<![CDATA[The rapid population growth and dense settlements in Surabaya have led to an increase in waste volume, which reached 2,600 tons per day in 2021 (Pratama & Fitriyah, 2021), a significant rise compared to 1,075 tons in 2011 (Kurniawan, 2016). To address this issue, the local government continues to innovate by adding waste management facilities and constructing compost houses (Meriatna et al., 2019). One compost house in Surabaya, which still employs a semi-manual composting process, is the Wonorejo Compost House. The composting process is carried out over one month without the addition of a bioactivator, resulting in slower decomposition and less optimal compost quality. Therefore, this study investigates the addition of Effective Microorganisms (EM4) as an activator. The aim of this research is to analyze the impact of EM4 addition and turning frequency on compost production. The research factors include testing of pH, temperature, moisture content, Nitrogen (N), Phosphorus (P), Potassium (K), Organic Carbon, and C/N Ratio. These tests were conducted using a Factorial Randomized Block Design (RBD) with two factors: EM4 concentrations of 0.1% v/b, 0.3% v/b, and 0.5% v/b, and turning frequencies of once every day, once every three days, and once every five days over the course of one month, resulting in 9 treatment combinations with 3 replications, for a total of 27 treatments. Data analysis was performed using ANOVA, and compost quality was determined through Multiple Attribute Decision Making (MADM). The results indicated that the best treatments for pH were found with EM4 concentrations of 0.3% and 0.5% and turning frequencies of once every day and once every five days. The best treatment for temperature was observed with 0.1% EM4 and turning once every day. These parameters were in accordance with the Indonesian National Standard (SNI 19-7030-2004).]]>
