Tailored Surface Porosity of Polyethylene-Based Co-continuous Structures for Moving Bed Biofilm Reactor Carriers

Abstract

Moving bed biofilm reactors (MBBRs) are often used in wastewater treatment. Using MBBR carriers with a porous surface is beneficial to the adhesion of microorganisms and the growth of biofilms. Polyethylene (PE) carriers with highly open and connected pores are designed by constructing a co-continuous structure of PE/polyethylene oxide (PEO) blend, which was followed by the removal of PEO with water. It is found that the extrudates of PE/ PEO (w/w, 4/6) blend exhibit a co-continuous pore structure; however, PEO cannot create a porous surface. The polar rigid filler calcium carbonate (CaCO 3 ) is proposed to be preferentially distributed in the PEO phase, thus increasing its surface energy, reaching a goal of a porous surface successfully on the base of retaining the internal co-continuous porous structure. The content and size of CaCO 3 can further tune the morphology and pore size of the porous surface. The prepared PE porous carriers display a 200 μm-thick biofilm comprising a large number of filamentous bacteria and a small number of coccal and rob bacteria after an MBBR experiment for 30 days, which is also observed within the carriers as revealed by confocal laser scanning microscopy.

Seeding and Acclimatization of Microorganisms in a Moving Bed Biological Reactor (MBBR) for Process Optimization at a Compact Septage Treatment Plant

“…Carrier media purchased from Evolution Aqua Ltd. Englanda were in the form of circular polyethylene kaldnes K1 biofilm media with the specific gravity of 150 kg/m 3 ; diameter of 9.1 mm; length of 7.1 mm; and specific surface area of 500 m 2 /m 3 . Polyethylene carrier was employed in this study due to the advantage of thin, distributed and smooth biomass growth on their surface [15].…”

Novel carrier for seafood wastewater treatment using moving bed biofilm reactor system

“…In contrast, the porous carriers with high porosity and large surface area (up to 900 m 2 /m 3 ) can improve biofilm accumulation and protect the biofilm from fluid shearing and collision by providing sheltered anchoring points [32,33]. The interaction pathways of microorganisms in the porous structure of carriers have been well discussed in the literature [32][33][34][35][36]. Typically, the microorganisms are retained on a porous carrier in two different forms: (i) growing on the skeleton surface, and (ii) trapping in the pores of the carrier.…”