165 Jurnal Presipitasi Media Komunikasi dan Pengembangan Teknik Lingkungan e-ISSN: 2550-0023 Vol 20, No 1, 2023, 165-174 Article available at homepage presipitasi Original Research Article Optimizing Utilization of Hazardous Waste and Biomass as Solid Fuel for Co-Firing Fandy Ahmad Fauzy 1 , Etih Hartanti 1 *, Dyah Marganingrum 2 1 Environmental Engineering Study Program, Faculty of Civil Engineering and Planning, Institut Teknologi Nasional, Jalan P. H. H. Mustofa No. 23, Bandung, Indonesia 40124 2 National Research and Innovation Agency (BRIN), Jalan Cisitu Lama No. 12, Bandung, Indonesia 40135 *Corresponding Author, email: etih@itenas.ac.id Abstract Continuously high use of fossil fuels may lead scarcity of these energy sources in the future. Therefore, it is necessary to develop renewable energy to ensure its availability. One of the efforts in the development of renewable energy and the aims of this study is to examine the utilization Fly Ash (FA), Bottom Ash (BA) combined biomass sludge of Wastewater Treatment Plant (WWTP) and municipal solid waste) materials as an alternative energy source (briquette raw materials) for co-firing in textile industry boilers. Briquettes were made with a composition of 60% FABA and 40% biomass which were then varied in composition. The parameters measured were proximate, calorific value, and shatter index. The feasibility test of briquettes was carried out using a Tanner diagram, where all briquettes made can be burned as fuel. Optimum briquettes quality was measured based on the criteria according to the Minister of Environment and Forestry Regulation No. 06/2021. The results showed that the composition of three briquettes that had optimum quality and met the criteria were briquettes with composition 10%FA:50%BA:40%Biomass (variation of WWTP sludge and biomass) with a calorific value and sulfur content of 3,578 Kcal/kg and 0,70%; 3,890 Kcal/kg and 0,82%; and 3,864 Kcal/kg and 0,96%. Keywords: Biomass; bottom ash; briquettes; fly ash; sludge 1. Introduction Indonesia is a country that has the highest level of energy consumption in the Southeast Asia region, where energy consumption is dominated by the consumption of fossil energy. Every year, energy use continues to increase, but this increase is not accompanied by available energy sources to support this energy consumption. The high use of fossil fuels continuously raises concerns about the future scarcity and even exhaustion of these energy sources. Therefore, to avoid the scarcity of energy sources, it is necessary to develop renewable energy so that the sustainability and availability of energy can be continuously fulfilled (Afriyanti et al., 2020). One of the efforts in developing renewable energy is the use of biomass and hazardous waste as alternative energy sources. Biomass is a renewable energy source composed of biological materials. In general, biomass is a material that can be obtained from living things and used in large quantities. Biomass specifically refers to agricultural waste, forestry waste, animal manure, kitchen waste, and others (Yokoyama & Matsumura, 2008). Meanwhile, B3 waste is the residue of a business and/or activity that contains B3, which may be utilized to become a product that can be used as a substitute for raw materials, auxiliary materials, and/or fuel that is safe for human health and the environment (PerMen LHK 18/2020).