Biodegradation of mono azo dye-Reactive Orange 16 by acclimatizing biomass systems under an integrated anoxic-aerobic REACT sequencing batch moving bed biofilm reactor

Abstract

This study dealt with the biodegradation of Reactive Orange 16 (RO16) containing wastewater via a novel integrated anoxic-aerobic REACT sequencing batch moving bed biofilm reactor (SBMBBR). The chemical oxygen demand (COD) removal and biodecolorization from three design schemes pertinent to the effects of (i) dye concentration under stepwise approach, Scheme 1; (ii) dye concentration under shock load approach, Scheme 2 and (iii) hydraulic retention time (HRT) coupled with the increase of biocarrier filling ratio, Scheme 3 were evaluated orderly along the evaluation. A complete biodecolorization and over 97 % of COD removal were attained in Scheme 1. Although both COD removal and biodecolorization in Scheme 2 was deteriorated to approximate 40 % by successive RO16 shocks, the microbial strength in removing RO16 molecules (mg RO16/mg biomass) reflected a two-fold amelioration from 0.015 to 0.0304 as the result of actively metabolic system. The maximum co-substrate uptake also reduced from 100 % to 69 %. At higher biocarrier filling ratio (10 % (v/v)) in Scheme 3, the difference in COD removal and biodecolorization rates reflected an improvement of 0.16 and 0.30 % hour-1, respectively, throughout the anoxic-REACT period. However, the performance changed insignificantly due to the reduction of HRT. The presence of the attached-growth biomass system was of great importance, although the suspended-growth biomass dominated more than 76 % of the biomass system in SBMBBR.