Overview of Domestic Sewage Treatment Equipment

The concentration of rural farmers' residential areas is lower than that of cities, and the intensity of domestic sewage production is lower than that of cities. The financial resources of villages and towns are weak, and farmers have low incomes. Therefore, it is encouraged to adopt diversified domestic sewage treatment technologies that are economical, simple, effective, and combined with local agricultural production as much as possible to achieve harmless treatment and resource utilization of sewage.

The dynamic buried integrated treatment technology can be divided into biological contact oxidation method, SBR, A/O and A2/O according to the process. The principle of commonly used A/O treatment technology is that microorganisms in anoxic tanks reduce nitrate nitrogen and nitrite nitrogen in wastewater to gaseous nitrogen and release it, while decomposing difficult to degrade large molecule organic matter into small molecule easily degradable substances, which have the functions of denitrification, hydrolysis, and degradation of some organic matter; In the aerobic tank, most of the organic matter is treated by microorganisms and enters the secondary sedimentation tank for sludge water separation. After disinfection, it is discharged.

The A/O process degrades organic matter while denitrification, greatly reducing oxygen demand, and is an energy-saving biological treatment technology. In order to maintain a high nitrification rate, the reaction residence time is longer than that of ordinary activated sludge process, the sludge settling performance is good, the sludge growth rate is low, the remaining sludge amount is small, and the settling performance is good.

Working principle of domestic sewage treatment equipment

The removal of organic pollutants and ammonia nitrogen by domestic sewage treatment equipment mainly relies on the AO biological treatment process in the equipment. The working principle is at level A. Due to the high concentration of organic matter in sewage, microorganisms are in a state of hypoxia. At this time, microorganisms are facultative microorganisms. Therefore, level A tanks not only have a certain function of removing organic matter, reducing the organic load on subsequent aerobic tanks, and reducing the concentration of organic matter, but there is still a certain amount of organic matter and high NH3-N present. In order to further oxidize and decompose organic matter, and ensure smooth nitrification under carbonization, an aerobic biological contact oxidation tank with low organic load is set up at level O. There are mainly aerobic microorganisms and autotrophic bacteria (nitrifying bacteria) in the O-level pool. Aerobic microorganisms decompose organic matter into CO2 and H2O; Autotrophic bacteria (nitrifying bacteria) use inorganic carbon produced by the decomposition of organic matter or CO2 in the air as a nutrient source to convert NH3-N in wastewater into NO-2-N and NO-3-N. The effluent from the O-grade tank is returned to the A-level tank, providing an electron acceptor for the A-level tank, and ultimately eliminating nitrogen pollution through denitrification.

Characteristics of Domestic Sewage Treatment Equipment

1. Integrated treatment of BOD5, COD, NH3-N, fecal Escherichia coli, and pH

2. The entire equipment can be buried underground and does not occupy surface area;

3. The generated voice is low, the odor is minimal, and the impact on the surrounding environment is minimal

4. High degree of purification and low sludge production in the entire system;

5. High degree of automation, convenient management, no need for dedicated personnel to manage;

6. Stable technology and easy maintenance

7. Low energy consumption, saving operating costs

Process of domestic sewage treatment equipment

1. Primary sedimentation tank: The equipment's primary sedimentation tank is a vertical flow sedimentation tank, and the upward flow velocity of sewage in the deep sedimentation tank is 0.6-0.7 mm/s. The settled sludge is carried to the sludge tank by air.

2. Contact oxidation tank: After initial sedimentation, the water flows automatically to the contact tank for biochemical treatment. The contact tank is divided into three stages with a total residence time of more than 1 hour. The contact oxidation time of the reinforced equipment can reach 6 hours, and the filler is a novel filler that is easy to film and does not clog. The specific surface area of the filler is 160m2/m3, and the gas water ratio of the contact tank is around 12:1.

3. Secondary sedimentation tank: Biochemical wastewater flows into the secondary sedimentation tank, which consists of two vertical flow sedimentation tanks operating in parallel. The upward flow velocity is 0.3-0.4 millimeters per second. The sludge is discharged by air lifting to the sludge tank.

4. Disinfection pool and disinfection pool device; The disinfection pool is designed according to the standard of "TJ14-74" for 30 minutes. If it is hospital sewage, the retention time of the disinfection pool can be increased to 1-1.5 hours, and solid chlorine tablets can be used for contact dissolution disinfection. The disinfection device can continuously change the dosage according to the size of the water output, achieving the goal of adding more water and more medicine, and adding less water and less medicine. Other disinfection devices can be prepared separately.

5. Sludge tank: All sludge from the primary and secondary sedimentation tanks is transported by air to the WSZ-A sludge tank for aerobic digestion. The clear liquid from the sludge tank flows back to the heat exchange oxidation tank for further treatment. After digestion, there is very little residual sludge, usually cleaned once every 1-2 years. The cleaning method is to use a suction truck to extend from the inspection hole of the sludge tank into the bottom of the sludge and carry out suction and transportation.

6. Fan room and fan: The fan of equipment SLZ-A/O is located above the disinfection area, and the inlet adopts double-layer sound insulation. The inlet has a muffler and fan filter, so there is no noise during operation. The fan adopts two rotary fans, which can automatically alternate operation. The operating life of a single wind turbine is about 30000 hours.

7. Regulation: Chemical wastewater has the characteristic of variable water quality and quantity, which can vary greatly within a day or a shift, especially when materials flow into the wastewater due to abnormal operation or equipment or pipeline leaks. The changes in wastewater quality and quantity are detrimental to the normal functioning of drainage facilities and wastewater treatment equipment, especially biological treatment equipment, and may even cause damage. In this case, a common measure is to set up a regulating tank before the wastewater treatment system to regulate the water volume (averaging tank) and the water quality (homogenization tank), in order to ensure the normal progress of wastewater treatment. In addition, the averaging tank can also serve as a temporary storage for accident drainage.

8. Centrifugal separation: Centrifugal separation is used to treat wastewater by separating suspended particles in the wastewater using the centrifugal force generated by rapid rotation. When wastewater containing suspended particles undergoes rapid rotational motion, the larger solid particles are thrown to the periphery, while the smaller ones remain in the inner ring, thereby separating the wastewater from the suspended particles and purifying the wastewater.

Scope of application of domestic sewage treatment equipment

Suitable for domestic sewage treatment in residential areas, restaurants, hotels, nursing homes, schools, mines, factories, and similar industrial sewage treatment.