Removal of organic compounds using UV/H2O2 and UV/K2S2O

Abstract

The paper presents a study aimed at comparing the efficiency of pretreatment of landfill leachate by means of UV photooxidation using hydrogen peroxide (H2O2) and persulfate (S2O82–) in a falling film reactor. The leachate for the study originated from a stabilized solid waste landfill, as indicated by biochemical oxygen demand/chemical oxygen demand (BOD/COD) ratio of 0.08. The studies were conducted using variable doses of reagents, hydrogen peroxide, and persulfate, as well as variable irradiation times from 15 to 120 min. The pH, COD, total organic carbon (TOC), color, UV254nm absor-bance, and concentrations of residual H2O2 and S2O82– ions were determined during the study. Obtained results confirm the possibility of removing selected impurities applying UV method in combination with H2O2 and persulfate, while higher removal effect, especially with regard to COD and TOC, was achieved by using UV/S2O82– method, especially at a longer exposure time. The maximum COD and TOC removal effect in UV/H2O2 photooxidation was 15.6% and 7.3%. Using persulfate, COD removal efficiency was 22.9%, while TOC was 18.7%.