154 EnvironmentAsia 12(1) (2019) 154-161 DOI 10.14456/ea.2019.17 ISSN 1906-1714; ONLINE ISSN: 2586-8861 Comparison and Evaluation of Diferent Leachate Treatment Processes for Chemical Oxygen Demand and Color Removals - Statistical Assessment Salem S. Abu Amr 1 *, Abbas F. M. Alkarkhi 1 , Yusri Yusup 2 , and Mohammed J.K. Bashir 3 1 Malaysian Institute of chemical & Bioengineering Technology Universiti Kuala Lumpur, Malaysia 2 School of Industrial Technology, Universiti Sains Malaysia, Malaysia 3 Department of Environmental Engineering, Faculty of Engineering and Green Technology, Uni- versiti Tunku Abdul Rahman, Malaysia. *Corresponding Author: sabuamr@hotmail.com Received: May 16, 2018; Accepted: October 18, 2018 Abstract Te performance of seven oxidation treatments on stabilized landfll leachate namely; O 3 , Fen- ton, Fenton followed by O 3 , persulfate, persulfate followed by O 3 , simultaneous O 3 /Fenton, and simultaneous O 3 /persulfate were evaluated and compared. Te study aims to assess the variation between all the seven oxidation treatments with regards to COD and color removal. Te analysis of variance (ANOVA) and Tukey’s test showed that there were signifcant diferences between the performances of the treatments. Te O 3 treatment removed the lowest COD and color while the simultaneous O 3 /Fenton, Fenton followed by O 3 , simultaneous O 3 /persulfate and persulfate fol- lowed by O 3 removed the highest. Hence, these treatments are recommended to remove organics from stabilized landfll leachate. Keywords: Stabilized leachate; Treatment; Oxidation; Analysis of variance (ANOVA); Tukey’s test. Te international journal by the Tai Society of Higher Education Institutes on Environment EnvironmentAsia 1. Introduction Municipal solid waste comprises of do- mestic and commercial waste, construction debris, and sanitation residue (Agamuthu and Fauziah, 2011). Landflling is one of the most economical methods to dispose these waste (Tan et al., 2013; Bashir et al., 2018). Ninety percent of the capacity of the landflls are used to discard the solid waste. Tis large volume of solid waste can contaminate the underlying soil and seep into the groundwater (Shabiimam and Dikshit, 2012). Te landfll leachate contains several contaminants that could potentially cause detri- mental health efects, either due to direct contact (e.g., skin damage) or through drinking polluted water or eating contaminated crops (EPA, 2007). Moreover, soil and agricultural productivity can decrease if leachate-polluted water is used for irrigation (Alslaibi et al., 2010). Stabilized leachate, as indicated by a low BOD 5 /COD ratio (i.e., low biodegradability) is unsuitable for to be treated biologically. Tere- fore, additional physicochemical processes are necessary for the pre-treatment and post-treat- ment of leachate (Tauchert et al., 2006). Tus, before discarding leachate into the environment, dedicated treatment facilities are required (Goi et al., 2009). Considerable attention has