The city of Waxahachie, Texas has chosen Siemens Water Technologies to supply a 20.5 mgd submerged membrane filtration system for Phase I of the new Robert W. Sokoll Surface Water Treatment Plant. The system consists of four individual Memcor CS trains, fed with settled water from the Tarrant Regional Water District raw water pipeline in north central Texas. The $3.3 million plant is expected to begin operation in April 2009.
Located approximately 30 miles south of Dallas, the city of Waxahachie has partnered with Rockett Special Utility District (SUD) to jointly construct the water treatment plant. Drinking water from the plant will help serve the northern half of the city as well as Rockett SUD and numerous wholesale customers across the county. The engineer for the project is Alan Plummer Associates, Inc. of Ft. Worth, Texas.
The city chose the Memcor CS system because the system provided the lowest cost per gal of treated water compared to other membrane technologies. Other advantages of the system include: a physical barrier against harmful parasites like Cryptosporidium and Giardia, as well as bacteria; flexibility in handling raw water fluctuations while providing consistently high-quality effluent and sustained capacity; and fully automated operation, including verification of system integrity.
Memcor submerged membrane systems operate in an open tank design. Feedwater typically flows by gravity into the membrane cell. A suction pump draws filtrated water through the membranes up to 12 psi. Submerged systems are ideal for retrofitting exiting basins and increasing capacity in a small footprint. The system has fully-automated processes including backwash, cleaning and membrane integrity testing. Membrane modules are isolatable in groups of four.
The city of Waxahachie and the Rockett SUD both plan to expand the facility in 20 mgd phases to prepare for their growth as well as their wholesale customers’ growth over the next 50 years. By 2060, the city and Rockett SUD and their customers expect they will need more than 80 mgd. By the time construction of each phase is completed, the plant will be able to treat this capacity.