Sewage treatment process flow
The whole biochemical process is adopted, and the design is air flotation+anaerobic hydrolysis+biological fluidized bed+filtration process. Acidification and hydrolysis are used in anoxic part, and biological fluidized bed process is used in aerobic part. Mature and reliable process, simple operation and low investment and maintenance cost.
Sludge treatment: excess sludge from grid well, anoxic tank and secondary sedimentation tank is discharged into sludge concentration tank for concentration and internal digestion before being transported outside.
The supernatant of the sludge concentration tank is refluxed to the regulating tank.
Description of sewage treatment process flow
The sewage is collected in the grid well, and the grid in the grid well is used to intercept the larger floating objects and suspended substances in the water, and then it enters the regulating tank (pre-aeration is used in the regulating tank). After the water quality is homogenized, it is lifted to the aerated air flotation equipment by the water pump, and the oil and part of suspended substances in the sewage are removed by air flotation. Then it flows into the A-level acidification tank, where the sewage is hydrolyzed and acidified, and the macromolecular organic matter which is difficult to biodegrade is decomposed into the biodegradable micromolecule organic matter. The effluent from Grade A acidification tank flows into the integrated biological fluidized bed reactor by itself. Because the sewage is hydrolyzed and acidified in front, the biodegradability of the sewage is greatly improved, and a large number of microorganisms are used to completely remove the organic matter in the sewage. At the same time, aerobic microorganisms are used to carry out nitrification reaction, and ammonia nitrogen (NH3-N) in sewage is converted into nitrite (NO2-) and nitrate (NO3-). The effluent from the integrated biological fluidized bed reactor enters the discharge tank through the multi-media gradient density filter. The backwash sludge of the multi-media gradient density filter is lifted by the sludge pump to the sludge concentration tank for internal digestion, and then transported out regularly. The supernatant of the sludge concentration tank is refluxed to the regulating tank.
Process product description
Entrained air flotation is a new type of mechanical crushing air flotation technology, which is a system specially designed to remove oil, colloid and solid suspended matter from industrial and urban domestic sewage, and is mainly used for sewage pretreatment. At present, most domestic air flotation processes adopt dissolved air flotation (DAF). When treating restaurant wastewater with DAF, the process of air dissolving in water is often limited by various factors. The air compressor and circulating water pump used in DAF system not only consume a lot of electric energy, but also cause difficulties in equipment management and maintenance because the releaser is easily blocked.
(THK system introduction: THK system is a new technology invented by American HydroCal Environmental Protection Company 1985, which can effectively solve the problems existing in dissolved air flotation (DAF). THK system only introduces air into the system in the form of tiny bubbles (insoluble in water) because of its unique technology. There is no air compressor, dissolved air tank and circulating water pump, and air naturally enters the air flotation system through the suction pipe without releaser, so THK system has all-round advantages.
(1) is simple to operate, has no complicated mechanical equipment, has a high degree of automation, and basically does not need manual participation. Different from DAF dissolved air flotation system, it includes many necessary equipment, such as pressure vessel, air compressor and circulating pump.
(2) The operation flexibility is large, and it is suitable for a wide range of suspended solids concentration. Because the number of bubbles produced by THK system is four times that of DAF, THK system has no special requirements for the concentration of suspended solids in wastewater, and its application range is wide.
(3) Low operating cost. The energy consumption of THK system is low, which is only1/8 ~110 of DAF, and it can save 40~90% of operating expenses.
(4) The support has good integrity, small floor space and random installation position, and can be installed on the ground, underground or high places.
(5) No noise.
Integrated biological fluidized bed reactor
Biological fluidized bed technology is a new and efficient sewage treatment technology that rose in the 1970s. It is an important application of fluidized bed technology in the field of sewage treatment after it is widely used in the chemical industry.
Biological fluidized bed reactor organically combines the advantages of ordinary activated sludge process and biofilm process, and improves the treatment efficiency of sewage treatment system by introducing fluidization technology. In the biological fluidized bed reaction system, the carrier is in a fluidized state, which makes solid (biofilm), liquid (wastewater) and gas (air) fully contact, transfer and mix, the particles collide violently, the surface of biofilm is constantly updated, and microorganisms are always growing vigorously. This technology can maintain a high biomass concentration in the bed, with high mass transfer efficiency, fast substrate degradation of wastewater, short hydraulic retention time, high operating load 10 ~ 20 times higher than that of ordinary activated sludge process, strong impact load resistance, small reactor floor space and low capital investment and cost.
(1) The small particle size carrier of the biological fluidized bed provides a huge surface area for microbial growth, which makes the biological concentration of the reactor very high, reaching 4-5g/l, thus greatly increasing the volumetric load of the reactor, reaching 3-6kg/m3.d, even reaching10kg/m3.d;
(2) The mass transfer conditions in the reactor are good and the substrate transfer rate is high, so the biochemical reaction rate is fast, especially for the reaction system with good biodegradability and high organic concentration, the mixed mass transfer advantage of the biological fluidized bed is more obvious, and its biodegradation rate is fast;
(3) The high biomass and good mass transfer conditions make the biological fluidized bed reduce the volume of the reaction tank while maintaining its treatment efficiency, saving investment and occupying area;
(4) Compared with the activated sludge process, the biological fluidized bed has stronger impact load resistance, and there is no sludge bulking problem.
