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

A.K.Khambete, R.A.Christian

Abstract: The present study was conducted to determine the wastewater quality index and to study statistical interrelationships amongst different parameters. The equation was developed to predict BOD and WWQI. A number of water quality physicochemical 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 of 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 environmental monitoring in Gujarat State, India. Considerable uncertainties are involved in the process of defining the treated wastewater quality for specific usage, like irrigation, reuse, etc. The paper presents modeling of cognitive uncertainty in the field data, while dealing with these systems recourse to fuzzy logic. Also a statistical study is done to identify the main affecting variables to the WWQI. The Statistical Regression Analysis has been found to be highly useful tool for correlating different parameters. Correlation Analysis of the data suggests that TDS, SS, BOD, COD, O&G and Cl are significantly correlated with WWQI and DO of wastewater. The estimated BOD from independent variance 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 independent variance DO for maximum, minimum and average is 0.6212, 0.3074 and 0.4581 respectively. Out of eight parameters, TDS-BOD, TDS-COD, TDSCl, SS-BOD, SS-COD, and BOD-COD are significantly correlated. Present study shows that WWQI is influenced by BOD, COD, SS and TDS.

Keywords: Wastewater quality, Uncertainty, fuzzy set theory, correlation, Regression.

DOI: https://doi.org/10.15623/ijret.2014.0301030