C153773 Feasibility Study - Laserfiche WebLink

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I I I I I I I I I I I I I I I I I I I ex1reme low flow periods, the high ratio of treated effluent from upstream development results in contamination by organics. Activated carbon must be properly fed to alleviate this problem. In 1985, a plant expansion (add another 0.5 MGD module to a total treatment capacity of 1.0 MGD) and improvement project was planned('2). This project was bid, but not awarded because of lack of funds due to the failure of the Mt. Carbon District to develop successfully. The plant is of good, basic, long-life construction, being primarily reinforced concrete and masonry. It is a standard rate (3.5 gpm/sf filter rate) rapid sand type plant, which includes flocculation and settling treatment. These are the same processes which would be used under present design practices. A comprehensive performance evaluation(17) was prepared in 1993. This study identified 1 "major" and 5 "minimal" effect deficiencies of the present plant at a 0.5 MGD capacity. The major problem was lack of chlorine contact time. The plant does not have the architectural features nor support amenities which are usual in the municipal plant of this size. Improvements such as additional office, laboratory, and maintenance space were to be included in the expansion project. Another problem is lack of chlorine contact time for disinfection. The addition of ultra-violet was included in the expansion project to provide adequate disinfection. D. DISTRIBUTION SYSTEM The Distribution system now operates in one pressure zone. Treated water is pumped from the plant to the distribution system - with a 200,000-gallon storage tank governing the hydraulic gradient. The high water level of this tank is elevation 6021 feet. For normal pressure service this creates a "blue line" elevation (maximum elevation for residential water service) in the range of 591 0 to 5920 feet. However, some residences on the south side have been developed above this level, and have marginal pressures. The main business district lies at lower elevations, in the range of 5760 feet, which results in a static pressure of 112 psi - which is a reasonable maximum pressure. The present Morrison base pressure zone was created after preparation of the 1971 Master Plan, and is consistent with that plan. It is noted that the existing Mt. Carbon storage tank was situated so as to be compatible with the Morrison Base Pressure Zone. The Mt. Carbon tank was built during the period when Morrison was contractually obligated to supply water to Mt. Carbon. 7(}.(l80.Q35:MSfR-PLN II-11