Wastewater Treatment & Clean Energy: Turning Negatives into Positives

A Rhode Island wastewater treatment plant will soon be making use of clean, renewable wind power to supply some 40% of its electricity needs, significantly cutting its indirect greenhouse gas emissions and saving more than $1 million a year in the process. A Florida start-up is working to install a system that uses sludge from wastewater plants to generate clean energy.

Investment in combining clean energy and wastewater treatment is on the rise in the US, as public and private sector industry and businesses take on the increasingly pressing challenges of making clean, sustainable use of increasingly valuable water and energy resources. Such initiatives offer Triple Bottom Line benefits to private businesses and public utilities, both over the short- and long-term.
Three wind turbines will supply 4.5 megawatts (MW) -- 40% -- of electrical power for Providence, Rhode Island's Field Point wastewater treatment plant. The Narragansett Bay Commission is building the 365-foot wind turbines, which will begin being erected on-site in December, the city's WPRI news network reported.

Providence's Five Fields plant treats wastewater from local industry, businesses, homes and schools before it is discharged into Narragansett Bay. The cost of the the wind power project totals $12 million. Electricity production is slated to begin in March, 2012.

The plant's annual energy bill, currently some $2.8 million, will be reduced by $1.1 million once the wind turbines are up and running, according to the Ray Marshall, the Narragansett Bay Commission's executive director. Included in the projected savings is revenue the that will result from selling electricity to electric utility National Grid on days when the turbines generate more power than the plant needs.

Clean Power from Wastewater Sludge

Way down south on the East Coast, Pompano Beach's Power Green Energy awaits final approval from the Fort Lauderdale City Commission to begin work on a project that would turn sludge from wastewater treatment plants into renewable electricity for the state. If the start-up's rezoning application is approved, it expects to have the system up and running by the middle of 2012, according to a CBS Tampa report.

“To be able offset energy use for wastewater facilities with renewable energy or renewable gas from the very waste going into the facility in the first place is the optimum solution,” Patrick Serfass, executive director for the American Biogas Council, told CBS Tampa.

Power Green Energy's system employs anaerobic digesters that use wastewater sludge to produce bio-gas on a renewable basis. The company's goal with the Fort Lauderdale project is to produce 4 MW of electricity, enough to power some 1,000-plus homes.

“This is taking a negative and turning it into a positive for our environment,” PGE Co-Owner Amie Silverman told the South Florida Sun-Sentinel.

The process also clean-treats the wastewater sludge, turning Class-B biosolids into Class-A biosolids that are free of pathogens, bacteria and viruses. That goes a long way towards assuring that Ft. Lauderdale's world-famous beaches and Atlantic Ocean waters stay healthy for human and marine life.

Projects similar to these have also been completed or are under way in Orlando, Fla., Lake Forest and Orange County, California; North Carolina and Wisconsin.