AD: Promoting Health and Quality of Life in Developing Countries
Inadequate waste management leading to contaminated water supplies and human and cattle disease is a constant threat to the health, quality of life and productivity of people in developing countries. Rural populations also suffer from many pulmonary diseases as a result of poor indoor air quality due to heating and cooking without proper ventilation. Further, most of the developing world survives on subsistence farming and animal husbandry, both of which create significant organic waste.
This organic waste is typically burned for cooking or heating. Burning unprocessed organic waste is inefficient, yet cooking and heating are the most energy intensive activities in developing countries. Small-scale, rural anaerobic digesters offer both a source of energy and a sanitary method of waste disposal which can help control disease. Digesters can improve rural sanitation, reduce labor (collecting fuel wood), and reduce greenhouse gas emissions, improve respiratory health and increase agricultural productivity through improvements in soil quality.
Biogas is the result of the decomposition of organic waste under anaerobic conditions. In addition to methane gas, the decomposition process produces a slurry byproduct composed of phosphorus and nitrogen, which is typically used as a fertilizer. The process is relatively simple and is not as technologically intensive as ethanol and biodiesel production, which require more resources, advanced technology and investment, making it particularly suited for developing countries where organic wastes are abundant.
A small-scale anaerobic digester can be made from a variety of common materials. Digesters are most economical when located near the feedstock source, which serves to control transportation costs and inefficiencies. The decomposition process typically takes between six and 25 days, depending on the feedstock and size of the digester. A small-scale household digester has a useful life of approximately 20 years, takes about one week to build and costs between $100 and $1,700, with the expectation that the digester pay for itself within four to five years. Biogas burns like liquefied petroleum gas, which means a digester’s output can be connected to a stove or a light with a gauze mantle. A small-scale, household digester can run on the waste from one or two cows, five to eight pigs or four humans. This size digester would typically produce sufficient energy for cooking and some lighting (in addition to improved air quality and sanitary waste management, both of which significantly impact health in developing countries).
Developing countries face significant health concerns resulting from the contamination of hand-dug wells from surface sources. Using an anaerobic digester, communities can locate toilet facilities in or next to a house because such facilities are odorless and do not attract insects. Developing countries utilize dried animal waste as a cheap energy source for cooking and heating, but burning animal waste is uneconomical and releases toxic emissions which cause pulmonary disease such as tuberculosis and lung cancer. At the same time, crop residues are often burned in an effort to reduce the cost of storage and handling, even though the result is reduced soil quality. Ineffective waste management systems lead to illness and disease. For example, it is estimated that worldwide there are nearly 80 million cases of dysentery, of which approximately 700,000 are fatal. A digester can kill the dysentery bacteria in 30 hours.
Effective implementation of rural digesters requires a focus on farmer and community education. For example, many rural farmers do not realize that crop residue and animal waste can produce more energy after it is processed by a digester than by traditional drying methods. Further, costs or initial construction and lack of government support are barriers to the establishment of digesters in certain areas. Efficient utilization of digesters also requires interagency cooperation between utilities, municipalities and local agriculture. Countries such as China (with 50 million households using biogas) and India (4 million) have been particularly effective in establishing biogas as an energy source. Other countries, such as the U.S. with its low natural gas prices, have not been as successful.
Authors: Kate Bechen
Attorney, Michael Best & Friedrich LLP
Partner, Michael Best & Friedrich LLP