Disinfection By-Products Formation Potential Along the Melendiz River, Turkey; Associated Water Quality Parameters and Non-Linear Prediction Model

Abstract

Organic matters in raw water have a potential to generate harmful disinfection byproducts such as trihalomethanes (THMs) and haloacetic acid (HAA) during the chlorination process. The aim of this study was to investigate the trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP) in Melendiz River and to determine the effect of several factors including water quality parameters, distance, and seasonal variation. Water samples (n = 93) were collected at Melendiz River during December 2015–November 2016. The range of THMFP and HAAFP was 47.28–3348.73 μg/L and 41.42–4952.68 μg/L, respectively. ANOVA analysis was performed to understand the impact of the seasonal and/or distance changes on DBPs formation. It was found that the seasonal variations (sig. ≤ 0.01) are more effective than distance variations (sig. > 0.80) at Melendiz River. Finally, a non-linear statistical model was developed based on Multiple Stepwise Regression Analysis using highly correlated water quality parameters with TTHM and THAA5 in Pearson Correlation Analysis. According to the results, among all factors, flow, dissolved organic carbon (DOC), UV254, UV272, bromide, temperature, and additional chlorine dose have a remarkable effect on THMFP and HAAFP. Especially, the Pearson correlation (P) values for the DOC and the Chlorine dosages are 0.583, 0.786 and 0.994 and 0.865 for THMFP and HAAFP models, respectively. In addition to this, the high R2 (0.95) values were obtained when compared to other predictive models. The local model development should be utilized because each water source has different organic characterization. For this reason, the development of local models for each water source is important for achieving more consistent results.