Challenge: To maximize use of water available from the Leo J Vander Lans Advanced Water Treatment Facility (LVL AWTF) for replenishment of local drinking water aquifers. 

Solution: INTERA is part of a multi-firm team that is leading the permitting, design, construction oversight, and commissioning for a 2 million gallons per day (MGD) injection well and two regulatory monitoring wells to inject LVL AWTF advanced treated recycled water for groundwater replenishment. This treatment facility receives tertiary-treated water from the Long Beach Water Reclamation Plant and provides up to 8 MGD of advanced treated recycled water for injection at the Alamitos Seawater Intrusion Barrier Project (Alamitos Barrier Project) and the new inland injection well. The new injection well helps to maximize the beneficial use of advanced treated water for replenishment of local drinking water aquifers and improves the efficiency and performance of the LVL AWTF by reducing fluctuations in the production rate of the treatment processes. 

INTERA performed modeling analyses using the Alamitos Barrier Model (previously developed by INTERA) to evaluate siting and feasibility of injecting up to 8 MGD from the LVL AWTF at potential new inland injection wells, with increased extraction from existing production wells. Particle tracking simulations were performed to evaluate residence times and travel paths of the recycled water to ensure that the injection and extraction wells would meet Title-22 requirements. INTERA geologists developed the design of the new inland injection well and prepared plans and technical specifications for bidding. We provided field oversight throughout the drilling, construction, and testing of the injection well and triple-nested monitoring wells for Title-22 compliance. Completed testing of the injection well indicates high efficiency and greater than anticipated capacity.  

INTERA led the preparation of the Updated Title-22 Engineering Report (T-22 Report), including the proposed inland injection well and other updates required to bring the T-22 Report into full compliance with current permit requirements, regulations, and recycled water policy. We assisted WRD in developing a permitting strategy in coordination with the Regional Water Quality Control Board (RWQCB) and California Department of Drinking Water (DDW). We are currently developing work plans and designs for an intrinsic tracer study for the inland injection well and an added tracer study for the Alamitos Barrier Project, both required by Title-22 Indirect Potable Reuse regulations for subsurface groundwater replenishment. We will also support WRD in implementing both tracer studies and perform analysis and reporting to validate groundwater modeling results.  

Results: Preliminary testing on the injection well indicates that it will operate at high efficiency with greater than anticipated capacity. Risks associated with potential delays in Title-22 permitting have been effectively mitigated through proactive outreach to DDW and RWQCB.