Conventional Wastewater Treatment Systems | Jinwantong

Conventional wastewater treatment refers to a series of physical, chemical and biological processes used to remove pollutants from sewage or industrial effluent before discharge or further reuse. It is widely applied in municipal sewage plants, factories, residential communities, food processing facilities, oil-containing wastewater projects and general industrial wastewater treatment systems.
A standard conventional treatment process usually begins with preliminary treatment. Mechanical grilles or bar screens remove large solids such as plastics, fibers, food residues and other debris. This step protects pumps, pipes and downstream equipment from blockage or damage. For wastewater with sand, grit or heavy particles, grit removal may also be included.
The next stage is often primary treatment, where sedimentation tanks, lamella clarifiers or other solid-liquid separation equipment remove settleable solids. In some industrial applications, chemical coagulation and flocculation are added to improve removal efficiency. For wastewater containing oil, grease or floating solids, a DAF dissolved air flotation machine can be used before or after primary treatment to separate light contaminants effectively.
After primary treatment, the system enters secondary biological treatment. This stage uses microorganisms to degrade organic pollutants such as COD and BOD. Conventional activated sludge systems are common, while MBBR and MBR processes are often selected when projects require compact design, stable operation or better effluent quality. MBBR uses biofilm carriers to support microbial growth, while MBR combines biological treatment with membrane filtration.
For many projects, secondary treatment is followed by clarification and sludge treatment. A sedimentation tank or lamella clarifier separates biological sludge from treated water. The returned sludge may be recycled to maintain biological activity, while excess sludge is sent to dewatering equipment. A screw press sludge dewatering machine or other sludge treatment equipment can reduce sludge volume and disposal cost.
Depending on the discharge standard, tertiary treatment may be added. This can include filtration, disinfection, chemical phosphorus removal, advanced clarification or other polishing steps. Automatic dosing systems are commonly used to prepare and dose coagulants, flocculants, acid, alkali or disinfectants, helping maintain stable operation.
For B2B buyers, the most important point is that conventional wastewater treatment should not be selected only by flow rate. Key design factors include influent COD, BOD, TSS, oil and grease, ammonia nitrogen, phosphorus, pH, temperature, peak flow, sludge production, available land and required effluent quality. Qingdao Jinwantong can provide single equipment or integrated treatment configurations based on project requirements.