Effect of Transient Organic Load and aeration changes to Pollutant Removal and Extracellular Polymeric Substances

The effects of synthetic wastewater that contained 20 mg/L Cu(II) on the removal of organic pollutants in a sequencing batch reactor were investigated. Results of continuous 20 mg/L Cu(II) exposure for 120 days demonstrated that the chemical oxygen demand (COD) removal efficiency decreased to 42% initially, followed by a subsequent gradual recovery, which peaked at 78% by day 97. Effluent volatile fatty acid (VFA) concentration contributed 67 to 89% of the influent COD in the experimental reactor, which indicated that the degradation of the organic substances ceased at the VFA production step. Meanwhile, the varieties of soluble microbial products (SMP) content and main components (protein, polysaccharide, and DNA) were discussed to reveal the response of activated sludge to the toxicity of 20 mg/L Cu(II). The determination of Cu(II) concentrations in extracellular polymeric substances (EPS) and SMP throughout the experiment indicated an inverse relationship between extracellular Cu(II) concentration and COD removal efficiency.

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Correlating Microbial Community Characteristics with Environmental Factors along a Two-Stage Biological Aerated Filter

Water ◽

10.3390/w12123317 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3317

Author(s):

Yuchen An ◽

Songmin Li ◽

Xiaoling Wang ◽

Yuyang Liu ◽

Ruonan Wang

Keyword(s):

Microbial Community ◽

Environmental Factors ◽

High Throughput Sequencing ◽

Pollutant Removal ◽

Organic Load ◽

Biological Aerated Filter ◽

Community Characteristics ◽

Two Stage ◽

Degrading Bacteria ◽

Aerated Filter

The purification effect of a biological aerated filter (BAF) mainly comes from the microorganisms in the reactor. Understanding the correlation between microbial community characteristics and environmental factors along the filter has great significance for maintaining good operation and improving the removal efficiency of the filter. A two-stage BAF was employed to treat domestic sewage under organic loads of 1.02 and 1.55 kg/m3·d for 15 days each. 16S rDNA high-throughput sequencing technology and redundancy analysis were applied to explore the correlation between microbial community characteristics and environmental variables. The results showed that: (1) the crucial organic-degrading bacteria in the A-stage filter were of the genus Novosphingobium, which had a significant increase in terms of relative abundance at sampling outlet A3 (135 cm of the filling height) after the increase of organic load; (2) the microbial communities at different positions in the B-stage filter were similarly affected by environmental factors, and the main bacteria associated with nitrogen removal in the B-stage filter were Zoogloea and Rhodocyclus; and (3) to improve the pollutant removal performance of this two-stage biological aerated filter, a strategy of adding an internal circulation in the B-stage filter can be adopted.

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454 pyrosequencing-based characterization of the bacterial consortia in a well established nitrifying reactor

Water Science & Technology ◽

10.2166/wst.2015.295 ◽

2015 ◽

Vol 72 (6) ◽

pp. 990-997 ◽

Cited By ~ 20

Author(s):

Rocio Ramirez-Vargas ◽

Nancy Serrano-Silva ◽

Yendi E. Navarro-Noya ◽

Rocio J. Alcántara-Hernández ◽

Marco Luna-Guido ◽

...

Keyword(s):

