Affiliations 

  • 1 Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia; Department of Environmental Health, Faculty of Health Sciences, UiTM Puncak Alam, 42300 Kuala Selangor, Malaysia
  • 2 Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia; Center for Research in Waste Management, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
  • 3 Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
  • 4 Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia. Electronic address: khengsoo@um.edu.my
Waste Manag, 2018 Jun;76:575-581.
PMID: 29503052 DOI: 10.1016/j.wasman.2018.02.047

Abstract

In this work, the feasibility of coagulation-flocculation coupled with UV-based sulfate radical oxidation process (UV/SRAOP) in the removal of chemical oxygen demand (COD) of stabilized landfill leachate (SLL) was evaluated. For coagulation-flocculation, ferric chloride (FeCl3) was used as the coagulant. The effect of initial pH of SLL and COD:FeCl3 ratio on the COD removal was evaluated. The result revealed that COD:FeCl3 ratio of 1:1.3 effectively removed 76.9% of COD at pH 6. The pre-treated SLL was then subjected to UV/SRAOP treatment. For UV/SRAOP, the sulfate radical (SR) was generated using UV-activated persulfate (UV/PS) and peroxymonosulfate (UV/PMS). The dosage of oxidant and reaction time were found to be the main parameters that influence the efficiency of COD removal. On the other hand, the effect of initial pH (3-7) and the type of oxidant (PS and PMS) was found to have no significant influence on COD removal efficiency. At optimum conditions, approximately 90.9 and 91.5% of COD was successfully removed by coagulation-flocculation coupled with UV/PS and UV/PMS system, respectively. Ecotoxicity study using zebrafish showed a reduction in toxicity of SLL from 10.1 to 1.74 toxicity unit (TU) after coagulation-flocculation. The TU remained unchanged after UV/PS treatment but slightly increased to 1.80 after UV/PMS treatment due to the presence of residual sulfate ion in the treated effluent. In general, it can be concluded that coagulation-flocculation coupled with UV/SRAOP could be a potential water treatment method for SLL treatment.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.