Navigating the Maze of Cost Effective Treatment Options to Address Capacity Needs and Comply with Water Quality Objectives

摘要

Faced with a strong demand for housing starts in the rapidly growing new town of Mountain House, California, the Mountain House Community Services District (MHCSD) and the housing developer (Trimark Communities), sought a way to solve the dilemma of addressing regulatory concerns about stringent microbial removal and disinfection by-products, while also doubling the capacity of their existing 2.5 mgdTrident～R filter WTP quickly and cost-effectively. The Mountain House WTP currently serves a population of approximately 3500 people in three master planned neighborhoods. The Community of Mountain House is projected to have an ultimate population of approximately 44,000 in 12 neighborhoods. Raw water from the California Aqueduct is transferred to the WTP from a remote pump station, owned and operated by the Byron Bethany Irrigation District, located 3-miles away. The project involved the evaluation of a variety of water treatment options including additional pretreatment ahead of the existing WTP to increase its capacity from 2.5 to 5 mgd. Leased membrane filtration units, high rate pretreatment options, enhanced disinfection with UV disinfection, and additional Trident～R units were all evaluated. The interim capacity project was delivered using an accelerated design and construction method that involved prepurchase of key process components to meet capacity and water quality objectives. The paper will present the treatment technologies selected for the expansion and details of the accelerated design and construction method used to achieve the project goals.