Application of Thermophilic Aerobic Digestion (TAD) in the reprocessing and protein enrichment of agricultural wastes for animal feed use ABSTRACT Agricultural and food industry wastes constitute significant proportions of world wide agricultural productivity. These wastes include fruit, vegetables, root / tuber, sugar industry and animal / livestock / fisheries wastes. They represent valuable biomass and potential solutions to problems of animal nutrition world-wide if appropriate technologies are deployed for their reprocessing into feed. In addition, reutilization of these wastes should help to address growing global demands for environmentally sustainable methods of production and pollution control. Various technologies are potentially available for the valorization of these wastes. In addition to conventional waste management, other processes that may be used include solid substrate fermentation, ensiling and high solid or slurry processes. In particular, the use of slurry processes in the form of Thermophilic Aerobic Digestion (TAD) is gaining prominence because of its potential advantages over conventional waste reprocessing technologies. In addition to capacity for self-heating, other advantages include capacity to achieve rapid, cost effective waste stabilization/pasteurization and protein enrichment of wastes for animal feed use. TAD is particularly suited for use with wastes generated as slurries, at high temperature or other high COD wastes and being considered for upgrading and recycling as animal feed supplement. Reprocessing of agricultural wastes by TAD has been shown to result in very significant protein accretion and effective conversion of mineral nitrogen supplement to high value feed grade protein for use in animal nutrition. The use of thermopiles in the process has significant safety benefits and may be optimized to enhance user confidence and acceptability. KEYWORDS: Thermophilic Aerobic Digestion (TAD), animal feed supplement, protein enrichment; agricultural wastes 1. INTRODUCTION Waste treatment by microbiological process is an age old process. However, scientific knowledge of the processes involved is relatively recent. Traditionally, methods of wastes treatment emphasized the removal of wastes from areas in which they were not wanted [1]. Hence, waste management processes were synonymous with waste disposal. These actions were inspired by man’s desire to protect his immediate environment, and applied to both human and agricultural wastes. The early methods of waste treatment did not distinguish between wastes in terms of whether such wastes were reusable or not. Increase in the scale of the problems of environmental pollution, as well as changes in social attitude, have led to multidisciplinary approaches to the problems of waste management and pollution control. Increasing pressures on resources also mean that the vast quantities of organic materials that remain from human Department of Microbiology, University of Nigeria, Nsukka Enugu State, Nigeria J. Obeta Ugwuanyi * *jerry.ugwuanyi@unn.edu.ng Trends in Chemical Engineering Vol. 13, 2010