The environment has taken center stage in the Obama administration, but a California-based municipal water and wastewater utility, which operates five water-recycling facilities for 880,000 residents 35 miles east of Los Angeles, already has spent the last five years embarking on a comprehensive strategy to reduce its energy use and to generate the majority of its electrical needs through renewable biogas, energy generated onsite, and solar power.
The Inland Empire Utilities Agency (IEUA), located in San Bernardino County, was formed as a wholesale water utility in 1950 to become a member agency of the Metropolitan Water District (MWD) of Southern California to receive imported water from the Colorado River. IEUA has grown to a regional wholesale water and wastewater utility with a current electrical consumption of about 12 MW annually.
About one-third of the water distributed by the IEUA is imported from the MWD via the California State Water Project (SWP) and from the Colorado River from MWD's aqueduct built in the 1930s. The remaining two-thirds is derived from local ground-water and surface runoff.
But importing water to southern California is very energy-intensive: The SWP uses about six times the energy, and the Colorado River uses about four times the energy of a local groundwater well in Ontario, Calif., to supply the IEUA service area.
The SWP does not pay the entire bill, though. Charges are billed to the MWD, which in turn bills the IEUA its prorate share based on water delivery.
Overall, energy use by water and waste-water utilities in California is a significant issue: About 19% of all electrical consumption in the state is related to pumping, treating, and distributing water. Energy use will only increase with population growth. The service area of the IEUA is expected to grow by an estimated 50% over the next 20 years to about 1.3 million people.
Given the growth trends, the agency's five-member, elected board of directors and management team recognized the need to develop new local water supplies to offset the need for additional imported water, to reduce the potential for drought in its 242-square-mile service area, and to reduce its net energy use.
In addition, climate change likely will affect water supplies in California and the arid Southwestern portions of the United States in the next decade as reported by the U.S. Bureau of Reclamation.
As result of a feasibility study commissioned by a National Science Foundation grant of $1.5 million and conducted by the RAND Corp., the IEUA decided to increase investments in local supplies by adopting a multifaceted strategy that would capitalize on increased conservation, recycled water, and stormwater capture in the local groundwater aquifers. Specifically, the IEUA decided to accelerate water conservation practices; expand a water distribution system for irrigation and industrial uses by replacing drinking water with recycled water; and utilize local groundwater supplies as effectively as possible.
The strategy was designed to increase water supply reliability while reducing the utility's dependence on imported water.
In the past five years the utility and seven of its municipal customers have invested more than $350 million in new water infrastructure, including a new 75-mile recycled water pipeline distribution system that delivers recycled water from four existing waste-water recycling plants to industries, parks, schools, golf courses, and other irrigation customers. The recycled water treatment process ranges from primary to tertiary treatment, including filtration and disinfection. The new distribution system consists of pump stations, pipelines, and reservoirs that deliver recycled water from the treatment facilities to the customers' sites.
Additionally, 20 new wells were added to the Chino Basin, which is now home to more than 100 municipal wells and 150 agricultural and industrial wells. The basin is a mixture of sand, gravel, silt, and clay soils, so most new wells are easy to drill.
Groundwater recharge facilities — a combination of 19 existing flood control retention basins and new recharge basins — have been improved at a cost of $50 million to enhance stormwater capture and to increase capacity to more than 110,000 acre-feet annually. Basin maintenance, including silt removal to maintain recharge capacity, averages $500,000 annually.
With federal and state funding, the cost of developing the new local supplies is cost-effective compared to purchasing imported water from MWD. Although each city council sets its rates and charges differently, the increased use of recycled water will offset the need for more imported water — ultimately reducing costs to customers by 10% to 20% as the population increases.
The recycled water distribution system from the utility's wastewater plants throughout its service area is a key part of the program. Through a $200 million capital improvement budget — funded by low-interest loans from the State Revolving Fund, revenue bonds, both state and federal grants, as well as local property taxes, connection fees, and user charges — the utility plans to increase its annual daily amount of reuse to more than 50 mgd from 15 mgd in the next three years, increasing the amount of produced recycled water reused to more than 85% from just 25%. The energy savings of using recycled water over importing water will be equivalent to about 7,500 kWh per 1 million gallons of water.
To further increase self-sufficiency, the IEUA began a comprehensive energy efficiency program in 2002 that includes:
Energy of audits of all facilities, including the sewer collection and wastewater treatment facilities
- A LEED Plantinum Administrative Building complex that uses 15% of the energy needs of a comparable building (with heating and cooling recovery, solar on the roof, and efficient lighting)
- A 3-MW dairy cow power project with grant funding from the California Energy Commission, a $5 million USDA Natural Resources and Conservation Service grant, and a $2.3 million renewable energy grant from the U.S. Department of Energy for projects using new technology using biogas
- The installation of internal combustion engines and optimized self generation of biogas supplemented with natural gas
- The use of hybrid and electric vehicles.
As a result, the IEUA has adopted a goal to be off the electric grid by 2020 through maximum use of renewable energy, optimizing energy usage, and implementation of new generation technologies. Current total electrical usage is about 13 MW annually and will increase to 18 MW as a result of the increased pumping of recycled water to customers.
Finally, the utility has implemented a program to maximize its local reuse of biosolids recovery through composting.
Through a joint project with the Sanitation Districts of Los Angeles County, it's composting all 75,000 tons of biosolids its service area produces every year and selling it to city parks, golf courses, and landscapers from an enclosed converted warehouse building used by the IEUA. The distance from the IEUA sewage treatment plants to the local composting plant is a few miles, compared to the 150- to 320-mile trip to haul biosolids away from the metropolitan Los Angeles area. Those reduced trips have reduced fuel consumption, air pollution, and CO2 emissions by the utility's fleet of 50 vehicles by more than half.
Today the IEUA operates four tertiary wastewater plants with a combined capacity of approximately 85 mgd. It produces and distributes about 20 mgd of recycled water, operates a 25-mgd groundwater desalination plant to produce drinking water, a dairy manure/food waste anaerobic digester facility, and an indoor biosolids composting facility. IEUA produces recycled water, renewable energy at its waste-water treatment plants, and biosolids and cow manure compost products.
— Atwater is the CEO/general manager of the Inland Empire Utilities Agency in Chino, Calif.