Wastewater Treatment Plant

Contractor/Certified Operator for Utilities
Operations Services

Operator/Mechanic
Justin Keller

Trainee
Shaun Hollars
Chad Reedy

Wastewater treatment usually takes place in 2 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 of. A grit chamber is a large tank which 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 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.

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 the average, each person in the U.S. contributes 50-100 gallons of wastewater every day.

HOW DO 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 that the water put back into our lakes or rivers has enough oxygen to support life.

WHAT IS SLUDGE?

Sludge can be a useful by product of treated wastewater. Sludge may be treated (thickened) to remove some of its water, then further processed by stabilization that allows raw sludge to be decomposed in digester tanks. In some cases, special chemicals are used for stabilization. Stabilized sludge has no odor and is free of disease-causing organisms. Some nontoxic sludge can be safely used as soil conditioner to improve the soil for crops in some areas of the nation. Sludge can also improve the soil for lawns, fields, parks, and fuel. Using certain processes, sludge 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. If it can’t be safely used, sludge must be buried in approved landfills or burned using special technology to prevent air pollution.

WHO OPERATES TREATMENT PLANTS?

The daily operation of a treatment plant is the work of highly-skilled people. It requires:

• A plant manager to ensure that the plant has enough money, trained personnel and equipment to carry out its job.
• Maintenance personnel to prevent mechanical failures and solve problems with equipment.
• Plant operators who know how to treat wastewater properly before discharging it into the environment. Most operators must have a license after being trained and passing an exam.

ARE THERE ANY SPECIAL CHALLENGES IN TREATING WASTEWATER?

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. 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 entering the treatment system through cracks or joints in sewer lines or storm drains places an extra burden on a facility.The amount and kind of wastewater entering a treatment plant can change quickly. Plant operators must be ready to respond to these changing conditions.

WHAT CAN I DO TO HELP?

Dispose of Household Products Safely. 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.

Learn about your local water supplies and any possible threats they face. 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. Be aware of your treatment plant’s effort to provide clean water. Help make sure it has the money, equipment. and personnel to get the job done. Visit your local treatment plant. Learn what special problems it must solve and what you can do to help. 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.