A Review of Features, Benefits and Costs of Tunnel Composting Systems in Europe and in the USA

Odour control is identified as the critical technical issue for the success of composting projects. Tunnel composting has the advantages that the compost can be kept aerobic, all the excess air is collected for treatment and that building corrosion, that leads to fugitive emissions, is prevented. Data is given for the number of installations in Holland and USA. Rough costs indicate that tunnel composting has comparable costs to other s mechanised systems. Two types of tunnel system are described: batch and plug flow and their features compared.