Abstract
A pre-coagulation and bio-filtration system for water reuse applications is discussed with a pilot plant treating actual municipal sewage for one year. Although denitrification is not accomplished perfectly when pre-coagulation is applied due to lack of organics, concentrations of SS, TATU-BOD, T-N and T-P in the effluent are less than 3mg/L, 10mg/L, 13mgN/L and 0.2mgP/L, respectively, under total hydraulic retention time of 2.0h in the bio-filter part. Without adding coagulants, T-N concentrations in the effluent of less than 10mgN/L are achieved. The potential denitrification rate of 0.5kgN/(m3·d) and nitrification rate of 0.3kgN/(m3·d) are obtained even in the cold season. Backwashing is operated automatically. Therefore this process is proved to be applicable with easy maintenance.
