What is the Sewage Treatment Plant and how this works?

sewage treatment plant

Sewage Treatment is the process of converting wastewater into usable water. Wastewater contains a lot of bacteria, chemicals, etc. Water treatment aims at reducing the contaminants to acceptable levels to make the water safe for discharge back into the environment use of the environment.

There are two stages wastewater treatment plants.

Chemical Physical water treatment: Uses chemical reaction and physical process to treat water. Physical wastewater treatment plants are mostly used to treat wastewater from industries, factories, and manufacturing firms because most of the wastewater from these industries contain chemicals and other toxins that can harm the environment.

Biological water treatment plant: Use biological matter and bacteria to break down the matter. These treatment systems are ideal for treating wastewater from households and business premises.

Primary Treatment

 As sewage water enters a plant for treatment, it flows through a bar screen, which removes large floating objects such as wood, leaf, plastic, and sticks that might clog pipes or damage equipment.

When the speed of the flow through one of these tanks is reduced, the suspended solids will gradually sink to the bottom, where they form a mass of solids called raw primary biosolids. Biosolids are usually removed from tanks by pumping, after which it may be further treated for use as a fertilizer, or disposed of in a landfill.

Over the years, primary treatment alone has been unable to meet many communities’ demands for higher water quality.

To meet them, cities and industries normally treat to a secondary treatment level, also use advanced treatment to remove nutrients and other contaminants.

Secondary Treatment

The secondary stage of treatment removes about 80 percent of the organic matter in sewage by making use of the bacteria in it.

The activated sludge process speeds up the work of the bacteria by bringing air and sludge heavily laden with bacteria into close contact with sewage. After the sewage leaves the settling tank in the primary stage, it is pumped into an aeration tank, where it is mixed with air and sludge loaded with bacteria and allowed to remain for several hours.

During this time, the bacteria break down the organic matter into harmless by-products. From the aeration tank, the partially treated sewage flows to another sedimentation tank for removal of excess bacteria.

The treated water from the stage can be discharged into the drains or can be used for landscaping and irrigation purpose.

Tertiary Treatment:

After secondary treatment, if you want to use the water for flushing then it has to pass through sand filter and carbon filter to remove any suspended solids, color and smell from the water.

Household Water Treatment

The most common types of household water treatment systems consist of:

Filtration Systems : include activated carbon charcoal filterseither designed within a pitcher installed filter, ultraviolet (UV) light units, reverse osmosis, water distillers (whole system or portable counter), or another form of water treatment process.

Water Softener: A water softener is a device that reduces the hardness of the water. A water softener typically uses sodium or potassium ions to replace calcium and magnesium ions, the ions that create “hardness.”

Distillation Systems: Distillation is the process of boiling waterand the steam is collected in a container, leaving may solid contaminants behind

Disinfection: Disinfection is a chemical process of killing or deactivating microorganisms.