Transformation of organic matters in sewage during A2O and soil aquifer treatment processes

Abstract

 This study revealed characteristics of dissolved organic matters (DOM) transformation during soil aquifer treatment (SAT) by comparison to Anaerobic-anoxic-oxic(A2O) treatment. SAT pilot-scale column experiment was conducted. Primary effluent from wastewater treatment plant, A2O treated water and SAT effluent were fractionated using DAX-8, XAD-4 and ion exchange resins. Each fraction was investigated functional groups by FT-IR and 1H-NMR techniques. As the results of these DOM analysis, hydrophilic neutral, transphilic and hydrophobic acids fractions account for 80.8% of residual DOM after SAT. Residual DOM included original DOM in primary effluent and produced DOM during SAT by bioactivity.

 Although trihalomethanes formation potential (THMsFP) was able to be reduced during both A2O treatment and SAT, it was found that the THMsFP of hydrophilic-neutral(HiN) fraction and its specific THMsFP were increased after SAT. Biodegradation by-products could be one of the main HiN components which increase the THMsFP. It is necessary to understand the behavior of the fraction when SAT effluent is used for drinking water source.