Generation, characterization and reuse of solid wastes from a biodiesel production plant.

The aim of this study was to identify and characterize industrial solid wastes generated by a biodiesel production plant in Brazil, as well as to present strategies for the management of these materials. This plant produces every year around 100,000tons of biodiesel from vegetable oils and animal fats. The methodology of the study included technical visits, interviews with the operational and environmental management staff as well as analysis of documents, reports and computerized data systems. An approach to reduce the generation of hazardous waste was investigated. It was take into account the amount of raw material that was processed, reduction of landfill disposal, and the maximization of the their recycling and reuse. The study also identified the sources of waste generation and accordingly prepared an evaluation matrix to determine the types of waste with the higher potential for minimization. The most important residue of the process was the filter material impregnated with oil and biodiesel, requiring, therefore, measures for its minimization. The use of these residues in the production of ceramic artefacts (light bricks) was considered to be very promising, since no significant effect on the physico-chemical and mechanical properties of the artefacts produced was observed. Phytotoxicity test using seeds of Lactuva sativa (lettuce), Brassica juncea (mustard), Abelmoschus esculentus (okra), Chrysanthemum leucanthemum (daisy), Dendranthema grandiflorum (chrysanthemum) and Allium porrum (leek) were carried out. The results clearly show incorporation of the waste material into bricks did not influence relative germination and relative root elongation in comparison to control tests.