Effectiveness of bioremediation on biostimulation sewage sludge, evaluated by the Allium cepa test

Abstract

Sewage Sludge (SS) is a residue generated during the wastewater treatment process. Due to its increasing production, in the order of tons, its disposal has become one of the main environmental problems nowadays. As SS is a compound rich in organic matter and nutrients, some authors propose that it can be used as an agricultural additive, allowing the reduction of costs with its landfill, recycling of nutrients and replacement of synthetic fertilizers. However, some toxic substances and pathogens microorganisms may be present in SS, precluding its use in agriculture. Thus, new technologies that promote decontamination of SS and allow its agricultural use, in an environmentally sustainable way, have been requiring. Among these technologies, the bioremediation process that uses indigenous microorganisms to promote mineralization of contaminants is well recommended. The aim of this project is to present a possible solution for the reuse of this waste as an additive in agricultural soils. Therefore, detoxification of aerobic SS samples from a domestic sewage treatment plant is being proposed by means of bioremediation process, using agricultural industry (sugarcane bagasse) and domestic (coffee grounds) wastes as biostimulant agents. The evaluation of the effectiveness of this process will be performed by means of bioassays with the test organism Allium cepa, with the purpose of characterizing the ecotoxicogenetic potential of SS, assessing toxic, cytotoxic, genotoxic and mutagenic effects during 0, 2, 4 and 6 months of biostimulation process. (AU)