CONTROL DEVICE FOR CHEMICAL INJECTING QUANTITY OF SLUDGE TREATING APPARATUS

摘要

PURPOSE:To perform satisfactory adjustment of sludge by comparing values of pH measured for an FeCl3 injecting tank and a Ca(OH)2 injecting tank with predetermined values of pH and controlling the quantities of FeCl3 and Ca(OH)2 to be injected in accordance with the difference of pH between the measured values and the predetermined values. CONSTITUTION:Comparison of pH measured in an FeCl3 injecting tank 1 and preset value therefor, for example 3.5-5.5 is performed by a pH controller 8, and the control of the quantity of FeCl3 to be injected is done by controlling a motor valve 11a in accordance with the difference between both values. The control of the quantity of Ca(OH)2 to be injected is performed by controlling a motor valve 16 basing on the difference between the value of pH in a Ca(OH)2 injecting tank and a preset value, for example 11-12. The quantity of Ca(OH)2 to be injected is obtd. as an output of a pH controller 14 which is used as an input of set value to a Ca(OH)2 injection controller 15.