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The conversion of waste material into fertilizer and biogas helps protect the environment in five principal ways:
The generated biogas can replace traditional energy sources like firewood and animal dung, thus contributing to combat deforestation and soil depletion.
Biogas can contribute to replace fossil fuels, thus reducing the emission of greenhouse gases and other harmful emissions.
By tapping biogas in a biogas plant and using it as a source of energy, harmful effects of methane on the biosphere are reduced.
By keeping waste material and dung in a confined space, surface and groundwater contamination as well as toxic effects on human populations can be minimized.
By conversion of waste material and dung into a more convenient and high-value fertilizer ('biogas slurry'), organic matter is more readily available for agricultural purposes, thus protecting soils from depletion and erosion.
Biogas Technology for Development
Farmers, industrial estates, municipalities and governments have diverging concepts of development. They can use biogas technology in different ways to contribute to their own development objectives.
►Benefits for Biogas Users
Farmers may want to substitute inputs such as fertilizers, household and engine fuels by biogas slurry and the biogas itself. A biogas system can relieve farmers from work that they have formerly spent on dung disposal or dung application on their fields. By using biogas for cooking, lighting and heating, life quality for the whole family can improve. Improved stables, if they are part of the biogas system, can increase the output of animal husbandry. Improved farmyard manure may raise the yields of plant production.
Industrial estates can, by processing their waste in a biogas plant, fulfill legal obligations of waste disposal. They can, at the same time, generate energy for production processes, lighting or heating.
Municipalities can use biogas technology to solve problems in public waste disposal and waste water treatment. The energy output of biogas digestion is usually not a priority, but may respond to public energy demands such as street lighting, water pumping and cooking in hospitals or schools.
National Governments have macro-economic interests that may render biogas technology an interesting option in overall development plans. On a national scale, a substantial number of working biogas systems will help reduce deforestation, increase agricultural production, raise employment, and substitute imports of fossil fuels and fertilizers. If macro-economic benefits are obvious and quantifiable, a government may even consider to subsidize biogas systems to bridge a micro-economic profitability gap.
Craftsmen, engineers and maintenance workers
Craftsmen, engineers and maintenance workers have long been overlooked as a target group for biogas promotion. Not only does biogas technology open market niches for masons, plumbers, civil engineers and agronomists, they are often the most effective promoters of biogas technology.
Framework for Biogas Technology
A positive contribution of biogas technology can only materialize, if the technology works. The development of biogas technology has passed the experimental stage. Trials with uncertain outcome can only be accepted if the costs of failure are not to be paid by the end-users. Whatever the chosen design of the biogas plant may be, those in charge for its dissemination bear the responsibility to deliver a reliable, durable and user-friendly product.
Only appropriate designs will perform satisfactory and will have a favorable cost-benefit ratio.
Existing basic designs of biogas systems have to be adapted to the following framework conditions:
climatic and soil conditions;
the quality of substrate to be digested;
the quantities of substrate;
the prioritization of expected benefits;
the availability of skills for operation, maintenance and repair.
The policies of governments and donor organizations cannot turn immature technologies and inappropriate designs into success stories, nor can they create an artificial demand for alternative energy or improved fertilizer. But where a national need for energy alternatives exists and the increasing burden of water pollution, deforestation and soil depletion is felt, governments can asupport biogas dissemination by a legal framework against unsustainable use of natural resources and in favor of green technologies.
Donor organizations can provide take-off funding and initial technical assistance where biogas technology is hitherto unknown.
The 'Critical Mass' of Biogas Systems
For small and medium scale farmers, the investment in a biogas system is a considerable risk. Besides the confidence in the technology itself, they need reassurance from neighbors and colleagues. Farmers believe what they see. The more working biogas systems are around, the more they will be willing to invest. In addition, professional (commercial) advice, maintenance and repair will only evolve, if a sufficient number - the 'critical mass' - of biogas systems are established in the area.