There are over 16,000 publicly-owned treatment works in the United States, serving 75% of the total population. Although these facilities aren’t responsible for the drinking water flowing through our water pipes, they nonetheless play an extremely important role in our society.
Wastewater describes all the water that has been used, either in residential, business, or industrial settings. If this water was not treated before being released back into the environment, we’d be facing serious health issues (such as typhoid outbreaks and gastrointestinal illnesses). As lucky as we are to have access to such facilities, they don’t necessarily enforce the most environmentally-friendly practices. One wastewater treatment plant in Medina County, Ohio, decided to break this habit; by choosing to invest between $30 million and $35 million for anaerobic digesters and a Cambi system rather than the cheaper $17 million it would cost to update their current heat treatment process, they have found a better way to treat wastewater.
Anaerobic digestion describes the natural process in which microorganisms break down organic materials. The process produces biogas (composed of mostly methane and carbon dioxide), a renewable resource that can be used to power engines, fuel boilers and furnaces, and produce mechanical power. The Medina County treatment facility is using their biogas for electricity.
“We would be able to produce our own electric here at the plant, and we could also be more environmentally friendly,” said county administrator Scott Miller. “In reality, it’s not costing us anything because the savings is being used to cover the cost of the bond.”
The process runs 24 hours a day, seven days a week and translates to an estimated savings of $1.4 million per year. When the bacteria convert the waste sludge into a 60% methane product, it is burned in an engine and used to help power the treatment process. Traditional aeration systems require 25% to 60% of the energy usage of the entire plant; with anaerobic systems, that energy can be saved — and even gained.
“This is actually a net gain in energy that we’re using to reduce the amount of power that we’re going to use to run the process, run the plant itself,” said Philip Cummings, superintendent of the plant, who has spent the last 44 years treating wastewater.
About one in eight people in the world don’t have access to clean water. Although we are fortunate enough to live in a nation with a vast number of wastewater treatment plants, they aren’t as green as they could (and should) be.
Understandably, the Medina County plant is proud of their commitment to this greener way of doing things; they hope more facilities will follow in their footsteps and switch to environmentally-friendly — and financially worthwhile — anaerobic digester systems.
“We want to be on that cutting edge,” Miller said. “We want to be out in front and we want to be the leaders.”