For some time now a number of articles appearing in the national dailies and here at the Ghanaweb site have been making increasing mention of biogas technology. My intention in this article is to not only shed some light on the working of the technology, but also to attempt to advance simple arguments why the nation needs to take concrete steps to ensure public awareness of the importance of biogas exploitation and possibly even come out with official policy support.

Much has been said and written about the deplorable state of the environment in most of our cities, towns and villages. As we make strides in our efforts to improve the country’s agricultural output it can not -and must not!- escape us that the expected growth of the livestock (and crop) industry would create opportunities for the proper disposal of large quantities of manures generated at diaries, swine and poultry farms, in addition to crop waste. Some major pollution problems are associated with this waste. These include surface and groundwater contamination, and surface air pollution caused by dust, odours, and ammonia. In addition, another major problem results from concern about the contribution of methane emissions to global climate change.

At the same time, a close examination of our environmental regulations reveals the lack of guidelines for dealing with animal manure, a non-point source of water pollution. With increasing concentrations of manure this would mean that the risk of water pollution from waste spills, runoff from fields, and leakage from storage facilities would also increase.

What is Biogas?

Biogas is produced by bacteria in the process of bio-degradation of organic material under anaerobic (no-air) conditions. An important part of the biogeochemical carbon cycle is the natural generation of biogas, and methanogens (methane producing bacteria) constitute the last link in a chain of micro-organisms which degrade organic material and return the products of decomposition to the environment. As a result of this process biogas, a renewable source of energy is generated.

Knowledge of the fundamental processes involved in methane fermentation is necessary to be able to plan, build and operate biogas plants. First, anaerobic fermentation involves the activities of three different bacterial communities. Next, the process of biogas-production depends on various parameters. For example, changes in ambient temperature can have a negative effect on bacterial activity. As with any pure gas, the characteristic properties of biogas are pressure and temperature-dependent. The properties are also affected by the moisture content. Here the factors of main interest are: change in volume as a function of temperature and pressure, change in calorific value as a function of temperature, pressure and water-vapor content, and change in water-vapor content as a function of temperature and pressure. Biogas has a calorific value of 6 kWh/m3, which corresponds to about half a litre of diesel oil. The net calorific value depends on the efficiency of the burners or appliances. Methane is the valuable component from the viewpoint of using biogas as a fuel.

A careful look at biogas plants reveals separate design-and-deployment paths in industrialized and developing countries. Although the biogas produced by a digester can be used as it is- just in the same way as any other combustible gas- it is normally the case that further treatment or conditioning is necessary to for example, reduce the hydrogen-sulfide content in the gas. When biogas is mixed with air at a ratio of 1:20, a highly explosive gas forms. Leaking gas pipes in enclosed spaces constitute, therefore, a hazard. Nevertheless, there have been no reports of dangerous explosions caused by biogas so far.

The three main types of simple biogas plants are the balloon, fixed-dome and floating-drum ones.

Benefits

Properly functioning biogas plants have several benefits for their users, society, and the environment at large. These include:

? production of energy (heat, light, electricity) ;

? transformation of organic waste into high quality fertilizer;

? improvement of hygienic conditions through reduction of pathogens, worm eggs and flies;

? reduction of workload, mainly for women, in firewood collection and cooking;

? environmental advantages through protection of soil, water, air and woody vegetation;

? micro-economical benefits through energy and fertilizer substitution, additional income sources and increasing yields of animal husbandry and agriculture;

? macro-economical benefits through decentralized energy generation, import substitution and environmental protection. Thus, under concrete, favorable conditions, biogas technology can contribute substantially to conservation and development. However, the required high investment capital and other limitations of biogas technology require thorough consideration.

Costs

Although biogas systems have proven to be economically viable under specific conditions, it still remains a fact that the poorer strata of rural populations often cannot afford the investment cost for a biogas plant. This development hinders the large-scale deployment of biogas plants, a condition which could precede economic viability in low-income areas. In spite of the aforementioned, constant improvements in technological design, and financial support from the state –seen as alternative investments to mitigate future costs of import of fuel, organic fertilizers, health, sanitation and environmental budgets, etc.- could help make the case for biogas plant construction projects economically feasible.

Fuel and Fertilizer Substitution

In Ghana, just as in most other developing countries, the dual problems of progressive deforestation due to high demand for firewood and the need for fertilization are most profound. Huge sums of money are spent on importation of chemical fertilizers. But it has been established that the amount of technically available nitrogen, potassium and phosphorous in the form of organic materials is around eight times as high as the quantity of chemical fertilizers actually consumed in developing countries. And especially for small farmers, biogas technology is a suitable tool for making maximum use of scarce resources. For after extraction of the energy content of dung and other organic waste material, the resulting sludge still remains a good fertilizer, capable improving general soil quality as well as ensuring higher crop yields.

Awareness, Popularization, and Promotion Programs

No program of promoting the construction and use of biogas plants would yield much desired results without detailed and elaborate efforts to create public awareness of the technology, its benefits, and pitfalls. In view of the wide range of participants (farmers, residents, local authorities, skilled workers and professionals, e.g. civil and mechanical engineers, etc.) that the dissemination of biogas technologies affect, it would be most helpful to consider the benefits to this wider group before actual project implementation. Of much importance is the need for awareness creation within the government, since the impacts and issues of biogas technology concern so many different governmental institutions (e.g. agriculture, environment, energy, and economics). It is thus necessary to identify and include all responsible government departments in the dissemination and awareness-raising process.

Prospects

Today, in the fields of municipal sludge treatment, industrial wastewater purification and treatment of agricultural wastes biogas technology has reached maturity and is enjoying an upswing in such developing countries in Asia (as in India) and Latin America, whereas a Europe is currently experiencing a boom in municipal treatment of waste using anaerobic digestion . Large-scale biogas projects are have been completed or are underway in several developing countries due to the ability of the project developers and governments to recognize the agricultural, environmental and energy issues involved, and hence correctly identify the multifaceted benefits to society. Moreover, previous research conducted in Ghana point to the need to adopt such an approach in evaluating biogas projects.

International and bilateral funding programs are in existence, and are ready to be sourced, as demonstrated by the latest report in the mass media on a project initiated by Third Millennio Foundation, an international humanitarian and environmental organization based in Italy and the United Kingdom, that has offered to finance a waste-to-energy project in Ghana.

Global concern over increasing emission of greenhouse gases, increasing water consumption and water pollution, declining soil fertility, unsatisfactory waste management and the growing rate of deforestation is largely due to the unsustainable resource use systems that prevail. Ghana is a signatory to international agreements on sustainable development, and has duty to take measures to help realize goals spelt out in them, by initiating action home. This must be done first by adopting appropriate policies, setting targets, and then putting in place implementation of projects that help achieve the targets set.

Biogas technology can be said to be an important hardware component in the chain of measures to counteract the problems enumerated above. International institutions exist that are committed to play a lead role in networking and information exchange to ensure that the potential of biogas technology is recognized and made optimal use of. Moreover, companies that have proven designs are known, and all that is left is for government to draw a roadmap: a roadmap that could be crucial to the success of all agriculture-related PSI (Presidential Special Initiatives).
Biographical Notes: The author, Nana Omane, is the Omanhene in Hamburg for the Kwahu Traditional Area. He is an entrepreneur, and Chairman of the MAKA GROUP, a body of Ghanaians living abroad interested in making investments in the environmental and energy sector in Ghana.


Views expressed by the author(s) do not necessarily reflect those of GhanaHomePage.