Biochar applied in the removal of emerging contaminants present in wastewater

Abstract

Biochar is a carbon-rich solid obtained by heating in atmosphere with little or no oxygen. Biochar is an adsorbent widely applied in agriculture for soil bioremediation, fertilizer slow-release as well as to removal of pathogenic microorganisms, organic and inorganic contaminants in environmental matrices. Besides biochar wide usage, lack of studies are related to theremoval efficiency of emerging contaminants present in wastewaters such as sewage. Emergingcontaminants are present in wastewaters at concentration level ranging from mg/L to ng/L.Ecotoxicological effects are being reported, mainly for pharmaceuticals compounds, which present harmful effects even at concentration levels varying from ¼g/L to ng/L. There is nolegislation to control the discharge of pharmaceuticals compounds in wastewater. Based on this, the aim of this project is to develop a new adsorbent to remove emerging contaminants presentin wastewaters. This research project is focused to evaluate the removal efficiency using sixpharmaceuticals compounds: caffeine, carbamazepine, fluoxetine, venlafaxine, ciprofloxacin and norfloxacin. Sugarcane bagasse is a residue obtained from sugar and ethanol production used as heating source or sold by U$ 25,00 per ton. Pelletisation process will be done in a hydraulic press machine followed by torrefaction in a tubular oven or in a muffler with temperature varying from 250 to 290 oC. The pellets obtained will be characterized by infrared spectroscopy, scanning electron microscopy, elemental analysis (C, H, O, N, S), surface area, thermal analysis, nuclear magnetic resonance, zeta potential and isoelectric point in order to establish the removal mechanisms involved. First study is the adsorption capacity in water using batch anaerobic reactors. Each pharmaceutical compound separately at concentration level of 500 ng/L, followed by isotherms evaluations in a concentration from 200 to 900 ng/L. Also, adsorption of all pharmaceutical compounds in inactivated sludge will be evaluated. The last part of this project is the application of biochar as support material to anaerobic sludge in a continuous horizontal fixed-bed reactor. As future perspective to obtain a low-cost adsorbent from industrial residue, environmental friendly, efficient to remove emerging contaminants present in wastewaters. Moreover, biochar as support material to anaerobic sludge in a continuous-flow anaerobic reactors substituting polyurethane foams. (AU)