Influence of edta and dtpa on the activated sluge treatment of a synthetic TCF effluent

摘要

A laboratory scale activated sludge s ystem was used to study the biodegradation of EDTA and DTPA in a synthetic TCF 9Total Chlorine Free) effluent. The efficiency of the system and the biological effect of the chelants, was evaluated through the chemical-biological parameters. Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Sludge VOlume Index (SVI) and the counting of rotifers and vorticella in the sludge. For both chelants, the degradation rate decrease by increasing their concentrations in the effluent. Also it was observed, a significant decrease in the capacity to COD removal and only a small loss of the BOD removal efficiency. The population of rotifers in the activated sludge s ystem was the most affected by the chelants, being totally inhibited when the concentration of EDTA was near to 100 mg/L.