Effective biofilm control in a membrane biofilm reactor using a quenching bacterium (Rhodococcus sp. BH4)

Abstract

The biofilm thickness in membrane biofilm reactors (MBfRs) is an important factor affecting system performance because excessive biofilm formation on the membrane surface inhibits gas diffusion to the interior of the biofilm, resulting in a significant reduction in the performance of contaminant removal. This study provides innovative insights into the control of biofilm thickness in O2‐based MBfRs by using the quorum quenching (QQ) method. The study was carried out in MBfRs operated at different gas pressures and hydraulic retention times (HRTs) using QQ beads containing Rhodococcus sp. BH4 at different amounts. The highest performance was observed in reactors operated with 0.21 ml QQ bead/cm2 membrane surface area, 12 HRTs and 1.40 atm. Over this period, the performance increase in chemical oxygen demand (COD) removal was 25%, while the biofilm thickness on the membrane surface was determined to be 250 μm. Moreover, acetate and equivalent oxygen flux results reached 6080 and 10 640 mg·m−2·d−1 maximum values, respectively. The extracellular polymeric substances of the biofilm decreased significantly with the increase of gas pressure and QQ beads amount. Polymerase chain reaction denaturing gradient gel electrophoresis results showed that the microbial community in the MBfR system changed depending on operating conditions and bead amount. The results showed that the QQ method was an effective method to control the biofilm thickness in MBfR and provide insights for future research.

Quorum sensing unveils the sludge floccule‐assisted stabilization of aerobic granules in granule‐dominated sequencing batch reactors

“…As a specific form of biofilm in wastewater treatment, a threshold concentration of AHLs was likely to be a prerequisite for aerobic granules (Wang et al, 2021). If the floccules overgrew in an aerobic granules SBR, it would induce an inevitable AHL‐quenching that further destroys the microbial aggregates (Taşkan et al, 2020; Yu et al, 2016). On the other hand, a relatively high AHL concentration was also found to cause a less significant bacterial adhesion (Wang et al, 2021), which would undermine the stability of granules.…”

Pathways to Water Sector Decarbonization, Carbon Capture and Utilization

“…Moreover, maintaining a highly active biofilm in MABR could still be a challenge, as proper strategies to couple flow velocity or turbulence with moderate aeration rate should be implemented to keep the biofilm with optimum thicknesses (Martin & Nerenberg, 2012). Noticeably, quorum quenching was employed in an MABR, and it was demonstrated to control the EPS content as well as the thickness of biofilm via the degradation of acyl homoserine lactone (AHL) signal molecules (Taşkan et al, 2020). To make MABR a cost-effective decarbonized technology for advanced wastewater treatment, proper biofilm management as well as cost-effective membranes should be developed in the future.…”

A rotating bioreactor for the production of biofilms at the solid–air interface

“…Examples of biofilm bioreactors using support materials include sequencing batch reactors (Arrojo et al, 2004; Irvine & Ketchum, 1989; Münch et al, 1996), continuous stirred tank reactors (Kunduru & Pometto, 1996; Ramasamy & Abbasi, 2000; Tyagi & Ghose, 1982; Xu, 2019), packed‐ or fluidized‐bed reactors (Mallikarjuna & Dash, 2020; Özkaya et al, 2019; Sahu et al, 2009; Shen et al, 2017; Shieh & Keenan, 1986), and trickling bed reactors (Devarapalli et al, 2016; Jensen et al, 2021; Tsapekos et al, 2021). Rotating disc contractors or membrane bioreactors are common examples where biofilm production occurs on the bioreactor surface, and those are typically used in wastewater treatment plants (Costa et al, 2017; Melo, 2003; Renaudie et al, 2021; Taşkan et al, 2019). The latter bioreactor variant also comes with the advantage of easily separating the biofilm after usage and enhancing biofilm attachment and growth by chemically modifying the reactor surface (Lackner et al, 2009; Terada et al, 2004; Yamamoto et al, 1989).…”

“…Rotating disc contractors or membrane bioreactors are common examples where biofilm production occurs on the bioreactor surface, and those are typically used in wastewater treatment plants (Costa et al, 2017;Melo, 2003;Renaudie et al, 2021;Taşkan et al, 2019). The latter bioreactor variant also comes with the advantage of easily separating the biofilm after usage and enhancing biofilm attachment and growth by chemically modifying the reactor surface (Lackner et al, 2009;Terada et al, 2004;Yamamoto et al, 1989).…”