The effect of the supplementation with a primary carbon source on the resistance to oxygen exposure of methanogenic sludge

Anaerobic methanogenic consortia have a considerable resistance to oxygen exposure. Yet, most research has been focused on the study of the tolerance to oxygen of anaerobic immobilized biomass. Less is known on the potential of the anaerobic suspended biomass for withstanding exposure to oxygen and the effect of a primary degradable substrate on such resistance. Thus, the objective of this work was to determine the effect of the amount of a primary degradable substrate (sucrose) on the resistance of a methanogenic suspended biomass to oxygen exposure. It was found that the inhibition of disperse anaerobic sludge by oxygen exposure decreases when the concentration of the supplemented carbon source increases. This is in agreement with the fact that aerobic respiration of the added substrate by the facultative heterotrophic bacteria, always present in this type of sludge, has been found in previous studies as one of the main mechanisms protecting methanogens against O2. From a practical point of view, this suggests that aeration of anaerobic systems should be possible without inhibiting the activity of methanogenic bacteria if an adequate ratio between oxygen and COD feeding is maintained. Such a ratio will depend however on the wastewater initial COD concentration.

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Modelling simultaneous removal of trichlorfon and glucose in a hybrid bioreactor containing magnetically immobilized biomass

Water Science & Technology ◽

10.2166/wst.1998.0614 ◽

1998 ◽

Vol 38 (4-5) ◽

pp. 179-186 ◽

Cited By ~ 2

Author(s):

Guang Hao Chen ◽

Hiroaki Ozaki ◽

Yutaka Terashima

Keyword(s):

Mathematical Model ◽

Carbon Source ◽

Experimental Results ◽

Simultaneous Removal ◽

Industrial Wastewaters ◽

Suspended Biomass ◽

Immobilized Biomass

This paper focuses on a simultaneous removal of trichlorfon and glucose that was added as carbon source for degradation requirement of trichlorfon. A hybrid bioreactor, having both suspended and magnetically immobilized biomass, was used for investigating this removal of both substances. To evaluate the respective roles of these two types of biomass, a mathematical model was developed and also verified well with experimental results. It has been found that the suspended biomass plays a key role in removing both substances in the system. This is due to complete coexistence of both trichlorfon-degrading and glucose-removing bacteria completely in each type of the biomass. Such a system would be applicable to the treatment of complex industrial wastewaters that contain easily biodegradable organics as well as refractory pollutants.

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Organic Matter Removal in a Simultaneous Nitrification-Denitrification Process Using Fixed-Film System.

10.21203/rs.3.rs-959611/v1 ◽

2021 ◽

Author(s):

Perla Gonzalez ◽

Ana Aguilar Ruiz ◽

Andrea Reynosa Varela ◽

Ulises Durán Hinojosa ◽

Marco Garzón Zuñiga ◽

...

Keyword(s):

Organic Matter ◽

Nitrogen Compound ◽

Upflow Anaerobic Sludge Blanket ◽

Swine Wastewater ◽

Uasb Reactor ◽

Anaerobic Sludge ◽

Organic Matter Removal ◽

Fixed Film ◽

Suspended Biomass ◽

Anaerobic Sludge Blanket

Abstract This study focused on evaluating different support media for COD and nitrogen compound removal from an Upflow Anaerobic Sludge Blanket (UASB) reactor fed with swine wastewater. Maximum specific nitrification (MSNA) and denitrification (MSDA) activity tests were performed in two fixed-film systems with (1) polyurethane foam (R1) and (2) polyethylene rings (R2). The results showed that the R2 system performed more efficiently than R1, reaching organic matter removal of 77 ± 8% and nitrogen of 98 ± 4%, attributed to higher specific denitrifying activity recorded (5.3 ± 0.34 g NO3--N/g VTS ∙h). In this sense, MSDA tests indicated that the suspended biomass was responsible for at least 70% of nitrogen removal in the form of ammonium compared with 20% attributed to biomass in the form of biofilm. On the other hand, 40 ± 5% of initial nitrogen could not be quantified in the system effluents, but 10 ± 1% was attributed to loss by volatilization. According to the analyses, the previous information infers the development of simultaneous nitrification-denitrification (SND) routes. Respect to the analyses of microbial diversity and abundance in the biofilm of R2 rings, the presence of the genus Pseudomonas dominated the prokaryotic community of the system in 54.4%.

