Question

long answer questions how does microorganisms help in sewage treatment plants

Answer 1

micro organisms react with the sewage and decompose the organic matter present in it due to which the harmful and poisonous particles are removed from the sewage and they can be used as manure for plants.. the non bio degradeable or poisonous part is dumped away from the city.

Answer 2

Sewage treatment plants use microorganisms to destroy the biological material in sewage. The the liquid portion, or effluent of sewage, which is rich in suspended organic matter and some pathogenic microbes. This liquid portion will ultimately be released into rivers or the sea but it is vital to first reduce the organic matter content and eliminate harmful microbes. To do this the liquid is fed into an aeration tank containing a complex community of microbes. The contents of the tank are mixed mechanically with air or air is bubbled through the tank. The microbes then use the organic material in the sewage as their source of carbohydrate for respiration.Aerobic respiration is the most efficient way of breaking down organic matter although some compounds in the effluent are not broken down completely. The tanks often contain porous solid materials, on which biofilms can develop, increasing the numbers of microbes and so the efficiency of the breakdown process. During this process, a fairly solid material known as activated sludge is formed. This contains a mix of microbes and undigested material. Since it contains all of the essential microbes to break down incoming waste, some of it is added to batches of new sewage . After this aerobic digestion, and a variety of other purification procedures, the liquid portion of the sewage is usually safe to discharge into rivers or the sea. The remaining activated sludge material is subjected to various other types of biological processes to reduce further the amount of organic matter it contains. Anaerobic bacteria are often used in this subsequent stage, since, although they grow more slowly, they can break down more complex materials that are difficult to degrade using microbes that respire aerobically. The gases produced in this anaerobic process are carbon dioxide and methane, a mixture called biogas, which can be collected and subsequently burned for energy production.