Process flow of domestic sewage treatment——Principle and process

The basic principle of biological contact oxidation method for purifying wastewater is the same as that of general biofilm method, which uses biofilm to adsorb organic matter in wastewater. Under aerobic conditions, organic matter is oxidized and decomposed by microorganisms, and the wastewater is purified.

The biofilm in the biological contact oxidation tank is composed of microbial flocs, filamentous bacteria, fungi, protozoa, and metazoa. In the activated sludge process, filamentous bacteria are often a factor that affects the normal biological purification effect; In the biological contact oxidation tank, filamentous bacteria form a three-dimensional structure between the gaps of the packing material, greatly increasing the contact surface between the biological phase and the wastewater. At the same time, filamentous bacteria have strong oxidation ability for most organic matter and are highly adaptable to changes in water quality load, making them a powerful factor in improving purification capacity.

Biological contact oxidation methodBODThe load is related to the substrate concentration of the wastewater, and for lowBODConcentration（50～300The filling material for each cubic meter of wastewater per day (milligrams per liter) is used2～5kg(BOD

The advantages of biological contact oxidation method are: high purification efficiency; Short processing time required; Strong adaptability to changes in organic load of incoming water; No need for sludge reflux, and there is no problem of sludge expansion; Easy operation and management.

Process flow of domestic sewage treatment——design basis

1Wastewater discharge is carried out to ensure that the effluent quality meets the required standardsGB8978-1996The first level discharge standard of the Comprehensive Wastewater Discharge Standard;

2The emission of odorous gases shall comply with the "Emission Standards for Odor Pollutants"（GB14554-93）Secondary standards in China;

3Noise emissions shall comply with the "Industrial Enterprise Boundary Noise Standards"（GB12348-90）In the middleIIClass standard;

4The discharge of waste residue shall comply with the "Trial Standards for Industrial 'Three Wastes' Discharge"（GBJ-73）The corresponding regulations in;

5Sludge shall comply with the "Control Standards for Pollutants in Agricultural Sludge"（GB4284-84）The relevant regulations in.

Process flow of domestic sewage treatment——overview

The initial design of integrated sewage treatment equipment is mainly aimed at the treatment of domestic sewage and similar industrial organic sewage. The main treatment method is to use the currently mature biochemical treatment technology - contact oxidation method. The water quality parameters are based on the general quality of domestic water, and the inflow isBOD 20Omg/lOut of the waterBOD 20mg/lIndicator design. The contact oxidation process adopts a push flow biological contact oxidation tank, and its sewage treatment equipment is more effective than a fully mixed or two-stage series fully mixed biological contact oxidation tank. Compared to traditional activated sludge tanks, it has a smaller volume, stronger adaptability to water quality, good shock load resistance, stable effluent quality, and will not cause sludge expansion. A new type of elastic three-dimensional packing material is used in the pool, with a large specific surface area and easy biofilm formation and detachment by microorganisms. Under the same organic load conditions, it has a high removal rate of organic matter and can improve the solubility of oxygen in the air in water. With the continuous development of technology, the application fields of integrated sewage treatment equipment are also increasing

Process flow of domestic sewage treatment——Process flow of integrated buried domestic sewage treatment equipment
1.Grille pool: responsible for intercepting floating miscellaneous goods in sewage to ensure the normal operation of subsequent treatment equipment.
2.Regulating tank: used to regulate water quality and quantity. Generally, the capacity of the regulating tank is the processing capacity per hour6-10Use a lift pump to lift it to the anoxic tank.
3.Hypoxia tank: The anoxic tank is designed for denitrification treatment. The sewage separated by a grid is pumped into the anoxic tank by a sewage lift pump in the regulating tank and mixed with the reflux nitrification liquid in the tank. The anoxic tank is placedNZP-IIType fillers serve as carriers for denitrifying bacteria and are effective against nitrogen; Phosphorus; The removal effect of sulfides is good, with a residence time of2Combined with the sludge tank in the previous process to form the hourA／OThe processing technology is used to achieve the purpose of dephosphorization and denitrification. 、

4.Biological contact oxidation tank: divided into two stages, total biochemical time6Hour, adopted by the previous levelNZP-IType filling material, which has excellent water flow characteristics. The second stage uses flow carrier filling material (Japanese technology), which is more conducive to microbial growth and load treatment than surface building blocks30kgBOD／m3?dIt is a general soft filler7More than twice the size, the biochemical tank adopts a central corridor micro hole explosion gas, and the sewage continuously circulates in the biochemical tank, fully contacting the organisms on the packing material to achieve rapid degradation of organic matter.
5.Secondary sedimentation tank: Biochemical wastewater enters the secondary sedimentation tank, and the surface load of the secondary sedimentation tank is designed0.9-1.2m3／m2?hThe secondary sedimentation tank is a lifting adjustable liquid level, tooth shaped collection tank, with uniform water collection and good water discharge effect. The sludge in the secondary sedimentation tank is lifted to the sludge tank.
6.Disinfection pool: According to national standards:TJ14-74The retention time of the production and disinfection pool is30In minutes, the disinfectant used is solid chlorine pills or bleach powder, or aerospace sterilization stone. (Only)BZHC-CThe equipment has a disinfection tank
7.Sludge tank: The pollutants intercepted by the grid and the sludge from the secondary sedimentation tank enter the sludge tank, which is equipped with a sludge digestion system. The clear liquid on the sludge tank flows back to the regulating tank.
8.The fan and distribution cabinet are both located in the equipment room. Generally, there are two fans running alternately in the equipment room. When one fan fails, the other can start the equipment on its own and continue to operate; When the sewage is cut off, the fan can automatically stop running to protect the normal growth of organisms.