Influence of the initial substrate to microorganisms concentration ratio on the methanogenic inhibition test

I. Moreno-Andrade; G. Buitrón

doi:10.2166/wst.2003.0348

Influence of the initial substrate to microorganisms concentration ratio on the methanogenic inhibition test

Water Science & Technology ◽

10.2166/wst.2003.0348 ◽

2003 ◽

Vol 48 (6) ◽

pp. 17-22 ◽

Cited By ~ 11

Author(s):

I. Moreno-Andrade ◽

G. Buitrón

Keyword(s):

Methane Production ◽

Concentration Ratio ◽

Suspended Solids ◽

Great Influence ◽

Biomass Concentration ◽

Inhibition Test ◽

Initial Concentration ◽

Initial Biomass Concentration ◽

Initial Substrate

The influence of the initial substrate to microorganisms ratio (So/Xo) on the inhibition of the methane production caused by 4-chlorophenol, 4CP, was studied. The effect of the 4CP on glucose degradation was evaluated measuring the quantity of methane produced during the test. One part of the inoculum was used as it came from its origin and another was fed with ethanol in order to maintain its activity. The inhibition tests were carried out using the same initial concentration of glucose, three initial suspended solids concentrations and eight initial concentrations of 4CP. The use of ethanol-acclimatized sludge presented a great influence on the inhibition results, since the inhibition was greater in the raw sludge than the acclimated one. Significant differences in the inhibition tests were found depending on the initial So/Xo ratio with respect to the glucose as substrate. It was observed that the inhibition decreases as the So/Xo decreases, in other words as the initial biomass concentration increases. When the results were analyzed in respect to the 4CP it was observed that the inhibition increases as the So/Xo increases. Also, it was observed that for the same value of So/Xo there is an increase of the inhibition when the quantity of Xo decreases.

Download Full-text

Determination of the Maintenance Requirements of Activated Sludge

Water Science & Technology ◽

10.2166/wst.1993.0154 ◽

1993 ◽

Vol 28 (7) ◽

pp. 139-142 ◽

Cited By ~ 9

Author(s):

J. Chang ◽

P. Chudoba ◽

B. Capdeville

Keyword(s):

Wastewater Treatment ◽

Process Development ◽

Biomass Concentration ◽

Growth Yield ◽

Kinetic Studies ◽

Initial Biomass Concentration ◽

Aerobic Wastewater Treatment ◽

Initial Substrate ◽

Maintenance Requirements ◽

The Cost

Maintenance energy plays an important role both in basic kinetic studies and in process development. Numerous studies have been devoted to the maintenance concept in various microbial fields but very few in biological wastewater treatment. Using a fermenter coupled to a mass spectrometer, we investigated the influence of the ratio So/Xo (ratio between initial substrate concentration and initial biomass concentration) on the observed sludge growth yield of an oxic-settling anaerobic (OSA) system. By measuring the substrate removed, the oxygen consumed and the carbon dioxide produced, we were able to estimate the substrate fraction used for maintenance purposes. The results indicate that at a high So/Xo ratio, a greater proportion of the substrate is devoted to maintenance thus significantly decreasing the observed growth yield. These findings are of particular importance in view of the cost associated with the disposal of excess sludge in aerobic wastewater treatment processes.

Download Full-text

Explanation of Biological Meaning of the So/Xo Ratio in Batch Cultivation

Water Science & Technology ◽

10.2166/wst.1992.0455 ◽

1992 ◽

Vol 26 (3-4) ◽

pp. 743-751 ◽

Cited By ~ 83

Author(s):

P. Chudoba ◽

B. Capdeville ◽

J. Chudoba

Keyword(s):

Mixed Culture ◽

Biomass Concentration ◽

Batch Cultivation ◽

Kinetic Constants ◽

Cell Multiplication ◽

Waste Products ◽

Substrate Removal ◽

Initial Biomass Concentration ◽

Initial Substrate ◽

Exogenous Substrate

It is shown that the most important parameter in batch cultivation of mixed cultures is the ratio of the initial substrate concentration to the initial biomass concentration (So/Xo as COD/biomass). When the ratio is sufficiently low (below 2-4 depending on the mixed culture history) no cell multiplication takes place during the exogenous substrate removal. Under these conditions, a biomass increase is mostly due to the synthesis of storage polymers. It is also shown that the observed yield, Yobs, decreases with increasing So/Xo ratio. Under the high So/Xo conditions, more energy is spent for cell multiplication, which results in greater part of substrate being oxidized. Batch cultivation at high So/Xo ratios results also in higher concentrations of microbial polymers produced as waste products of mixed culture microorganisms. It is concluded that for the biodegradation studies with the aim to obtain kinetic constants it is necessary to work at low So/Xo ratios to prevent mixed culture microorganisms from substantial multiplication. This is necessary because cell multiplication during batch cultivation of mixed culture changes the proportion among slow-growers and fast-growers. This is the only way to obtain the kinetic constants which are representative of the original mixed culture.

