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6 <br /> removed in the ion-exchange column, then the column effluent would report to the ElectroClear and a <br /> dischargeable effluent would be achieved. <br /> Operation of WWTP <br /> To this point, everything had been relatively straight forward. However, upon startup of the ion- <br /> exchange column we found there were only one to two mg/kg Mo in the process water instead of the 18 <br /> mg/kg contained only a few years earlier. After the fact reflection leads us to believe that the addition of <br /> the ferric sulfate in the assimilation of the oxide tailing pond water during this period removed the <br /> dissolved Mo from the process water. In effect an ion-exchange column had been designed and <br /> constructed to remove dissolved Mo which no longer existed: <br /> The ion-exchange column began operations in 1977, and shut down by 1979. The process water <br /> was piped straight into the heavy metals recovery unit. This unit was far from being an economical unit, <br /> but it was required to meet the terms of a permit. At 126 1/s, the electroclear units were consuming <br /> approximately 6000 amps @ 24 volts. With the cost of power, the initial cost for treatment approached <br /> $0.53/m3 treated. This was an incredibly expensive process, so by 1980 research was begun to develop <br /> more economical methods of treating the water, considering not just chemical improvements but also <br /> mechanical improvements. The electrolysis electrodes had a short life. When the second set of electrodes <br /> required replacement, the units were converted to dissolved air flotation. Savings were realized from initial <br /> cost, replacement cost, and power consumption. Process research continued, and numerous methods <br /> were tested on a plant scale. The final process was the tried and true method of caustic precipitation. <br /> Discharae Volume Corrections <br /> When the company received its first water permit in 1974, the State, the EPA, and the Company <br /> were all under the impression that snowmelt bypasses would cease to be necessary. This would be <br /> accomplished by running the WWTP continuously, depleting the water system during the winter, thereby <br />