Aeration tank odour by dimethyl sulphoxide (DMSO) waste in sewage

2007 ◽  
Vol 55 (5) ◽  
pp. 319-326 ◽  
Author(s):  
D. Glindemann ◽  
J.T. Novak ◽  
J. Witherspoon
Keyword(s):  
Bulk Water ◽  
Sulphate Reduction ◽  
Anaerobic Sludge ◽  
Aeration Tank ◽  
Dimethyl Sulphide ◽  
Reduction Mechanism ◽  
Anaerobic Conditions ◽  
Sludge Flocs ◽  
Oxidation Resistant

Sewage plants can experience dimethyl sulphide (DMS) odour problems by at least one mg/L dimethylsulphoxide (DMSO) waste residue in plant influent, through a DMSO/DMS reduction mechanism. This bench-scale batch study simulates in bottles the role of poor aeration in wastewater treatment on the DMSO/DMS and sulphate/H2S reduction. The study compares headspace concentrations of sulphide odorants developed by activated sludge (closed bottles, half full) after six hours under anoxic versus anaerobic conditions, with 0 versus 2 mg/L DMSO addition. Anoxic sludge (0.1–2 mg/L dissolved oxygen, DO) with DMSO resulted in about 50 ppmv DMS and no other sulphide, while DMSO-free sludge was free of detectable sulphides. Anaerobic sludge (no measurable DO to the point of sulphate reduction) with DMSO resulted in 22/4/37 ppmv of H2S/methanethiol (MT)/DMS, while DMSO-free sludge resulted in 44/8/2 ppmv of H2S/MT/DMS. It is concluded that common “anoxic” aeration tank zones with measurable DO in bulk water but immeasurable DO inside sludge flocs (nitrate reducing) experience DMSO reduction to DMS that is oxidation resistant and becomes the most important odorant. Under anaerobic conditions, H2S from sulphate reduction becomes an additional important odorant. A strategy is developed that allows operators to determine from the quantity of different sulphides whether the DMSO/DMS mechanism is important at their wastewater plant.

The role of sulphate reduction on the reductive decolorization of the azo dye reactive orange 14

2006 ◽  
Vol 54 (2) ◽  
pp. 171-177 ◽  
Author(s):  
F.J. Cervantes ◽  
J.E. Enriquez ◽  
M.R. Mendoza-Hernandez ◽  
E. Razo-Flores ◽  
J.A. Field
Keyword(s):  
Electron Donor ◽  
Azo Dye ◽  
Redox Mediator ◽  
Sulphate Reduction ◽  
Anaerobic Sludge ◽  
Biological Mechanisms ◽  
Azo Reduction ◽  
Reactive Orange ◽  
The Impact

The aim of this study was to investigate the impact of a broad range of sulphate concentrations (0–10 g SO4−2 L−1) on the reduction of an azo dye (reactive orange 14 (RO14)) by an anaerobic sludge. An increase in the sulphate concentration generally stimulated the reduction of RO14 by sludge incubations supplemented with glucose, acetate or propionate as electron donor. Sulphate and azo dye reductions took place simultaneously in all incubations. However, there was a decrease on the rate of decolorization when sulphate was supplied at 10 g SO4−2 L−1. Abiotic incubations at different sulphide concentrations (0–2.5 g sulphide L−1) promoted very poor reduction of RO14. However, addition of riboflavin (20 μM), as a redox mediator, accelerated the reduction of RO14 up to 44-fold compared to a control lacking the catalyst. Our results indicate that sulphate-reduction may significantly contribute to the reduction of azo dyes both by biological mechanisms and by abiotic reductions implicating sulphide as an electron donor. The contribution of abiotic decolorization by sulphide, however, was only significant when a proper redox mediator was included. Our results also revealed that sulphate-reduction can out-compete with azo reduction at high sulphate concentrations leading to a poor decolorising performance when no sufficient reducing capacity is available.

The important role of non-covalent interactions for the vibrational circular dichroism of lactic acid in aqueous solution

2021 ◽  
Author(s):  
Sascha Jähnigen ◽  
Daniel Sebastiani ◽  
Rodolphe Vuilleumier
Keyword(s):  
Lactic Acid ◽  
Circular Dichroism ◽  
Computational Study ◽  
Bulk Water ◽  
Vibrational Circular Dichroism ◽  
Ab Initio Molecular Dynamics ◽  
Non Covalent Interactions ◽  
Circular Dichroïsm ◽  
Covalent Interactions

We present a computational study of vibrational circular dichroism (VCD) in solutions of (S)-lactic acid, relying on ab initio molecular dynamics (AIMD) and full solvation with bulk water. We discuss...

