Rivers are one of the most important natural resources on our planet, providing water for drinking, irrigation, transportation, and recreation. Unfortunately, many of the world’s rivers have become polluted due to the discharge of untreated sewage and other wastewater. Sewage treatment plants play a critical role in protecting rivers from pollution by treating wastewater before it is discharged into waterways.
Why Sewage Treatment Plants are Important?
Sewage treatment plants are important for several reasons. First and foremost, untreated sewage can contain harmful pathogens such as bacteria, viruses, and parasites that can cause serious health problems for humans and wildlife. By treating wastewater, sewage treatment plants remove these pathogens and make the water safe for human and animal consumption.
In addition to pathogens, untreated sewage can also contain a variety of pollutants such as nutrients, heavy metals, and organic compounds. These pollutants can cause eutrophication, a process where excessive nutrients cause algae to grow rapidly, leading to oxygen depletion and fish kills. Sewage treatment plants remove these pollutants, preventing eutrophication and other harmful environmental impacts.
How Sewage Treatment Plants Protect Rivers?
Sewage treatment plants protect rivers in several ways. First, they remove pathogens from wastewater, making the water safe for human and animal consumption. This is critical for rivers that are used for drinking water or recreational purposes.
Second, sewage treatment plants remove pollutants such as nutrients, heavy metals, and organic compounds. This prevents eutrophication and other harmful environmental impacts such as oxygen depletion and fish kills. In addition, by removing pollutants, sewage treatment plants improve the overall water quality of the river, making it more hospitable to wildlife and promoting biodiversity.
Finally, sewage treatment plants can also help reduce the volume of wastewater discharged into rivers during periods of high flow. By storing and treating wastewater during these times, sewage treatment plants can help prevent flooding and protect rivers from the erosive effects of high flows.
Effective Sewage Treatment Plants
There are several types of sewage treatment plants, each with its own set of advantages and disadvantages. The most effective types of sewage treatment plants are:
Membrane Bioreactor Sewage Treatment Plants
Membrane bioreactor sewage treatment plants use a combination of biological processes and membrane filtration to treat wastewater. The process begins with primary treatment, followed by an aeration tank where bacteria consume the organic matter in the wastewater. The wastewater is then filtered through a membrane to remove remaining pollutants and pathogens.
Activated Sludge Sewage Treatment Plants
Activated sludge sewage treatment plants use a biological process to treat wastewater. The process begins with primary treatment, followed by aeration tanks where bacteria consume the organic matter in the wastewater. The wastewater is then treated with chemicals to remove remaining pollutants and pathogens.
Sequencing batch reactors (SBR)
This is a type of activated sludge process for the treatment of wastewater. SBR reactors treat wastewater such as sewage or output from anaerobic digesters or mechanical biological treatment facilities in batches.
Oxygen is bubbled through the mixture of wastewater and activated sludge to reduce the organic matter (measured as biochemical oxygen demand (BOD) and chemical oxygen demand (COD)). The treated effluent may be suitable for discharge to surface waters or possibly for use on land.
Water enters through the inlet valve and the tank is filled while the mixing is provided by the air blowers. Aeration of the mixed liquor is performed during the second stage by the use of fixed or floating mechanical pumps or by transferring air into fine bubble diffusers fixed to the floor of the tank. No aeration or mixing is provided in the third stage and the settling of suspended solids starts. During the fourth stage the outlet valve opens and the “clean” supernatant liquor exits the tank.
Aeration times vary according to the plant size and the composition/quantity of the incoming liquor, but are typically 60 to 90 minutes. The addition of oxygen to the liquor encourages the multiplication of aerobic bacteria and they consume the nutrients. This process encourages the conversion of nitrogen from its reduced ammonia form to oxidized nitrite and nitrate forms, a process known as nitrification.
To remove phosphorus compounds from the liquor, aluminum sulfate (alum) is often added during this period. It reacts to form insoluble compounds, which settle into the sludge in the next stage.
EcoBud
It is an advanced, low powered, fully automated and low maintenance sewage treatment system developed by Hydromo. Treatment of the effluent in ECOBUD is based on natural biological augmentation which requires very low power. It works on a combination of Anaerobic digestion, which is a process in which microorganisms convert organic matter into biogas in the absence of oxygen, in a primary settling tank, followed by Aerobic biological oxidation, clarification and polishing by natural filters of sand and fibers. The system includes pretreatment of effluent using an oil and grease skimmer, primary clarifier, fixed bed bioreactor and MBBR based Biological treatment of the sewage. Polishing of final water is done by Multi grade bed filtration. EcoBud works on a combination of Biological processes which include solids to bio gasification in an anaerobic primary settling tank, followed by an aerobic biological oxidation, clarification and polishing by natural filters of sand and fibers.
Conventional Sewage Treatment Plants
Conventional sewage treatment plants use a combination of physical, chemical, and biological processes to treat wastewater. The process begins with primary treatment, where solids are removed from the wastewater using screens and settling tanks. The remaining wastewater is then treated with chemicals and biological agents to remove pathogens and pollutants.
In conclusion, sewage treatment plants play a critical role in protecting rivers from pollution. By removing pathogens and pollutants from wastewater, sewage treatment plants make the water safe for human and animal consumption, prevent eutrophication and other harmful environmental impacts, and improve the overall water quality of the river. There are several types of sewage treatment plants, each with its own set of advantages and disadvantages. It is important to invest in sewage treatment infrastructure to protect our rivers and ensure a sustainable future for generations to come.
