Tanzania, like many other developing countries, has a significant proportion of its population living in cities, municipalities, and rural shantytowns with relatively high population densities. Nonexistent or inadequate facilities for disposal of waste is a major public health problem, leading to the spread of infectious diseases, with resultant death and loss of productive capacity due to illness.
The conventional approach to addressing this problem in densely populated areas is through sewage systems and treatment plants, modelled after developed countries. Yet this does not seem to be appropriate for many small towns in rural areas, shantytowns surrounding cities and municipalities, and rural institutions including schools, hospitals, prisons, and army camps.
The conventional approach falls short for a number of reasons. Only about 10 percent of the national population is directly connected to water supplies. Even this is seasonal, and vulnerable to climate and breakdowns in the supply systems. It is difficult to provide adequate maintenance and servicing even for existing waste drainage systems. Lack of funds and the lag time in construction make it even more difficult to expand systems at a pace matching that of population concentration in crowded areas. In short, there is an urgent need for cheaper and practical means for safe disposal of human wastes.
Most people, when they use the term fertilizer, think primarily of artificial fertilizer. This is a shortsighted approach, particularly when the availability of factory-processed mineral fertilizers is questionable.
In Tanzania, the entire national supply of artificial fertilizer comes from one factory, the Tanzania Fertilizer Company, based in Tanga on the northeast coast. This factory, in operation since 1972 has, theoretically, an installed capacity of 105,000 metric tons a year. But in twenty years of operation the maximum annual production achieved was 69,000 metric tons in 1981. In 1989, the most recent year for which statistics are available, production was only 27,000 metric tons (see Appendix 1).
This is only about 10 percent of estimates of the national fertilizer demand. And these estimates include only those few potential users who are aware of the importance of fertilizer, those who can afford it, and those who can be reached by this facility-probably fewer than 10 percent of the population involved in agriculture. The usage of artificial fertilizer in agriculture in Tanzania is, therefore, highly restricted.
On the one hand existing factory capacity is not utilized. The reasons for this vary, including lack of regular machinery maintenance; insufficient supply of spare parts and aging of production facilities; and shortage and untimely supplies of raw materials such as ammonia, sulphur, and sulphate of potash, due to foreign exchange constraints.
Outside the factory there are additional problems. The transportation infrastructure is inadequate for delivering fertilizer to users when it is needed. There are insufficient extension programs to educate the users on the importance and utilization of the fertilizer. And the costs are prohibitive for many rural communities.
Citing such problems, Mr. Ndekiro, the marketing manager of Tanzania Farmers Association (TFA) in Arusha, also noted that irregular output from the fertilizer factory also affected the viability of its suppliers. Minjingu Mines, which supplies rock phosphate, cannot count on selling all it produces. The tarmac road between Minjingu and Arusha rail head and the fifty special railway wagons meant to ferry rock phosphates from Arusha to Tanga are underutilized.
Both fertilizer imports (approximately 80 percent of supplies) and inputs for the fertilizer factory require scarce foreign exchange. Under these conditions, there is little prospect of the fertilizer shortage being solved by artificial fertilizers.
Biolatrines can provide a solution to the public health problem of waste disposal and to the agricultural problem of fertilizer shortage. But there are a number of initial obstacles that must be confronted and overcome.
Establishment of a biolatrine system, particularly one which includes effective mechanisms for usage of the effluents, requires capital investment in the initial facility as well as in maintenance. With effective use of the effluent for improved agricultural production, it may be possible to reach a break-even point of additional income to cover the investment. But it is unlikely that the prospects will be good enough to justify commercial loans to start-up biolatrine projects.
There is also a major problem of public acceptance for biolatrine technology, given cultural, traditional, and religious values and fears concerning the use of human excrete. There is resistance to the idea, including among literate opinion-makers who might be expected to take the lead and who are responsible for making decisions on behalf of institutions.
Some people go as far as not accepting biogas in their kitchen as long as it has been produced from human excrete. It will be even more difficult to convince them to accept the bio-effluents from the same digesters for usage on their fields. There is suspicion of the safety of plants grown using such fertilizer. Promotion of biolatrine technology requires a significant push from the government. It can only be effective if first demonstrated in institutions such as schools and colleges, hospitals, prisons, and army camps. Reluctance to adopt the technology can be overcome only by practical demonstrations of its usefulness and safety, followed by extensive efforts at promotion.