The Chemical Treatment Of Wastewater

Wastewater is the liquid that drains from toilets, showers, sinks and bathtubs into sewers, together with the water that flows down storm drains or rainwater runoff. It contains human excrement, detergents used to wash clothing and dishes, food scraps, oils, plastics, sand, grit, heavy metals and other materials. Wastewater treatment is needed to remove the harmful substances, leaving clean, usable water that can be returned to the environment. For more visit https://www.waterandwastewater.com/

Municipal wastewater treatment plants are responsible for treating the sewage and industrial wastewater generated by local residents and businesses. The process of wastewater treatment is regulated by government bodies, and facilities must be licensed to operate. Failure to meet regulations can result in fines or even closure of the facility.

Water and Wastewater

Many of the chemicals found in wastewater are toxic to people, animals and plants. The most dangerous of these are the heavy metals such as lead and cadmium, which can cause cancer and other health problems in humans. Other chemicals that need to be removed from wastewater include phosphates, which can cause the overfertilisation of rivers, streams and lakes, resulting in useless plant growth (eutrophication). Phosphates are often found in detergents, fertilisers, soaps and human waste.

There are a number of different processes for the chemical treatment of wastewater. Many of these are based on adsorption, precipitation and filtration. For example, phosphorus in wastewater can be removed by passing the water through a filter that contains a special form of aluminium oxide that binds with phosphorus in the water and makes it insoluble. Another common method is to use chemicals that change the surface properties of substances so they can be separated from wastewater. Coagulants are added to the wastewater to change their magnetic charges, causing them to attract instead of repel each other and coalesce into larger masses that can be skimmed off or filtered out.

In the final step of wastewater treatment, a membrane or filter is used to remove any remaining contaminants. This can be done by ion exchange or reverse osmosis. This is a very important part of the treatment process, as it is the only way to ensure that no organic matter remains in the finished product.

Most cities and towns have a sewerage system that conveys sewage and other liquid waste from homes, factories and businesses to wastewater treatment plants. It consists of a network of pipes, chambers, manholes and pumping stations that carry the waste to the plant.

The sewage is treated in three stages, known as primary, secondary and tertiary treatment. The first step involves screens and settling tanks that separate solids from the wastewater. This is followed by disinfection, which can be achieved using chlorine or UV light. In the second stage, bacteria are used to break down the soluble organic compounds in the wastewater. This is a managed aerobic or anaerobic process that can reduce the BOD in the wastewater to safe levels for discharge. Chemicals can also be used to help this process along, such as coagulants and flocculants.