PROJECTING VIRUS INACTIVATION EFFICIENCY IN CHLORINE DISINFECTION TOWARDS HYGIENIC SAFETY MANAGEMENT OF WASTEWATER EFFLUENT WITH AN ENVIRONMENAL PREDICTIVE MICROBIOLOGICAL APPROACH

Abstract

 Required disinfection strength for wastewater effluent need to be determined based on a mathematical model that connects the operational parameters (e.g., CT value) and log reduction value (LRV) of viruses. However, an inactivation kinetics model applicable to wastewater effluent with fluctuated water quality has not been developed. This study aimed to develop an inactivation kinetics model of which predictors were water quality indices and operational parameters, using regularized regression analysis. The dataset of the LRV of the genus enterovirus and the experimental condition were collected through a literature review to be used in the model construction. We found that automatic relevance determination with interaction terms resulted in better prediction performances. Finally, we performed chloramine disinfection test using a laboratory strain of Enterovirus 71 and secondary treated wastewater in order to validate the developed model, and demonstrated that prediction accuracy was higher and overestimation of LRVs were reduced in Bayesian ridge regression with interaction terms. However, the virus LRV were overestimated especially when the observed LRV was lower than 2 LRV. These results suggested that the prediction performance is affected by the strain-dependent chlorine sensitivity of enteroviruses and other factors which lower the efficacy of chlorine disinfection of wastewater effluent. In order to improve the applicability of the developed model, further studies need to identify the unknown factors that affect the disinfection efficacy.