Effects of Al3+ on pollutant removal and extracellular polymeric substances (EPS) under anaerobic, anoxic and oxic conditions

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

Environmental Technology ◽

10.1080/09593330.2022.2029952 ◽

2022 ◽

pp. 1-26

Author(s):

Weiqing Jiang ◽

Xingrong Yao ◽

Fan Wang ◽

Yajing Li ◽

Suiyi Zhu ◽

...

Keyword(s):

Extracellular Polymeric Substances ◽

Pollutant Removal ◽

Organic Load

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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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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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Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

10.26434/chemrxiv.10001924.v1 ◽

2019 ◽

Author(s):

Yoshihide Furuichi ◽

Shogo Yoshimoto ◽

Tomohiro Inaba ◽

Nobuhiko Nomura ◽

Katsutoshi Hori

Keyword(s):

Formation Process ◽

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Waste Treatment ◽

Large Cell ◽

Dlvo Theory ◽

Bacterial Cells ◽

Chemical Production ◽

Discontinuous Surface ◽

Cell Cell

Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. Acinetobacter sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.

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Field-Scale Studies of Subsurface Flow Constructed Wetlands for Stormwater Quality Enhancement

Water Quality Research Journal ◽

10.2166/wqrj.1997.008 ◽

1997 ◽

Vol 32 (1) ◽

pp. 101-118 ◽

Cited By ~ 6

Author(s):

Q.J. ROCHFORT ◽

W.E. Watt ◽

J. Marsalek ◽

B.C. Anderson ◽

A.A. Crowder

Keyword(s):

Organic Carbon ◽

Constructed Wetlands ◽

Suspended Solids ◽

Nutrient Loading ◽

Subsurface Flow ◽

Reaction Rates ◽

Pollutant Removal ◽

Order Kinetic ◽

Dissolved Metals ◽

Subsurface Flow Constructed Wetlands

Abstract Two subsurface flow constructed wetlands were tested for pollutant removal performance in conjunction with an on-line stormwater detention pond, in Kingston Township, Ontario. The 4.9 m2 wetland cells were filled with 9 mm limestone gravel, and planted with cattail, common reed and spike rush. Changes in nutrient (total organic carbon, PO43- and NH4+), suspended solids and metal (Cu, Pb, Zn) concentrations were used to assess performance. Contaminant removal occurred through a combination of physical, chemical and biological means. As with any biological system, variation in performance of stormwater wetlands can be expected to occur as a result of fluctuations in contaminant loading, contact time and ambient environmental conditions. Storm pond effluent was delivered in continuous flow through the wetlands (during baseflow and event conditions), with a detention time of 1 to 3 days. The wetlands were able to maintain removal rates of up to 39% for orthophosphate even during the more severe conditions of fall dieback. Average removal of suspended solids (46%) and dissolved metals (Cu 50%) remained similar throughout all tests. Organic carbon was reduced by less than 10% during these tests. Low nutrient levels in the pond effluent were supplemented by spiking with sources of carbon, nitrogen and phosphorus during pulsed loading conditions. Daily sampling produced a time series, which illustrated the rates of decline in concentration of nutrients. First order kinetic assimilation rates ranged from 1.7 d-1 for NH4002B to 0.12 d-1 for organic carbon, which were noticeably lower when compared with municipal and industrial wastewater treatment rates. Three methods of sizing stormwater wetlands (impervious surface area, volumetric load and kinetic reaction rates) were compared using the same design storm and data from this study. From this comparison it was seen that the kinetic sizing approach proved to be the most versatile, and allowed for adaptation to northern climatic conditions and anticipated nutrient loading.

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Performance and Modelling of a Highway Wet Detention Pond Designed for Cold Climate

Water Quality Research Journal ◽

10.2166/wqrj.2009.027 ◽

2009 ◽

Vol 44 (3) ◽

pp. 253-262 ◽

Cited By ~ 7

Author(s):

Jes Vollertsen ◽

Svein Ole Åstebøl ◽

Jan Emil Coward ◽

Tor Fageraas ◽

Asbjørn Haaning Nielsen ◽

...

Keyword(s):

Rate Constants ◽

Pond Water ◽

Pollutant Removal ◽

Cold Climate ◽

Traffic Load ◽

Substantial Part ◽

First Order ◽

Detention Pond ◽

Time Of Year ◽

Wet Detention Pond

Abstract A wet detention pond in Norway has been monitored for 12 months. The pond receives runoff from a highway with a traffic load of 42,000 average daily traffic. Hydraulic conditions in terms of inflow, outflow, and pond water level were recorded every minute. Water quality was monitored by volume proportional inlet and outlet samples. During most of the year, excellent pollutant removal was achieved; however, during two snowmelt events the pollutant removal was poor or even negative. The two snowmelt events accounted for one third of the annual water load and for a substantial part of the annual pollutant discharge. The performance of the pond was analyzed using a dynamic model and pollutant removal was simulated by first-order kinetics. Good agreement between measurement and simulation could be achieved only when choosing different first-order rate constants for different parts of the year. However, no relation between the rate constants obtained and the time of year could be identified, and neither did the rate constants for different pollutants correlate. The study indicates that even detailed measurements of pollutant input and output allow only average performance to be simulated and are insufficient for simulating event-based variability in pond performance.

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Filtration resistance induced by ammonia oxidizers accumulating on the rotating membrane disk

Water Science & Technology ◽

10.2166/wst.1998.0690 ◽

1998 ◽

Vol 38 (4-5) ◽

pp. 443-452

Author(s):

Katsuki Kimura ◽

Yoshimasa Watanabe ◽

Naoki Ohkuma

Keyword(s):

Membrane Filtration ◽

Extracellular Polymeric Substances ◽

Drinking Water Treatment ◽

Treatment Method ◽

Operating Conditions ◽

Transmembrane Pressure ◽

Ammonia Oxidizers ◽

Filtration Resistance ◽

Rotating Membrane Disk ◽

Membrane Disk

Membrane filtration and oxidation of ammonia were simultaneously performed by using a rotating membrane disk module. Nitrification performance, composition of the accumulated cakes on the membrane and the filtration resistances were investigated under five different operating conditions. The filtration resistance due to the accumulated cake on the membrane was found to be dominant in this treatment method, compared to the resistance due to the micropore plugging or irreversible adherence. The cake consisted mainly of iron, humic substances and bacteria. The possibility that extracellular polymeric substances were related to the cake resistance was also shown. The composition of the cake depended on the length and the condition of operation. Accumulation of ammonia oxidizers caused by oxidation of low concentrations of ammonia (less than 1 mg/l) did not increase transmembrane pressure significantly. Therefore, the application of this treatment method for drinking water treatment is feasible. Filtration resistance due to the micropore plugging or irreversible adherence to the membrane was caused by organic substances.

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