Abstract
A rapid technique was adopted and customized to assess the assimilable organic carbon (AOC) content of water for UV/H2O2 treatment applications. Indigenous consortium was used as inoculum and cells grown were counted using flow cytometry. Residual H2O2 after UV/H2O2 treatment was found to inhibit microorganisms’ regrowth, leading to incorrect AOC measurement. Therefore, Catalase immobilized on a polymeric support was used to eliminate the residual H2O2 prior to the AOC bioassay without affecting the water quality and the AOC. The choice of microbial consortium was found to influence the result of the AOC bioassay, suggesting that indigenous inoculum should be used for each individual sample set. Three days of incubation at 30°C were enough for the microorganisms to reach their stationary phase. Addition of minerals was found to be necessary, affecting the outcome of the AOC test. The method presented in this article will be valuable for monitoring AOC levels at different stages of water treatment train, especially when UV/H2O2 is used as one of treatment steps.
Acknowledgments
The authors thank Drs. Siva Sarathy and Mihaela Stefan from Trojan Technologies for their cooperation and technical feedback. We also thank Dr. F. Hammes from EAWAG for his kind inputs. Andy Johnson at the biomedical research centre of UBC is also acknowledged for his assistance on the FACS machine. RES`EAU-WaterNET Strategic Network and Natural Sciences and Engineering Council of Canada (NSERC) are acknowledged for financial support.