Extracellular Polymeric Substances ◽

High Throughput Sequencing ◽

Removal Rate ◽

Nitrifying Bacteria ◽

Organic Load ◽

Continuous Stirred Tank Reactor ◽

Bacterial Consortia ◽

Continuous Stirred Tank ◽

Planktonic Community

This present study aimed to characterize the bacterial community in a well-established nitrifying reactor by high-throughput sequencing of 16S rRNA amplicons. The laboratory-scale continuous stirred tank reactor has been supplied with ammonium (NH4+) as sole energy source for over 5 years, while no organic carbon has been added, assembling thus a unique planktonic community with a mean NH4+ removal rate of 86 ± 1.4 mg NH4+-N/(L d). Results showed a nitrifying community composed of bacteria belonging to Nitrosomonas (relative abundance 11.0%) as the sole ammonia oxidizers (AOB) and Nitrobacter (9.3%) as the sole nitrite oxidizers (NOB). The Alphaproteobacteria (42.3% including Nitrobacter) were the most abundant class within the Proteobacteria (62.8%) followed by the Gammaproteobacteria (9.4%). However, the Betaproteobacteria (excluding AOB) contributed only 0.08%, confirming that Alpha- and Gammaproteobacteria thrived in low-organic-load environments while heterotrophic Betaproteobacteria are not well adapted to these conditions. Bacteroidetes, known to metabolize extracellular polymeric substances produced by nitrifying bacteria and secondary metabolites of the decayed biomass, was the second most abundant phylum (30.8%). It was found that Nitrosomonas and Nitrobacter sustained a broad population of heterotrophs in the reactor dominated by Alpha- and Gammaproteobacteria and Bacteroidetes, in a 1:4 ratio of total nitrifiers to all heterotrophs.

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Effect of Increased Influent COD on Relieving the Toxicity of CeO2 NPs on Aerobic Granular Sludge

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16193609 ◽

2019 ◽

Vol 16 (19) ◽

pp. 3609 ◽

Cited By ~ 1

Author(s):

Xiaoying Zheng ◽

Yuan Zhang ◽

Wei Chen ◽

Weihong Wang ◽

Hang Xu ◽

...

Keyword(s):

Extracellular Polymeric Substances ◽

Oxygen Demand ◽

Granular Sludge ◽

Inhibitory Effect ◽

Environmental Risks ◽

Pollutant Removal ◽

Aerobic Granular Sludge ◽

Long Term Effects ◽

Negative Effects

Due to the increased use of cerium oxide nanoparticles (CeO2 NPs), their potential environmental risks have caused concern. However, their effects on the aerobic granular sludge (AGS) process and the later recovery of AGS are still unclear. In this study, we comprehensively determined the changes in pollutant removal and the levels of extracellular polymeric substances (EPS) in AGS that were exposed to CeO2 NP treatments (0 (the control, R0), 1 (R1), and 5 (R5) mg/L), following an increase in the influent chemical oxygen demand (COD). An increase in the CeO2 NP concentration enhanced their inhibitory effect on the removal of total nitrogen (TN) and total phosphorus (TP), and promoted the production of polysaccharides (PS) and proteins (PN) in loosely bound EPS (LB-EPS) or tightly bound EPS (TB-EPS), as well as the dissolved organic carbon (DOC) components in EPS, but had no long-term effects on the removal of organic matter. When the addition of CeO2 NPs was stopped and the concentration of influent COD increased, the TN and TP removal efficiencies in R1 and R5 slowly increased and recovered. In R1, they were only 4.55 ± 0.55% and 2.71 ± 0.58% lower than in R0, respectively, while the corresponding values for R5 were 5.06 ± 0.46% and 6.20 ± 0.63%. Despite the LB-EPS and TB-EPS concentrations in the R1 and R5 treatments recovering and being similar to the levels in the control when no CeO2 NPs were added, they were still slightly higher than in the R0, which indicating that the negative effects of CeO2 NPs could not be completely eliminated due to the residual CeO2 NP levels in AGS.

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The Use of Clay-Polymer Nanocomposites in Wastewater Pretreatment

The Scientific World JOURNAL ◽

10.1100/2012/498503 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 28

Author(s):

Giora Rytwo

Keyword(s):

Colloidal Stability ◽

Colloidal Suspension ◽

Sewage Treatment ◽

Quality Parameters ◽

Pollutant Removal ◽

Organic Load ◽

Rapid Reduction ◽

Colloidal Matter ◽

Repulsive Forces ◽

Treatment Step

Some agricultural effluents are unsuitable for discharge into standard sewage-treatment plants: their pretreatment is necessary to avoid clogging of the filtering devices by colloidal matter. The colloidal stability of the effluents is mainly due to mutual repulsive forces that keep charged particles in suspension. Pretreatment processes are based on two separate stages: (a) neutralization of the charges (“coagulation”) and (b) bridging between several small particles to form larger aggregates that sink, leaving clarified effluent (“flocculation”). The consequent destabilization of the colloidal suspension lowers total suspended solids (TSSs), turbidity, and other environmental quality parameters, making the treatments that follow more efficient. Clay-based materials have been widely used for effluent pretreatment and pollutant removal. This study presents the use of nanocomposites, comprised of an anchoring particle and a polymer, as “coagoflocculants” for the efficient and rapid reduction of TSS and turbidity in wastewater with a high organic load. The use of such particles combines the advantages of coagulant and flocculant by neutralizing the charge of the suspended particles while bridging between them and anchoring them to a denser particle (the clay mineral), enhancing their precipitation. Very rapid and efficient pretreatment is achieved in one single treatment step.

