The design of this equipment is mainly for the treatment of domestic sewage and similar industrial organic sewage. Its main treatment method is the contact oxidation method, which is currently a mature biochemical treatment technology. The water quality parameters are calculated according to the general domestic sewage water quality design, with inlet BOD5 calculated at 200mg/l and outlet BOD5 calculated at 20mg/l. The process overview consists of six parts: primary sedimentation tank, contact oxidation tank, secondary sedimentation tank, disinfection tank and disinfection device, sludge tank, fan room and fan. The following is a detailed discussion:
(1) Primary sedimentation tank: The primary sedimentation tank of this equipment is a rigid flow sedimentation tank. The upward flow rate of sewage in the sedimentation tank is 0.6-0.7 millimeters per second, and the settled sludge is lifted to the sludge tank by air. (2) Contact oxidation tank: The water after initial sedimentation flows automatically to the contact tank for biochemical treatment. The contact tank is divided into three parts, with a total residence time of more than 4 hours. The enhanced equipment can achieve a contact oxidation time of up to 6 hours. The packing material is a novel trapezoidal packing material, which is easy to film and does not block. The specific surface area of the packing material is 160m2/m3, and the gas water ratio of the contact tank is about<12:1. (3) Secondary sedimentation tank: The biochemical wastewater flows into the secondary sedimentation tank, which is a parallel operation of two vertical flow sedimentation tanks with an upward flow rate of 0.3-0.4 mm/s. The sludge is discharged by air to the sludge tank. (4) Disinfection pool and disinfection device: The disinfection pool is designed to last for 30 minutes according to the "TJ14-74" standard. If it is hospital sewage, the disinfection pool can increase the residence time to 1-1.5 hours. The disinfection method adopts the contact dissolution of solid chlorine tablets, and the disinfection device can continuously change the dosage according to the size of the water and drought, achieving the goal of adding more water and more medicine, and adding less water and less medicine. Other disinfection devices can be prepared separately if needed. (Note: If used for industrial wastewater, disinfection tanks and disinfection devices can be omitted.) (5) Sludge tank: All sludge from the primary and secondary sedimentation tanks is carried by air to the WSZ-A sludge tank for aerobic digestion. The supernatant of the sludge tank is added to the contact oxidation tank for further treatment. After digestion, there is very little remaining sludge, which is usually cleaned once every 1-2 years. The cleaning method can be to use a suction truck to reach into the bottom of the sludge tank through the inspection hole for suction and then transport it outside. (6) Fan room and fan: The fan room of equipment WSZ-A is located above the disinfection pool. The inlet of the fan room adopts double-layer sound insulation and the air inlet has a muffler, so there is no sound barrier during operation. The fan adopts two L-shaped Roots blowers, which can automatically alternate operation. The operating life of a single fan is about 30000 hours. The equipment structure is difficult to maintain and upkeep due to its buried installation. Therefore, in the design of the equipment, its maintenance free nature was considered, and the entire equipment structure is reasonable and reliable. At the same time, it is also considered that even if some faults occur, the equipment can be accessed through its various inspection holes. All facilities of the equipment are located in several boxes, which are made of A3 steel plates with a thickness of 8mm. The boxes are connected by seamless steel pipes, and both the inside and outside of the equipment are coated with chlorosulfonated polyethylene anti-corrosion coating promoted by the Ministry of Chemical Industry. The equipment is generally coated with 8 layers of this coating: 2 layers of primer and 6 layers of topcoat.
The equipment is suitable for the treatment of domestic organic wastewater in residential areas, hotels, nursing homes, schools, mines, factories, and similar industrial organic wastewater treatment.
