The project aims to solve the problems of rural sanitation caused by the irregular disposal of family waste. It emerges as a technology, which is necessary for the management of a rural environment without a sewage network or any type of treatment for the waste produced by human activity. To ensure the responsible disposal of these wastes, two biodigesters with evapotranspiration basin for gas production were implanted. The system consists of an underground fermentation tank, where human waste and organic household waste are treated, with parasitological and bacteriological efficiency between 95% and 99%. Throughout the process biogas is produced, which replaces cooking gas (LPG) efficiently.

Adapted by Mr. Diego Andrei Reimann to the climatic reality of the mountains region – whose negative temperatures are frequent during the winter –, the two biodigesters implanted in rural properties of São José do Cerrito – SC presented expressive results: (1) adequate treatment of human waste from rural properties, with a processing capacity of 2,500 liters of waste per month (or every 30 days); (2) reduction of family expenses with the use of firewood and other energy sources: within 45 days it is possible to produce the amount of gas equivalent to a 13kg LPG cylinder; and (3) reduction of greenhouse gas emissions, the burning of the methane gas generated by the biodigesters results in steam and carbon dioxide, and the impact of CO2 on the atmosphere is 21 times lower than methane.


A - General information


START: October 2010 (in progress).

EXECUTING ENTITY: Company of Agricultural Research and Rural Extension of Santa Catarina - EPAGRI

CO-EXECUTING ENTITY: Rural Producer Mr. Diego Andrei Reimann.

SUBMITTED BY: Denizete Monteiro de Lima Mota.

RESOURCES: Proprietary and Third Parties.

VALUE RANGE: Up to US$5,000.

CATEGORY: Project.

MAIN THEME AREA: Environment.

KEYWORDS: Environment, Environmental Sanitation, Renewable Energy, Biodigester, Organic Waste. 

TARGET AUDIENCE: Family farmers and farmers associations


Municipality of São José do Cerrito - State of Santa Catarina.


Rural properties of the communities of Toca da Onça (in 2010), Salto dos Marianos (in 2014) and Santo Antônio dos Pinhos (ongoing implementation). All municipalities of São José do Cerrito, which is part of the Canoas basin; CISAMA/AMURES consortium of Serra Catarinense, State of Santa Catarina. . 


B - Description of the practice



Human activity generates waste that pollutes and contaminates the environment when it is not well managed. In the rural areas of Santa Catarina, it is a common practice to dispose of the human waste in cesspits, commonly exposed to the soil, that directly or indirectly end up taking these residues to the rivers, creating a cycle of soil and water contamination.

There is a concern on the part of the Epagri technicians in creating alternatives to treat the waste and to reduce the means of contamination. During the Microbacia-2 Program (2002-2010), through the Environmental Education project, the rural area of the municipality received a significant number of development projects in the area. Thirty-six protections of river sources, recovery of riparian forest in degraded areas and the implementation of 123 toilets with root zone treatment septic tanks were performed. Thinking of viable and efficient alternatives for the treatment of human waste and renewable energy generation, the rural owner, Mr. Diego Andrei Reimann, and the technician, Ms. Heloisa Gogacz of the Microbacias-2 Program, with the help of Epagri, used the program resources to invest in the construction of a biodigester. In a rudimentary way, the first biodigester with a banana tree circle was built, which reached the expected objective and is still in operation. The pilot project worked as reference unit, received farmers, technicians and residents of the region, and was the subject of regional news features. The current biodigesters – which are being installed – have the same technique and purpose. Some specific changes were made in order to optimize the process, such as increasing the waste and gas storage capacity.



Implement residential biodigesters with evapotranspiration basin on rural properties for the production of gas from organic waste and human waste.

Specific objectives: 

  • Contribute to the family household economy through the generation of energy from solid waste, produced in rural properties;
  • Positively impact the basic sanitation management of the municipality of São José do Cerrito;
  • To avoid environmental pollution and the proliferation of diseases related to the lack of basic sanitation;



The irregular disposal of human waste and its negative impacts on the rural environment have promoted the development of a technology of easy propagation, with low cost, high durability materials, use of local workforce and low maintenance. It was necessary to think of alternatives for the smart use of this waste, matching environmental responsibility and household economy. To meet these requirements, in 2010 Epagri's technicians and the rural landowner built a biodigester with evapotranspiration basin for gas production.

