1995-08-11_REVISION - M1977493 (12)

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Overview of Climax Lime Plant Operation In 1993 a different method for quicklime preparation and addition to the water at Climax requiring treatment was adopted because of inordinate operation and maintenance pulverized costs attributable mesh)quicklime to eslaking was A method used in the eastern states was implemented whereby added directly to the flow stream through a cyclonic mixing chamber to avert the need for formalized "slaking". When the AFF was submitted in May 1994 this method was still thought to be practical. The scope of the AFE included moving the existing lime addition point from the TDH building to the McNulty Gulch/W, 2 Dam location, and to minimize the cost of this relocation what ver eatab Bible. Thecesse that the for the relocation wss to facilitate addition of lime to so of the gracticable use of Robinson Reservoir pumps could be Nnimized. One was added as a Coming storage conventional 310 was included in the AFE, and one detention-type slaker The direct addition method depends an a reliable supply of pulverized and highly reactive lime for successful application. it became apparent that the method was infeasible when the first trial during peak runoff conditions ensued during June 1994. Portable, batch-type slakers have been used since that time to improve the utilization efficiency of lime. These have marginally provided enough reagent for treating the waters for discharging, but are operator and maintenance intensive and infeasible during winter months. In addition, the use of process water for slaking has proven to cause lime waste of 15 to 20 percent according to published data from the National Lime Association. A thorough study of the past and expected future use of Ems, the current technology and chemistry of lime slaking,and other considerations such as storage requirements and operating costs was precipitated by the failure of the direct-addition method. The current design is the result of those efforts. The model for the proposed plant is a water treatment facility at Columbus, Ohio where two Wallace & Tiernan paste-slakers of the same capacity (8,000 pounds per hour) as those proposed for the McNulty station have been operating for many years at exceptionally low manpower requirements and with optimum lime usage. Three slakars, each rated at 8,000 pounds per hour and their accompanying storage silos rated at four truckloads each are now proposed. The peak(ate of Time addition in recent years at Climax has been six truckloads per day which is equivalent to 12,500 pounds per hour. The largest sized WIT slaker is 8,000 pounds per hour and therefore two would be required during peak runoff conditions based on historical use. The third slaker and silo are justified for two reasons: 1) during peak runoff in wet years there would be a back-up unit to bridge unexpected equipment down-time, and 21 the combined storage capacity of 12 truckloads would bridge over the longest experienced period of non-delivery ttwo days) at peak demand conditions. Should additional on-site storage be required, bulk storage in a separate bin and pneumatic transfer to the three "day-bins" could be constructed and easily integrated into the current design. Other facilities that have added to the scope of the original concept have been the addition of a water storage tank, a larger building to house the equipment,and facilities to ensure a clean water supply for slaking and routine housekeeping operations such as washdown and a small restroom. The evaluation of slaker technology showed that paste-type slakers are the eoest o�d fe�S provided that a law-sulfate water supply can be acquired; and that ball-mill type effective (though more costly from a capital and operating cost standpoint) if such a water supply is not feasible. A test well has been drilled near the lime plant and, in conjunction with1a upple avail efor slaking. supply that already flows past the plant, will ensure that the low-sulfa w ill te water supply Ball-mill type slakers will not be necessary with this water supply. The observed low-cost operation Of the Columbus, Ohio plant is believed to be attainable with the current design,