Evaluation of bench-scale solar photocatalytic reactors for degradation of phenolic wastewaters

Abstract

Four bench-scale solar photocatalytic reactors were fabricated viz. solar photocatalytic single-baffle reactor (SPSBR), solar photocatalytic multiple-baffles reactor (SPMBR), solar photocatalytic cascade reactor (SPCR) and solar photocatalytic pond reactor (SPPR) of 5-L capacity. Evaluation of the reactors performance was carried out by varying the volume of wastewaters in the range of 1–5 L and the recycle flow rates in the range of 250–750 mL/min for the degradation of phenolic wastewaters. The single-baffle reactor gives the maximum phenol removal efficiency irrespective of all volume of wastewater. The phenol removal efficiency increases when the recycle flow rate is increased from 250 to 500 mL/min and then decreased for the recycle flow rate of 750 mL/min. The single-baffle reactor showed the maximum phenol removal efficiency with recycle flow rate of 500 mL/min. For untreated pulp and paper mill wastewater of 200 mg/L phenol concentration, the BOD₅/COD ratio is 0.02, while solar photocatalytic treatment of 4 h enhanced the biodegradability values to 0.80.

Keywords:

• Solar photocatalytic reactors
• Titanium dioxide
• Phenolic wastewaters
• Recycle flow rate
• Hydrogen peroxide
• Biodegradability