Biogás by anaeróbica decomposition [ to publish ] The production of biogás by anaeróbica decomposition is a considered way useful to treat biodegradable remainders since it produces a value fuel besides of generating a efluente that can be applied as conditioning of ground or generic installment. Biogas has like average a calorific power between 4,500 to 5,600 (five thousands six hundred) kilocalorias by cubic meter. This gas can be used to produce electrical energy by means of turbines or generating plants to gas, in furnaces, stoves, dryers, boilers, or other systems of combustion to gas, properly adapted for such effect. Biogas is called to the mixture constituted by methane CH4 in a proportion that oscillates between a 50% to a 70% and carbon dioxide containing small proportions of other gases like hydrogen, nitrogen and sulfide of hydrogen. But that is a biodigestor? [ to publish ] A biodigestor is a natural system that takes advantage of the anaerobic digestion (in absence of I oxygenate) the bacteria that already live in the dung, to transform this into biogás and fertilizer. Biogás can be used as combustible in the kitchens, or illumination, and in great facilities it is possible to be used to feed a motor that generates electricity. The fertilizer, call biól, initially has considered a product secondary, but at the moment this considering itself of the same importance, or greater, than biogás since it provides to the families farmers with a natural fertilizer that strongly improves the yield of the harvests. The familiar biodigestores of low cost have been developed and widely are implanted in countries of the Asian Southeastern, but in South America, single countries like Cuba, Colombia and Brazil have developed this technology. These models of familiar biodigestores, constructed from tubular polyethylene sleeves, characterize by his low cost, easy installation and maintenance, as well as to require only of local materials for their construction. For that reason apropiadá is considered one ` technology. The lack of firewood to cook in different regions from Bolivia does to these interesting systems for their diffusion, spreading and dissemination on great scale. The families dedicated to agriculture, usually are proprietors of small amounts of cattle (two or three cows for example) and can, therefore, take advantage of the dung to produce their own fuel and an improved natural fertilizer. One is due to consider that the accumulated dung near the houses supposes a center of infection, scents and flies that will daily disappear to the introduced being the dung in the familiar biodigestor. Also it is important to mainly remember the amount of respiratory diseases that suffer, the women, by the inhalation of smoke when cooking in spaces closed with dry firewood or bosta. The combustion of biogás does not produce visible smoke and its ash load is infinitely smaller than the originating smoke of burns it of wood. In the case of Bolivia, where three regions differentiated like plateau, valley and tropic exist, this technology was introduced in 2002 in Mizque, (2200 m.s.n.m. Cochabamba) like part of the technological transference to a cochabambina ONG. Since then, in constant collaboration by Internet with institutions of Cambodia, Vietnam and Australia and the ONG of Cochabamba, these systems has been adapted to the plateau. The first experience was in 2003 installing an experimental biodigestor to 4100 m.s.n.m. that it took advantage of the effect conservatory. This preliminary design underwent a development to lower the price of costs and to adapt it to the rural conditions maintaining the spirit of appropriate technology. They are the three basic limits of the biodigestores: the water availability to make the mixture with the dung that will be introduced in the biodigestor, the amount of cattle that has the family (three cows is sufficient) and the appropriation of the technology on the part of the family. The familiar biodigestores of low cost [ to publish ] This model of biodigestor consists of taking advantage of tubular polyethylene (of black color in this case) employee in its solar natural color transparency in carps, to have a camera of several cubic meters closed hermetically. This hermetism is essential so that the biological reactions take place anaeróbias. The tubular polyethylene film is moored by its ends to conduction pipes, of six inches of diameter, with recycled strips of league of the cameras of the wheels of the cars. With this system, calculating properly the inclination of these pipes, obtains a hermetic tank. To the flexible being the tubular polyethylene is necessary to construct to one ` cuná that it lodges it, or digging a ditch or raising two parallel walls. One of the pipes will serve as entered as raw material (dung mixture with 1:4 water). In the biodigestor a balance of hydraulic level is reached finally, by which, according to the amount of dung mixed with water that is introduced, it will leave a certain amount fertilizer by the pipe of the other end. Due to the oxygen absence inside the sealed chamber, the contained anaerobic bacteria in the own dung begin to digest it. Firstly one takes place a phase of hydrolysis and fermentation, later a acetogénesis and finally the metanogénesis by which methane takes place. The gaseous product called biogás, really has other gases in its composition as they are dioxide of carbon (20-40%), molecular nitrogen (2-3%) and sulfhídrico (0,5-2%), being the most abundant methane with 60-80%. The conduction of biogás until the kitchen becomes direct, maintaining all the system to the same pressure: between 8 and 13 cm of water column depending the height and the type on furnace. This pressure is reached incorporating in the conduction a safety valve constructed from a bottle of refreshment. ` is included teé in the conduction, and while it follows the line of gas, the third end of the pipe is introduced in the water contained in the bottle of 8 to 13 cm. Also adds reservorio, or warehouse of biogás, in the conduction, allowing to store about 2 to 3 cubic meters of biogás. These systems adapted for plateau have to be located in ` cunas’ buried to take advantage of thermal inertia the ground, or two heavy walls of marinates in case it is not possible to be dug. In addition it is locked in to them to the biodigestores in a conservatory of a single water, supported on the sidewalls of marinates. In the case of biodigestores of tropic or valley, the conservatory is unnecessary but it is had to protect the plastic with a semishade. The costs in materials of a biodigestor can vary of 110 dollars for tropic to 170 dollars for plateau, since in the height they have greater dimensions and they require of solar carp. Adaptation of the biodigestores [ to publish ] The biodigestores have to be designed according to their purpose, to the disposition of cattle and type, and to the temperature to which they are going to work. A biodigestor can be designed to eliminate all the dung produced in a farm of pigs, or like tools of basic cleaning in a school. Another objective would be the one to provide with five hours of combustion in a kitchen a family, for which already we know that 20 kilos of fresh dung are required daily. As one commented previously, the obtained liquid fertilizer very is appraised, and a biodigestor designed for such aim has to allow that the raw material is greater time inside the sealed chamber as well as to reduce the mixture with water to 1:3. The room temperature in which it is going to work the biodigestor indicates the necessary time of retention so that the bacteria can digest the matter. In 30 atmospheres of ºC 10 days are required about, to 20 ºC about 25 and in plateau, with conservatory, the temperature of about 10 work is of ºC of average, and 55 days of time of retention are required. It is by this, that stops one mima amount of incoming raw material requires a greater volume five times for the sealed chamber in the plateau that in the tropic. Lessons learned in spreading and dissemination [ to publish ] In all this process of development, spreading and dissemination of this technology in Bolivia are several learned lessons. The introduction of the biodigestores in a family means that no longer it is required to look for firewood daily to cook, task normally assigned to the women and children. For that reason it is necessary that she is the woman the one that takes control of the technology like new fuel to cook. To even make the kitchens of biogás the improved mud kitchens have adapted traditional so that the combustion of biogás is more efficient. This liberation of the service load of the women implies greater availability of time for other productive uses, qualification, social participation, etc. On the other hand, the wide-awake fertilizer production greater interest in the man, since usually it takes care of the cultures, and therefore is important to enable to him in its use properly so that it also takes control of the technology that provides to him with an ecological and natural fertilizer. The children and children also it is important to have them in account, and to make them contributor like part of the family, avoiding who in games or vandalism, could damage the biodigestor. The strategy for the spreading and dissemination of this technology that has been seen more guessed right is through demonstrative biodigestores. This is, to install one or two biodigestores by community, in a municipal farm if there are educational interest of the authorities or in farms or centers ` modeled that they exist, so that the neighbors see their operation, handling and benefits. This strategy is not aggressive and it occurs to know a technology new, so that the families will have own information and criteria to decide the convenience of introducing, or no, a biodigestor in his houses and farming handling. In later visits to the communities a greater dissemination to the interested families can be done already. A lesson of last learned hour is simultaneously to introduce the demonstrative biodigestores in two families in a community, so that a mutual support between both families as far as work, doubts and transmission of knowledge is generated. The participation of the family in all the installation of biodigestor aid to its appropriation and understanding of the technology. Cases have occurred in which the family has disassembled and returned to mount a biodigestor to consider another location more suitable, or to repair it. The own work of the family digging the ditch that will serve as ` cuná, installing the line of biogás from the biodigestor to the kitchen is important to value it. When a biodigestor settles is made its first filling with great amount of dung and water, until inner mud covers the mouths of the entrance pipes and exit to assure an atmosphere anaeróbia. It is important to make a pursuit later, since the biodigestor will