Role of vertical mixing in controlling the oceanic production of dimethyl sulphide

Nature ◽  
10.1038/46516 ◽  
1999 ◽  
Vol 402 (6760) ◽  
pp. 396-399 ◽  
Author(s):  
Rafel Simó ◽  
Carlos Pedrós-Alió
Keyword(s):  
Vertical Mixing ◽  
Dimethyl Sulphide

scholarly journals Moisture Induced Degradation of Porous Low-k Materials

2006 ◽  
Vol 914 ◽  
Author(s):  
Mikhail Baklanov ◽  
David O'Dwyer ◽  
Adam M Urbanowicz ◽  
Quoc Toan Le ◽  
Steven Demuynck ◽  
...  
Keyword(s):  
Water Film ◽  
Internal Surface ◽  
Hydrophobic Surface ◽  
Adsorbed Water ◽  
Bulk Water ◽  
Oh Groups ◽  
Film Bulk ◽  
Low K

AbstractInteraction of moisture with porous low-k films is evaluated by using in situ ellipsometry setup. The adsorbed water amount is calculated from change of refractive index measured during the adsorption. Pristine low-k films reversibly adsorb 2 - 5% of water that reflects presence of constitutive hydrophilic centrums. Plasma and thermal treatments increase the number of hydrophilic centrums. Once the amount of these centrums has reached a certain critical value sufficient to form a continuous water film, bulk water condensation is observed. Change of properties during the water adsorption in the damaged films is not fully reversible. Each additional adsorption cycle increases the dielectric function of the film because of decreasing porosity, increasing skeleton density and shrinkage. The pressure corresponding to the bulk condensation allows us to calculate internal contact angle (internal surface energy) of low-k materials. The water molecules adsorbed on separate OH groups play the role of a catalyst that hydrolyses the siloxane bridges initially present on hydrophobic surface.

Microbial characteristics of a methanogenic phenol-degrading sludge

2005 ◽  
Vol 52 (1-2) ◽  
pp. 73-78 ◽  
Author(s):  
T. Zhang ◽  
S. Z. Ke ◽  
Y. Liu ◽  
H.P. Fang
Keyword(s):  
Dna Analysis ◽  
Pcr Amplification ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Chain Reaction ◽  
Microbial Characteristics ◽  
Polymerase Chain ◽  
Anaerobic Sludge Blanket

Microbial properties of a methanogenic granular phenol-degrading sludge were characterized using the 16S rRNA/DNA-based techniques, including polymerase chain reaction (PCR) amplification, cloning, DNA sequencing, and fluorescence in situ hybridization (FISH). The sludge was sampled from an upflow anaerobic sludge blanket reactor, which removed 98% of phenol (up to 1260 mg/l) in wastewater at 26°C with 12 hours of hydraulic retention. Based on DNA analysis, the Eubacteria in the sludge was composed of 13 operational taxonomy units (OTUs). Two OTUs, one resembling Clostridium and the other remotely resembling Desulfotomaculum, were likely responsible for the conversion of phenol to benzoate, which was further degraded by five Syntrophus-resembling OTUs to acetate and H2/CO2; methanogens lastly converted acetate and H2/CO2 into methane. The role of six remaining OTUs remains unclear. Overall, the sludge was composed of 26±6% Eubacteria and 74±9% methanogens, of which 54±6% were acetotrophic Methanosaetaceae, 14±3% and 3±2% were hydrogenotrophic Methanomicrobiales and Methanobacteriaceae, respectively.

Granular Sludge Formation in the Anaerobic Expanded Micro-Carrier Bed Process

1989 ◽  
Vol 21 (4-5) ◽  
pp. 109-120 ◽  
Author(s):  
M. Yoda ◽  
M. Kitagawa ◽  
Y. Miyaji
Keyword(s):  
Scale Up ◽  
Granular Sludge ◽  
Laboratory Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Expanded Bed ◽  
Sludge Formation ◽  
Support Materials ◽  
Anaerobic Sludge Blanket

The anaerobic expanded micro-carrier bed (MCB) process, which utilizes fine (50-100 microns) support materials as expanded bed media, was found to have the ability to cultivate granular sludge similar to that formed in the upflow anaerobic sludge blanket (UASB) process. Two laboratory-scale MCB reactors were studied with VFA and glucose wastewaters to clarify the role of the micro-carrier and the influence of substrates on granular sludge formation. Based on these results, a scale-up model with a reactor volume of 800 1 was successfully operated using molasses wastewater to demonstrate the feasibility of granular sludge formation in the MCB process.

Effects of Temperature and pH on the Settleability of Activated Sludge Flocs

1990 ◽  
Vol 22 (9) ◽  
pp. 249-254 ◽  
Author(s):  
F. Dilek Çetin ◽  
Gülerman Sürücü
Keyword(s):  
Activated Sludge ◽  
Volume Index ◽  
Aeration Tank ◽  
Effluent Quality ◽  
Sludge Flocs ◽  
Secondary Clarifier ◽  
Different Temperatures ◽  
Effects Of Temperature ◽  
Two Parameters ◽  
Physiological And Biochemical

In efficient and economical treatment of wastewaters,the settleability of activated sludge is of prime importance. Efficient settlement in the secondary sedimentation tank is required, both to keep the desired effluent quality and to sustain the necessary amount of microorganisms in the aeration tank. On the other hand, the settleability of microorganisms in the secondary clarifier is very dependent on the physiological and biochemical nature of activated sludge flocs, which are determined by the conditions of the aeration tank. In this research, effects of temperature and pH of aeration basin on settleability of activated sludge were studied. Settleability was measured by zone settling velocity and sludge volume index (SVI). Five different temperatures and four different pH values were operated in the aeration basin. It was found that the settleability of activated sludge is greatly affected by these two parameters.

