Effective biotreatment of acidic mine water and hospital wastewater using fluidized-bed reactors

Enriched Co-Treatment of Pharmaceutical and Acidic Metal-Containing Wastewater with Nano Zero-Valent Iron

“…This performance may be due to mine water-binding with organic molecules [26,50]. On the other hand, the sulfates were reduced by 70% in phase I, which is lower than the previous studies published for similar FBR application in the absence of nZVI [13]. At the end of phase III, the increase in Fe could well be due to microbial Fe decrease of FePO4 and Fe(OH)3 [12,51].…”

“…As an alternative, an aerobic process is preferred to remove high strength organic matter. This cotreatment strategy's efficacy is better described in Makhathini et al [13]; however, the heavy metals such as Pb, As, and Mn were not documented as they experienced a low removal rate in this system. As such, the cotreatment needs to be enhanced to assess its efficacy under the presence of nZVI, specifically to assess the heavy metals.…”

“…Since this study continues from the published work of Makhathini et al [13], there was no need to assess treatment process feasibility. However, nZVI in the biotreatment was to be explored for its possibility in this treatment system.…”

“…An existing laboratory-scale fluidized bioreactor was converted to an nZVI reactor (Figure 1). The reactor used an effective bed volume of 1400 mL, which was packed with silica sand as a biomass carrier; further details on the rector specification are discussed on Makhathini [13]. As part of the initialization stage, the bioreactor was on recycle operation for 24 h, and the bed fluidization was kept approximately 15-25% after the biofilm was developed.…”

“…The hydraulic retention time (HRT) was not rigorously varied since the previous study had given some insight on its effect [13]. This study gradually reduced the HRT from 24 to 16 then later to 8 h while maintaining the feed rate relatively constant.…”