STATISTICAL ANALYSIS TO IDENTIFY THE MAIN PARAMETERS TO EFFECTING WWQI OF SEWAGE TREATMENT PLANT AND PREDICTING BOD

Abstract

The present study was conducted to determine the wa stewater quality index and to study statistical int errelationships amongst different parameters. The equation was developed to predict BOD and WWQI. A number of water quality ph ysicochemical parameters were estimated quantitatively in wastewater samples following methods and procedures as per governing authority guidelines. Wastewater Quality Index (WWQI) is regarded as one of the most effective way to communicate wastewater quality in a collective way regarding wastewater quality parameters. The WWQI o f wastewater samples was calculated with fuzzy MCDM methodology. The wastewater quality index for treated wastewater was evaluated considering eight parameters subscribed by Gujarat Pollution control Board (GPCB), a governing authority for environment al monitoring in Gujarat State, India. Considerable uncertainties are involved in the process of defining the treated wastewater q uality for specific usage, like irrigation, reuse, etc. The paper presents modeling of cognitive uncertaint y in the field data, while dealing with these syste ms recourse to fuzzy logic. Also a statistical study is done to identify the main affecting variables to the WWQI. The Statistical Regres sion Analysis has been found to be highly useful tool for correlating different parame ters. Correlation Analysis of the data suggests tha t TDS, SS, BOD, COD, O&G and Cl are significantly correlated with WWQI and DO of wastewater. The estimated BOD from independent var iance DO for maximum, minimum and average is 25.35 mg/L, 2.65 mg/L and 13 .56 mg/L respectively. While estimated WWQI from in dependent variance DO for maximum, minimum and average is 0.6212, 0.3074 and 0.4581 respectively. Out of eight parameters, T DS-BOD, TDS-COD, TDSCl, SS-BOD, SS-COD, and BOD-COD are significantly c orrelated. Present study shows that WWQI is influen ced by BOD, COD, SS and TDS.