Aerobic Co-composting of Spent Mushroom Medium Using Food Waste Fermented Liquid

Spent mushroom medium and dried sludge from bioethanol industry can be utilized into beneficial organic compost after completion the composting process. Food waste fermented liquid and commercially effective microorganisms (EM) from EMRO Sdn. Bhd. were used as the microbial inoculant for the aerobic composting. Three kg of composting pile made of spent mushroom and dried sludge are used to obtain a 23.07 C/N ratio at the initial composting process. In order to ascertain the impact of composting process in seven days, the sample from each of the composting beds for analysis of temperature, pH, moisture, and total organic matter was assessed. Food waste fermented liquid and commercial EM composts reached the thermophilic phase (40 °C) after a day of the composting process. Moisture content showed a significant result for both composting piles on day 1 due to the highest evaporation of water at the thermophilic phase. The composting process was not extended until reached stability and maturity phases; thus, the pH for both composting piles was recorded at 9, which is far from the stable compost normally at neutral pH (~7). The organic matter content of each composting pile showed gradually decreased during the composting process. The degradation rate for the composting pile using food waste fermented liquid showed slightly higher than commercial EM which was 0.0363 and 0.0232 day 1, respectively. In conclusion, food waste fermented liquid shall be used as a replacement for EM commercial as a microbial inoculant for the composting process based on the results shown in this study.