Microbial population structure changes in a suspended carrier biofilm reactor

2006 ◽  
Vol 54 (9) ◽  
pp. 145-153
Author(s):  
R.C. Wang ◽  
X.H. Wen ◽  
Y. Qian
Keyword(s):  
Population Structure ◽  
Microbial Population ◽  
Biofilm Reactor ◽  
Laser Scanning Microscopy ◽  
Nitrifying Bacteria ◽  
Confocal Laser ◽  
Ammonia Oxidizing Bacteria ◽  
N Removal ◽  
Quinone Profile ◽  
Suspended Carrier

The changes of microbial population structure in biofilm caused by variations of COD/NHNH+4-N ratio in influent were investigated in a suspended carrier biofilm reactor (SCBR). When COD/NHNH+4-N was 10, the highest COD removal reached was about 73.8 per cent, whereas the highest NH+4-N removal, about 55.9 per cent, was reached when COD/NH+4-N was 5. By using fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) observation, it was found that the thickness of the biofilm formed on the carrier was about 80 to 120 μm, and ammonia-oxidizing bacteria (AOB) and nitrifying bacteria existed mainly in the upper layer about 20 to 30 μm. The results of the quinone profile analysis showed that when the COD/NH+4-N increased, the microbial diversity (DQ) increased, while the proportions of AOB and nitrifying bacteria in the biofilm communities decreased.

Experimental and simulation analysis of community structure of nitrifying bacteria in a membrane-aerated biofilm

2007 ◽  
Vol 55 (8-9) ◽  
pp. 283-290 ◽  
Author(s):  
S. Matsumoto ◽  
A. Terada ◽  
Y. Aoi ◽  
S. Tsuneda ◽  
E. Alpkvist ◽  
...  
Keyword(s):  
Cluster Size ◽  
Laser Scanning ◽  
Simulation Analysis ◽  
Current Model ◽  
Membrane Surface ◽  
Laser Scanning Microscopy ◽  
Nitrifying Bacteria ◽  
Confocal Laser ◽  
Ammonia Oxidizing Bacteria ◽  
Microelectrode Measurements

Until now, only few attempts have been made to assess biofilm models simulating microenvironments in a biofilm. As a first step, we compare the microenvironment observed in a membrane aerated biofilm (MAB) to that derived from a two-dimensional computational model with individual ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) embedded in a continuum EPS matrix. Gradients of oxygen were determined by means of microelectrodes. The change in nitrifying bacterial populations with the biofilm depth was quantified using fluorescence in situ hybridization (FISH) in combination with a confocal laser scanning microscopy (CLSM). Microelectrode measurements revealed that oxic and anoxic or anaerobic regions exist within the MAB. The oxygen profile predicted by the model showed good agreement with that obtained by microelectrode measurements. The oxic part of the biofilm was dominated by NSO190 probe-hybridized AOB, which formed relatively large clusters of cells directly on the membrane surface, and by the NOB belonging to genus Nitrobacter sp. On the other hand, NOB belonging to genus Nitrospira sp. were abundant at the oxic-anoxic interface. The model prediction regarding AOB and Nitrobacter sp. distribution was consistent with the experimental counterpart. Measurements of AOB cluster size distribution showed that colonies are slightly larger adjacent to the membrane than at the inner part of the biofilm. The sizes predicted by the current model are larger than those obtained in the experiment, leading to the arguments that some factors not contained in the model would affect the cluster size.

Influence of C/N Ratio on SND and Microbiological Analysis in Catching Bed Biofilm Reactor Using Acrylic Resin Fiber as Carrier Materials in Civil Engineering

2012 ◽  
Vol 568 ◽  
pp. 89-93
Author(s):  
Yan Zhang ◽  
Zheng Yang Yang ◽  
Li Li Wang ◽  
Xu Ying Zhao ◽  
Huan Guang Liu ◽  
...  
Keyword(s):  
Civil Engineering ◽  
Removal Rate ◽  
Acrylic Resin ◽  
Biofilm Reactor ◽  
Easy Access ◽  
Fish Analysis ◽  
Microbiological Analysis ◽  
Ammonia Oxidizing Bacteria ◽  
N Removal ◽  
Carrier Materials

In this study, effect of C/N ratio on denitrification were investigated using four sets of parallel catching bed reactors, which were using acrylic resin fiber (ARF) as carrier materials. The results indicate that this process which was used in wastewater treatment of civil engineering can get better COD and nitrogen removing performance. NH4+-N removal rate reduced with the increasing of C/N ratio, and the average removal rate of COD and the total nitrogen (TN) increased when C/N ratio is increased. When C/N ratio exceeded 12, TN removal rate has no obvious growing. Meanwhile, fluorescent in situ hybridization (FISH) analysis indicated that the biomass in the biofilm were much richer than which in the suspension, and the ammonia oxidizing bacteria have a easy access to be dominant bacterial community in lower C/N ratio.

