Research and Development
The United States Environmental Protection Agency (USEPA) and The Nevada Division of the Environmental Protection implement regulations that establish specific requirements for drinking water purveyors. At the Truckee Meadows Water Authority (TMWA) the development of new technology and continuing research activities provide a thorough understanding of the treatment of drinking water for the highest quality at the least cost. The research conducted by TMWA is focused on not just meeting but exceeding all existing and new standards and continually improving water quality.
The USEPA has recently promulgated a new standard of 10 ug/L for arsenic. TMWA currently meets existing arsenic standards and has been actively researching new technologies to ensure compliance with future standards. Arsenic removal technologies such as adsorption medias and coprecipitation with metal coagulants have been thoroughly tested and evaluated. Testing during the summer of 2001 demonstrated that the Glendale Water Treatment Plant removes approximately 95% of the arsenic from the influent using coprecipitation with an aluminum coagulant following pH adjustment. Arsenic concentrations of less than 2 ug/L were achieved, exceeding all proposed arsenic standards.
Using high quality treated surface water to recharge groundwater during the winter months is currently being investigated as a means of enhancing the overall capacity of the water supply and distribution system to withstand possible periods of extended drought. Treated drinking water from the water distribution system is injected into groundwater wells during the winter when water demand and consumption is low and then recovered during the summer when water demands are significantly greater. The recovered water has also been found to remain at high quality meeting drinking water standards and may improve water quality within in the aquifer. During 2000, approximately 1,700 acre-feet were injected during recharge. Efforts nearly doubled in 2001 during which 3,100 acre-feet were injected during recharge.
A concentrated chlorine bleach solution is used as a disinfectant throughout the water distribution system in the Truckee Meadows. Chlorine is extremely effective in preventing growth of bacteria and other microorganisms and is extremely benign to human consumption. The USEPA has established standards to control concentrations of disinfectant chemicals used in drinking water and the disinfection by products (e.g., trihalomethanes and haloacetic acids) that may form in water after a disinfectant has been used. Ongoing research is currently monitoring and evaluating the performance of the disinfectant and the formation of disinfection by products. Alternative disinfectants and oxidants are also being considered.
The pilot plant system located at the Glendale Water Treatment Plant can be operated to simulate treatment conditions and processes of both the Chalk Bluff and Glendale Water Treatment Plants. The pilot plant system, which draws water from the Truckee River, has been used in the past to develop treatment schemes for rapidly changing raw water conditions that occur during intense rainfall events and spring runoff. The pilot plant system has also been used to test various water treatment chemicals in order to identify the most effective and cost efficient treatment scheme for use at each treatment facility.
TMWA has worked closely with the University of Nevada, Reno on several projects including groundwater recharge and recovery and the effects of pH adjustment to optimize treatment processes at the water treatment plants. TMWA is also a member of the American Water Works Research Foundation, which is the leading research organization in the water treatment industry.
