The Treatment Of Sewage And Wastewater

A wastewater treatment plant is a place where sewage is processed to remove solid wastes, make it less offensive or dangerous and prepare it for reuse. The process of treating wastewater is regulated by governments in order to protect water supplies and prevent the spread of diseases. Many different types of chemicals and pollutants can be found in wastewater, depending on the industry or activity that created it. For example, antifreeze, oils and dyes can be present in wastewater from automotive manufacturing or repair shops, while paint thinners, solvents, detergents, paper and textile dyes may be found in industrial wastewater.

wastewater bar screens begins with the collection of sewage from households and businesses. The sewage is then transported by pipes, pumping stations and manholes to the treatment plant, a network that is sometimes called a sewerage system (see also sewerage). The treatment of sewage and wastewater involves primary (solid removal), secondary (bacterial decomposition) and tertiary (extra filtration) treatment processes.

Chemical treatment is used to destabilize the fine solid particles in wastewater, so that they clump together and settle out of the water. The first step is usually to use a chemical coagulant, such as aluminum or iron salts, to reduce the negative electrical surface charges of the particles. This allows the particles to attract each other and coalesce into larger groups, so that they can be easily skimmed or filtered out of the wastewater.

The next step is chemical oxidation, such as using oxygen or caustic soda to convert toxic metals in the wastewater into insoluble forms. This is necessary for removing toxic substances such as copper, lead and mercury. The oxidation process can also be used to remove other metallic contaminants, such as arsenic and manganese, from the water.

Oils in the wastewater can be removed by physical separation processes such as centrifugal separating, sand removal, and filtration. The chemical process of flotation, in which substance particles stick to fine air bubbles due to adhesive forces is also a common treatment method.

A range of other chemical processes are used to treat odors in the wastewater and to control the growth of harmful bacteria. Odor control is especially important because, if it cannot be controlled, the odors and bacteria can pollute nearby surface water and groundwater sources.

Once the sewage has been treated, it is usually sent back to the household or business that generated it for further use. This can be for irrigation, washing machinery and equipment, or for toilet flushing. In some cases the wastewater can even be used to supply drinking water, which is referred to as reclaimed or recycled water.

It is the responsibility of all citizens and businesses to ensure that their wastewater is treated properly and that the resulting reclaimed water is safe to use. Failure to comply with regulations can result in fines or even the revocation of a company's licence to operate. It is also vital to test the wastewater regularly to make sure that the quality of the reclaimed water meets standards.