The resources for the implantation of the first biodigester came from the Microbacias 2, a project of the state government whose objective at the time of its implementation was to implement actions to support small farmers and environmental recovery/preservation. The location was chosen based on the voluntary interest of the farmer in carrying the project out. Some meetings were conducted with residents of the locality Toca da Onça to include families close to the capture system. However, they were resistant to the new technique and it was difficult to engage people.

The system consists of an underground fermentation tank, where human waste and organic household waste are treated, with parasitological and bacteriological efficiency between 95% and 99%. The gas is produced from biomass (human waste) and the biodigester works by gravity, favoring automatism. Low pressure is used, which helps to make the system very safe.

The construction of the biodigester counted on local workforce and the support of Epagri's technicians. The biodigester can be built with several materials, which makes it possible to choose the best cost-benefit relationship. The gas is piped underground, directly into the stove, thus simplifying the installation. The system is able to absorb all the waste produced in the property. To maximize its yield, the waste from domestic animals, leaves and organic garbage are added to it, which helps the compound decomposition and fermentation.

After the implantation of the first biodigester in the municipality, other rural landowners sought information and showed interest in the application of waste management technology in their houses. Therefore, a new biodigester was installed in Salto dos Marianos (2014) and another one is being installed in Santo Antônio dos Pinhos, all rural communities of São José do Cerrito-SC. Recently, the Associação de Criadores de Frangos Caipira, Ovos caipira e outras aves (Association of Breeders of Free Range Hens, Free Range Eggs and other poultry) of São José do Cerrito was benefited by the public notice of the Fundação de Amparo à Pesquisa e Inovação do Estado de Santa Catarina (FAPESC, Research and Innovation Support Foundation of the State of Santa Catarina) with the project of implantation of biodigesters in 27 rural properties of the municipality.

Throughout the execution of the project, some changes were carried out in order to facilitate the installation of the biodigesters, especially the ones related to materials acquisition. Considering the deadlines established by FAPESC, Epagri's technicians and the association's farmers decided to acquire a ready-to-use fiberglass reactor, reducing the workforce for the construction of solid brick. On the other hand, new expenses were created, such as the acquisition and installation of complementary materials. This project is still being implemented because it depends on the farmer's resources availability.

The methodology used to create and execute this project was and continues to be a process of collective construction and environmental education. Little by little it is possible to raise awareness of the rural community on the importance of taking care for the environment. In this sense, Epagri often develops lectures, meetings and field activities that demonstrate the relation between rural activity and waste production. In other words, the management of human waste through the biodigester provides new possibilities for the use of gas – from household use to the use in the heating lamps for chicks.



For organizational reasons, the results obtained through the project: "Biodigester Construction with Evapotranspiration Basin for Gas Production" were sorted into quantitative and qualitative.  

Quantitative Results:

  • Responsible management of all human waste from family property, storage capacity of 5 thousand liters of waste;
  • There was a reduction in the volume of the family's human waste directly exposed to the environment in the order of 0.166m³ / day;
  • Substitution of LPG (petroleum by-product) by biogas (renewable fuel), with similar calorific value and less polluting power. The project avoids the release of methane (flammable component of the biogas) into the atmosphere. Methane contributes 21 times more to the greenhouse effect than carbon dioxide. When methane is burned, carbon dioxide and water vapor are released, both with a much lower polluting power than carbon monoxide (resulting from the burning of LPG) or methane when not burned;
  • Gas production equivalent to a 13kg LPG cylinder in a period of 45 days. In order to reach such production, it is necessary a mixture of approximately 50% waste and 50% water, totaling 0.166m³ / day. This percentage includes the water from the toilet flush. The expected maximum amount of digestate is slightly lower than the amount of influent, when there is no vegetation in the evapotranspiration basin (when seedlings were newly planted, for example);
  • Generation of 2.8m³ / month of digestate during the 45 days period. Digestate is a waste rich in organic matter and with high concentration of phosphorus and nitrogen, applied in agriculture to improve soil conditioning;
  • Reduction of the use of firewood and other energy sources. It is estimated that a rural property spends around 3 m³ of firewood per month to perform household cooking activities. With the use of gas, this consumption of firewood has been reduced;
  • When compared to the activities for maintenance and use of the wood stove, the use of gas provided a reduction in the time for the family to cut, store and use firewood. It is estimated a reduction of 10 hours of work per month.

