By Jay Landers

In its latest move in support of its ambitious plan to boost wastewater reuse and reduce reliance on imported water, California’s Inland Empire Utilities Agency recently hired the program management firm Jacobs to manage the expansion of its recycled water system. By enabling the IEUA to purify wastewater to an advanced level, the expansion will help the agency increase local groundwater supplies within Southern California’s Chino Basin and conduct indirect potable reuse on a larger scale.

In a related milestone, the environmental engineering firm Brown and Caldwell recently announced the completion of the preliminary design of the new advanced water purification facility that will anchor the IEUA’s expansion of its recycled water system.

Seeking sustainable supplies

A regional wastewater treatment agency and wholesale distributor of imported water, the IEUA serves approximately 935,000 people within its 242 sq mi service area in western San Bernardino County. To this end, the IEUA operates five water recycling plants, a groundwater treatment facility, a composting facility, a wetlands and educational park, and renewable energy projects.

As it happens, the IEUA’s service area overlaps to a great degree with the Chino Basin, a large valley with geotechnical conditions that enable the storage of tremendous volumes of groundwater.

Although groundwater from the basin constitutes a large portion of the local drinking water supply, the region also frequently relies on water imported by means of the California State Water Project, the massive storage and delivery system used to transfer flows from water-rich Northern California to arid Southern California. In some years, imported water can constitute as much as 30% of the water used in the basin. However, during periods of drought, imported water supplies can be decreased, sometimes substantially.

In a bid to promote the sustainable use of groundwater and development of local water supplies, the IEUA has long engaged in wastewater recycling as a means to stretch existing supplies. Currently, the agency’s water recycling plants treat a combined total of more than 50 mgd, says Andrea Carruthers, the communications officer for the agency. The recycled water is then distributed throughout the IEUA’s service area for the purposes of agriculture, municipal irrigation, industrial uses, and groundwater replenishment.

Multiple benefits

For its part, the IEUA intends to expand its wastewater recycling system by adding new treatment and conveyance facilities. The expansion is a key component of the IEUA’s Chino Basin Program, an ongoing effort to boost local water supplies, increase water system flexibility, and reduce reliance on imported water.

In an innovative twist, the CBP also aims to benefit Northern California. By providing groundwater to a contractor involved with the California State Water Project, the CBP will facilitate an exchange by which water may be released from Oroville Dam in Northern California to the Feather River. These releases will benefit salmon populations in particular and the environment more broadly.

Major components

Following a competitive solicitation process, the IEUA board of directors approved on July 19 a master services contract with Jacobs for services related to program management, owner engineering, and strategic funding guidance associated with the expansion of the agency’s recycled water system. Other duties will include design, permitting, community outreach, and strategic advisory services. The two-year contract includes a not-to-exceed amount of $9.1 million.

“As climate change creates increasingly unpredictable water supply conditions in Southern California, IEUA is proactively investing to secure a sustainable, resilient water supply,” said Ron Williams, a senior vice president and general manager, Americas, for Jacobs, in an Aug. 10 news release. “By mobilizing global major program management capability, we'll help IEUA and its partners bring this innovative regional water management program from concept to reality.”

Major components of the planned regional water management system include an intrabasin system for conveying recycled water, groundwater injection and replenishment, and the 13.4 mgd AWPF. The latter “will be able to produce up to 15,000 acre-ft per year of purified water for indirect potable reuse using groundwater augmentation,” Carruthers says.

This volume of treated water is “enough water for nearly 100,000 residents” and will “create a more sustainable, drought-resilient local water supply in the Chino Basin,” according to the Jacobs release.

Demonstration planned

In late August, Brown and Caldwell announced that it had completed the preliminary design of the AWPF. “The preliminary design, developed in partnership with Water Systems Consulting Inc., provides the technical feasibility, planning-level design, and preliminary costs” for the facility, according to an Aug. 29 news release from Brown and Caldwell.

“We congratulate IEUA and program partners on this significant milestone vital to the program’s success,” said Andrew Lazenby, P.E., the project management director for Brown and Caldwell, in the release. “The AWPF is central to CBP operations and considered key infrastructure for IEUA to diversify its water portfolio while maintaining compliance with local groundwater replenishment and augmentation requirements.”

To be located at the IEUA’s Regional Water Recycling Plant No. 4 in Rancho Cucamonga, the AWPF will employ equalization, microfiltration, reverse osmosis, disinfection by means of ultraviolet light and advanced oxidation, and product water conditioning, according to Brown and Caldwell’s release. A pump station will convey water treated at the facility to a new wellfield for aquifer replenishment and eventual indirect potable reuse.

The facility’s RO treatment process will comprise a high-recovery system that is expected to recover more than 88% of the influent flow rate feeding the AWPF, Carruthers says.

A demonstration version of the AWPF will be constructed to pilot-test the technology. Although discussions regarding the demonstration facility are ongoing, the pilot project “would further evaluate water quality considerations on high-recovery reverse osmosis and provide additional benefits of public outreach, operator training, and early regulatory engagement to meet the objectives of the program,” Carruthers says.

Construction of the various components that constitute the recycled water system expansion will begin in 2028, with facilities expected to come online by 2030, Carruthers says.

This article is published by Civil Engineering Online