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Wastewater includes substances like human waste, food scraps, oils, soaps, and chemicals. In homes, wastewater comes from sinks, showers, bathtubs, toilets, washing machines, and dishwashers. Businesses and industries also produce wastewater. Wastewater treatment can also be called sewage treatment. Wastewater treatment is the process of converting wastewater into water that can be discharged back into the environment.
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According to the U.S. Environment Protection Agency, wastewater treatment one of the most common forms of pollution control in the U.S. Wastewater contains bacteria, viruses and disease-causing pathogens which can negatively impact human health. Decaying organic matter, debris, and other substances in wastewater are known to cause harm fish, wildlife and their natural habitat.
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The Wastewater Treatment Process
For the most part, the wastewater treatment process is a natural process. Treatment facilities are designed to speed up the natural process of purifying water because the natural process wouldn’t be able to clean the billions of gallons of wastewater produced in today’s world.
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All WEP Wastewater Treatment Plants
Preliminary treatment is the first step to treating wastewater when it comes into the facility. It’s main purpose is to get rid of the larger solids and debris.
Screening is a critical first step in wastewater treatment. Larger items found in wastewater can create blockages and damage facility equipment. The screening process is the same principle as sifting dirt or sand. As the size of the screen decreases, it catches smaller particles. Screens are paired with rakes. The rake’s job is to prevent the screens from clogging by removing the debris they catch. Screenings usually consist of garbage, rags, leaves, sticks and baby wipes.
To remove the smaller debris that passes through the screens, wastewater travels through a grit chamber. A grit chamber is a long, circular tank that slows the flow of the water, allowing heavier particles, like sand and gravel to settle to the bottom of the tank.
Primary treatment is similar to preliminary treatment in its purpose to remove solids from the wastewater.
Primary settling tanks hold wastewater for a few hours and let gravity do it’s thing. Solids gradually sink to the bottom of these tanks. The settled solids, known as sludge, are collected from the bottom of the tank and removed. Mechanical arms at the top of the primary settling tanks skim the surface of the water, removing grease and other floatables.
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All WEP Wastewater Treatment Plants
ACTIVATED SLUDGE AERATION TANKS
Secondary treatment is a bubbling brew of biological activity. Microorganisms are introduced to the wastewater in activated sludge aeration tanks, where they feed on the organic matter and suspended solids leftover from primary treatment. Dissolved oxygen is added into the mixture, creating the ideal environment for the microorganisms to thrive, creating an active, healthy suspension of biological solids, mostly made of bacteria, which is called activated sludge. Time in the tank allows the microorganisms to absorb the organic materials.
After several hours, the brew moves into settling tanks, where the activated sludge created in the aeration tanks, settles out of the water, similar to the primary settling tanks.
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Only Metro Syracuse & Baldwinsville-Seneca Knolls Wastewater Treatment Plants handle this step.
After secondary treatment is complete, the wastewater looks clean and roughly 85% to 90% of the organic matter has been removed. At this point, water is safe to be released to the environment. Going one step further, Metro and the Baldwinsville-Seneca Knolls Wastewater Treatment Plants provide tertiary treatment to its wastewater.
BIOLOGICAL AERATED FILTRATION
Biological aerated filtration or BAF is a process in which ammonia is removed from the wastewater. Ammonia is toxic to fish and takes a lot of oxygen from water as it converts to nitrates. As nitrates, the nutrient promotes the growth of algae. Ammonia and nitrates in the water result in excessive nutrients causing dense growth of plant life and death of animal life from the lack of oxygen.
Removing ammonia from the wastewater is similar to the activated sludge aeration tanks in secondary treatment. This is a biological process using helpful microorganisms that breakdown the ammonia into nitrites and nitrates, which are more stable forms of nitrogen.
HIGH-RATE FLOCCULATED SETTLING (HRFS)
Like nitrogen, high levels of phosphorous in wastewater can cause the dense growth of plant life and upset the surrounding habitat. Phosphorous encourages algae growth. Limited quantities of algae are beneficial, but too much can lead to problems.
To reduce the levels of phosphorous, coagulants are added to the wastewater that stick to phosphorous molecules, causing them to form larger particles. Then micro-sand is added to increase the molecules’ size, forming a concentrated sludge. That sludge is weighed down, sinking to the bottom of the tank where it is siphoned out of the water.
UV lights are used as a chemical-free way to rid the wastewater of any lingering pathogens before its discharged to the environment. UV lights destroy the genetic material in bacteria, viruses and other micro-organisms so they cannot reproduce. This process is only necessary during warmer months of the year.
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| That’s how wastewater becomes clean water! |
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