Waste water treatment is essentially a process to treat sewage or wastewater, remove impurities, and transform it into a usable stream of liquid which can then be returned back into the water system with suitable environmental impact, or further processed for other uses. Depending on the extent of the problem, the process might be a one-step process like washing out a pond or river or use advanced systems for more complex tasks such as removing industrial wastes and treating raw sewage. There are basically three main types of waste water treatment.
In the simplest form, a wastewater treatment facility removes the solids and liquids in water before returning it to a natural environment. It is usually done by using ultra-filtration and selective adsorption, where solid particles are filtered or washed out with clean water. This step is often considered as the ‘most economical’, especially if it involves the use of municipal wastewater.
Chemical is also an important step that takes place in a wastewater treatment facility. The most common chemical is activated carbon. This substance works by breaking down dissolved substances and turning them into granular material. Carbon and other organic compounds are then separated, combined, are broken down into their constituent molecules, and then re-purified as a solution. This type of wastewater treatment is sometimes also referred to as distillation.
The other form is known as mechanical treatment involves the introduction of microorganisms and chemicals into water. Microorganisms help eliminate unwanted microbes and organisms by neutralizing the toxins in water by breaking them down into their constituent parts. When they are broken down and separated, they are able to pass through the microfilter to reach the wastewater treatment plant. Chemical reactions, either physical or chemical, result when the microorganisms and chemical are combining to make a solution suitable for human consumption.
The last and final step is a combination of both processes, known as multi-stage or multi-purification. Multi-stage is an amalgamation of all these methods to return water to its natural state, and in turn produce safe drinking water. The most common process employed is ion exchange, wherein the dissolved substances are replaced by heavy ions (like calcium and magnesium) to improve the pH of water. and enhance its biological activity, and clarity.
The purpose of wastewater treatment is to prevent pollution, damage to soil and water quality, and other environmental damage. Soil erosion is also a major concern. In some cases, plants have been built near river beds, lakes and reservoirs to capture and filter wastewater before it reaches water treatment plants. It prevents sediment from being carried away by the runoff from the groundwater by collecting it in a reservoir and then sending it back into the water system as treated wastewater.