Treatment Efficiency and Formation of Disinfection By-Products in Advanced Water Treatment Process

Abstract

This study found that advanced and traditional chlorination water purification processes significantly reduced turbidity and concentrations of ammonia-N (NH₃-N), nitrite nitrogen, iron, and manganese. Pellet-softening treatment was effective in reducing alkalinity and total hardness (TH) concentrations. Low TH concentrations are known to reduce cardiovascular death rate. Both total organic compound (TOC) and total dissolved solids (TDS) concentrations are typically considered precursors of trihalomethanes (THM_S) and haloacetic acid (HAA₅). In this study, advanced and traditional chlorination water purification processes were not effective in reducing TOC and TDS concentrations. In the formation of disinfection byproducts (DBPs), the THM_S and HAA₅ were efficiently removed by flocculation/sedimentation and the biological activated carbon (BAC) treatment processes. Postchlorination can reproduce THM_S and HAA₅ levels in a freshwater reservoir. Bromate concentration's lower detection limit were treated by the ozonation process during the study periods. Advanced treatment processes should controlled the doses of ozone and postchlorine to avoid produce DBPs.