TechTip: Decision Maker’s Guide to Compost Production

As seen in this issue’s article on the use of wastewater in Dakar, waste disposal in cities in developing countries presents both a problem for urban hygiene and at the same time an opportunity for farmers in terms of irrigation or fertilization of urban farms.

As cities grow, so grows the amount of waste they generate. Often disposed of in illegal landfills or left on river banks or roadsides, untreated organic waste presents considerable health and environmental problems for municipal authorities. However, if organic waste is safely processed into compost, urban farmers benefit from improved harvests, and the city benefits from an improvement in waste management. The excess compost can also be sold, providing an additional source of income for farmers or waste collectors.

The Decision Maker’s Guide to Compost Production is a simple piece of decision support software for compost planning aimed at users in the South, developed by the German Agency for Technical Cooperation (GTZ) and the private consulting and engineering firm Gesellschaft für Infrastruktur und Umwelt (GFI Umwelt).

The guide is an aid to decision-making for municipal organic waste collection and processing, making it easy for those responsible to construct a sustainable and economically viable composting system. It takes the user through the process of planning and designing a composting system, and the stages of recording, collecting, treating and processing organic waste, taking into account local conditions.

For long-term treatment of soils, only quality compost can ensure that plant production is not retarded and the environment is not damaged. Therefore, for organic waste to be recycled for agricultural uses, it must be carefully separated prior to collection. Such a system of separation and collection requires careful planning, dealing with a range of technical, organizational, administrative, legal and financial questions. This is impossible without a clear waste management strategy. Furthermore, for a composting system to be sustainable, it must also be financially viable.

In the planning phase, the user receives information concerning the operating costs of composting per year and per tonne of compost, whether there will be gains or losses, the distribution of costs, and areas where financial savings may be made. The software then determines the best possible method of technical implementation related to the user’s cost constraints.

The guide queries the user about local conditions. It then divides the processes of organic waste collection and composting into distinct sub-processes, and the user then chooses the best method and receives a report on the expected costs and revenues immediately. The user may then vary the parameters to optimize the result.

The software does not require any specialist knowledge. It uses Microsoft Excel as its software platform and operates without need of a keyboard. It can be completely controlled by a mouse and run on any PC with a Pentium processor and Microsoft Office 97 and above.

The software comes with a source book containing instructions on how to construct various composting systems, as well as tips on how to solve common problems. The source book contains six training modules with step-by-step explanations, covering the treatment of organic waste for compost, marketing and distribution, and economic and legal aspects. The final module includes a series of case studies from Benin, Burkina Faso, Germany, Indonesia, Poland and Tunisia.

Both the source book and software are available in English and German. The guide can be ordered for €30 from GFI Umwelt.

08 December 2006

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