METHOD DEVELOPMENT FOR MEASURING BIODEGRADABLE ORGANIC-CARBON IN RECLAIMED AND TREATED WASTEWATERS

Analyses that measure oxygen demand, such as biochemical oxygen demand (BOD) and chemical oxygen demand (COD) analyses, have long been used as indicators of contamination and wastewater treatment plant efficien cy. They measure the tendency of pollutants to react with oxygen, whic h is generally a good indicator of the stability or level of treatment . Both parameters include reactions with organic as well as inorganic substances and suffer from a lack of precision and accuracy at low con centrations, which are becoming increasingly more important. Biodegrad able dissolved organic carbon (BDOC) analysis is a relatively new proc edure that has advantages over both BOD and COD analyses, including in sensitivity to inorganic oxidations. A modified BDOC procedure was dev eloped to characterize the performance of advanced treatment methods, such as those used in municipal water reclamation and secondary-treate d wastewaters, where moderately low dissolved organic carbon concentra tions (4 to 15 mg/L) are routinely encountered. The development of the modified BDOC procedure was based on a combination of the existing ba tch BDOC protocol and BOD techniques. Various aspects and incubation c onditions were investigated to finalize the procedure. Nitrification d oes not interfere with the procedure. It is possible to simultaneously determine the soluble BOD (SBOD) under certain conditions. The proced ure has reduced variability and increased precision as compared to BOD and COD analyses.