backup), to work three shifts a day (i.e. 24 hours), the maximum capacity of centrifugal thickeners for 45m3 / h, after concentration of the average solids rate of 5%, supporting the motor power of 1.1kW. centrifugal dewatering machine for the maximum capacity of 25m3 / h, the average solids rate of dewatering ≥ 20%, supporting the motor power of 30kW. centrifugal thickening and dewatering of sludge machines were The sludge centrifugal thickening and dewatering machine is equipped with sludge feeding pump, sludge crusher, flocculant dispensing device, etc. The sludge dewatering room is also equipped with de-cemented cake screw conveyor, etc., in which the sludge feeding pump adopts Borg pump made in Germany. The plane size of the thickening and dewatering room is 36m×15m, and the height is 8.5m.4. Harmless treatment of sludge contains a lot of harmful substances in the urban sewage sludge, and there is secondary pollution in the long-term stockpile, but there are a large number of organic materials in it, and the sludge will be harmless after appropriate treatment. The treated sludge can be directly landfilled, or as nutrient soil, backfill, etc.. Sludge harmless treatment plane size is 48m×22m.2.3 Plane design1.Plane design principlesPlane design principles are: reasonable layout, smooth water flow, compact layout, as little as possible, and clear functional zoning.2.Functional zoningThe treatment plant plane is divided into pre-plant area, production area and reserved area according to function, and there are roads and green belts separating each area. Pre-plant area is arranged in the northwest side of the treatment plant, external to the north of Hongkong Street, and the outside world to facilitate contact; internal and production separated from the green belt, to ensure that the beautiful environment of the pre-plant area. Pre-plant area is arranged with comprehensive building, machine shop, garage and warehouse. The area in front of the plant is large, and the upstairs of the comprehensive building can overlook the whole plant. As the intake pipe is in the northwest of the sewage plant, the tail water of the treatment plant is discharged into (Weichuan River). Therefore, the intake pump house, fine grating and sand sedimentation tank is arranged on the west side, and the biochemical tank is arranged close to it, which makes the process flow smooth. The auxiliary production structures are relatively centralized and arranged in the upwind direction of the plant; the sludge treatment area is arranged in the downwind direction of the dominant wind direction in summer, far away from the front area of the plant, in order to maintain a better environment in the front area of the plant. 3. plant roads for the convenience of transport and equipment installation, maintenance, the road is arranged in a ring shape, and each structure (building) has a road connected to it, and the main road in the plant is 7m wide, and the secondary road is 4m wide, with a turning radius of more than 9-12m, concrete road surface. 4. water supply in the plant area The water supply in the plant area is provided by the municipal water supply company and comes from the surrounding water supply trunk pipeline, with a pressure of more than 4kg/cm2. The water supply in the plant area is mainly used for living, flushing of structures and equipments, landscaping and fire-fighting, etc. The diameter of the water supply trunk pipeline is DN10.5mm. The diameter of water supply trunk pipe is DN200, and the plant is in the form of ring network, which is good for fire fighting and safe water supply.5. Drainage in the plant is rain and sewage diversion system, and the rainwater in the plant is collected by the rainwater outlet of the road and then converged into the plant rainwater pipeline, and discharged into the nearby river by self-flowing; the domestic sewage in the plant, the production sewage, the sewage of the washing pool, the water of the emptying water of the structure, the night of clearing and so on, are collected through the sewage pipeline of the plant and then converged into the water intake pump room, which is processed together with the sewage in the plant.6. 6. Water utilization considerations reserved for the long-term water reuse system site, for the long-term water reuse in large quantities for industry, farmland irrigation, urban landscape and so on laid the foundation.