Full Description

Water systems across the United States have experienced the loss of chlorine residual and nitrification in some shapeor form. Some utilities may be self-inflicting these problems, but in other cases the physical configuration of thewater distribution system creates perfect conditions for bacteria to grow. Other systems are taking a closer look attheir disinfection strategy to determine if the chemical doses are enough to meet the disinfection criteria or, in somecases, if overfeeding disinfection chemicals is adversely affecting the treatment and distribution process.Sustaining a chlorine residual in the distributions system without forming DBP's is a balancing act by itself. Addingthe optimization of chemicals to the formula makes it even more challenging. This paper presents a case study at the Greenbelt Municipal and Industrial Water Authority (GMIWA)where the loss of chlorine residual led to an evaluation of the disinfection strategy, resulting in chemical cost savings. GMIWA operates an 8.0 MGD conventional watertreatment plant and a 120 mile linear distribution system that supplies water to five primary customers and 23 smallsystems across 5 counties in northwestern Texas. The GMIWA operated a free chlorine system until highoccurrences of disinfection byproducts (DBPs) forced them to evaluate disinfection alternatives. The TexasCommission on Environmental Quality (TCEQ) approved the GMIWA's request to use chloramines as adisinfectant on November 3, 2003 to reduce formation of DBPs in the distribution system. This three-year casestudy evaluated the disinfection strategy at the water treatment plant (WTP) to optimize the use of chemicals andanalyze the chlorine residual loss and nitrification in the distribution system and unusual DBP concentrations. Includes tables, figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 7File Size: 1 file , 850 KB