Optimization of Household Organic Waste Composting Using the Biopot Composting Method and Rice Washing Water as a Starter Culture

Abstract

Household organic waste management in Sungai Langka Village was implemented using the biopot composting method combined with rice-washing water as a starter culture. Organic waste was collected at 08:00 WIB from two hamlets: Hamlet 1, consisting of 7 households, generated 8.45 kg/day, while Hamlet 2, consisting of 5 households, generated 7.25 kg/day, resulting in 15.7 kg/day from 12 households. This study aimed to identify the composition of household organic waste, analyze the physical and chemical characteristics of the compost, and determine the percentage of organic waste reduction. Each biopot pipe was filled with 1 kg of organic waste under four treatments: P0 without starter culture, P1 with 100 ml, P2 with 200 ml, and P3 with 300 ml of rice-washing water starter culture. Composting was conducted for 31 days based on maturity indicators, including temperature stabilization, near-neutral pH, dark color, earthy odor, and waste reduction. The results showed that starter culture dosage influenced composting performance. P2 showed the best overall descriptive performance, with the highest waste reduction of 76% and favorable compost characteristics. Most parameters met SNI 19-7030-2004 and SNI 7763:2024, although moisture content required further drying or curing