Process Improvement of Bioconversion of UTP Leaves Waste into Compost using Pilot Composters

Universiti Teknologi PETRONAS (UTP) is a private university of 400 hectares and mostly covered with greens. Every day, UTP produce huge amount of green wastes such as fallen leaves, branches and vegetable scraps. Other than collecting them and disposing them or burning them, composting can be an alternative in reducing green wastes in UTP. This goal of this paper is aimed to study the effect of composting key parameters on the quality and maturity of piles of compost. Parameters like initial C:N ratio particle size, moisture content, porosity, aeration rate, amount of worm inside the pilot composters, and turning frequency is fixed. From this paper, it is a goal to determine ideal C:N ratio to compost green waste which is leaves, branches and vegetable scraps in Malaysia. Research papers suggested that C:N ratio is highly significant in determining a mature and quality compost. The carbon content is related to nitrogen content because carbon contributed to the organic amount in the compost whereas nitrogen contributed for the nutrient content in compost, thus, an ideal C:N ratio is suggested to range between 25 and 30 for fast and effective composting. Since vegetable scraps are rich in nitrogen and dried leaves contain higher carbon content, by performing four composting experiments in four identical pilot composters, varying the mixture ratio of dried leaves and vegetable scraps to C:N ratio of 20, 25, 30, 35, parameters such as temperature profile, pH profile, moisture content, Total Nitrate Content (TKN), Total Organic Carbon Content (TOC), and C:N aqueous are determined. Throughout the experiments, manual turning at a frequency of one turn per three days for every composter is done. Composting temperature and pH are monitored and recorded once per 3 days to plot the temperature profile and pH profile, in order to determine the compost maturity. Concentration of carbon and nitrogen are measured at the end of the experiment to determine the quality of compost. C:N aqueous are measured based on the result of TOC and TKN. According to research, it was suggested composts which have matured has a C:Naqueous of 5–6.