Structural Features of Biomass in a Hybrid MBBR Reactor

Abstract

The structural features of biomass present in the hybrid MBBR (Moving Bed Biofilm Reactor) aeration tank were studied in two subsequent periods, which differed in hydraulic and substrate loads. The physical characteristics of attached-growth biomass, such as, biofilm thickness, density, porosity, inner and surface fractal dimensions, and those of suspended-growth biomass, such as, floc size distribution, density, porosity, inner and surface fractal dimensions, were investigated in each study period and then compared. The results indicated that biofilm always had a higher density, geometric porosity, and a larger boundary fractal dimension than flocs. Both types of biomass were found to exhibit at least two distinct Sierpinski fractal dimensions, indicating two major different pore space populations. With the increasing wastewater flow, both types of biomass were found to shift their structural properties to larger values, except porosity and surface roughness, which decreased. Floc density and biomass Sierpinski fractals were not affected much by the system loadings.

Removal of Carbon and Nitrogen Compounds in Hybrid Bioreactors

“…The higher biomass loading -the higher attached biomass concentration (the same -lower suspended biomass concentration). This phenomenon was also observed by other authors [26]. The elevated pH caused the ammonia release and inhibition of the second phase of nitrification and this way the total nitrogen removal process was shorten by elimination of two elementary processes: nitratation and denitratation ( figure 8).…”

“…Some authors indicated that in continuous-flow MBBR in which SND process was established, the microbial community structures of biofilm are related to C/N ratios [25]. In MBBRs the volume concentration ratio of biofilm to the activated sludge flocs cab be even higher: 5-13 [26] than for separated attached biomass and suspended biomass systems. Some important differences between biofilm and flocs features in MBBRs were found by Xiao end Garnczarczyk [26].…”

“…In MBBRs the volume concentration ratio of biofilm to the activated sludge flocs cab be even higher: 5-13 [26] than for separated attached biomass and suspended biomass systems. Some important differences between biofilm and flocs features in MBBRs were found by Xiao end Garnczarczyk [26]. They observed 3 -5 times higher geometric porosity in biofilm than in activated sludge flocs.…”

Biological Fixed Film Systems

“…The results showed that it was desirable to maintain an influent formaldehyde concentration lower than 202.2 mg/L, as this concentration could achieve a good biofilm morphology while not inhibiting its microbial activity. The structural features of biomass present in the hybrid moving bed biofilm reactor (MBBR) aeration tank were studied in two subsequent periods, which differed in hydraulic and substrate loads (Xiao and Ganczarczyk, 2006). The results indicated that biofilm always had a higher density, geometric porosity, and a larger boundary fractal dimension than flocs.…”

Polishing of Chemical Oxygen Demand (COD) Using Moving Bed Bio-Reactor

“…The MBBR reactor volume has no unused space, an advantage of having the biofilm reactors totally mixed. MBBR has a great advantage over the activate sludge process as MBBR does not require sludge recirculation nor a large sedimentation tank [2,3].…”