DETERMINING METHOD OF SLUDGE CONCENTRATION IN AERATION VESSEL

摘要

PURPOSE:To determine the accurate sludge concentration of a mixed liquid, by simulating the concentration of the mixed liquid in each section vessel on the basis of the relation among the main flow, branch flow and sludge concentration in the section vessel to establish relation fromulae and effecting calculation. CONSTITUTION:Primarily processed sewage flows from the first settling pond A into the first section vessel 4a of an aeration tank 1 through a valve 31 and a flow meter 32. Sludge returned from a last settling pond or a sludge well B flows into a section vessel 4a through a valve 33 and a flow meter 34. The concentration of mixed liquid in each of section vessels 4a-4e is simulated on the basis of the relation among the main flow, accessory flow and sludge concentration in the section vessel while using the ratio of the main flow to the accessory flow as a parameter. Relation formulae are thus established for the mixed liquid concentrations of the section vessels. Calculation is effected on the basis of the time series of numerical values obtained from concentration meters to determine the sludge concentration of the mixed liquid.