ABSTRACT Firewood is still a major source of household energy in most parts of the world, including Brazil. This study establishes baseline fuelwood consumption for domestic cooking by rural families in Bahia, Brazil, as part of a socioenvironmental project centered on stove substitution. The project, titled “Fogão do Mar” (Seaside Stove), engaged families in adopting more efficient stoves to replace the traditional open-air, rudimentary models. The study involved household visits and interviews with 103 low-income rural families to estimate firewood consumption for domestic cooking. The results showed that all households have liquid petroleum gas (LPG) stove, but most of the families prefer to use a firewood stove for cooking. The annual per capita consumption of firewood was estimated to be 1,297±952 kg, which is higher than estimate by governmental data (560 kg), as well as other rural regions. Therefore, the consumption of firewood is regionalized. Economic factors are decisive in the choice of fuel for cooking.

A escassez de fontes energéticas e as altas taxas de mortalidade do rebanho são dois grandes problemas para os agricultores familiares no semiárido brasileiro. De setembro de 2006 a abril de 2007 um reator contínuo com gasômetro em PVC flexível, com 33 m³ de volume, instalado na Estação Experimental da EBDA, Jaguarari, Estado da Bahia, foi monitorado quanto aos parâmetros bioquímicos, microbiológicos e parasitários do afluente e efluente, sendo avaliadas a produção e a composição do biogás, além da utilização do biofertilizante em capim-elefante. Com o manejo adequado, o poder poluente dos dejetos foi reduzido significativamente. Microbiologicamente, a eficiência de remoção de coliformes totais e fecais se manteve acima de 98% enquanto os ovos dos principais endoparasitos foram eliminados com o tratamento. A produção de biogás foi de 0,061 m³ kg-1 de esterco. Basicamente, o biogás apresentou, em sua composição, 58 e 34% de metano e gás carbônico, respectivamente. O biofertilizante (pH 7,5) foi uma boa fonte de nutrientes, sobretudo de nitrogênio (64 g 100L-1, 80% na forma amoniacal) e potássio (214 g 100L-1), aumentando a produção de forragem sem alterações significativas na composição bromatológica, digestibilidade "in vitro" da matéria seca e teor de minerais.

The scarcity of energy resources and the high livestock mortality rates are perpetual problems for small farmers of the Brazilian semi-arid region. From September 2006 to April 2007 a continuous reactor, of 33 m³ with gasometer in PVC flexible film, was installed at the EBDA Experimental Station, Jaguarari, Bahia State and the affluent and effluent biochemical, microbiological, and parasitological characteristics were monitored, the biogas production and composition being evaluated, as well as the use of the biofertilizer in elephant grass. With adequate management, the pollution power of residues reduced significantly. Microbiologically, the efficiency of total and fecal coliforms remotion was above 98%, when the main endoparasite eggs were eliminated after treatment. The biogas production was 0.061 m³ kg-1 of manure. The biogas showed in its composition basically 58 and 34% of methane and carbonic dioxide, respectively. The biofertilizer (pH 7.5) was a great source of nutrients, mainly nitrogen (64 g 100L-1, 80% ammoniacal form) and potassium (214 g 100L-1), increasing forage production, without significant changes in the chemical composition, "in vitro" dry matter digestibility, and mineral content.