FPUD adds PFAS treatment to Conjunctive Use Project work

The Fallbrook Public Utility District has amended its design contract for the Santa Margarita River Conjunctive Use Project so that the groundwater treatment plant can also remove per and polyfluoroalkyl substances (PFAS) contaminants from the treated water.

A 5-0 FPUD board vote Jan. 27 approved an amendment to the design contract with Infrastructure Engineering Corporation which will provide IEC with an additional $771,143 and which will provide FPUD with treatment process selection, design services, and construction administration for the additional facilities.

"We'll take a very aggressive approach in water quality," said FPUD general manager Jack Bebee.

The Santa Margarita Conjunctive Use Project being pursued by FPUD, Camp Pendleton and the U.S. Bureau of Reclamation will enhance groundwater recharge and recovery capability within the lower Santa Margarita River basin and develop a program which will increase available water supplies for FPUD and Camp Pendleton.

Facilities within the lower basin will be constructed to capture additional surface runoff, which currently flows to the Pacific Ocean, during high stream flow periods. The surface water will be recharged through existing groundwater ponds and stored in groundwater basins during wet years while being "banked" for water rights statistics.

The water will be used to augment supplies during dry years, which will reduce the reliance on imported water provided from San Diego County Water Authority sources.

The Conjunctive Use Project will include improvements to the diversion works, increased capacity to the head gate and the O'Neill Ditch, improvements to seven existing recharge ponds, installation of new groundwater production wells and gallery wells, water treatment at either an existing or an expanded or new water treatment plant, and a bidirectional pipeline which could deliver water to FPUD while also providing the Marine Corps with an off-base water supply should conditions warrant.

The amount of water obtained will depend on weather conditions. FPUD will not receive any water in the event of an extreme drought. The minimum water delivery to FPUD will be 580 acre-feet for a very dry hydrological year, 1,300 acre-feet for a below-normal year, 3,100 acre-feet for a normal year (based on the average over the past 50 years), 5,120 acre-feet for an above-normal year, and 6,320 acre-feet for a very wet year.

A potential additional allocation of 400 acre-feet is possible, and FPUD also has the first right of refusal for excess water sold rather than used by Camp Pendleton which could provide FPUD with up to 1,500 additional acre-feet annually while also providing Camp Pendleton with revenue for operations and maintenance.

The Camp Pendleton infrastructure will include piping to deliver the water to the boundary of the Naval Weapons Station and Fallbrook behind the FPUD solar facility site on Alturas Road. Construction of the facilities from the NWS boundary is FPUD's responsibility.

The water will be treated at the Alturas Road plant and delivered into FPUD's distribution system. FPUD's costs will include a groundwater treatment plant, a distribution system to the Gheen Zone east of Stage Coach Lane, the Gheen Pump Station and a storage tank with piping, and construction management and supervisory control and data acquisition (SCADA) system integration.

The State Water Resources Control Board has a State Revolving Fund loan program which provides water agencies with low-interest loans. In January 2017 FPUD's board authorized an application for a State Revolving Fund loan from the State Water Resources Control Board to construct the Santa Margarita River Conjunctive Use Project, and the funding agreement for a loan of $53,334,000 to repaid over 30 years at an interest rate of 1.9% was finalized June 20, 2019.

The loan agreement was finalized prior to the July 10, 2019, deadline for bids and assumed a $51 million construction cost along with $2,334,000 for construction management and SCADA integration. Filanc Alberici JV had the low bid amount of $54,398,232, and FPUD worked with the State Water Resources Control Board to amend the agreement so that the additional $3.4 million can also be funded by the State Revolving Fund loan.

In January the State Water Resources Control Board approved a loan amount of $62,935,885 which includes a contingency of $5,440,000 as well as the construction, design and construction management costs. The contingency will allow the PFAS treatment to be funded by the loan.

"We think we have enough to cover the treatment," Bebee said.

The preliminary estimate is that the PFAS treatment work will add between $4 million and $5 million to the original $54,398,232 amount.

FPUD will also pursue grants to cover the cost of the additional treatment facilities, although the contract amendment allows that work to be combined with the other construction.

"We're doing it now so that everything can be done at the same time," Bebee said.

FPUD will use reserves to fund Santa Margarita River Conjunctive Use Project payments until the financing from the state is received. The use of reserves was approved on a 4-0 FPUD board vote Dec. 9, with Don McDougal absent.

"We have an approved State Revolving Fund loan, but the state is a little backed up in processing it," Bebee said.

Per and polyfluoroalkyl substances are a group of man-made chemicals which include perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and other chemicals.

PFAS chemicals have been manufactured and used in many industries since the 1940s, and the commercial use includes clothes, cosmetics, dental floss, furniture, carpets, pizza boxes, popcorn bags, nonstick cookware, lubricants, paints and firefighting foams.

PFOS was phased out of production in the United States in 2002 and PFOA was phased out in the United States in 2015, although those chemicals are still present in some imported products.

Because PFOS and PFOA do not break down and can accumulate over time those chemicals exist in the environment and in the human body. Exposure to PFAS chemicals may result in adverse health effects, and the U.S. Environmental Protection Agency is undertaking studies to determine whether maximum contaminant levels for PFOS and PFOA should be established.

In the interim, the EPA has set an advisory target of 70 parts per trillion (ppt) for PFOA and PFOS combined. The state's Division of Drinking Water has established notification levels of 5.1 ppt for PFOA and 6.5 ppt for PFOS, and Division of Drinking Water staff plans are to issue new response levels of 10 ppt for PFOA and 40 ppt for PFOS.

Last year the state Legislature passed Assembly Bill 756, which requires water providers whose systems exceed PFOA or PFOS response levels to shut off those sources or to issue extensive public notification.

An actual limit will be set once scientific research on health effects produces more data. The plans of the Division of Drinking Water staff also include reviewing five other PFAS substances for potential notification and response levels, although no timing for those results has been provided.

FPUD staff recommended treating the PFAS contaminants with a combination of granular activated carbon and reverse osmosis. The groundwater treatment plant utilizes greensand filters for iron and manganese removal followed by reverse osmosis and chlorination.

Reverse osmosis removes more than 99% of salts which pass through the process, so some flow bypasses the reverse osmosis process to meet the district's overall salt target.

The contract amendment with IEC will produce design documents for the additional granular activated carbon facilities. Once the treatment facilities are finalized a change order to the contract with Filanc Alberici JV, if not a separate construction contract for the facilities, will be brought to the FPUD board for approval.

In October 2014, the FPUD board awarded a $3,205,140 design contract to Infrastructure Engineering Corporation. The design work included an implementation plan and potential phasing options to balance upfront capacity costs with the project yield.

Funding for only the phasing, modeling, and preliminary design tasks was authorized at the time of the initial award. Subsequent design changes increased the total contract amount to $3,207,759, not including the additional amount for the PFAS control approved last month, and in September 2015 the funding for the final design was authorized.

Even with the additional treatment facilities the overall water costs from the Conjunctive Use Project are expected to be less than the price of imported water provided by the San Diego County Water Authority.