Upgrading well water disinfection systems

By Randy Walsh, Albuquerque Water Utility Div., Albuquerque, New Mexico

Figure 1: Standard ClorTec On-Site Hypochlorite Generating System.

The City of Albuquerque, New Mexico, depends on groundwater from 93 deep aquifer wells to supply drinking water to more than 400,000 users. The city is fortunate to have this source of water which is relatively free of bacteria. However, it must use disinfection systems to meet EPA and local regulations for water quality in its extensive storage and distribution facilities. The total production capacity of all wells is 294 million gallons a day (mgd), but conservation measures resulted in peak usage last year of only 169 mgd.

Disinfection takes place at reservoirs that receive water from well fields containing from one to eight wells. Until recently, chlorine gas from 150 lb. containers was being used for disinfection. Because of the inherent hazards of handling chlorine gas, plus more stringent regulations on its use, the Albuquerque Water Utility Division (AWUD) undertook an investigation of viable alternative disinfection technologies. The conclusion was to switch to on-site generation of sodium hypochlorite (NaOCl).

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