Catalytic thermal treatment (catalytic thermolysis) of a rice grain-based biodigester effluent of an alcohol distillery plant

Abstract

The catalytic thermolysis (CT) process is an effective and novel approach to treat rice grain-based biodigester effluent (BDE) of the distillery plant. CT treatment of rice grain-based distillery wastewater was carried out in a 0.5 dm³ thermolytic batch reactor using different catalysts such as CuO, copper sulphate and ferrous sulphate. With the CuO catalyst, a temperature of 95°C, catalyst loading of 4 g/dm³ and pH 5 were found to be optimal, obtaining a maximum chemical oxygen demand (COD) and colour removal of 80.4% and 72%, respectively. The initial pH (pH_i) was an important parameter to remove COD and colour from BDE. At higher pH_i (pH 9.5), less COD and colour reduction were observed. The settling characteristics of CT-treated sludge were also analysed at different temperatures. It was noted that the treated slurry at a temperature of 80°C gave best settling characteristics. Characteristics of residues are also analysed at different pH.

Keywords:

• biodigester effluent
• chemical oxygen demand
• catalytic thermolysis
• catalyst
• CuO

Disclosure statement

No potential conflict of interest was reported by the author(s).

Funding

Authors gratefully acknowledge Chhattisgarh Council of Science and Technology (CGCOST), Raipur, India for providing research grants to support this work.