Integrated biological fluidized bed reactor is the latest product gradually developed on the basis of "three-phase biological fluidized bed". By optimizing the reactor structure, the technical integration is improved, which has the characteristics of high treatment efficiency, low energy consumption, small floor space and simple operation and maintenance, and can be widely used in the treatment of high concentration and good biodegradability sewage such as catering wastewater, food and brewing.
The integrated biological fluidized bed reactor has the following advantages:
(1), the volumetric load of the reactor can reach 7 ~13 kg COD/m3 d under the condition of typical urban sewage influent quality, and the COD removal rate is 80% ~ 90% when the influent cod is 400 ~ 1000 mg/L;
(2) It occupies 40% ~ 50% of the traditional sewage treatment process, greatly reducing the intensity of operation and management.
(3) The integrated biological fluidized bed reactor not only maintains the advantages of the traditional three-phase fluidized bed, such as good mixing performance, fast mass transfer rate, large biomass and high organic load, but also solves the problems of the traditional three-phase fluidized bed, such as excessive growth of biofilm thickness, uneven mixing and mass transfer, and difficulty in membrane removal.
(4) Small carrier loss: Because the reactor adopts horizontal circulation and central sedimentation area for solid-liquid separation, the carrier is hardly lost in the whole reaction process by using the difference of sedimentation performance between the carrier and the biofilm.
(5) Good fluidization performance of carrier: In order to ensure full fluidization of carrier, the traditional three-phase biological fluidized bed must adopt large height-diameter ratio without reflux. The integrated biological fluidized bed reactor adopts the form of water circulation, and realizes good carrier fluidization through aeration and push flow of jet aerator. At the same time, because there is no upflow zone and downflow zone, there is no carrier stratification in the traditional three-phase fluidized bed, and the carrier fluidization uniformity is good, which is very beneficial to the good growth of biofilm.
(6) High oxygen transfer efficiency: In the traditional three-phase biological fluidized bed, all gases escape from the top of the reactor, while in the BFBR biological aerobic fluidized bed, the liquid circulates in the reactor, which prolongs the gas-liquid contact time, so the oxygenation efficiency is high.
In the case process, the effective volume of the integrated biological fluidized bed reactor is1100m3, the hydraulic retention time is about 2h, the influent CODcr concentration is designed to be 700mg/L, the effluent CODcr concentration is 100mg/L, and the CODcr removal rate is above 80%.
Removal effect of ammonia nitrogen: the integrated biological fluidized bed reactor adopts a reactor with anoxic-aerobic denitrification function. When the influent is typical domestic sewage, the NH3-N concentration of the effluent can reach the first-class discharge standard of GB 8978- 1996.
Removal effect of SS: The effluent containing biochemical sludge in the reactor has high removal efficiency through the multi-media gradient density filter, and the effluent SS can be controlled below10 mg/L. ..
TP removal effect: The removal of TP by the reactor is the result of microbial metabolism and sludge discharge. The average removal rate of TP is 50%, but a multi-media gradient density filter is added at the end of the reactor. If iron salt and aluminum salt are added for flocculation and chemical phosphorus removal, the average concentration of TP in effluent is 0.88mg/L, and the total removal rate is 85%.
Multimedia gradient density filter
In the water reuse system of sewage treatment, filtration equipment is the key. Through physical filtration, solid particles in water are removed and suspended solids in wastewater are reduced. At present, the water treatment and filtration system of reclaimed water reuse in China mostly adopts simple equipment such as sand filtration, and sand pool is the main filtration equipment. Sand pool is a typical particle filtration method, which uses sand and gravel as filtration medium, and realizes filtration through the adsorption of particle filter material and the interception of solid suspended matter in water by pores between sand grains. Small specific surface area, small sewage interception, slow filtration speed and low filtration accuracy are not suitable for rapid filtration of suspended solids in reclaimed water reuse system.
Multi-media gradient density filter adopts asymmetric fiber bundle materials with different particle sizes and densities as filter materials, which has the advantages of both particle filter materials and fiber filter materials. Through the special structure, the pores of the filter bed quickly form a gradient density with large top and small bottom, which makes the filter have high filtration speed, large pollutant retention and easy backwashing, and is especially suitable for filtering solid suspended matter in the reclaimed water reuse system.
Secondary pollution prevention and control
1, odor control
1. All pools in the sewage station are sealed to prevent odor from escaping;
B, every pool that may produce odor should have ventilation and aerobic digestion ducts to reduce odor.
2. Noise control
A, the system facilities are designed in the corner of the factory building, which has little impact on the outside world;
B, choose a low-noise fan, the machine noise is less than or equal to ≤80dB, the inlet and outlet of the fan adopt a muffler, the base adopts an isolation pad, and the inlet and outlet of the air duct adopt flexible rubber soft joints and other vibration and noise reduction measures;
C. Ensure the environmental noise: ≤60dB during the day and ≤ 50dB at night.
3. Sludge treatment
A, part of sludge generated in the sludge treatment process is discharged into a sludge pool for gravity concentration and aerobic digestion and decomposition, so as to reduce the sludge volume and improve the stability of the sludge;
B, the excess sludge in the sludge pool is regularly pumped out by the cleaning management department, which effectively solves the sludge outlet and avoids secondary pollution.
Electrical control and production management
1. The automatic control system within the scope of this project is configured for the sewage treatment process. Automatic control specialty mainly involves the interlocking of water pump and liquid level, alarm, alternating action of fan and normal operation of solenoid valve in sewage treatment system.
2, control level, automatic and manual combination.
For reference only.