Highly efficient phenol degradation in a batch moving bed biofilm reactor: benefiting from biofilm-enhancing bacteria

Abstract

In this study, the efficiency improvement of three moving bed biofilm reactors (MBBRs) was investigated by inoculation of activated sludge cells (R1), mixed culture of eight strong phenol-degrading bacteria consisted of Pseudomonas spp. and Acinetobacter spp. (R2) and the combination of both (R3). Biofilm formation ability of eight bacteria was assessed initially using different methods and media. Maximum degradation of phenol, COD, biomass growth and also changes in organic loading shock were used as parameters to measure the performance of reactors. According to the results, all eight strains were determined as enhanced biofilm forming bacteria (EBFB). Under optimum operating conditions, more than 90% of initial COD load of 2795 mg L −1 was reduced at 24 HRT in R3 while this reduction efficiency was observed in concentrations of 1290 mg L −1 and 1935 mg L −1 , in R1 and R2, respectively. When encountering phenol loading shock-twice greater than optimum amount-R1, R2 and R3 managed to return to the steady-state condition within 32, 24 and 18 days, respectively. SEM microscopy and biomass growth measurements confirmed the contribution of more cells to biofilm formation in R3 followed by R2. Additionally, established biofilm in R3 was more resistant to phenol loading shock which can be attributed to the enhancer role of EBFB strains in this reactor. It has been demonstrated that the bacteria with both biofilmforming and contaminant-degrading abilities are not only able to promote the immobilization of other favorable activated sludge cells in biofilm structure, but also cooperate in contaminant degradation which all consequently lead to improvement of treatment efficiency.

Efficacy of 2,4-Di-tert-butylphenol in Reducing Ralstonia solanacearum Virulence: Insights into the Underlying Mechanisms

“…30 Bacteria in biofilms exhibit robust resistance to antibacterial agents, and phenols have been shown to enhance biofilm formation in Streptococcus mitis, Fusobacterium nucleatum, and Porphyromonas gingivalis. 31,32 Surprisingly, our results indicated a notable absence of black colonies in the presence of 0.5, 1, and 2 mM 2,4-DTBP on Congo red agar (Figure 2C), suggesting their ability to inhibit biofilm formation. Previous studies have elucidated the inhibitory effects of phenol, including the disruption of cell membranes.…”

Purification Effect of the Aquaculture Wastewater and Sediment by Microbial Nanospheres with Different Material Ratios and Dosing Methods

“…On the one hand, the results indicated that the method of multiple addition could ensure higher microbial activity to degrade more OM than that using one-time addition. Sahar et al came to a similar conclusion about multiple addition measure to promote performance of pollutant purification in biological strengthening technology [42]. On the other hand, appropriate aeration could further improve the removal rate of OM in sediment.…”

Bioaugmentation Performance of a Bacterial Consortium for Moving Bed Biofilm Reactor (MBBR) Treating Municipal Wastewater

“…The moving bed biofilm reactor (MBBR) is a wastewater treatment process that uses plastic carriers with a buoyancy close to water to support the development of the bioactive microbial biofilm [3,4]. This MMBR technology benefits by inoculation with bacterial strains with organic pollutant degradation ability and promoting biofilm formation [5][6][7].…”