© 2018 Semarang State University  Corresponding author: E-mail: dhias.hakika@che.uad.ac.id ISSN 2303-0623 e-ISSN 2407-2370 JBAT 11(1) (2022) 1 – 7 Jurnal Bahan Alam Terbarukan Accredited SINTA 2 by Ministry of Research and Technology/National Research and Innovation Agency SK No. 200/M/KPT/2020 http://journal.unnes.ac.id/nju/index.php/jbat p-ISSN 2303 0623 e-ISSN 2407 2370 Detoxification of Distillery Wastewater by AOP Fenton for the Enhancement of Biogas Production Dhias Cahya Hakika 1,  , Sarto 2 , Aswati Mindaryani 2 , Muslikhin Hidayat 2 , Zahrul Mufrodi 1 DOI: https://doi.org/10.15294/jbat.v11i1.35844 1 Department of Chemical Engineering, Faculty of Industrial Technology, Universitas Ahmad Dahlan, Jl. Jend. Ahmad Yani Banguntapan Bantul 55191, Indonesia 2 Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika 2 Yogyakarta 55281, Indonesia Article Info Abstract Article history: Received April 2022 Accepted June 2022 Published June 2022 Distillery wastewater from the bioethanol industry contains a high level of organic content which can be converted into biogas. However, the presence of toxic compounds in this wastewater could inhibit biogas production. Therefore, prior detoxification of distillery wastewater is required. Fenton, one of the Advanced Oxidation Process (AOP) methods, was selected due to its high performance to degrade organic pollutants, short reaction time, and the process is simple and easy. Additionally, this method can also be used as a pretreatment for biogas production. This paper aims to study the improvement of biogas production from distillery wastewater by applying AOP Fenton as a pretreatment method. The experiment consists of two stages, the first was application of AOP Fenton to the distillery wastewater in order to determine its effect on the concentration of COD and some toxic compounds such as phenol and sulfate. The second stage was biogas production through anaerobic digestion process, which was carried out under two conditions of raw materials: (i) distillery wastewater without pretreatment of AOP Fenton as a control and (ii) distillery wastewater that has been treated with AOP Fenton as pretreatment. Results show a remarkable decrease in COD concentration by 45%, phenol (63%), and sulfate (18,6%) from distillery wastewater after applying AOP Fenton. It implies that the application of AOP Fenton significantly detoxified distillery wastewater. As a biogas pretreatment, this method also increased biogas production by 33% higher, from 2.399 mL (without pretreatment) to 3.191 mL (with pretreatment). It indicates that AOP Fenton increased the biodegradability of distillery wastewater. Thus, it was easier to be converted into biogas. Keywords: biogas; COD; Distillery wastewater; Fenton reaction; Phenol; Sulfate INTRODUCTION Along with the global outbreak of the coronavirus (Covid-19), there has been a significant surge in demand for alcohol in order to meet the needs of sterilization or sanitation. Alcohol or ethanol, as a raw material used in the manufacture of alcohol-based hand sanitizers, disinfectants, and antiseptics, is one of the essential compounds in handling the Covid-19 pandemic. This condition causes several ethanol industries to increase their production capacity, especially in Indonesia. Most of the bioethanol factories in Indonesia use molasses (sugarcane molasses) as raw material because the production costs are considerably low (Setyawati et al., 2015). On the other hand, the bioethanol industry from molasses produces liquid waste that can harm the environment if disposed directly into the water body. This liquid waste, also known as distillery wastewater or vinasse, has high organic matter content with the value of chemical oxygen demand (COD) concentration is more than 150,000 mg/L. It is also acidic (pH 3.5–5) with dark brown color and unpleasant odor. The volume of