What is Wastewater?
Wastewater, commonly known as sewage, is water people have used for various purposes. In the residential setting, wastewater is generated in kitchens, laundry rooms, and bathrooms. In the industrial environment, wastewater is produced during operations like agriculture or manufacturing.
Untreated wastewater cannot be reused or even discharged into the water bodies or the environment as it contains numerous impurities and pathogens. Since wastewater consists primarily of water, sewage treatment plants are necessary to make the water usable again for numerous purposes.
Why Are Sewage Treatment Plants Necessary?
Have you ever considered why sewage treatment is such a necessity in today’s day and age? These are some primary reasons sewage treatment plants are gaining popularity worldwide.
Environmental Conservation
Untreated water cannot be pumped back into nature due to adverse environmental effects. The pollutants in the sewage can contaminate the water and kill plants and animals. It can also make places uninhabitable and make drinking water unsafe.
Another reason why sewage water can be a hazard to the environment because it can start increasing algal bloom. Often found in sewage water with a high concentration of nitrogen or phosphorus comes in contact with freshwater supplies.
The nutrients accumulate in freshwater in a method known as eutrophication.
Human Health
If untreated wastewater is released back into the environment, it can negatively impact human health. Diseases such as cholera, dysentery, typhoid, and schistosomiasis can spread easily if sewage water does not undergo treatment.
Water Shortage
Water shortage is a massive problem all around the world. Improving water scarcity depends a lot on conserving and recycling water. Wastewater and sewage treatment are a valuable part of the entire process. With proper wastewater and sewage treatment, this water can be used for industrial processes or even for drinking water if the process is advanced enough.
Phases Of Sewage Treatment Plants
Wastewater must undergo three main treatment stages: primary, secondary, and tertiary, to be used for industrial or residential use. Several sewage treatment plants add pretreatment before the primary treatment process begins.
Pretreatment
The primary purpose of pretreatment is to filter solid particles from wastewater via a physical process. When the pretreatment occurs, sewage water goes into the treatment tanks and basins. Tree limbs, tree branches, plastic, and other debris, are filtered out during this process.
EQ or Equalization tanks are built in the pretreatment process to regulate the water flow and promote settling. Small particles such as coffee grounds, dirt, gravel, sand, and eggshells are removed with the help of the grit chambers.
The steps of pretreatment depend on the type of wastewater. Wastewater which contains a high percentage of grease and fat, it will be removed during pretreatment with the help of blowers to generate easily skimmable greasy froth.
During pretreatment, chemical procedures can also be used instead of physical ones. The wastewater’s pH is adjusted to change the impurities’ structures. This chemical process allows the solid waste particles to clump together to form a heavy mass that can be filtered. This process is called coagulation and flocculation.
Primary Treatment
The primary treatment in a sewage treatment plant utilises screens, grit chambers, and sedimentation tanks to get waste and harmful bacteria out of sewage water. Before the ejection of the quality water, the sewage passes through many cleaning processes. When sewage is influent in the plant for treatment, it comes across to a screen for removal of large floating objects that can block or damage pipes or equipment.
After completing the primary screening process, water falls into a grit chamber where small objects are separated from the water. It set cinders, sand, and stones at the bottom.
After the two procedures for removing large and small objects, sewage water contains many suspended solids with organic and inorganic materials. For complete water purification, minute waste particles need to be removed. A sedimentation tank is used for this part of the process. In this tank, solids sink to the bottom as and when the flow of water gets reduced. This solid collection is known as raw primary biosolids; formerly, sludge is thrown out of the tank through pumping.
Gradually, this primary method cannot meet the increased quality demands of the community. So, secondary and advanced methods are developed to fulfill the needs of cities and industries.
Secondary Treatment
Using the trickling filter and activated sludge process, this stage throws out around 85% of the water’s organic and inorganic waste material.
After completion of the primary stage and when effluent leaves the sedimentation tank, a trickling filter comes into play. The trickling filter is around a six-foot-deep bed of stones through which sewage flows. Partially treated sewage gets transmitted to another sedimentation tank after trickling the filter to remove bacteria.
Nowadays, the activated sludge process is used in place of a trickling filter. The process is fast and early results are compared to the tricking filter. After the primary stage sedimentation tank, sewage flows into the aeration tank. It is blended with air and sludge loaded with bacteria for a few hours to break down the organic matter. Like a tricking filter, partially treated sewage is sent to another sedimentation tank for further processing.
At the end of the stage, the effluent of the sedimentation tank is disinfected with the help of chlorine to remove odour and kill pathogenic bacteria before being discharged to water communities.
Tertiary Treatment
Tertiary treatment deals with additional disinfection and filtration. Tertiary treatment is not always necessary in sewage treatment plants.
Tertiary treatment relies on various processes — first filtration and then disinfection:
Filtration: Tertiary treatment usually utilises filters like sand filters or carbon adsorption filters to extract impurities from the wastewater.
- Chlorination: Several sewage treatment plants apply chlorine to the water to disinfect it. Chlorine is cost-effective and is a staple in many sewage treatment plants.
- Ultraviolet (UV) disinfection: Tertiary treatment often utilises UV light to eliminate or disinfect any microorganisms in the wastewater and makes them benign.
- Ozone treatment: Sewage treatment plants can also utilise ozone treatment for disinfecting. Ozone treatment is much more effective than chlorine, but it is not used often due to its cost and equipment requirements, such as special corrosion-resistant machinery. It also generates toxic gases, so plants must consider the expenses and uses of this particular treatment before using it.
- Ion exchange: Tertiary treatment utilises ion exchange, which trades benign ions for unwanted ones — much like water softener substitutes unwanted calcium and magnesium ions with good sodium ions.
Other Plans
Increasing pollution problems is putting additional weight on Industrial wastewater treatment plants and Sewage treatment plants and system. The number of toxic substances, heavy metals, and chemicals in water has increased dramatically. Advanced waste treatment techniques and better wastewater systems that separate chemicals, absorb carbons, and filter the water are used to get the purified water.
Why Choose Cleantech Water For Your Sewage Treatment Plant
If you are wondering which sewage treatment plant manufacturer to choose, the correct answer is Cleantech Water. Cleantech aims to provide excellent sewage water treatment systems that are hassle-free, easy to use, and efficient in execution. To learn more, contact +91-9099915539 / +91-7935660299 or mail us at info@cleantechwater.co.in.
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