Anaerobic 35°C and 55°C Treatment of a BCTMP/TMP Effluent: Sulphur Management Strategies

1994 ◽  
Vol 29 (5-6) ◽  
pp. 433-445 ◽  
Author(s):  
R. J. Stephenson ◽  
R. M. R. Branion ◽  
K. L. Pinder
Keyword(s):  
Hydrogen Sulphide ◽  
Effective Means ◽  
Management Strategies ◽  
Sulphate Reduction ◽  
Anaerobic Sludge ◽  
Thermomechanical Pulp ◽  
Treatment Efficiency ◽  
Sulphur Compounds ◽  
Experimental Apparatus ◽  
Molybdenum Addition

Pulp manufacture uses sulphur in a variety of forms and these sulphur compounds ultimately end up in the effluent. Under anaerobic conditions, sulphite and sulphate are reduced to sulphide, presenting problems of toxicity, odour, corrosion, and reduced methane yields and treatment efficiencies. The fate of these inorganic sulphur compounds in a bleached chemi-thermomechanical pulp/thermomechanical pulp (BCTMP/TMP) effluent mixture was examined in two phase anaerobic reactors at 35°C and 55°C. The following sulphur management strategies were investigated: 1) controlling the pH of the acidogenic reactor, 2) inhibiting the sulphur reducing bacteria via molybdenum addition to the feed tank, and 3) stripping the hydrogen sulphide dissolved in the methane phase reactor liquor by recycling hydrogen sulphide-free off gas. The laboratory scale experimental apparatus consisted of upflow anaerobic sludge bed pre-treatment or acidogenic reactors followed by hybrid upflow anaerobic sludge bed/fixed film methanogenic reactors. At 35°C, controlling the pH of the acidogenic reactors with sodium carbonate from 5.5 (uncontrolled) to 8.0 in order to shift the formed sulphide species to the less toxic ionic form appeared to be ineffective in promoting wastewater treatment efficiency. Molybdenum addition to the wastewater at levels from 0.1 to 1.0 mM was effective at 1.0 mM in retarding sulphate reduction or sulphide formation. Hydrogen sulphide stripping, using ferric chloride scrubbed and recycled off gas, appeared to be the most effective means of sulphur management for this type of wastewater under these conditions. Tbermophilic 55°C anaerobic treatment was also studied using the same effluent, inocula and sulphur management strategies. Overall, both the treatment efficiency and the sulphate reduction were lower for the thermophilic runs compared to the mesophilic runs. Raising the acidogenic phase reactor pH from 7.0 to 7.5 to 8.0 appeared to have no significant effect on organic carbon removal efficiency or on sulphate reduction. Molybdenum inhibition of sulphur reduction was not as marked as for the 1.0 mM level at 35°C, perhaps due to the already low baseline sulphate reduction efficiency at 55°C. Stripping hydrogen sulphide from the reactor liquor helped to promote the treatment efficiency and lowered the sulphide and sulphate levels. Similar to the 35°C study, sulphide removal by gas stripping appeared to be the most effective means of sulphur management

scholarly journals The role of bulk water in conversion of the gel to the L-subgel phase in phosphatidylethanolaminewater system

2001 ◽  
Vol 41 (supplement) ◽  
pp. S130
Author(s):  
H. Aoki ◽  
T. Koto ◽  
M. Kodama
Keyword(s):  
Bulk Water ◽  
Subgel Phase

The role of the flow pattern in wastewater aeration tanks

2010 ◽  
Vol 61 (2) ◽  
pp. 407-414 ◽  
Author(s):  
M. Gresch ◽  
D. Braun ◽  
W. Gujer
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Compartment Model ◽  
Plant Performance ◽  
Aeration Tank ◽  
Key Factors ◽  
Direct Observations ◽  
Conservative Tracer

Reactor hydraulics is one of the key factors for plant performance and plant control. The residence time distribution is a good but limited indicator of reactor hydraulics. A more detailed view is obtained by direct observations within the reactor. Two different techniques (conservative tracer, reactive tracer) are discussed to detect major anomalies in the flow field of a wastewater aeration tank. Experiments with conservative tracers give valuable information over a very limited period of time making the analysis of the flow field difficult. On the other hand, reactive tracers can be monitored long term which helps identifying the flow pattern provided that a high spatial and temporal resolution of the measurements is applied. Experimental data is used to determine the structure and the parameters of a compartment model that corresponds well with the measurements.

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