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Show by timer shall be removed or replaced with demand controlled equipment ( or other such units with specific standards of efficiency) within a set time frame. Alternates and Treatment Costs Home Ion Exchange The standard household treatment process consists of an ion exchange unit using salt as the exchange ion. The costs associated with household water softening treatment include the purchase price and installation of the treatment unit as well as periodic operational expenses. The purchase price of softeners varies widely from $ 400 to $ 4,000 and differs by as much as $ 1,500 for units of comparable capacity and efficiency. Prices in Salt Lake City appear to be somewhere between $ 1,000 and $ 1,500, installed. Annual operating costs total roughly $ 31.50, which includes salt, electricity and water ( wasted during regeneration). The average Utah household softener consumes about 500 pounds of salt per year. A brief survey of Salt Lake area grocery stores found the average price of salt was around $ 2.50 per 50 pound bag. Thus the average annual cost for salt is approximately $ 25. Softeners consume about 3 watts of electricity. This equates to an annual cost of about $ 2.00. Annual water brine stream waste is approximately 5,000 gallons per unit, valued at about $ 4.50. The annual treatment cost of household softening was determined to be approximately $ 135 per household or $ 1.35 per 1,000 gallons of water ( assuming 100,000 gallons treated per unit per year) by amortizing the capital and operation costs over the useful life of a unit. Several representatives from the water softening industry estimated the life of a unit is about 15 years. The analysis assumed a capital cost of $ 1,000 and an annual interest rate of 5 percent. Regional Treatment Several treatment processes may be used to soften water on a regional basis, such as membrane softening ( or reverse osmosis), distillation and lime softening. Considering the quality of the water sources in the state of Utah, lime softening would generally be the most economical regional treatment process. Lime softening is a process which removes hardness from water by the addition of slaked lime. The lime causes calcium carbonate and magnesium hydroxide to precipitate. The precipitates are allowed to settle and are removed as sludge. When comparing regional lime softening to household ion exchange treatment, one consideration is that regional treatment using lime softening is most economical when it is used in those communities which use surface water as a sole source supply. Data obtained from the Division of Drinking Water suggest that about one third of the sources supplying Utah communities are surface waters. Where surface waters are not the source of supply, community distribution systems are commonly fed from a number of scattered wells. In addition, many communities in Utah are small, making regional treatment uneconomical. Another consideration is that lime softening is about 98 percent water efficient. And because the minerals removed during the process are disposed of as sludge, there is a net reduction of TDS in the domestic wastewater stream. In terms of economics, a number of studies have shown that regional lime softening has a lower annual treatment cost than household ion exchange. But in Utah the cost per household would be very nearly the same. With regional treatment, the entire domestic water supply ( 308 gpcd, USGS for 1990) must be treated, including outdoor uses such as irrigation. In contrast, household devices treat only the water used indoors. While lime softening would cost about $ 0.50 per 1,000 gallons, the annual cost per household would be $ 175 because more water is treated per household. Household Treatment Devices Two household treatment devices, reverse 81 |