Pyrolysis of Scenedesmus obliquus biomass following the treatment of different wastewaters

Abstract

ABSTRACT: The potential of Scenedesmus obliquus biomass, after treating several wastewaters (WWs) (urban, dairy and brewery industries, cattle and poultry breeding), was evaluated for the production of bio-char, bio-oil and bio-gas, through a pyrolysis process. The experiments were carried out in a fixed bed reactor at a temperature of 748 K during 15 min. The thermochemical behaviour of each microalga was assessed by thermogravimetry analysis and infrared spectroscopy. The bio-oils obtained were also quantified and characterized. The results reveal that (i) all microalgae show a similar thermal degradation behaviour; (ii) microalga grown in urban WW shows a lower percentage of lipids; in dairy and cattle WWs, it shows a high percentage of both proteins and lipids, and in poultry and brewery WWs, it shows a higher carbohydrates content; (iii) the microalga grown in poultry WW shows the lowest protein content, whereas the urban grown microalga showed the highest protein content; (iv) the bio-oil obtained by pyrolysis process showed yields in the range 30-60% (w/w) and showed a high content of aromatic compounds.