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DESCRIPTION OF PRETREATMENT SYSTEM <br /> Contents of the concentrated chemical baths are transferred to an <br /> above ground tank for collection and equalization. The collected <br /> liquor will then be pumped to an above ground neutralization <br /> pretreatment system. The pH adjustment system consists of a series of <br /> three tanks controlled by panel mounted pH meters connected to pH <br /> probes in the treatment tanks. The probe senses the pH of incoming <br /> liquor and initiates the flow of sodium hydroxide solution (30% in <br /> winter, 50% in summer) to achieve a pH of 6. 5-9 . 8 exiting the <br /> neutralization train. If the outlet pH from the third tank is below <br /> 6. 5, a three-way valve automatically diverts the flow back to the <br /> equalization tank. The pH will stay diverted until a minimum 6 . 5 pH <br /> is obtained. A totalizing flow meter is attached to the discharge <br /> line to monitor the flow rate. All control instruments will have <br /> audible alarms with flashing lights to signal an out of control <br /> condition or high level in the tanks. The proposed location for the <br /> new treatment system is shown on the attached plot plan. <br /> Dragout rinse water is typically processed through the on-site <br /> recycle water unit. when this unit is down due to either operational <br /> problems or routine maintenance, the dragout rinse water will be <br /> handled through the neutralization pretreatment system and discharged <br /> to the City. <br />