What are the components of an underground sewage treatment system? You might not know much about it, so let me introduce this knowledge to you.
1. Primary sedimentation tank: The primary sedimentation tank of the equipment is a vertical flow sedimentation tank. The upward flow velocity of sewage in the sedimentation tank is 0.6-0.7 mm / s. The settled sludge is lifted to the sludge tank by air.
2. Secondary Settling Tank: After biological treatment, the wastewater flows into the secondary settling tank, which consists of two vertical flow sedimentation tanks operating in parallel. The upward flow velocity is 0.3-0.4 mm / s. Sludge is removed by air lifting to the sludge tank.
3. Fan Room and Fans: The fan room is located above the disinfection pool. The inlet uses double-layer sound insulation, and the air inlet has a silencer and fan filter, so there is no noise during operation. Two L- type Roots blowers are used, which can automatically alternate operation. The service life of a single blower is approximately 30,000 hours.
4. Contact Oxidation Tank: After primary sedimentation, the water flows by gravity to the contact tank for biochemical treatment. The contact tank is divided into three stages, with a total retention time of over 1 hour. The enhanced equipment can achieve a contact oxidation time of up to 6 hours, using novel trapezoidal packing material. This material facilitates biofilm formation and prevents clogging. The specific surface area of the packing material is 160 m²/m³ , and the air-to-water ratio in the contact tank is approximately 12 : 1 .
5. Disinfection tank and disinfection device: The disinfection tank should conform to specifications. For hospital wastewater, the retention time can be increased to 1-1.5 hours, using solid chlorine tablets for contact dissolution disinfection. The disinfection device should be able to continuously adjust the dosage according to the outflow rate, achieving the goal of adding more chemicals for higher outflow rates and less chemicals for lower outflow rates. Other disinfection devices can be configured separately.
6. Sludge Tank: All sludge from the primary and secondary sedimentation tanks is airlifted to the WSZ-A sludge tank for aerobic digestion. The clarified liquid from the sludge tank is returned to the contact oxidation tank for further treatment. Very little sludge remains after digestion, and it is generally cleaned every 1-2 years. Cleaning can be done using a vacuum truck, which can be inserted through the inspection port into the bottom of the sludge tank to suction and remove it.