A new method for extraction of extracellular polymeric substances from biofilms and activated sludge suitable for direct quantification of sorbed metals

2001 ◽  
Vol 43 (6) ◽  
pp. 25-31 ◽  
Author(s):  
S. Wuertz ◽  
R. Spaeth ◽  
A. Hinderberger ◽  
T. Griebe ◽  
H.-C. Flemming ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Microbial Population ◽  
Zinc Concentration ◽  
Extraction Procedure ◽  
Cation Exchange Resin ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Sorption Behavior ◽  
Gradual Change

A method for extraction of extracellular polymeric substances (EPSs) with a dicyclohexyl-18-crown-6 ether was developed to determine levels of organic and inorganic contaminants sorbed to EPS. The crown ether selectively binds alkaline and alkaline earth metals but not heavy metals. The effectiveness of the extraction procedure was higher than that of 2 other methods tested and comparable with that of a method based on a cation exchange resin. On average it was possible to extract 20% of the TOC, 12% of the total protein content, and 4% of the total carbohydrate content of sludge or biofilm biomass. Metal sorption studies in activated sludge showed no influence of exposure time on the fractionation of metals within the biomass. Metals sorbed mostly to cellular material. In biofilms 12.2% of the cadmium and 9.1% of the zinc added was found in the EPS. In activated sludge EPS contained only 2.9% zinc. The distribution of metals within the biomass was dose dependent. The percentage of metals found in EPS decreased with increasing metal concentration. This indicates a higher affinity of metals for cellular binding sites. Time course experiments in a rotating biofilm annular reactor, which consisted of an external cylinder with removable slides and an internal solid drum, revealed a gradual change in zinc concentration associated with EPS, although the total zinc concentration in the biomass remained constant. Concurrently, the amount of extractable EPS decreased. This was a consequence of a microbial population shift, with bacterial counts decreasing and algal and fungal biomass increasing. Using confocal laser scanning microscopy and the fluorescent metal complexing agent Newport Green for in situ detection of zinc it was shown that metals were bound to algae and fungi in the latter part of the experiment. The biofilm became more and more heterogeneous coinciding with a decrease in EPS. To summarize, the observed sorption behavior of metals cannot be explained with the conventional paradigm of EPS ashydrophilic gel. Obviously, different binding mechanisms must be invoked to explain the role of EPS in the sorption and removal of toxic substances in activated sludge and biofilm systems. It is important to consider the microbial population to understand differences in sorption in different matrices.

scholarly journals Nitrogen removal via a single-stage PN–Anammox process in a novel combined biofilm reactor

2017 ◽  
Vol 77 (6) ◽  
pp. 1483-1492 ◽  
Author(s):  
Yue-mei Han ◽  
Feng-xia Liu ◽  
Xiao-fei Xu ◽  
Zhuo Yan ◽  
Zhi-jun Liu
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Ammonia Oxidation ◽  
Biofilm Reactor ◽  
Nitrifying Bacteria ◽  
Anammox Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
High Ammonia ◽  
Total Nitrogen Removal ◽  
Anammox Process

Abstract This study developed a partial nitrification (PN) and anaerobic ammonia oxidation (Anammox) process for treating high-ammonia wastewater using an innovative biofilm system in which ammonia oxidizing bacteria grew on fluidized Kaldnes (K1) carriers and Anammox bacteria grew on fixed acryl resin carriers. The airlift loop biofilm reactor (ALBR) was stably operated for more than 4 months under the following conditions: 35 ± 2 °C, pH 7.5–8.0 and dissolved oxygen (DO) of 0.5–3.5 mg/L. The results showed that the total nitrogen removal efficiency reached a maximum of 75% and the total nitrogen removal loading rate was above 0.4 kg/(d·m3). DO was the most efficient control parameter in the mixed biofilm system, and values below 1.5 mg/L were observed in the riser zone for the PN reaction, while values below 0.8 mg/L were observed in the downer zone for the Anammox reaction. Scanning electron microscopy and Fluorescence In Situ Hybridization images showed that most of the nitrifying bacteria were distributed on the K1 carriers and most of the Anammox bacteria were distributed within the acryl resin carriers. Therefore, the results indicate that the proposed combined biofilm system is easy to operate and efficient for the treatment of high-ammonia wastewater.

