Evaluation of detoxification by sludge associations of water treatment plants and sewage treatment plants using Allium cepa bioassay

Abstract

The Water Treatment Plants (WTP) and the Sewage Treatment Plants (STP) use methodologies aiming to decrease water bodies damage and guarantee the quality of water to make it available for population. However, treatment processes generate residue, called sludge (S). The sewage sludge (SS) has favorable characteristics to be reused in agriculture, as fertilizers or soil conditioner, as it presents large amounts of organic matter. Nevertheless, using this residue without previous proper treatment can produce negative impacts on the environment, as it contains harmful substances, such as metals and potentially toxic organic compounds. The bioremediation is a process for wastes treatment, which uses microorganisms capable of decomposing pollutants. This study aims to evaluate the desintoxification efficiency of WTP and STP, bioremedied for 6 months through tests with Allium cepa. The cytotoxic, genotoxics and mutagenics agents will be evaluated in this study using samples of pure S (WTP and STP) and association samples between S of WTP and S of STP, and also of S with soil (WTP and STP), before and after the bioremediation process. This study aims to find a more sustainable alternative for WTP sludge, which is more recalcitrant, associating it to a more organic material like sewage sludge, for the purpose of improving its biodegradability. (AU)