“…One study conducted in Indonesia focus on identify various raw materials used in biogas production. These materials include cow dung (Hariansyah, 2009), buffalo and horses (Umam, 2019), activated sludge, kitchen waste (Widyastuti & Mulyani, 2018), tapioca flour waste (Sensih & Prayitno, 2020), carp pond waste (Irawan & Khudori, 2015), quail feces (Sudarman, 2018), human feces (Arnando et al, 2015), and even waste water hyacinth (Darnegsih, 2016) have been explored for biogas production. In addition to the raw materials, other research in Indonesia has examined the effectiveness of using effective microorganisms-4 (EM-4) in biogas production (Tira & Umbara, 2018).…”