Cleaning Up Your Wastewater Generates Power

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DES MOINES, Iowa – Every day the Des Moines Metropolitan Wastewater Reclamation Authority serves about 500,000 people. That means, on average, it treats 63 million gallons of water per day. That would be the equivalent of 950 Olympic-Sized pools every day or 40 pools every hour.

“We are essential. Without us, sewage would be in roads and streets,” Royce Hammitt, Operation Manager. “The river or lakes wouldn’t be swimmable or fishable.”

WRA is made up of 17 metro area municipalities, counties, and sewer districts. They work together to protect public health and to enhance the environment by recycling wastewater and being the preferred treatment facilities for hauled liquid wastes.

Hammitt has been at WRA since 1989 and the biggest change he’s noticed is the push to become “green.”

“Renewable is very important to what we do every day. It reduces cost for our ratepayers. It reduces our costs here and that benefits everyone,” said Hammitt. ”It also makes up feel good because it reduces our green footprint.”

Each day the facility generates over 36,000 kWh of electricity from biogas. That is enough electricity to power 1,200 Iowa households.

“It’s more reliable and efficient than wind turbines or solar power,” says Larry Hare, treatment manager. “We are running 24/7. When the wind isn’t blowing they can’t produce energy and when it’s dark you can’t get solar power.”

The WRA includes a conveyance system and a treatment facility. The system connects each of the participating communities in Dallas, Polk, and Warren Counties to the wastewater treatment facility. The system includes 125 miles of sanitary sewer with pipe sizes up to 144” in diameter, equalization basins and lift stations.

With the facility running so efficiently, they are able to run it with fewer staff than ever before.

“Well the plant uses more sensors and less staff,” said Hammitt. “Originally, when I was hired there were 164 employees, now there is 104.”

The treatment facility uses a combination of physical, advanced biological, and chemical processes to treat the wastewater as it flows through the plant. These processes produce high quality recycled wastewater discharged to the Des Moines River, treated biosolids that are land applied on farm fields for nutrient value and soil amendment, and biogas utilized for electrical and heat generation.

Hammitt said it’s very important for the community to know what the facility does so they can further help in protecting Iowa’s water.

“They need to appreciate what they are doing for the environment,” said Hammitt. “I want them to be aware that whatever they are putting down the drain comes to us and it shows them how it impacts the environment.”