Project Title: On-Farm Organic Waste Composting Trial for Organic Farmers: Demonstration Project

Applicant: The Hong Kong Baptist University

Project Proponent: Dr. Jonathan Wong

Total Approved Grant: $138,812.23

Duration: 15/6/2003 - 14/4/2006

Project Status/Remarks: Completed

Scope:
The present proposal aims to develop on-farm composting trial using waste coming from nearby sources with the dual purposes of composting production and waste recycling. A suitable site would be identified at Tai Lung Experimental Station of AFCD for establishment of a demonstration composting system. The principal investigator would also arrange training workshop in composting techniques for farmers.

Summary of the Findings/Outcomes:
Compost is a major ingredient to maintain good soil for crop growth in organic farming. The unavailability of compost locally has significant impact on the soil quality of the organic farms. The present project aims at developing an on-farm composting system to help farmers produce compost. The first trial was performed at the Tai Lung Experimental Farm of Agricultural, Fisheries and Conservation Department. The composting system consisted of an aeration system, a time controller, and a biofilter. Organic wastes such as pig manure, brewery waste or soybean residue were co-composted with green wastes including leaves and twigs in these trials. Each composting trial was run for a period of 60 days with daily monitoring of temperature. The composting parameters indicated that the compost became mature after 28 to 42 days as indicated by the seed germination ratio and the C/N ratio. The pathogens in the compost were well below the safety requirement for compost. The final products had good nutrient contents and all heavy metal contents were well below the stipulated levels. The weekly odour measurement of the composting set up did not reveal any significant odour emission indicating the effectiveness of the biofilter. The low cost on-site composting technology was transferred to two local organic farms which demonstrated the technology developed was feasible to be used in Hong Kong organic farming sector.