The city of Buffalo, Wyo., is among the many smaller U.S. water systems for which reliance on surface water means treatment changes are needed to comply with the Stage 2 Disinfectant and Disinfection Byproduct Rule (Stage 2 DBPR). The U.S. Environmental Protection Agency (EPA) mandate expands the scope of an earlier Stage 1 rule aimed at minimizing consumer exposure to disinfectants and disinfection byproducts (DBPs) in a community’s drinking water.
Superlatives flow easily when describing the new $300-million water treatment plant (WTP) for the city of Winnipeg, Manitoba, Canada. The world-class facility entered service in December 2009 after a decade of studies, design and construction. With normal upkeep and maintenance, the 12,000-sq-meter plant with an initial capacity of 400 million liters per day has an estimated design life of 75 years. Given that Winnipeg’s population of 650,000 presently needs only 256 million liters per day, the surplus offers the city a potential revenue stream in selling water to other communities.
In what has become a growing trend, the new Point of the Mountain Water Treatment Plant (POMWTP) in Draper, Utah, incorporated a multi-barrier approach to address specific disinfection issues shared by many surface water treatment facilities. The Metropolitan Water District (MWD) of Salt Lake & Sandy integrated a mix of complementary treatment barriers that resolve current issues while instilling the needed capabilities to adapt to changing regulatory requirements.
Few would dispute that adequate water supply always has been the lifeblood of any community. Entering the last decade, the existing Freedom District Water Treatment Plant (WTP), owned by the Carroll County, Md., Bureau of Utilities, had access to plenty of source water in the 3,100-acre Liberty Reservoir. The service area’s steady growth, however, squeezed the 3-million-gal-per-day (mgd) capacity of the county’s water plant.
Management at the 7 million gal per day (mgd) wastewater treatment plant and water reclamation facility in Smithfield,N.C., credits a deep-bed biofiltration system as the key contribution to the utility’s continued compliance with state regulations for total nitrogen discharge limits in spite of ongoing rapid growth in its service demand.
In 2006, the plant’s total nitrogen discharge to the Neuse River Basin was only 23,000 lb, against an annual mass limit of 67,467 lb. A $22 per lb fine is mandated for exceeding that limit.
It has been known for hundreds of years that membranes can be used for solids removal and concentration in potable water treatment schemes. In recent years, new low-pressure membranes have greatly enhanced effluent quality to meet increasingly strict regulations. In addition, water treatment professionals have discovered that the performance of these membranes can be improved when a pretreatment system is utilized to reduce the contaminants that cause fouling.