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Fate ofCryptosporidiumoocysts,Giardiacysts, and microbial indicators during wastewater treatment and anaerobic sludge digestion

Canadian Journal of Microbiology ◽

10.1139/w99-001 ◽

1999 ◽

Vol 45 (3) ◽

pp. 257-262 ◽

Cited By ~ 37

Author(s):

Christian Chauret ◽

Susan Springthorpe ◽

Syed Sattar

Keyword(s):

Wastewater Treatment ◽

Clostridium Perfringens ◽

Heterotrophic Bacteria ◽

The Other ◽

Anaerobic Sludge ◽

Somatic Coliphages ◽

Aerobic Wastewater Treatment ◽

Sludge Digestion ◽

Cryptosporidium Oocysts ◽

Anaerobic Sludge Digestion

The extent of reduction in selected microorganisms was tested during both aerobic wastewater treatment and anaerobic digestion of sludge at the wastewater treatment plant in Ottawa to compare the removal of two encysted pathogenic protozoa with that of microbial indicators. Samples collected included the raw wastewater, the primary effluent, the treated wastewater, the mixed sludge, the decanted liquor, and the cake. All of the raw sewage samples were positive for Cryptosporidium oocysts and Giardia cysts, as well as for the other microorganisms tested. During aerobic wastewater treatment (excluding the anaerobic sludge digestion), Cryptosporidium and Giardia were reduced by 2.96 log10and 1.40 log10, respectively. Clostridium perfringens spores, Clostridium perfringens total counts, somatic coliphages, and heterotrophic bacteria were reduced by approximately 0.89 log10, 0.96 log10, 1.58 log10, and 2.02 log10, respectively. All of the other microorganisms were reduced by at least 3.53 log10. Sludge samples from the plant were found to contain variable densities of microorganisms. Variability in microbial concentrations was sometimes great between samples, stressing the importance of collecting a large number of samples over a long period of time. In all cases, the bacterial concentrations in the cake (dewatered biosolids) samples were high even if reductions in numbers were observed with some bacteria. During anaerobic sludge digestion, no statistically significant reduction was observed for Clostridium perfringens, Enterococcus sp., Cryptosporidium oocysts, and Giardia cysts. A 1-2 log10reduction was observed with fecal coliforms and heterotrophic bacteria. However, the method utilized to detect the protozoan parasites does not differentiate between viable and nonviable organisms. On the other hand, total coliforms and somatic coliphages were reduced by 0.35 log10and 0.09 log10, respectively. These results demonstrate the relative persistence of the protozoa in sewage sludge during wastewater treatment.Key words: Cryptosporidium, Giardia, indicators, wastewater, sludge.

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Performance of UASB based sewage treatment plant in India: polishing by diffusers an alternative

Water Science & Technology ◽

10.2166/wst.2011.333 ◽

2011 ◽

Vol 63 (4) ◽

pp. 680-688 ◽

Cited By ~ 11

Author(s):

R. Walia ◽

P. Kumar ◽

I. Mehrotra

Keyword(s):

Sewage Treatment ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Total Coliform ◽

Point Of View ◽

Upflow Anaerobic Sludge Blanket ◽

Uasb Reactor ◽

Anaerobic Sludge ◽

Detention Ponds ◽

One Year

In India, recently, upflow anaerobic sludge blanket (UASB) based sewage treatment plants (STPs) have come up in a big way. Sequence adopted: screens- grit chambers- UASB reactors followed by one-day detention ponds (DP). Performance of DPs located at five STPs (27–70 ML/d) was evaluated over a period of one year from July 2004 to July 2005. The installation of these non-algal ponds reduced land requirement, but from treatment point of view it at best offered only removal of solids washed out of the UASB reactor. Total coliform count in the effluent from ponds ranging from 106 to 109 MPN/100 mL is more than the maximum permissible limit of 10,000 MPN/100 mL. A need has, therefore, been felt to evaluate the possibility of aerating the effluent from UASBR. During aeration, ORP and DO increase, whereas COD and BOD decrease. In a continuous aeration ~50% reduction in COD and nearly 50% increase in DO saturation (DO/DOs) can be achieved by increasing ORP from −100 to 122 mV. Regression equation established between ORP and COD/CODi & DO/DOs may find wide application.

