Effect of addition of an exogenous exopolymeric substance in UASB and EGSB reactors

2006 ◽  
Vol 54 (2) ◽  
pp. 25-31 ◽  
Author(s):  
E. Vivanco ◽  
A. Puñal ◽  
R. Chamy
Keyword(s):  
Relative Abundance ◽  
Extracellular Polymeric Substances ◽  
Operational Performance ◽  
Microbial Populations ◽  
Unstable State ◽  
Operational Parameters ◽  
Start Up ◽  
Exopolymeric Substance ◽  
Granule Maturation

The operation of two different reactor configurations (UASB and EGSB), while treating medium and low concentrated wastewater (MCW and LCW, respectively), was studied. The MCW (5 g COD/l) was initially supplied for reactor start up and granule maturation, being subsequently changed to the LCW (0.5 g COD/l), with which led the reactors to an unstable state associated with the deterioration of granule characteristics, in terms of extracellular polymeric substances (EPS) content and composition. The addition of pectin as an exogenous EPS was considered as a way to directly act on granule characteristics and its effect was studied by monitoring the operational parameters as well as by following the EPS content and composition within granules and the dynamics of microbial populations. The effect of adding pectin led to a significant recuperation of the operational performance in both reactors, associated with the increase in Archaea relative abundance, this likely related to the major presence of Methanosaeta-like microorganisms in granules with higher activity and stability.

scholarly journals Effects of Operational Parameters on Biofilm Formation of Mixed Bacteria for Hydrogen Fermentation

2020 ◽  
Vol 12 (21) ◽  
pp. 8863
Author(s):  
Jie Mei ◽  
Huize Chen ◽  
Qiang Liao ◽  
Abdul-Sattar Nizami ◽  
Ao Xia ◽  
...  
Keyword(s):  
Formation Process ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Packed Bed ◽  
Dark Fermentation ◽  
Laser Scanning Microscopy ◽  
Packed Bed Reactor ◽  
Confocal Laser ◽  
Operational Parameters

Dark fermentation of organic wastes, such as food waste and algae, via mixed hydrogen-producing bacteria (HPB) is considered a sustainable approach for hydrogen production. The biofilm system protects microorganisms from the harmful environment and avoids the excessive loss of bacteria caused by washout, which ensures that the dark fermentation process remains stable. In this study, a downflow anaerobic packed-bed reactor was commissioned to investigate the biofilm formation process of mixed HPB under various operational parameters. Scanning electron microscopy indicated changes in surface morphology during the biofilm formation period. Proteins and polysaccharides in extracellular polymeric substances were identified by confocal laser scanning microscopy to reveal their distribution characteristics. A hydraulic retention time of 0.5 d, a substrate concentration of 15 g/L and an HPB inoculum ratio of 35% were identified as the optimal operational parameters for biofilm formation. The diversity of bacteria between suspension and biofilm showed significantly different distributions; Clostridiales and Lactobacillales were identified as the dominant orders in the biofilm formation process. The abundances of Clostridiales and Lactobacillales were 15.1% and 56.2% in the biofilm, respectively.

Effects of extracellular polymeric substances on granulation of anoxic sludge in sequencing batch reactor

2012 ◽  
Vol 66 (3) ◽  
pp. 543-548
Author(s):  
Binbin Wang ◽  
Shunlian Liu ◽  
Hongmei Zhao ◽  
Xinyan Zhang ◽  
Dangcong Peng
Keyword(s):  
Extracellular Polymeric Substances ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Cation Exchange Resin ◽  
Granular Sludge ◽  
Extracellular Proteins ◽  
Extracellular Polysaccharides ◽  
Positive Role ◽  
Start Up ◽  
Sludge Granulation

Variations of extracellular polymeric substances (EPS) and its components with sludge granulation were examined in a lab-scale sequencing batch reactor (SBR) which was fed with sodium nitrate and sodium acetate. Ultrasonication plus cation exchange resin (CER) were used as the EPS extraction method. Results showed that after approximately 90 d cultivation, the sludge in the reactor was almost granulated. The content of extracellular polysaccharides increased from 10.36 mg/g-VSS (volatile suspended solids) at start-up with flocculent sludge to 23.18 mg/g-VSS at 91 d with matured granular sludge, while the content of extracellular proteins were almost unchanged. Polysaccharides were the major components of EPS in anoxic granular sludge, accounting for about 70.6–79.0%, while proteins and DNA accounted for about 16.5–18.9% and 4.6–9.9%, respectively. It is proposed that EPS play a positive role in anoxic sludge granulation and polysaccharides might be strongly involved in aggregation of flocs into granules.

scholarly journals Insights into the Variations of Hao-Dependent Nitrifying and Nir-Dependent Denitrifying Microbial Communities in Ammonium-Graduated Lake Environments

2019 ◽  
Vol 9 (16) ◽  
pp. 3229
Author(s):  
Zhao ◽  
Chen ◽  
Qu ◽  
Jin ◽  
Zheng ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Microbial Communities ◽  
Relative Abundance ◽  
Spatial Scales ◽  
Biogeochemical Cycles ◽  
Nitrifying Bacteria ◽  
Microbial Populations ◽  
High Nitrogen ◽  
Hydroxylamine Oxidoreductase ◽  
Nitrosomonas Oligotropha

