Overview of Sewage Treatment
Sewage treatment refers to the professional purification process that eliminates harmful contaminants from domestic and industrial wastewater. Through a complete set of physical, chemical, and biological treatment technologies, sewage treatment plants purify polluted water to meet environmental discharge standards, ensuring safely recycled or discharged water into natural water bodies.
Modern sewage treatment systems are designed to handle diverse wastewater sources. They cover not only conventional toilet sewage but also kitchen wastewater, laundry drainage, and various types of industrial factory waste liquid, realizing comprehensive water pollution control for residential and commercial scenarios.
Three Core Stages of Wastewater Treatment
1. Physical Treatment Process
Also named mechanical treatment, this is the primary purification stage of wastewater treatment. It relies on professional mechanical equipment including filter screens, sieves, grinders, blowers, and specialized sedimentation tanks to intercept and separate suspended solids, large particles, and visible impurities in raw sewage. This physical filtration effectively removes most macroscopic pollutants and lays a solid foundation for subsequent deep purification.
2. Biological Treatment Process
Biological purification is the key stage for decomposing organic pollutants in wastewater. This process utilizes natural microorganisms such as beneficial bacteria and nematodes to biodegrade complex organic waste substances in sewage. After full biological decomposition, organic pollutants are converted into stable and easily separable substances, facilitating subsequent centralized separation and disposal, and greatly reducing water organic pollution load.
3. Chemical Treatment Process
As the advanced purification stage, chemical treatment further polishes water quality to a high standard. Combining precise filtration, osmosis, nanofiltration and other chemical purification technologies, this process removes residual tiny impurities, harmful bacteria, viruses and toxic substances in the water. It can eliminate up to 99% of pollutants, making the treated water close to potable water quality and fully compliant with safe environmental discharge requirements.
Extended Aeration Activated Sludge System
For small-volume wastewater treatment scenarios, the extended aeration activated sludge process is widely adopted as an efficient and stable treatment method.
The system consists of aeration basins and secondary sedimentation tanks. It uses aerobic microorganisms to biodegrade oxygen-consuming pollutants in wastewater, with continuous air supply in aeration tanks to maintain microbial activity. Different from conventional processes, the extended aeration mode features longer hydraulic retention time and sludge age, ensuring more sufficient pollutant decomposition.
After aeration treatment, the mixed wastewater flows into secondary clarifiers. The slowed water flow enables sludge sedimentation to form clear and clean effluent. Meanwhile, floating scum on the water surface is completely collected and transported to the digester for centralized treatment, achieving thorough sewage purification.
Key Benefits of Professional Sewage Treatment
Maintain reusable clean water resources: Effectively purify polluted water bodies and restore water usability for recycling and secondary utilization.
Reduce environmental pollution: Cut down sewage discharge hazards and minimize damage to soil, rivers and ecological environments.
Eliminate pathogenic bacteria: Kill harmful microorganisms and disease-causing bacteria through professional chemical and biological treatment to avoid waterborne diseases.
Control odor pollution: Realize efficient deodorization during treatment and reduce peculiar smell emission from sewage.
Realize water resource recycling: Process and purify wastewater for industrial and civil reuse, saving water resources and reducing operational costs.
