PENGARUH BAHAN PIPA TERHADAP PELURUHAN KONSENTRASI KLORIN DALAM SISTEM DISTRIBUSI AIR MINUM

Abstract

The main disinfectant used in drinking water distribution systems to preserve microbiological quality is chlorine. However, over time, the concentration of chlorine tends to decrease due to interactions with pipe surfaces (wall decay) and chemical reactions in water (bulk decay). This study uses a first-order decay mathematical model to examine the chlorine decay rate under batch conditions, PVC pipes, and iron pipes. The research was conducted through laboratory tests with an initial chlorine concentration of 1.80 mg/L, observed over 7 days. The measured data were compared with predictions from the mathematical model, ????(????) = ????0 ????^?????????????. Model fit analysis was performed using the Root Mean Square Error (RMSE) and coefficient of determination (R²). The results showed that, under batch testing, the chlorine concentration decreased to 0.46 mg/L with a rate constant ???? = 0.12 day^?1; under PVC pipe conditions, it decreased to 0.30 mg/L with ???? =

0.17 day^?1; and under iron pipe conditions, it decreased to 0.15 mg/L with ???? = 0.25 day^?1.The highest model accuracy was achieved in the batch test, with RMSE = 0.06 and R² = 0.98, while PVC and iron pipe tests had lower accuracy with RMSE values of 0.08 and 0.10, and R² values of 0.96 and 0.95, respectively. The study concluded that the pipe material significantly affects the chlorine decay rate, with iron resulting in the highest decay due to complex surface interactions. This study provides a calibrated database and chlorine decay model for water–material interactions (PVC vs. iron) under controlled test conditions