Qualitative Results:

  • In terms of public health, the use of gas does not produce ashes and soot;
  • Potential respiratory problems caused by smoke inhalation (CO²) are avoided; It also helps in the prevention of diseases related to lack of basic sanitation;
  • By means of the appropriate waste treatment, it eliminates the bad smell due to the exposure of such waste, including solid ones;
  • Following the guidelines of the National Solid Waste Policy, the biodigester provides an environmentally appropriate option for the disposal of solid organic waste from rural property; In addition to human waste, it is possible to destine to the biodigester: old papers, cut grass, tree leaves and other types of straw,
    Reduction of the volume of organic waste destined to the municipal landfill.



For the implantation and maintenance of residential biodigesters with evapotranspiration basin in a familiar unit it is necessary:

Human Resources: : 

- 1 professional technician who masters the practice
- 3 people in the workforce, available for 6 days (mason, helpers);

Material resources:

- an area of approximately 60m³
- machine hours (backhoe) to prepare the site (it depends on the area and ground conditions)
- materials for the construction and installation: One Kit containing: 1 fiber septic tank; 3 cement bags; 1m³ of gravel, 0.5 m³ of fine sand; 1m³ of coarse sand; 4 1 "x 3" x 3m laths; 1 gallon (3.6 kg) of synthetic resin adhesive; 50 solid bricks; 1Kg annealed wire; 22m nursery mesh; 26m2 pop mesh; 2 5mm iron bars; 1 1m3 water tank; 1 5m3 water tank; 1 set guide for gasometer; 4 100mm PVC pipe; 3 100mm PVC knee; 1 100mm x 50mm PVC reducing bush; 1 50mm PVC sewage pipe; 3 25mm PVC pipe; 7 100mm CAP; 4 25mm flanges; 1 32mm x 25mm reducing bush; 1 25mm LR glove; 1 25mm LR PVC knee; 7 25mm PVC knees; 1 spray synthetic enamel; 1 CPVC glue; 2 25mm tee connection; 1 100mm PVC "Y" connection and 1 100mm tee connection with sealing rings.

Total implementation value: R$9,000.00 (value may vary depending on the availability of materials and workmanship of the property).



The first biodigester was implemented as a reference unit in 2010, in the community of Toca da Onça, São José do Cerrito - SC. The interest of farmers of the municipality made it possible to take the project to the community of Salto dos Marianos and Santo Antônio dos Pinhos. Currently, the Associação de Criadores de Frangos Caipira, Ovos caipira e outras aves (Association of Breeders of Free Range Hens, Free Range Eggs and other poultry) of São José do Cerrito was benefited by the FAPESC public note for the implantation of 27 biodigesters in rural properties of the municipality.

The practice may be adopted by other technical assistance and rural extension institutions, as well as by farmers who are interested in biodigesters construction. The methodology used for the replication of the technology includes workshops, lectures, local workforce training and adaptation of materials and equipment. A technical bulletin is currently being elaborated describing all technology and the social, environmental and economic results. It will be made available to the community of São José do Cerrito and other interested parties.



Once it is a very cold region, the model was adapted to meet our needs. In 2010 a mini pilot biodigester was installed serving as a demonstration unit, in the property of the technician who owns the technology, with the support of Microbacias 2 Project. Currently there are two units in operation, and there is a forecast for the installation of other twenty-seven units. Throughout the project implementation process, the resistance of the local population to the new practice made it difficult to extend the system to other residents near the biodigester. It is worth highlighting the need of working on the collective awareness of the benefits of the appropriate human waste management, and the social / environmental problems they cause when they are incorrectly disposed of.

In São José do Cerrito, as well as in other agricultural municipalities, rural properties do not have sewage treatment or sewer system. The idea of implanting a mini biodigester came from the need to provide appropriate disposal for human waste. In order to continue with the project, it was necessary to involve other parties, such as the Associação de Criadores de Frangos Caipira, Ovos caipira e outras aves (Association of Breeders of Free Range Hens, Free Range Eggs and other poultry) of São José do Cerrito - SC and the FAPESC.

It is also important to highlight the difficulty of raising funds; the ecological awareness of the population and the sewage treatment are not a priority of the municipality or a cultural habit of the region. Another issue is the farmer's concern to generate income through his agricultural production. In this case, the priority will be the investment in production and only after profitable results the farmer will be interested in the property's waste management.



There are several models of biodigesters: Canadian, Indian, Chinese, among others. The practice is original because it adapts the technique and the necessary structure to the climatic conditions of the region.




It is possible to visit to the site at any time of the year – upon previous scheduling – from Tuesday to Thursday.
Number of Visitors: Up to 20 people.

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