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Mayflower Acid Feed System <br /> The high pH water decanted from Mayflower Treatment Pond is adjusted to a pH of <br /> 6.5 - 9.0 at the Mayflower Pump Station by dripping sulfuric acid into the water stream <br /> at the outlet of the 42 inch decant pipe. Sulfuric acid is stored in a 10,000 gallon stainless <br /> steel tank in the Mayflower Pump Station. The discharge pH is automatically controlled with <br /> primary and backup controllers and alarms, and is continuously recorded. When a high or <br /> low pH is recorded, personnel are notified by the system alarm as detailed in the system <br /> alarm chart. <br /> Acid Pump Capacity <br /> "A" 16.6 GPM "C" 18.1 GPM <br /> "B" 83 GPM "D" 83 GPM <br /> Primary System <br /> The primary system has a controller reading stream pH, from a probe at the bridge. This <br /> controller sends a signal to the variable speed control to speed up or slow down the motor on <br /> the selected acid pump, to adjust the pH to the set point (usually 7.8). The drive on the left <br /> will control A & B and the drive on the right will handle C & D. Instructions for turning on or <br /> off pumps & drives are located on the drive cabinets. <br /> Operating Procedures / Controls <br /> Upon entering the building notice any leaks or fumes. In the control room check the gauge <br /> pH and the pH circular chart. At the set point 7.8, the gauge will give you the current pH. <br /> The pH circular chart will give you a history of the pH at the bridge. Next, check the acid tank <br /> level. Make note of the acid pump output by turning the switch to output on the controller. <br /> A good range is 25% to 75%. Note the stroke on the acid pump that is running. If the output on <br /> the controllers is high or low the stroke on the pump can be turned in (more acid) or out <br /> (less acid). The controller should then keep the variable drive at the correct RPM for that <br /> stroke and pH. Remember that high flow and low pH may require the same amount of acid <br /> as low flow and high pH. If you need to make an adjustment, it is important to wait 10-15 <br /> minutes to allow the system to stabilize. Making an adjustment on top of an adjustment <br /> before the full effect takes place can multiply your problems. <br /> Alarms <br /> see System Alarms <br />