Technical paper Effective pine bark composting with the Dome Aeration Technology Cristina Trois a, * , Andreas Polster b a CRECHE Centre for Research in Environmental, Coastal and Hydrological Engineering, School of Civil Engineering, Survey and Construction, University of KwaZulu-Natal, Durban 4041, South Africa b Dresden University of Technology, Institute for Process Engineering and Environmental Technology, Helmholtzstraße 14, 01062 Dresden, Germany Accepted 13 December 2005 Available online 24 February 2006 Abstract In South Africa garden refuse is primarily disposed of in domestic landfills. Due to the large quantities generated, any form of treat- ment would be beneficial for volume reduction, waste stabilization and resource recovery. Dome Aeration Technology (DAT) is an advanced process for aerobic biological degradation of garden refuse and general waste [Paar, S., Brummack, J., Gemende, B., 1999a. Advantages of dome aeration in mechanical–biological waste treatment. In: Proceedings of the 7th International Waste Manage- ment and Landfill Symposium, Cagliari, 4–8 October 1999; Paar, S., Brummack, J., Gemende, B., 1999b. Mechanical–biological waste stabilization by the dome aeration method. Environment Protection Engineering 25 (3/99). Mollekopf, N., Brummack, J., Paar, S., Vor- ster, K., 2002. Use of the Dome Aeration Technology for biochemical stabilization of waste prior to landfilling. In: Proceedings of the Wastecon 2002, Waste Congress and Exhibition, Durban, South Africa.]. It is a non-reactor open windrow composting process, with the main advantage being that the input material needs no periodic turning. A rotting time of only 3–4 months indicates the high efficiency. Additionally, the low capital/operational costs, low energy inputs and limited plant requirements provide potential for use in aerobic refuse stabilization. The innovation in the DAT process is the passive aeration achieved by thermally driven advection through open windrows caused by temperature differences between the degrading material and the outside environment. This paper investigates the application of Dome Aeration Technology to pine bark composting as part of an integrated waste management strategy. A full-scale field experiment was performed at the Bisasar Road Landfill Site in Durban to assess the influence of climate, waste composition and operational conditions on the process. A test windrow was constructed and measurements of temperature and airflow through the mate- rial were taken. The process monitoring revealed that prevailing climatic conditions in a subtropical location do not affect the high effi- ciency of this technology. However, the composition of the input material can be detrimental for production of high quality compost because of a lack of nitrate. Ó 2006 Elsevier Ltd. All rights reserved. 1. Introduction South Africa, as many other emerging countries, is fac- ing high levels of unemployment and a severe shortage of food supply, particularly in rural areas. Extreme weather conditions, heavy rainfalls alternating with extensive droughts, cause soil water logging and desiccation, reduc- ing the availability of nutrients and affecting the growth of sensitive crops. In this context, the aerobic composting of garden refuse seems an appropriate strategy to promote sustainable development. The mechanical–biological treatment of garden and organic refuse results in waste stabilization and decreased landfill emissions, while providing a pathogen-free soil con- ditioner that can improve water retention and ion exchange capacity, leaching of nutrients in the root zones and the movement of air in the soil matrix. Cost reduction by waste minimization and increase of landfill space availability rep- resent clear advantages of composting, together with a good potential for job creation, land remediation and improvement of public health. The main effects of composting consist in the degrada- tion of readily degradable fractions and transformation (mainly humification) of slowly degradable matter, such as organic substances present in kitchen and garden refuse, 0956-053X/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.wasman.2005.12.015 * Corresponding author. Tel.: +27 31 260 3065; fax: +27 31 260 1411. E-mail address: troisc@ukzn.ac.za (C. Trois). www.elsevier.com/locate/wasman Waste Management 27 (2007) 96–105