| 摘要 |
<p>PURPOSE:To provide a dephosphorization method and apparatus in which the dephosphorization function is maintained without troubles by dephosphorizing the dewatering filtrate of digested sludge even when DO in inflow water is elevated with the decrease in phosphorus concentration in water to be treated. CONSTITUTION:A dissolved oxygen meter 40 and a flow meter 41 are installed in inflow water 11; a dewatering filtrate temporary storing tank is equipped with a pH meter 43, a pH feedback controller 44, and an alkali injection device 45. A polymeric coagulant is injected to concentrated digested sludge which was digested in an aerobic-anaerobic tank 42, and the sludge is dewatered with a dewaterer 25. The reagent injection ratio is calculated on the basis of the stoichiometric relationship between phosphorus and a dephosphorization reagent obtained from the data on the phosphorus concentration in the dewatering filtrate and the dissolved oxygen in the inflow water. The final reagent injection ratio is determined by multiplying the calculated reagent injection ratio by the data on the flow rates of the dewatering filtrate and the inflow water. In this way, the treatment to make phosphorus insoluble is conducted by injecting the reagent to make phosphorus insoluble to the dewatering filtrate, providing the dephororization method and apparatus.</p> |
