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The following case studies are to illustrate the interaction of the various factors described above by means of concrete experience gained during dissemination programmes or projects.
In China, biogas plants are built under the pigsty. The kitchen is in the direct vicinity of the plant. The toilets are always connected to the plant, meaning that the plant also serves as a septic tank. The liquid slurry is scooped off every day. This method, involving a great amount of work, is only possible because human excrement has been used traditionally as a fertiliser without taboos for hundreds of years. Buckets of liquid manure are carried on a yoke, something which would be impossible in predominantly Islamic countries. In this region the biogas plants are promoted by the state and the province by means of mass campaigns and dissemination programmes and have thus become part of normal agricultural technology. The purpose of promotion was mainly to improve the energy situation of rural households who found it difficult to meet their demand of energy due to high population density and the bad supply of firewood and fossil sources of energy. Apart from this' the "comprehensive" use of biogas plants, i.e. the efficient use of the slurry, was promoted. Since almost complete privatisation of biogas dissemination and the better supply of energy for rural households, the number of plants disseminated per year has fallen from several ten thousands to some thousands. The lower profit margins in rural areas are leading to an increasing number of qualified entrepreneurs moving to urban areas to construct wastewater plants.
The biogas plant stands somewhere on the farm, often near to the kitchen. The cattle are tethered in the open air. Many farmers have their own wells, or the village well is in the near vicinity. The women collect the dung with their hands from the ground and dilute it with water mixing the substrate - also with their bare hands. This method is only possible because cow dung is seen as being "clean". There is a long tradition of plastering the floor in the house and the terrace with cow dung every week. Dried cow dung is common as fuel. A biogas plant is very welcome as the dung can be used as a source of energy and also provides nutrients for the plants, which is not possible when the dung is burned. Collecting the dung daily and touching it with bare hands is the tradition in farm households. Where societies are not Hindu, this methods encounters great prejudice. The cattle are taken to the river to drink. This means they only leave small quantities of urine on the farm. In the summer months it is so hot and so dry that the slurry cannot be channelled to the fields in open ditches as it immediately dries up. The slurry flows into a depression where it is covered from time to time with agricultural or kitchen waste. During the preparation for seeding, the "compost" is transported to the fields by ox and cart. Biogas dissemination is possible here since the operation of a plant can be smoothly integrated into previous working procedures. In this region, plant dissemination is carried out mainly by one highly professionalised non-governmental organisation which employs approx. 500 permanent members of staff. There are approx. 2,000 trained masons available for construction at given points. Thanks to the integration of biogas technology in the administrative structures which considerably facilitates the acquisition of customers and the handling of finance matters, to the state subsidy programme and to the financial involvement of foreign donors who cover the costs of overheads, the organisation today disseminates approx. 8,000 plants annually.
The method of keeping animals and the climate here are similar to the situation described above in Central India. Despite this' biogas dissemination encounters great difficulties. Farmers and their wives are not used to collecting dung since there is plenty of fuelwood growing around the scattered settlements. Collecting wood means no extra work for the women as they bring it with them when coming home from the fields. The fields are often far away from the farms, there are no ox-carts. Organic fertilisation here is carried out by driving the cattle over the fields after the harvest. Cow dung is normally considered "unclean". There is a shortage of water and only few farmers have their own well. Under such conditions, biogas technology hardly has any chance of seeing a great demand. In order to make use of biogas extensively, the farmers would have to completely change their farming and working procedures. A complete re-structuring of the agricultural systems would be necessary: indoor stabling of dairy cows and a regular production of fodder grass would have to be introduced. The animals would have to be given water in the sheds to save water for the biogas plant; the amount of work involved in looking after the cattle would have to be substantially increased. In addition to these problems on the demands side, there are also problems on the supply side. The agricultural extension services are in an overall structural crisis. The counterpart organisation, despite its high involvement, is not able to support a biogas programme with the funds it has available.
The conditions at this project location in contrast are almost ideal. Normally, composting is carried out directly in the sheds by covering heaps of dung with straw and then pushing them to the side every day. Flies and insects in the sheds are quite common. The farmers are interested in a solution to this problem. A dairy cattle programme introduced by a private cooperative which attaches great importance to hygiene in the sheds makes it clear for the farmers that the compost heap in the shed can be an economic disadvantage. Organic fertilisation is a tradition and is carried out carefully. When a biogas plant is built, dung and urine are pushed into the biogas plant or collected outside the shed. The slurry overflowing, either flows directly onto the fodder fields or is processed into compost which can be transported. The composting of slurry only means little adjustment for the farmers. These favourable conditions are enhanced by a healthy economic situation of the farmers. The counterpart organisation also has expert competence and good access to the target groups. Highly qualified craftsmen also make it easier to establish know-how for building. However, future financing of the biogas programme is still uncertain. The task for the project here is to establish biogas technology also financially on a state level.
The dissemination situation in the Coffee-Banana Belt of Mt. Meru in Tanzania is contradictory. A number of factors favourable to dissemination meet in this region. The area is marked by a bad development of the infrastructure. There is a need for an improvement in the supply of energy for farms and households. Large numbers of the target group carry out intensive mixed farming and have a relatively high income. Organic fertilising is hardly practised in the region. As the volcanic soils are rich in nutrients, the farmers can only be interested very slowly in organic fertilisation. One point on the programme of the project entails distributing the slurry to neighbouring fodder fields via simple irrigation ditches. In the region there are, in the meantime, approx. 250 well functioning biogas plants over a relatively small area which have made the biogas plant a well-known capital and durable investment. The demand is balanced by a competent supply. The project activities produced a number of well qualified craftsmen and technicians who now build plants independently of the counterpart organisation However, the price of the plant is an obstacle to widespread dissemination. With economic liberalisation, larger consumer and investment alternatives have appeared for the farmers with a higher income and have had a limiting effect on the development of demand. Although the government is interested in biogas technology, the future of the counterpart organisation is still uncertain due to the non-existence of state funds.
A study of potential shows a favourable picture for biogas dissemination. This region of approximately 575,000 hectares has a theoretical potential of approx. 20,000 plants for all areas of application of agricultural biogas plants. Infrastructure as regards electricity is insufficient. A large number of the farmers in the target group have a good financial position. Agriculture is extensively promoted by the state. Although local craftsmen cannot provide the same standard of quality as e.g. in Central Java, the establishing of an efficient dissemination programme should prove to be no problem. Regarding water management, the region has been developed in the past by an efficient organisation with modern management and selective methods. However, if sustainable dissemination is to be achieved, a coherent policy on the part of the Moroccan government will be necessary. This policy will have to provide the agricultural development agencies with a mandate and will have to ensure financial security for a future biogas programme. Limiting factors here could be the relatively easy access to fossil energy sources and the too low temperatures in some regions during the winter months.
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