ABSTRACT Currently, concern about the burning of fossil fuels and the consequences for the planet has increased and become the agenda of discussions at global levels. In this sense, biofuels are an important alternative, and this article seeks to review the literature on the use of microalgae as raw material for the manufacture of biodiesel, the transesterification process as a conversion method, the technologies used to optimize this process, the characteristics of biodiesel that are required by Brazilian legislation, and the challenges for production. Brazil has a very large potential for the production of these biofuels but their production on a large scale still requires further studies so that it can be part of the country’s energy matrix, including in the agro-industrial sector. Currently levels sense alternative method legislation countrys country s matrix agroindustrial agro industrial sector

Este trabalho teve como objetivo avaliar a eficácia de sistemas alagados construídos no tratamento de águas residuais da agroindústria de laticínios. Os sistemas foram submetidos a diferentes taxas de carregamento orgânico e nutrientes a um tempo de detenção hidráulica de 3,5 dias aplicando um caudal de 7,5 L dia-1. Foram implantadas seis unidades experimentais por meio de tanques de polietileno com volume útil de 75 L, usando como meios suportes brita n° 0 em três dos sistemas e brita n° 0 e areia em outros três, na proporção de 80% brita e 20% areia. Quatro unidades foram cultivadas e duas mantidas como testemunhas. As espécies selecionadas para cultivo foram as macrófitas Typha domingensis e o Hedychium coronarium. As eficiências médias na remoção de nitrogênio e fósforo ficaram entre 42 e 50% e 39 a 43%, respectivamente, nos leitos vegetados e entre 28 a 30% e 16 a 19% nos leitos não vegetados, havendo diferenças significativas entre leitos cultivados e testemunhas (p < 0,05). Em termos de remoção de DBO e DQO não houve diferenças significativas (p>0,05) entre os sistemas, apresentando estes eficácias médias de remoção 89 a 91% para DBO e 82 a 86% para DQO.

This work had as objective to evaluate the effectiveness of constructed wetlands systems in wastewater treatment of agribusiness of dairy products. The systems were submitted rates of organic load and nutrients to hydraulic detention time 3.5 days by applying a flow of 7.5 L day-1. Were implanted six experimental units by means of polyethylene tank with a net volume of 75 L, using as means crushed stone nº 0 in the three of the systems and crushed stone nº 0 and sand in the other three, in the proportion of 80% and 20% sand. Four units were cultivated and two maintained as witnesses. The species selected for cultivation were the macrophytes Typha domingensis and Hedychium coronarium. The efficiencies sized in the nitrogen and phosphorus were between 42 to 50%, and 39 to 43%, respectively, in beds vegetated and 28 to 30% and 16 to 19% in the beds not vegetated, and there are significant differences between beds cultivated and witnesses (p<0.05). In terms of the removal of DBO and DQO there were no significant differences (p>0.05), between the systems, presenting these efficacies averages of removing 89 to 91% for DBO and 82 to 86% for DQO.