United Water improves treatment facility in Rhode Island

United Water improves treatment facility in Rhode Island
United Water completed a $52 million design-build-operate project at the City of East Providence Water Pollution Control Facility that is reducing odors, improving plant operations, and lowering nitrogen levels that impact Rhode Island’s Providence River and Narragansett Bay. (Photo courtesy of United Water)

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An extensive infrastructure upgrade of a United Water wastewater treatment facility serving East Providence, R.I., has made the facility more operationally friendly and efficient. United Water operates the plant for the city.

In October, United Water, one of the leading U.S. providers of water and wastewater services, completed a $52 million design-build-operate project at the City of East Providence Water Pollution Control Facility that is reducing odors, improving plant operations, and lowering nitrogen levels that impact Rhode Island’s Providence River and Narragansett Bay.

“The health of our city and its people depends on the health of our environment,” says East Providence Mayor Bruce Rogers. “The improvements at the treatment plant will go a long way to accomplishing this goal.”

The infrastructure work by United Water on the 54-year-old plant is the first major upgrade at the facility since the mid-1970s. The plant serves about 60,000 people in East Providence and Barrington, R.I. Plant capacity averages 10.4 mgd with a peak flow of 23 mgd.

United Water project manager David Gaipo says the improvements were made to bring the collection system and treatment plant into compliance with Rhode Island Department of Environmental Management regulations.

“Our proposal team took to heart the city’s request to be innovative and creative on this DBO project,” Gaipo says. “Our team also wanted to stay focused on enhancing the treatment process already in use at the plant. As a result, we identified alternative solutions to bring the collection system into compliance with new state mandates.”

United Water worked with AECOM, D’Ambra Construction, the Hart Companies and E.W. Audet & Sons to complete the upgrades. 

The DBO team reconfigured existing aeration basins for integrated fixed-film activated sludge (IFAS) technology and a biological nutrient removal (BNR) process. The new system, which is designed to cut nitrogen discharges in half, depends on naturally occurring microorganisms that use oxygen instead of chemicals to remove phosphorus and nitrogen during the wastewater treatment process.

The IFAS upgrades incorporate the positive traits of two fundamental biological treatment processes, Gaipo says. Namely fixed-film technology and suspended growth technology (conventional activated sludge), together into one hybrid system. The United Water team used an IFAS design from Infilco Degremont featuring METEOR technology. By combining high biomass quantities typical of IFAS fixed-film technologies with fluidization typical of a conventional activated sludge (CAS), the METEOR technology achieves high removal rates in a small volume.

“Each of four aeration tanks were modified to provide multiple aerobic and anoxic zones and intermediate pumping that are necessary to achieve enhanced BNR,” says Gaipo. “The BNR process is important to reduce algae buildup that in turn helps improve water quality for aquatic life and recreation use for fisherman.”

According to Gaipo, other upgrades for the plant include two new odor control systems to treat harmful and odorous gases, new sludge dewatering equipment, electrical and instrumentation improvements, new aeration blowers, a new rotary drum thickener, a headworks building built to provide better odor control, new RAS pumps, new primary clarifier mechanisms, and a new collection system that has nearly doubled the capacity to eliminate sewer system overflows (SSOs) into the river and bay.

The new headworks building was constructed to enclose the channels and equipment for odor control as well as protect the operations from environment and weather conditions.

In regards to the odor control objectives, Gaipo says one system has a new biofilter unit complete with a fan and control panel to ventilate and treat odorous air from the new headworks building and raw sewage pumping station wet well. The second system is an activated carbon scrubber from BIOREM that treats air from the clarifier weirs. The improvements also include a new belt press dewatering system with a totally enclosed dewatering press that has significantly reduced odors from the previously problematic operations, he noted.

In addition to renovations at the plant, United Water increased flow capacity at its Watchemoket Cove and Boyden Boulevard pumping stations, and restored a three-mile stretch of a municipal bike path, where a new pipeline was installed, so the path is more scenic and recreational friendly.

The design and construction project took three years to complete.

“We made sure the new plant design included scalable technologies that will enable modifications to meet future regulations and operational needs,” says Gaipo. “Our team was committed to minimizing development impacts. All improvements were constructed using low-maintenance and energy-conserving materials, and operate with energy-efficient equipment.”



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