Pilot-scale tests of an innovative ‘serial self-turning reactor’ composting technology in Thailand

Abstract

Composting facilities in Thailand have faced various operational problems, resulting in the emission of odours, incomplete digestion of waste organics, and higher than desired costs. Composting technologies imported from developed countries tend to be sized for larger communities and are otherwise not suited for the rural communities that comprise more than 80% of all communities in Thailand. This article addresses the research and development of a novel composting technology aimed at filling this observed need. The study was divided into two parts: (1) the development of a new composting technology and fabrication of a prototype configuration of equipment; and (2) scale-up and study on a pilot-scale using real rubbish. The proposed technology, called 'serial self-turning reactor (STR)', entailed a vertical flow composting system that consisted of a set of aerobic reactors stacked on a set of gravity fed turning units. In-vessel bioreactor technology enables the operator to control composting conditions. The researchers found that a tower-like STR results in flexibility in size scale and waste processing residence time. The pilot-scale experiments showed that the proposed system can produce good quality compost while consuming comparatively little energy and occupying a compact space, compared to traditional land-intensive windrow composting facilities.