Engineering solutions with a view for tomorrow.

City of Missouri City Surface Water Treatment Plant

As part of a regional water supply initiative, the City of Missouri City and Sienna Plantation MUD No. 1 selected eHT to provide design and construction services for a new surface water treatment plant to meet the Fort Bend Subsidence District groundwater conversion requirements. The long-term conversion plan is for an ultimate plant capacity of 33 MGD constructed in three phases. The first phase is a 10 MGD facility, and includes features incorporated into the planning and design that allows the plant to meet its second phase capacity of 20 MGD without constructing any major new structures. Increasing capacity to 20 MGD will require the addition of a new raw water pump, additional membrane modules and a new high service pump — all to be located in Phase I structures without expansion. Other cost saving features include separate construction contracts for site preparation and finished water storage, elimination of a disinfectant contact chamber, high rate (small footprint) clarifiers, equipment pre-purchasing for membrane and sodium hypochlorite generation equipment and the selection of aluminum chlorohydrate (ACH) as the coagulant to minimize chemical costs and reduce solids handling requirements. This plant design is a model for cost savings. Phase I of the plant (10 MGD) was bid at $27.1 million. The phased approach of plant construction simplified construction efforts to allow for multiple contractors working independently in their specialty, and has resulted in construction at approximately 90% of the estimated project cost.