The process of removing contaminants from wastewater and household sewage water is termed as sewage treatment. This includes physical, biological and sometimes chemical processes to remove pollutants. It is aimed towards producing environmentally safe sewage water which is also known as effluent, and solid waste, called sludge or biosolids, which is suitable for disposal or reuse like agricultural purposes and as a fuel source.
The quality of the water from mains, factories, farming, houses, and hospitals, commercial and industrial sites get reduced due to influence with contaminating constituents. Pollutants like organic wastes, suspended solids, bacteria, nitrates, and phosphates must be removed. The job of the sewage treatment plants is to make wastewater acceptable for reuse or for returning to the environment by reducing the concentration of contaminants to a safe level.
Steps followed in a sewage treatment plant process:
Generally, the sewage treatment process involves either two or three stages which are known as primary, secondary and tertiary treatment. Before these treatments, preliminary removal of rags, cloths, sanitary items, etc, is also carried out at municipal sewage works.
Primary Treatment
This process is usually Anaerobic where first, the solids are separated from the sewage. They settle out at the base of a primary settlement tank. Continuously being reduced in volume by the anaerobic process the sludge is gradually removed when it is about 30% of the tank volume.
Secondary Treatment
This process is aerobic, in which the liquid from the primary treatment which contains dissolved and particulate biological matter is progressively converted into clean water by using indigenous, water-borne aerobic micro-organisms and bacteria which digest the pollutants. Most of the time, this effluent is clean enough for discharge directly to rivers.
Tertiary Treatment
Sometimes, the effluent resulting from secondary treatment is not clean enough for discharge. This may be because the stream it is being discharged into is very sensitive, has rare plants and animals or is already polluted by someone’s septic tanks. The culprit is either Phosphorous or Ammoniacal Nitrogen or both. In Tertiary treatment, if Phosphorous is the cause then a continuous dosing system is used to remove it and in case of Ammoniacal Nitrogen, the sewage treatment plant process involves a nitrifying and then de-nitrifying stage to convert the Ammoniacal Nitrogen to Nitrogen gas which is harmless.
To make a treatment plant sufficient enough, it is essential to incorporate an exceptional range of equipment. In the Middle East, Dutco Tennant LLC is a renowned sewage treatment equipment supplier and has been serving the region for the last four decades. For any product requirement for treatment plants, check our wide inventory.
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