Biological nitrification and denitrification play significant roles in nitrogen-associated biogeochemical cycles. However, our understanding of the spatial scales at which microbial communities act and vary is limited. We used gene-specific metagenomic PCR to explore changes in nitrifying and denitrifying microbial communities within pristine lake and its branches, where the ammonium and dissolved organic carbon (DOC) concentrations form a gradient. The biomarkers hydroxylamine oxidoreductase and nitrite reductase genes indicated that strong relationships exist between the diversities and community structures of denitrifiers and ammonium gradients. It showed that the Nitrosomonas oligotropha cluster dominates the nitrifying bacteria in low-nutrition environments, while a new Nitrosomonas ureae cluster accounted for nearly 80% of the nitrifying bacteria in high-nitrogen environments. The distribution and diversity of nirS/K-dependent denitrifiers in the various habitats were similar, but predominantly affiliated with unknown clusters. Moreover, the abundance of all the hao genes dramatically outnumbered that of nir genes. The relative abundance of hao was clearly higher during eutrophication (13.60%) than during oligotrophy (5.23%), whereas that of nirS showed opposite tendencies. Overall, this study provides valuable comparative insights into the shifts in nitrifying and denitrifying microbial populations in lake environments with ammonium gradients, suggesting that unique dominant denitrifiers probably play an important role in the nitrogen cycle.

Start-up of two moving bed membrane bioreactors treating saline wastewater contaminated by hydrocarbons

2015 ◽  
Vol 73 (4) ◽  
pp. 716-724 ◽  
Author(s):  
R. Campo ◽  
N. Di Prima ◽  
G. Freni ◽  
M. G. Giustra ◽  
G. Di Bella
Keyword(s):  
Extracellular Polymeric Substances ◽  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Moving Bed ◽  
Biological Removal ◽  
Start Up ◽  
Suspended Biomass ◽  
Polyurethane Sponge ◽  
Microbial Products ◽  
The One

This work aims to assess the acclimation of microorganisms to a gradual increase of salinity and hydrocarbons, during the start-up of two moving bed membrane bioreactors (MB-MBRs) fed with saline oily wastewater. In both systems an ultrafiltration membrane was used and two types of carriers were employed: polyurethane sponge cubes (MB-MBRI) and polyethylene cylindrical carriers (MB-MBRII). A decreasing dilution factor of slops has been adopted in order to allow biomass acclimation. The simultaneous effect of salinity and hydrocarbons played an inhibitory role in biomass growth and this resulted in a decrease of the biological removal efficiencies. A reduction of bound extracellular polymeric substances and a simultaneous release of soluble microbial products (SMPs) were observed, particularly in the MB-MBRII system, probably due to the occurrence of a greater suspended biomass stress as response to the recalcitrance of substrate. On the one hand, a clear attachment of biomass occurred only in MB-MBRI and this affected the fouling deposition on the membrane surface. The processes of detachment and entrapment of biomass, from and into the carriers, significantly influenced the superficial cake deposition and its reversibility. On the other hand, in MB-MBRII, the higher production of SMPs implied a predominance of the pore blocking.

scholarly journals Influence of operational parameters on the start-up of a flocculation airlift bioreactor

1994 ◽  
Vol 2 (1-3) ◽  
pp. 181-188 ◽  
Author(s):  
M.Luísa Sousa ◽  
Manuel Mota ◽  
José A. Teixeira
Keyword(s):  
Airlift Bioreactor ◽  
Operational Parameters ◽  
Start Up

scholarly journals Start Up of a UASB Treating Malted Ingredient Manufacturing Wastewater

2018 ◽  
Vol 7 (2) ◽  
pp. 1 ◽  
Author(s):  
Ryland Cairns ◽  
Paul Mead
Keyword(s):  
Manufacturing Industry ◽  
Dairy Wastewater ◽  
Plant Performance ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Biological Interactions ◽  
Operational Parameters ◽  
Start Up ◽  
Stable Conditions

With a greater push to achieve waste management and renewable energy targets technologies such as anaerobic digestion (AD) have increased in popularity. One such technology option is the Upflow Anaerobic Sludge Blanket (UASB) reactor, these have been shown to be a particularly robust option for high strength organic wastewaters, such as those generated by the malted ingredient manufacturing industry. Despite their effectiveness they are reported to have lengthy and complex start ups due to the range of physiochemical and biological interactions influencing sludge blanket stability. This process can be sped up by seeding the plant from sludge from similar plants, however this is not always possible. This paper aims to investigate the start up of a full-scale mesophilic UASB treating malted ingredient wastewater that was initially seeded with a granular sludge treating dairy wastewater. Operational performance during the first 75 days of start up was comparable to that of a fully established plant with a COD removal efficiency in excess of 81.89% and a biogas methane concentration greater than 57.24%. During this period the plant remained operationally robust with the Organic Loading Rates (OLR) exuding the greatest influence on plant performance. Similar to operations during stable conditions key operational parameters such as HRT times, temperatures and pH did not exert a strong influence on the plant. 

Impact of Operational Parameters and Reservoir Variables during the Start-up Phase of a SAGD Process

2005 ◽  
Author(s):  
Jose Walter Vanegas ◽  
Luciane Bonet Cunha ◽  
Francisco J.S. Alhanati
Keyword(s):  
Operational Parameters ◽  
Start Up
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