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California treatment plant uses technology to promote efficiency
The Chino Basin Municipal Water District (CBMWD) was formed in 1950 to provide supplemental water to portions of San Bernardino, Riverside and Los Angeles counties. In 1973, CBMWD signed a contract with seven agencies in western San Bernardino County purchasing all of their individual treatment plants. In July 1998, CBMWD officially changed its name to the Inland Empire Utility Agency (IEUA).
Today, IEUA handles imported water, wastewater treatment and recycled water distribution from the cities of Chino, Chino Hills, Montclair, Upland, Ontario, Fontana and Rancho Cucamonga. Wastewater from the seven cities conveys into the regional trunk line and then moves into one of five wastewater treatment plants within the agency.
Regional Water Recycling Plant No. 1 (RP-1), IEUA’s largest plant, was built in 1948 by the city of Ontario with an initial capacity of 12 million gal per day (mgd). After a series of expansions in the 1970s, ’80s and ’90s, the plant now has a capacity of 44 mgd. Recently, RP-1 has been on the forefront of utilizing technology to promote efficiency.
One factor that has set RP-1 apart from other plants is its ability to reuse many of the byproducts produced during wastewater treatment. Solar panels produce about 830 kW of power during peak hours, and the plant also gets electricity from an in-house fuel cell process. Methane generated from the digester process goes through a reforming process that separates carbon and hydrogen. The hydrogen then goes through the fuel cell process, where it mixes with air and water to produce electricity and water. “It’s a very clean technology,” said Randy Lee, acting executive manager of operations for IEUA.
This process has given the plant the ability to power the entire facility using renewable energy. In 2012, the plant partnered with a private company to start the largest fuel cell facility in the U.S. using biogas, with a 2,800-kW capacity. Through a power-purchase agreement, the plant provides land and gas, and the private company provides the fuel cell and the ancillary equipment needed to support the project for 20 years. Commercial operations began Jan. 1, 2013.
The plant also recycles the water it produces. In 2013, approximately 31,000 acre-ft of water will be recycled. A large portion of this water will be distributed to industries for cooling, and to cities, golf courses, parks and schools for irrigation. About 10,000 acre-ft of this recycled water will be used for the plant’s groundwater recharge program. The plant manages 19 basins within its service area to recharge groundwater.
Out With the Old, In With the New
RP-1 also has begun work on a project to update its outdated dewatering facility and make it more efficient. According to Lee, the dewatering facility, which historically used belt presses to dewater digester sludge, had come to the end of its useful life. So, in November 2009, construction began on the new facility. One of its goals is to dewater sludge within an eight-hour period, because the facility is staffed 10 hours a day.
Another goal that the new dewatering facility will meet is the production of cake—dewatered sludge—at a minimum of 24%. “We historically get about 17% to 18% cake, so it’s a lot more efficient way to dewater sludge,” Lee said.
The new facility, which costs $27 million and is fully funded by the American Recovery and Reinvestment Act, will include four Alfa Laval centrifuges and two silos, which will allow RP-1 to have the flexibility of storing two days’ worth of dewatered sludge. The new facility is scheduled to be in full production by July 2013.
A Focus on Maintenance & Efficiency
Lee said as the plant moves forward, it will continue to focus on efficiency. “Every project we embark on these days, we always look at being energy efficient,” he said. For example, the plant always opts to use premium efficiency motors. Talks of switching blowers to make aeration systems more efficient also are frequent, because that is where most of the plant’s energy goes. “We also are looking into sub-metering at all of our big primary movers, maybe even down to the equipment level, so we know how much energy each piece of equipment is using,” Lee said. This would allow the plant to better manage its energy use.
Another area on which the plant is focused is maintenance. “We want to move away from reactive maintenance to get into more predictive and condition based monitoring, eventually moving into reliability center maintenance,” Lee said.
In order to do this, a training program has been implemented for staff, covering vibration and lube oil analysis and route cost analysis. “When something breaks we don’t just go in there and fix it,” Lee said. “We also have somebody else look at it and ask, ‘Why did it fail in the first place and how can we prevent this same failure in the future?’”