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Long-term evaluation of membrane bioreactor inoculated with commercial baker's yeast treating landfill leachate: pollutant removal, microorganism dynamic and membrane fouling

Water Science & Technology ◽

10.2166/wst.2019.067 ◽

2019 ◽

Vol 79 (2) ◽

pp. 398-410 ◽

Cited By ~ 2

Author(s):

Gabriela C. B. Brito ◽

Liséte C. Lange ◽

Vera L. Santos ◽

Míriam C. S. Amaral ◽

Wagner G. Moravia

Keyword(s):

Landfill Leachate ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Extracellular Polymeric Substances ◽

Baker’S Yeast ◽

Pollutant Removal ◽

Baker's Yeast ◽

Yeast Saccharomyces Cerevisiae ◽

Membrane Area ◽

Cake Layer

Abstract In this study, commercial baker's yeast (Saccharomyces cerevisiae) was employed as a novel inoculum for a membrane bioreactor (MBRy). It was applied to landfill leachate (LFL) treatment to remove recalcitrant organic compounds as well as for the assimilation of recalcitrant compounds, since yeasts have a high ability to break such compounds down. The MBR was inoculated with 10 g L−1 of commercial baker's yeast and was operated at a hydraulic retention time of 48 h and pH of 3.5. The specific air demand based on the membrane area (SADm) was maintained at 0.6 m3 h−1 m−2. The MBRy achieved chemical oxygen demand (COD), color, NH3, and humic substances removal of 68, 79, 68, and 50%, respectively. Furthermore, the MBRy showed lower fouling potential, which can be attributed to the low extracellular polymeric substances production, as the formation of a cake layer was the major mechanism of membrane fouling. The work demonstrated that novel MBR is a promising technology for treating recalcitrant landfill leachate.

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Microbial characteristics of landfill leachate disposed by aerobic moving bed biofilm reactor

Water Science & Technology ◽

10.2166/wst.2017.628 ◽

2017 ◽

Vol 77 (4) ◽

pp. 1089-1097 ◽

Cited By ~ 2

Author(s):

Guangzhi Wang ◽

Rui Chen ◽

Likun Huang ◽

Hemeng Ma ◽

Deying Mu ◽

...

Keyword(s):

Removal Efficiency ◽

Landfill Leachate ◽

Extracellular Polymeric Substances ◽

Ammonia Nitrogen ◽

Ammonia Removal ◽

Biofilm Reactor ◽

Pollutant Removal ◽

Nitrifying Bacteria ◽

Moving Bed Biofilm Reactor ◽

Moving Bed

Abstract An aerobic moving bed biofilm reactor (MBBR) was applied to treat landfill leachate generated from a domestic waste incineration plant. Pollutant removal efficiency of this reactor under stable operating condition was studied. The biomass, bacteria species, and microbial metabolism in this reactor were investigated. These results showed that the average removal efficiency of chemical oxygen demand (COD) and ammonia nitrogen in the aerobic MBBR achieved 64% and 97% in the optimum conditions, respectively. The three-dimensional fluorescence spectrum revealed that the content of soluble microbial byproducts from extracellular polymeric substances extraction in suspended sludge was much higher than that on biofilm, and the types of pollutants were various in different regions of the reactor. It also indicated that the MBBR system had a stable, rich and regular microorganism community, including large amounts of nitrifying bacteria and denitrifying bacteria. Scanning electron microscopy suggested that biofilm attached to the packing provided a good anoxic–aerobic micro environment system to achieve a high metabolic activity, which favored COD and ammonia removal.

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