Wastewater treatment process

　　Due to large populations and rapid economic development, cities generate a significant amount of wastewater. Rural and township areas, however, have limited wastewater treatment capacity due to their larger areas and smaller populations. Therefore, the advent of domestic wastewater treatment equipment is particularly welcome. This equipment not only improves wastewater treatment efficiency but also reduces the workload. Below is a detailed description of its process flow.

　　1. Primary Sedimentation Tank: The equipment's primary sedimentation tank is a vertical flow sedimentation tank. The upward flow velocity of wastewater in the deep tank is 0.6-0.7 mm/s. Settled sludge is lifted to the sludge tank using air.

　　2. Contact Oxidation Tank: After primary sedimentation, the water flows to the contact tank for biological treatment. The contact tank is divided into three stages, with a total retention time of more than 1 hour. The enhanced domestic wastewater treatment equipment has a contact oxidation time of up to 6 hours. The filler is a novel filler that is easy to form a biofilm and does not clog. The specific surface area of the filler is 160 m²/m², and the air-water ratio in the contact tank is around 12:1.

　　3. Secondary Sedimentation Tank: After biological treatment, the wastewater flows to the secondary sedimentation 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 using air lift to the sludge tank.

　　4. Disinfection Tank and Disinfection Device: According to the standard "TJ14-74", the disinfection tank retention time is 30 minutes. For medical wastewater, the disinfection tank retention time can be increased to 1-1.5 hours. Solid chlorine tablets are used for disinfection via contact dissolution. The disinfection device can continuously adjust the dosage according to the effluent volume, achieving the goal of adding more chemicals for larger effluent volumes and less for smaller volumes. Other disinfection devices can be configured separately.

　　5. Sludge Tank: All sludge from the primary and secondary sedimentation tanks is lifted by air to the sludge tank of the WSZ-A for aerobic digestion. The clarified liquid from the sludge tank is returned to the heat exchange oxidation tank for further treatment. Very little sludge remains after digestion; generally, cleaning is required only once every 1-2 years. The cleaning method involves using a vacuum truck to insert a suction pipe into the bottom of the sludge tank through the inspection hole for removal.

　　6. Blower Room and Blower: The blower for the domestic wastewater treatment equipment is located above the disinfection tank. The inlet uses double-layer sound insulation, and the air intake has a silencer and blower filter, resulting in noise-free operation. Two rotary blowers are used, which can automatically alternate operation. The operating life of a single blower is approximately 30,000 hours.

　　7. Adjustment: Chemical wastewater is characterized by variable water quality and quantity, which can vary significantly within a day or shift, especially when operations are abnormal or when equipment/pipeline leaks cause materials to enter the wastewater. These variations in wastewater quality and quantity are detrimental to the normal operation of drainage facilities and wastewater treatment equipment, particularly biological treatment equipment, and may even cause damage. In such cases, a common measure is to install an equalization tank before the wastewater treatment system to adjust the water quantity (flow equalization tank) and homogenize the water quality (quality equalization tank), ensuring the normal operation of wastewater treatment. In addition, the equalization tank can also temporarily store accidental wastewater.

　　8. Centrifugal Separation: Wastewater treatment using centrifugal separation utilizes the centrifugal force generated by rapid rotation to separate suspended particles in the wastewater. When wastewater containing suspended particles undergoes rapid rotational motion, heavier solid particles are thrown to the outer periphery, while lighter particles remain in the inner circle, thus separating the wastewater from the suspended particles and purifying the wastewater.

　　From the above process flow of the domestic wastewater treatment equipment, we can also understand its approximate configuration, the function of each component, and the data requirements. This should be helpful in understanding how to use the equipment correctly. In addition, we hope that through learning about various wastewater treatment knowledge, we can better understand the importance of environmental protection.