How to make sewage clear
Wastewater treatment is a critical environmental protection effort that aims to remove pollutants from residential and industrial effluents, making them clean and safe for discharge into the environment. There are many ways to achieve this, including physical, chemical, and biological treatment processes. This article will describe a few commonly used treatment methods and the scope of application for them.
1. Physical processing
Physical treatment is the separation of pollutants from wastewater through a physical process. Here are a few common physical treatments:
1.Screen filtration: By using a mesh filter material, large solids and suspended solids such as leaves, paper and plastic can be intercepted. This method is often used as the first step in a sewage treatment system to prevent large pieces of material from entering the subsequent treatment stage.
2.Sedimentation: By allowing the sewage to sit for a period of time, heavy solid particles will settle down and form sediment. These sediments can be collected and removed by equipment such as sedimentation tanks or precipitators.
3.Filtration: Filter media such as sand, charcoal or activated carbon are used to filter solids and suspended solids from the effluent. This method can be used to remove small particles, color, odor, and taste, among other things.
2. Chemical treatment
Chemical treatment is the use of chemicals to convert contaminants into harmless substances or to precipitate them for removal. Here are a few common chemical treatments:
1.Coagulation: By dosing a chemical such as polyaluminium chloride or ferric sulfate, the dispersed suspended solids are aggregated into larger particles to make subsequent precipitation or filtration easier.
2.Oxidation: The addition of oxidizing agents such as hydrogen peroxide or chlorine can convert organic pollutants into harmless substances. This method is often used to reduce the concentration of organic pollutants.
3.Neutralization: The use of neutral agents such as lime or lead nitrate can neutralize the pH and make the wastewater close to neutral. The right pH not only helps with subsequent biological treatments, but also helps to reduce the environmental impact.
3. Biological treatment
Biological treatment is the decomposition and degradation of pollutants through the use of microbial life activities. Here are a few common biological treatments::
1.Activated sludge method: Biodegradable in the presence of oxygen by treating activated sludge containing bacteria and other microorganisms with sewage. This method can effectively remove organic matter.
2.Constructed wetland: Wetland plants and microorganisms are used to absorb and decompose nutrients such as organic matter and nitrogen and phosphorus in sewage, so that sewage can be purified. Constructed wetlands can effectively handle low concentrations of organic matter and nutrients.
3.Biofilm reactor: Establishes a microbial membrane in flowing effluent, allowing microorganisms to adsorb and break down contaminants. This method is suitable for the treatment of high concentrations of organic matter.
Fourth, further processing methods
Once the effluent has been treated physically, chemically, and biologically, the following further treatment methods can be considered:
1.Secondary precipitation: A secondary precipitation process can be added after the primary precipitation to further remove residual suspended solids and sediments.
2.Activated carbon adsorption: Activated carbon is added during the treatment process to adsorb residual organic matter and odors.
3.Ozone treatment: Ozone can be used to remove residual organic matter and microorganisms. Ozone treatment can improve the oxidation of water and effectively kill bacteria and viruses.
Wastewater treatment is a complex and critical task. By using physical, chemical, and biological treatment methods, wastewater can be effectively purified and made clean and safe. However, the best treatment method will depend on the degree of contamination of the effluent and the specific treatment needs. Therefore, when designing and operating the sewage treatment system, the appropriate treatment method should be selected according to the actual situation, and the relevant environmental protection regulations and standards should be strictly followed.