Where does wastewater come from?
It comes from:
- Homes – human and household wastes from toilets, sinks, baths, and drains.
- Industry, Schools, and Businesses – chemicals and other wastes from factories, food-service operations, airports, shopping centers, etc.
On average, each person in the U.S. contributes 50-100 gallons of wastewater daily.
How do wastewater treatment plants protect our water?
A wastewater treatment plant:
- Removes Solids - This includes everything from rags and sticks to sand and smaller particles found in wastewater.
- Reduces Organic Matter and Pollutants - Helpful bacteria and other microorganisms are used to consume organic matter in wastewater. The bacteria and microorganisms are then separated from the water.
- Restores oxygen - Treatment facilities help ensure the water put back into our lakes or rivers has enough oxygen to support life.
How does a wastewater treatment plant work?
Wastewater treatment usually takes place in two steps:
- Primary treatment removes 40-50% of the solids. Sanitary sewers carry wastewater from homes and businesses to the treatment plant. Bar screens let water pass, but not trash. The trash is collected and properly disposed. A grit chamber is a large tank that slows down the flow of water. This allows sand, grit, and other heavy solids to settle at the bottom for removal later.
- Secondary treatment completes the process, so that 85-90% of the pollutants are removed. A secondary sedimentation tank allows the microorganisms and solid wastes to form clumps and settle. Some of this mixture, called "activated sludge," can be mixed with air again and reused in the aeration tank. A disinfectant, such as chlorine, is usually added to the wastewater before it leaves the wastewater treatment plant. The disinfectant kills disease-causing organisms in the water. After treatment, the water can be returned to nearby waterways. It can also be used on land for agriculture and other purposes.
FOG (fats, oil, grease)
Cooking oils and grease should be collected in a container, covered, and disposed of as solid waste in your household garbage. Fats, oils, and grease may go in as a liquid, but sooner or later they cool and build up on the sides of your pipes and collect in the sewer system. Fats, oils, and grease are a major cause of sewer line blockages and sewage backups.
What are biosolids?
Biosoilds can be a useful byproduct of treated wastewater. Solids collected during primary treatment may be treated (thickened) to remove some of its water, then further processed by stabilization. Thickened solids are allowed to decompose in digester tanks. In some cases, special chemicals are used for stabilization. Stabilized biosolids have no odor and are free of disease-causing organisms. Biosolids that meet federal and state standards can be safely used as:
- A soil conditioner to improve the soil for crops in some areas of the nation. Biosolids can also improve the soil for lawns, fields, and parks.
- Fuel. Using certain processes, biosolids can also be used to produce methane gas. The methane can then be burned to supply energy for a small power plant or for other purposes. Biosolids that do not meet federal and state standards must be disposed in approved landfills or burned using special technology to prevent air pollution.
Who operates treatment plants?
The daily treatment plant operation is conducted by highly trained and certified operators. It requires:
Are there any special challenges in treating wastewater?
- A plant manager/superintendent to ensure the plant has enough money, trained personnel, and equipment to conduct business.
- Maintenance personnel to prevent mechanical failures and solve equipment problems.
- Plant operators who know how to treat wastewater properly before discharging it into the environment. After a thorough training and exam process, operators are licensed through state standards.
What can I do to help?
- Nutrients - Phosphorus, nitrogen, and other chemical nutrients found in wastewater can damage lakes and rivers. These nutrients need to be changed into less harmful substances or removed before being released into the environment.
- Toxic Chemicals - Sometimes wastewater contains hazardous chemicals from industry, pesticides, etc. Controlling these chemicals may require pretreatment of wastewater by industries and the use of advanced tertiary treatment methods at the wastewater treatment plant.
- Water Infiltration - Water entering the treatment system through cracks or joints in sewer lines or storm drains places an extra burden on a facility.
- Changes in Water Flow - The amount and kind of wastewater entering a treatment plant can change quickly. Plant operators must be ready to respond to these changing conditions.
Don’t ever flush these 14 things down the toilet.
- Use and dispose of household chemicals properly. Don't pour solvents, pesticides, paint thinners, engine oil, or household cleaning products with hazardous chemicals down the drain or into a storm sewer. Take them to a recycling center or hazardous waste collection site. Use fertilizers and pesticides carefully and only as directed. Try to find safe alternatives to products that can harm water supplies.
- Be informed. Learn about your local water supplies and any possible threats the water supply faces. Know what your community is doing to protect your water supply. Help other citizens be aware of the importance of clean water in your community.
- Support your local wastewater treatment plant. Be aware of your wastewater treatment plant's effort to provide clean water. Help make sure the plant has the money, equipment, and personnel to ensure the water's safety. Visit your local wastewater treatment plant. Learn what special problems it must solve and what you can do to help. Use water wisely. Practice water conservation at home and at work. Fix leaks and install water-saving devices and appliances. Be aware of how much water you use in your household. Don't take this valuable resource for granted.
- Bathroom wipes –These “moist towelettes” are becoming an increasingly popular bathroom accessory. Despite the fact that they’re marketed to be flushed like toilet paper, these wipes are creating clogs and backups in sewer systems around the nation. Same thing goes for baby wipes and cleaning wipes.
- Feminine hygiene products –There is a good reason why every restaurant, mall or any public bathroom has a sign telling you NOT to flush feminine hygiene products down the toilet. They are inherently designed to absorb moisture and expand. The expansion makes them unsafe to pass through pipes and sewers
- Condoms –They probably seem small and very similar to toilet tissue, but these latex prophylactics are like kryptonite for sewage collection systems and wastewater treatment plants.
- Cotton balls and swabs – It might seem like these tiny bathroom tools would just get soggy and eventually break down in the sewer pipes, but they don’t. They eventually gather together in the bends of pipe, causing massive blockages.
- Prescription medicine – Many people feel like they’re doing the safe thing by flushing them, but it’s actually very dangerous. These drugs destroy bacteria, which are needed to process waste at the wastewater treatment plant and contaminate the river that the wastewater treatment plant discharges into.
- Paper towels – Most people think that they are designed to breakdown like toilet paper. They are not. Flushing them can cause big problems.
- Disposable diapers –Just because there is a mess in it, doesn’t mean that it belongs in the toilet. Diapers are made from plastic that’s designed to expand when it comes in contact with water. In the slim chance you get it down the drain, it will instantly be caught in the u-bend, and cause a terrible back up.
- Cat litter – Cat litter is made from sand and clay and should never be flushed down into a toilet.
- Band-aids – These are made from non-biodegradable plastic, which can cause terrible clogs in the sewer system.
- Dental floss – Despite feeling like string, dental floss is non-biodegradable. Once flushed, it loves to wrap itself around other objects in the pipeline, making tiny clogs bigger in an instant.
- Hair – Just because it’s part of our body doesn’t mean it can be safely flushed down the toilet. Like dental floss, it forms giant balls which trap other objects and creates massive blockages in sewer pipes.
- Latex gloves – Very similar to condoms in that they are made of latex, these create the same problems.
- Rags, cloth, mophead pieces- These cleaning supplies should be thrown away in the trash after their useable life has ended.
- Rope/string – These “cotton” items do not dissolve and can cause the same problems as dental floss.