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Acid pre-treatment of sewage anaerobic sludge to increase hydrogen producing bacteria HPB: effectiveness and reproducibility

Water Science & Technology ◽

10.2166/wst.2008.506 ◽

2008 ◽

Vol 58 (8) ◽

pp. 1623-1628 ◽

Cited By ~ 16

Author(s):

T. Tommasi ◽

G. Sassi ◽

B. Ruggeri

Keyword(s):

Biogas Production ◽

Methanogenic Bacteria ◽

Anaerobic Sludge ◽

Clostridium Species ◽

Batch Mode ◽

Fermentative Hydrogen Production ◽

Series Of Experiments ◽

Pre Treatment ◽

Fermentative Hydrogen ◽

Main Components

The present study is aimed to test the effectiveness and the reproducibility of the acid pre-treatment of sewage sludge to suppress the methanogenic bacteria activity, in order to increase the hydrogen forming bacteria activity, mainly Clostridium species. The treated sludge has been tested on glucose reach medium under mesophilic conditions (35°C), in batch mode to quantify the biological fermentative hydrogen production. In the whole series of experiments, the main components of biogas are hydrogen (52–60%) and carbon dioxide (40–48%); no methane and hydrogen sulphide were present in it. The rate of biogas production reached a maximum of 75 ml/lh. An overall mean hydrogen conversion efficiency was 11.20% on the assumption of maximum of 3 mol H2/mol glucose. Clostridium spp. multiplied ten times after 10 h of fermentation and over that thousand times at the end of fermentation.

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Working with energy and mass balances: a conceptual framework to understand the limits of municipal wastewater treatment

Water Science & Technology ◽

10.2166/wst.2013.124 ◽

2013 ◽

Vol 67 (10) ◽

pp. 2294-2301 ◽

Cited By ~ 48

Author(s):

J. M. Garrido ◽

M. Fdz-Polanco ◽

F. Fdz-Polanco

Keyword(s):

Energy Source ◽

Wastewater Treatment ◽

Nitrogen Removal ◽

Municipal Wastewater ◽

Waste Water Treatment ◽

Point Of View ◽

Energy Requirements ◽

Anaerobic Sludge ◽

Carbon Removal ◽

Self Sufficiency

At present all municipal waste water treatment plants (WWTPs) are energy consumers. Electrical energy requirements for oxygen transfer are large in secondary biological systems. Nevertheless, from a thermodynamic point of view chemical oxygen demand (COD) is an energy source. Combustion of every kilogram of COD releases 3.86 kWh of energy. In this manuscript some measures are presented, from a conceptual point of view, in order to convert the actual concept of wastewater treatment as an ‘energy sink’ to an ‘energy source’ concept. In this sense, electrical self-sufficiency in carbon removal WWTPs could be obtained by increasing the sludge load to the anaerobic sludge digester. Nitrogen removal increases the energy requirements of WWTPs. The use of a combined two-stage biological treatment, using a high loaded first stage for carbon removal and a second stage combined nitrification–anammox process for nitrogen removal in the water line, offers a way to recover self-sufficiency. This is not a proven technology at ambient temperature, but its development offers an opportunity to reduce the energy demand of WWTPs.

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Phenol degradation in horizontal-flow anaerobic immobilized biomass (HAIB) reactor under mesophilic conditions

Water Science & Technology ◽

10.2166/wst.2001.0212 ◽

2001 ◽

Vol 44 (4) ◽

pp. 167-174 ◽

Cited By ~ 29

Author(s):

R. M.L. Bolaños ◽

M. B.A. Varesche ◽

M. Zaiat ◽

E. Foresti

Keyword(s):

Removal Efficiency ◽

Phenol Degradation ◽

Oxygen Demand ◽

Operating Conditions ◽

Cod Removal ◽

Horizontal Flow ◽

Anaerobic Sludge ◽

Cod Removal Efficiency ◽

Immobilized Biomass ◽

Potential Use

A bench-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor was assayed aiming to verify its potential use for phenol degradation. The HAIB reactor consisted of a bore-silicate tube (100 cm long; 5.04 cm diameter) filled with polyurethane foam matrices containing immobilized anaerobic sludge. Before being subjected to phenol, the reactor was fed with synthetic substrate at the influent chemical oxygen demand (COD) of 1,028 mg.l−1 achieving 98% of COD removal efficiency. Thereafter, phenol as the sole carbon source was added under step-increasing concentrations from 50 to 1,200 mg.l−1. Phenol degradation was evaluated by gas chromatographic analysis of influent and effluent samples. Process monitoring included determinations of pH, volatile acids, alkalinity and COD. The HAIB reactor was operated at a constant hydraulic detention time (HDT) of 12 hours. After 33 days with 50 mg/l of phenol in the influent, the reactor achieved 98% of COD removal efficiency. Successful phenol degradation (efficiency removal of 99%) occurred for influent concentrations of 100, 300, 600, 900 and 1,200 mg.l−1 after 148, 58, 47, 29 and 7 days, respectively. The predominance of Methanosaeta-like, rods and methanogenic cocci could be observed in all the operating conditions, besides the presence of phenol oxidizing microorganisms as irregular rods. The results indicate that phenol degradation at very high rates can be accomplished in HAIB reactors containing acclimatized biomass.

