Insights into biofilm carriers for biological wastewater treatment processes: Current state-of-the-art, challenges, and opportunities

Abstract

Biofilm carriers play an important role in attached growth systems for wastewater treatment.This study summarizes the traditional and novel biofilm carriers utilized in biofilm-based wastewater treatment technology. The advantages and disadvantages of traditional biofilm carriers are evaluated and discussed in light of basic property, biocompatibility and applicability.The characteristics, applications performance, and mechanism of novel carriers (including slowrelease carriers, hydrophilic/electrophilic modified carriers, magnetic carriers and redox mediator carriers) in wastewater biological treatment were deeply discussed. Slow release 2 biofilm carriers are used to provide a solid substrate and electron donor for the growth of microorganisms and denitrification for anoxic and/or anaerobic bioreactors. Carriers with hydrophilic/electrophilic modified surface are applied for promoting biofilm formation. Magnetic materials-based carriers are employed to shorten the start-up time of bioreactor. Biofilm carriers acting as redox mediators are used to accelerate biotransformation of recalcitrant pollutants in industrial wastewater.

Enhanced Hydrophilic and Electrophilic Properties of Polyvinyl Chloride (PVC) Biofilm Carrier

“…Generally, biofilm-based wastewater treatment systems have several advantages: for example, their high active biomass concentration, short hydraulic residence time, low space requirements, and less sludge production. In particular, the microbial communities in biofilms are diverse, which allow degrading a wide range of organic pollutants [6]. Meanwhile, the attachment and formation of biofilms largely depend on the surface properties of the biofilm carrier, including the physical/chemical properties of the carrier surface, the charge properties of the carrier surface, and the surface roughness of the carrier and so on [7][8][9][10][11][12].…”

“…At the same time, its surface is relatively smooth, and its specific surface area is relatively small. Moreover, the surface of pure PVC is negatively charged, which is the same as the surface of bacteria [ 6 , 29 , 30 , 31 ]. These disadvantages make it difficult for bacteria and microorganisms to attach to PVC biofilm carriers.…”

Retechnologization of biological sewage water treatment facilities using mathematical modelling

“…Traditional biological sewage water treatment allows to remove the bulk of organic pollutants, to oxidize ammonium nitrogen to nitrate, but cannot provide a sufficient depth of removal of nitrogen and phosphorus compounds [6][7][8]. The issue of removal of nutrients is a priority in improving the quality of treated sewage water before discharge into fisheries reservoirs.…”

“…The biological method of deep removal of biogenic substances from sewage water makes it possible to achieve the total phosphorus content in treated waters of 1.0...1.5 mg/dm 3 , and the total nitrogen content of 8...10 mg/dm 3 (including protein, ammonium, nitrite and nitrate) in real biological treatment facilities. The biological method of phosphorus removal makes it possible to achieve a high quality of phosphorus treatment, but this process is very sensitive to the current quality of sewage water received for treatment and requires highly qualified technologists-operators [6][7][8][9][10].…”

CFD–DEM modelling of biofilm streamer oscillations and their cohesive failure in fluid flow

“…It is well known that biofilms have a significant impact on environment, human health, and a wide range of industries. For example, they play an important role in biological waste‐water treatment (Zhao et al, 2019). The presence of biofilms is the major cause for infections of medical devices (Cao et al, 2018; Hall‐Stoodley & Stoodley, 2009) and the clogging of industrial flow system, such as biofouling in membrane system (Vrouwenvelder et al, 2010).…”