Preparing San Clemente’s Sewer System for Future Flows

As a city’s landscape changes, the plans that anchor utility planning need to adjust alongside it. The City of San Clemente, which lies midway between Los Angeles and San Diego at the southern tip of Orange County, owns and operates a water reclamation plant (WRP), as well as recycled water distribution and urban runoff treatment facilities. By evaluating the city’s sewer capacity and identifying ways the city could augment the local recycled water sources, beneficially reuse urban runoff, improve coastal water quality, and reduce biosolids at their WRP, Woodard & Curran updated the city’s sewer master plan to reflect the current challenges facing the community.  

Hydraulic Analysis and Capacity Evaluation 

As a part of the sewer master plan update, Woodard & Curran ran hydraulic models for three of the city’s seven sewer trunk systems to analyze the hydraulic capacities of each collection system. Each analysis had a distinct goal—one system hadn’t seen major upgrades since 1975 and the city needed to determine if it has the capacity to handle tie ins from a nearby housing development to increase wastewater flows into the WRP, another system was evaluated to see if there was capacity to take additional flows from a nearby urban runoff treatment facility, and another system’s capacity needed to be evaluated under both existing and future flow conditions. The models were built using the InfoWorks ICM software application developed by Innovyze and following the capacity analyses the firm gave the city a set planning and project recommendations. Study also analyzed current impact on recycled-water quality due to existing and planned flows from two urban runoff treatment facilities. Increased salt loading is evident with study recommendation to construct a small-scale Reverse Osmosis treatment train to minimize impact on water quality.

Biosolids Reduction Technology Review  

Increasing biosolids hauling costs had become an issue at WRP and as a part of their sewer master plan update, Woodard & Curran explored options to reduce biosolids quantity and therefore further reduce cost for the final disposal. The firm considered multiple biosolids reduction alternatives including: mechanical heat drying, greenhouse solar drying, incineration, and gasification. The firm analysis concluded due to the limited footprint available and the small scale of the facility, indirect heat drying was the only viable option for the plant.  Two alternatives were developed and costed for a 2.0 TPH and a 1.5 TPH system.
 

Details

City of San Clemente
San Clemente, California

Team

Senior Water Resources Engineer
RMC, now part of Woodard & Curran
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