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Performance and bacterial diversity of bioreactors used for simultaneous removal of sulfide, solids and organic matter from UASB reactor effluents

Water Science & Technology ◽

10.2166/wst.2018.403 ◽

2018 ◽

Vol 78 (6) ◽

pp. 1312-1323 ◽

Cited By ~ 3

Author(s):

L. S. Azevedo ◽

I. M. P. Castro ◽

C. D. Leal ◽

J. C. Araújo ◽

C. A. L. Chernicharo

Keyword(s):

Organic Matter ◽

Elemental Sulfur ◽

Denaturing Gradient Gel Electrophoresis ◽

Heterotrophic Bacteria ◽

Packing Material ◽

Post Treatment ◽

Upflow Anaerobic Sludge Blanket ◽

Uasb Reactor ◽

Anaerobic Sludge ◽

Sulfur Bacteria

Abstract Two bioreactors were investigated as an alternative to post-treatment of effluent from an upflow anaerobic sludge blanket (UASB) reactor treating domestic sewage, with an aim of oxidizing sulfide into elemental sulfur, and removal of solid and organic material. The bioreactors were operated at different hydraulic retention times (HRTs) (6, 4, and 2 h) and in the presence or absence (control) of packing material (polypropylene rings). Greater sulfide removal efficiencies – 75% (control reactor) and 92% (packed reactor) – were achieved in both reactors for an HRT of 6 h. Higher organic matter (COD) and solid (TSS) removal levels were observed in the packed reactor, which produced effluent with low COD (100 mg CODL−1) and TSS concentrations (30 mg TSSL−1). Denaturing gradient gel electrophoresis results revealed that a metabolically diverse bacterial community was present in both bioreactors, with sequences related to heterotrophic bacteria, sulfur bacteria (Thiocapsa, Sulfurimonas sp., Chlorobaculum sp., Chromatiales and Sulfuricellales), phototrophic purple non-sulfur bacteria (Rhodopseudomonas, Rhodocyclus sp.) and cyanobacteria. The packed reactor presented higher extracellular sulfur formation and potential for elemental sulfur recovery was seen. Higher efficiencies related to the packed reactor were attributed to the presence of packing material and higher cell retention time. The studied bioreactors seemed to be a simple and low-cost alternative for the post-treatment of anaerobic effluent.

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Competition of methanogenic and sulfidogenic bacteria

Water Science & Technology ◽

10.2166/wst.1996.0062 ◽

1996 ◽

Vol 33 (3) ◽

pp. 99-110 ◽

Cited By ~ 37

Author(s):

A. Visser ◽

L. W. Hulshoff Pol ◽

G. Lettinga

Keyword(s):

Granular Sludge ◽

Methanogenic Bacteria ◽

Anaerobic Sludge ◽

Sulfide Concentration ◽

Anaerobic Granular Sludge ◽

Batch Reactors ◽

Sulfide Toxicity ◽

Sulfide Inhibition ◽

Total Sulfide ◽

Ph Range

The competition of acetotrophic methanogenic bacteria (AMB) and acetotrophic sulfidogenic bacteria (ASRB) was studied by assessing growth rates, activities and acetate and sulfate affinities at different pH levels and sulfide concentrations in batch reactors. Both anaerobic granular sludge and suspended anaerobic sludge were tested. The results indicate that at pH-levels below 6.9 AMB will outcompete ASRB, whereas above a pH of 7.7, ASRB will win the competition. If ASRB and AMB are present in granular sludge growth will be found in a wider pH-range than if they are present as suspended sludge. The affinities for acetate and the sulfide toxicity are dependent on the sludge form as well. In granular sludge the acetate affinities of ASRB and AMB are comparable, whereas in suspended sludge ASRB show a lower affinity than AMB. With respect to sulfide toxicity, the results indicate that above pH 7 sulfide inhibition in granular sludge is caused by the total sulfide concentration, while in suspended sludge the free H2S-concentration determines the toxicity. At high pH-levels growth is stronger inhibited than the activity.

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