take so many days as time of retention is had I consider in the heat of to enter production of biogás and fertilizer. In the case of the plateau this can daily suppose two months loading a biodigestor that does not even give waited for products, and therefore is necessary to accompany and to support to the family in this process so that it does not feel that the work is vain. It is important to take advantage of the own social structures each place, like for example the association of local milk producers or other types of associations. This way already a represtación form exists, of communication, call and of internal control that is not necessary to generate with each new project. In case of existing monetary subventions to acquire the materials, or on the part of ONGs, municipalities or any other type of aid, never it has to be total, and therefore it is necessary to make contributor to the family in the costs. It is important that the nonsingle family puts part of the manual labor for the construction of ` cuná, but that in addition contributes money. This amount of money can be variable according to the social context, but he is recommendable that is not inferior to 30$us. Of this form the families who decide to install a biodigestor, will do it in a very important degree of appropriation of the technology, in addition that forces to the institution or promoter to have a responsibility and to give guarantee in the empelados materials and the operation of the system. Otherwise, as much the appropriation of the technology on the part of the family as well as the commitment of the good one for doing of the installer can be smaller. Diffusion, spreading and dissemination [ to publish ] This triada of aspects goes to each other related. The dissemination of the technology with demonstrative facilities becomes the best mechanism of spreading between the potentially interested families. In order to be able to scatter this technology, and therefore to disclose it, it is necessary to have actors enabled in the design and installation of biodigestores, and therefore it is required of practical factories for them as average of diffusion of the technology. In one first stage the factories are directed to professionals of the rural development, either are of ONGs, municipal, promotional technicians rurares or other institutions, since of this form the technology is scattered by all the national scope. Whatever more dissemination and spreading greater demand of enabled people is required, and the last objective of all this process is that the technological transference is made of farmer to farmer. For it it is necessary to generate models of biodigestores already adapted to each ecoregión and use, that will come dice and dissemination with time. The projects with biodigestores can incorporate new elements with which it is complemented very well. An example is to include a latrine that directly connects its water-drainage with the biodigestor, so that it is done without séptica grave or extra handling in the case of the dry latrines. Also an improvement in the cattle infrastructure can be included, incorporating a cement floor with certain unevenness to the corrals. The daily cleaning of the corrals with water will do that this drag the accumulated dung until the biodigestor, facilitating the load and maintaining an atmosphere much more hygienic. Factories of diffusion of the technology [ to publish ] Having an appropriate technology, of great potential in Bolivia, but of little diffusion, spreading and dissemination, the best form to begin is through practical factories. The objective of these factories is to enable to people in the design, installation, proposal and execution of projects of dissemination of biodigestores. The factories consider of intensive form with a duration of three days. The first day the biological concepts treat that govern this natural system, occur to the keys and parameters for their design according to the objective of the biodigestor (generation of biogás, production of fertilizer or handling of organic remainders by environmental criteria). In addition it is invited to people with experience in biogás, projects of biodigestores, handling of the fertilizer, etc. so that they share his experiences with the assistants. The second day is most interesting, since near farmer for the installation of a biodigestor is transferred to the participants to some community. Previously the family already has constructed ` cuná where the biodigestor will be lodged. During a morning one along with works the participants and the family in the installation, passage by step, of the biodigestor. This day serves as practical exercise to the factory, nonsingle as far as technology, but also in the qualification of the family in its construction, handling and maintenance. And the third day classes on the execution of projects, their identification, planning, budgets and form of dissemination are distributed and execution. To afternoon, in a round table between all the participants, one in the mid term considers the forms of financing and sustainability of this technology in Bolivia. In addition a national mapeo of the first projects is made that would coordinate the participant institutions in the factory. From these factories the institutions are several that decide to incorporate to the familiar biodigestores of low cost in their programs of rural development. It is important to subsidize the technology initially.