scholarly journals Interception of Small Particles by Flocculent Structures, Sessile Ciliates, and the Basic Layer of a Wastewater Biofilm

2001 ◽  
Vol 67 (9) ◽  
pp. 4286-4292 ◽  
Author(s):  
Heinrich Eisenmann ◽  
Ioanna Letsiou ◽  
Anette Feuchtinger ◽  
Wolfgang Beisker ◽  
Ernst Mannweiler ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Particle Density ◽  
Biofilm Reactor ◽  
Laser Scanning Microscopy ◽  
Automated Image Analysis ◽  
Confocal Laser ◽  
Highly Active ◽  
Sequencing Batch Biofilm Reactor ◽  
Food Vacuoles ◽  
Hydrophilic Particles

ABSTRACT We investigated attachment processes of hydrophobic and hydrophilic particles (diameter = 1 μm) to mature biofilms grown on clay marbles in a sequencing batch biofilm reactor. During a treatment cycle with filtered wastewater containing different fluorescent beads, the progression of particle density in various biofilm compartments (carrier biofilm, basic biofilm layer, biofilm flocs, and sessile ciliates) was determined by flow cytometry, confocal laser scanning microscopy and automated image analysis. Particles were almost completely removed from wastewater by typical processes of particle retention: up to 58% of particles attached to clay marbles, up to 15% were associated with suspended flocs, and up to 10% were ingested by sessile ciliates. Ingestion of particles by ciliates was exceptionally high immediately after wastewater addition (1,200 particles grazer−1 h−1) and continued until approximately 14% of the water had been cleared by ciliate filter feeding. Most probably, ciliate bioturbation increases particle sorption to the basic biofilm. Backwashing of the reactor detached pieces of biofilm and thus released approximately 50% of the particles into rinsing water. Clay marbles in the upper part of the reactor were more efficiently abraded than in the lower part. No indications for selective attachment of the applied hydrophobic and hydrophilic beads were found. As a consequence of interception patterns, organisms at elevated biofilm structures are probably major profiteers of wastewater particles; among them, ciliates may be of major importance because of their highly active digestive food vacuoles.

Fluorescence in situ hybridization analysis of nitrifiers in piggery wastewater treatment reactors

2004 ◽  
Vol 49 (5-6) ◽  
pp. 333-340 ◽  
Author(s):  
D.J. Kim ◽  
T.K. Kim ◽  
E.J. Choi ◽  
W.C. Park ◽  
T.H. Kim ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Ammonia Concentration ◽  
Biofilm Reactor ◽  
Nitrifying Bacteria ◽  
Fish Analysis ◽  
Ammonia Oxidizing Bacteria ◽  
Piggery Wastewater

Fluorescence in situ hybridization (FISH) was performed to analyze the nitrifying microbial communities in an activated sludge reactor (ASR) and a fixed biofilm reactor (FBR) for piggery wastewater treatment. Heterotrophic oxidation and nitrification were occurring simultaneously in the ASR and the COD and nitrification efficiencies depend on the loads. In the FBR nitrification efficiency also depends on ammonium load to the reactor and nitrite was accumulated when free ammonia concentration was higher than 0.2 mg NH3-N/L. FISH analysis showed that ammonia-oxidizing bacteria (NSO1225) and denitrifying bacteria (RRP1088) were less abundant than other bacteria (EUB338) in ASR. Further analysis on nitrifying bacteria in the FBR showed that Nitrosomonas species (NSM156) and Nitrospira species (NSR1156) were the dominant ammonia-oxidizing and nitrite-oxidizing bacteria, respectively, in the piggery wastewater nitrification system.

Impact of protozoan grazing on nitrification and the ammonia- and nitrite-oxidizing bacterial communities in activated sludge

2007 ◽  
Vol 53 (5) ◽  
pp. 559-571 ◽  
Author(s):  
Amy J. Pogue ◽  
Kimberley A. Gilbride
Keyword(s):  
Activated Sludge ◽  
Laser Scanning ◽  
Ammonia Oxidation ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Batch Reactors ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrate Accumulation ◽  
Protozoan Grazing ◽  
Nitrite Nitrate

