Fernando Godinho de Araújo

Vermicompostagem de lodo de curtume em associação com esterco bovino utilizando Eisenia fetida

Tannery industry-generated sludge is an example of residue that causes important environmental problems. In this sense, the objective of the present study was to evaluate vermicomposting of tannery sludge, as a method of treatment this waste. Due to the toxic characteristics of the tannery sludge, it was mixed with cattle dung in various proportions, on dry weight basis. During 105 days, biomass, number of individuals (Eisenia fetida ), pH, moisture and temperature of the experimental units were assessed. The substrates were chemically characterized at the beginning and at the end of the vermicomposting process. No significant differences were observed in pH in groups with lower concentrations of sludge, there was a significant decrease in pH of the groups with higher concentrations of the residue during vermicomposting. Mg, Fe, Mn and Zn contents were high in the vermicompost in all treatments. The C/N ratio was low in the substrate of all treatments, indicating the maturation of the final substrate. The results indicate that vermicomposting promotes the conversion of sludge to manure in a short time interval, thus constituting a biotechnological process of treatment able to add agronomic value to this residue.