Question

flow chart and description for water and wastewater treatment facility.

Answer 1

Description:

The intake of water is from sources like river or lakes in a large quantity and it is always collected from the upstream side of rivers for intake

Smaller debris like fish, vegetation, and garbage are removed from the raw water by a protective bar and traveling screens before the water enter the low lift pumps.

Pumps are provided to lift the water from lower elevation to higher elevation

Coagulants like alum are used to form “floc”. This floc is formed and it is easy to be removed

by mixing, turbulence causes the flocculated water to form larger floc particles that become cohesive and increase in mass. This visible floc is settled due to gravity.

Flocculated water is applied to large volume tanks where the flow speed slows down and the dense floc settles due to sedimentation

Relatively floc free, settled water flows through a media filter by gravity. Filter media are made from layers of anthracite or granular activated carbon and sand. Gravel or synthetic materials support the media. Physical straining removes the remaining floc. Filters are periodically backwashed to clean off accumulated floc and other trapped impurities.

Filtered water in the clear well is used to backwash filters and kept in storage to ensure that disinfectants are in contact with the water long enough to inactivate disease-causing organisms.

A little amount of chlorine is added to the water after the treatment has been done this is called as post chlorination

A small dose of fluorine is also required to be added in water if the fluorine is added in excess quantity it causes dental problems and in fewer quantities, it causes skeletal problems

Distribution systems are comprised of large pipes known as trunk mains to deliver drinking water. Smaller diameter branch mains feed individual streets. Service connections to branch mains deliver water into residences. Pumping stations are used to increase pressure and to maintain adequate supply flows.

In a sewage treatment plant the intake is mainly from the sewer lines,for sewage treatment plants the main source of flow is due to gravity as soon as the intake is completed , the preliminary treatment consists of removing the debris of dead animals, branches and leaves of trees and other materials, after this preliminary treatment is completed they are sent for primary treatment in to the primary clarifier, where they are kept in an aeration tank if its an aerobic process,which gives primary sludge and after it is completed they are sent in to the secondary clarifier, in this secondary clarifier some portion of the sludge is returned called as returned sludge to the primary clarifier and again re-treated and finally the disinfectants are added and the effluent is released