In activated sludge, protozoa feed on free-swimming bacteria and suspended particles, inducing flocculation and increasing the turnover rate of nutrients. In this study, the effect of protozoan grazing on nitrification rates under various conditions in municipal activated sludge batch reactors was examined, as was the spatial distribution of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) within the activated sludge. The reactors were monitored for ammonia, nitrite, nitrate, and total nitrogen concentrations, and bacterial numbers in the presence and absence of cycloheximide (a protozoan inhibitor), allylthiourea (an inhibitor of ammonia oxidation), and EDTA (a deflocculating agent). The accumulations of nitrate, nitrite, and ammonia were lower in batches without than with protozoa grazing. Inhibition of ammonia oxidation also decreased the amount of nitrite and nitrate accumulation. Inhibiting protozoan grazing along with ammonia oxidation further decreased the amounts of nitrite and nitrate accumulated. Induction of deflocculation led to high nitrate accumulation, indicating high levels of nitrification; this effect was lessened in the absence of protozoan grazing. Using fluorescent in situ hybridization and confocal laser scanning microscopy, AOB and NOB were found clustered within the floc, and inhibiting the protozoa, inhibiting ammonia oxidation, or inducing flocculation did not appear to lower the number of AOB and NOB present or affect their position within the floc. These results suggest that the AOB and NOB are present but less active in the absence of protozoa.

scholarly journals Simultaneous Partial Nitrification and Denitrification Maintained in Membrane Bioreactor for Nitrogen Removal and Hydrogen Autotrophic Denitrification for Further Treatment

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 911
Author(s):  
Kun Dong ◽  
Xinghui Feng ◽  
Wubin Wang ◽  
Yuchao Chen ◽  
Wei Hu ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Dominant Role ◽  
Domestic Sewage ◽  
Biofilm Reactor ◽  
Partial Nitrification ◽  
Ammonia Oxidizing Bacteria ◽  
Autotrophic Denitrification ◽  
Membrane Biofilm Reactor ◽  
N Removal ◽  
Wide Range

Low C/N wastewater results from a wide range of factors that significantly harm the environment. They include insufficient carbon sources, low denitrification efficiency, and NH4+-N concentrations in low C/N wastewater that are too high to be treated. In this research, the membrane biofilm reactor and hydrogen-based membrane biofilm reactor (MBR-MBfR) were optimized and regulated under different operating parameters: the simulated domestic sewage with low C/N was domesticated and the domestic sewage was then denitrified. The results of the MBR-MBfR experiments indicated that a C/N ratio of two was suitable for NH4+-N, NO2−-N, NO3−-N, and chemical oxygen demand (COD) removal in partial nitrification-denitrification (PN-D) and hydrogen autotrophic denitrification for further treatment. The steady state for domestic wastewater was reached when the MBR-MBfR in the experimental conditions of HRT = 15 h, SRT = 20 d, 0.04 Mpa for H2 pressure in MBfR, 0.4–0.8 mg/L DO in MBR, MLSS = 2500 mg/L(MBR) and 2800 mg/L(MBfR), and effluent concentrations of NH4+-N, NO3−-N, and NO2−-N were 4.3 ± 0.5, 1.95 ± 0.04, and 2.05 ± 0.15 mg/L, respectively. High-throughput sequencing results revealed the following: (1) The genus Nitrosomonas as the ammonia oxidizing bacteria (AOB) and Denitratisoma as potential denitrifiers were simultaneously enriched in the MBR; (2) at the genus level, Meiothermus,Lentimicrobium, Thauera,Hydrogenophaga, and Desulfotomaculum played a dominant role in leading to NO3−-N and NO2−-N removal in the MBfR.

Membrane bioreactor versus conventional activated sludge system: population dynamics of nitrifiers

2005 ◽  
Vol 52 (10-11) ◽  
pp. 417-425 ◽  
Author(s):  
R. Manser ◽  
W. Gujer ◽  
H. Siegrist
Keyword(s):  
Activated Sludge ◽  
Community Composition ◽  
Membrane Bioreactor ◽  
Membrane Separation ◽  
Heterotrophic Bacteria ◽  
Microbial Community Composition ◽  
Laser Scanning Microscopy ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Conventional Activated Sludge

Although membrane bioreactors have attracted increasing attention in recent years, little research has been undertaken on the influence of the membrane separation on the microbial community composition. This paper compares the startup behaviour and the performance of the subsequent eight months of a membrane bioreactor with a conventional activated sludge pilot plant. Both plants were operated in parallel at the same sludge age and treated the same domestic wastewater. The identification of the nitrifying community composition using fluorescent in situ hybridization revealed only minor differences between the two reactors for both ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. Accordingly, both systems exhibited the same maximum nitrification rates. Confocal laser scanning microscopy showed that the aggregates formed by nitrifying bacteria were located mostly in the inner part of the flocs and were overgrown by heterotrophic bacteria. It is concluded that the membrane separation itself does affect neither the nitrifying community composition nor the nitrification performance. However, impacts on kinetic parameters are emphasized.

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