Download Full-text

Influence of So/Xo Ratio on Anaerobic Activity Test

Water Science & Technology ◽

10.2166/wst.1999.0373 ◽

1999 ◽

Vol 40 (8) ◽

pp. 9-15 ◽

Cited By ~ 1

Author(s):

Gloria Moreno ◽

Arturo Cruz ◽

Germán Buitrón

Keyword(s):

Substrate Concentration ◽

Reaction Rate ◽

Biomass Concentration ◽

Sole Source ◽

Yield Coefficient ◽

Initial Biomass Concentration ◽

Activity Test ◽

Initial Substrate ◽

Kinetic Coefficients ◽

Initial Substrate Concentration

The effect of the substrate/microorganism ratio during the development of anaerobic activity test was studied. The experimentation was carried out in serum bottles at 35°C. Two sets of experiments utilizing acetate and an azo dye (blue disperse 79) as the sole source of carbon were studied. It was observed that mixing has an important influence on the results. The initial substrate concentration and the initial biomass concentration had a significant effect on the reaction rate and on the biomass yield coefficient, Yobs. Different kinetic coefficients were found for the case of equal So/Xo ratio, but different initial substrate concentration.

Download Full-text

Application of dimensional analysis in removal prediction of 2-[4-(dimethylamino) styryl]-1-methylpyridinium iodide dye using humic acid coated magnetic nanoparticle

10.5194/egusphere-egu21-9142 ◽

2021 ◽

Author(s):

Anahita Esmaeilian ◽

Kevin E. O'Shea

Keyword(s):

Humic Acid ◽

Dimensional Analysis ◽

Concentration Ratio ◽

Magnetic Nanoparticle ◽

Equilibrium Concentration ◽

Sorption Process ◽

Dose Ratio ◽

Initial Concentration ◽

Liquid Systems ◽

Isotherm Equations

Numerous factors affect adsorption phenomena in solid&#8211;liquid systems. Critical factors are the sorbent dose and initial concentrations of the contaminants in the system. However, the combination of these two factors and their effects on removal prediction are largely unexplored. In this study, batch experiments were conducted to examine such effects on the adsorption of 2-[4-(dimethylamino) styryl]-1-methylpyridinium iodide cationic dye (2-ASP) in contaminated water to humic acid coated magnetic nanoparticles (HA-MNPs). Dimensional analysis and Buckingham&#8217;s &#960; theorem were subsequently used to assess the relationship between the sorbent dose, initial concentration, and percent removal. Results of dimensional analysis along with experimental data suggest that sorbent dose and sorbate concentration ratio are the main variables controlling sorption of dye on HA-MNPs. In conventional isothermal studies, the isotherm equations are developed based on experiments of one sorbent dose which cannot be generalized for all sorbent doses.&#160; In this study, a power function (Isotherm-like) model was obtained from the dimensional analysis that can describe precisely the sorption process of dye on HA-MNPs as a function of equilibrium concentration and sorbent dose ratio. Moreover, a relation is deduced for prediction of removal percent as a function of sorbent dose and initial concentration ratio with R2 of 0.98.Keywords: Remediation, Dimensional analysis, Isotherm-like model, Magnetic nanoparticle, Styryl pyridinium dyes, Water treatment

Download Full-text

On-chip MIC by Combining Concentration Gradient Generator and Flanged Chamber Arrays

Micromachines ◽

10.3390/mi11020207 ◽

2020 ◽

Vol 11 (2) ◽

pp. 207 ◽

Cited By ~ 2

Author(s):

Xiao-Yan Zhang ◽

Zhe-Yu Li ◽

Kose Ueno ◽

Hiroaki Misawa ◽

Nan-Qi Ren ◽

...

Keyword(s):

Bacterial Growth ◽

Concentration Gradient ◽

Microfluidic System ◽

Honeycomb Structure ◽

Inhibition Test ◽

Microfluidic Platform ◽

Initial Concentration ◽

Bacteria Growth ◽

Skilled Operator ◽

On Chip

Minimum inhibition concentration (MIC) of antibiotic is an effective value to ascertain the agent and minimum dosage of inhibiting bacterial growth. However, current techniques to determine MIC are labor intensive and time-consuming, and require skilled operator and high initial concentration of bacteria. To simplify the operation and reduce the time of inhibition test, we developed a microfluidic system, containing a concentration generator and sub-micro-liter chambers, for rapid bacterial growth and inhibition test. To improve the mixing effect, a micropillar array in honeycomb-structure channels is designed, so the steady concentration gradient of amoxicillin can be generated. The flanged chambers are used to culture bacteria under the condition of continuous flow and the medium of chambers is refreshed constantly, which could supply the sufficient nutrient for bacteria growth and take away the metabolite. Based on the microfluidic platform, the bacterial growth with antibiotic inhibition on chip can be quantitatively measured and MIC can be obtained within six hours using low initial concentration of bacteria. Overall, this microfluidic platform has the potential to provide rapidness and effectiveness to screen bacteria and determine MIC of corresponding antibiotics in clinical therapies.

Download Full-text

Some observations on the effects of accumulated benthic sludge on the behaviour of waste stabilisation ponds

Water Science & Technology ◽

10.2166/wst.2005.0467 ◽

2005 ◽

Vol 51 (12) ◽

pp. 217-226

Author(s):

C.J. Banks ◽

S. Heaven ◽

E.A. Zotova

Keyword(s):

Light Intensity ◽

Dissolved Oxygen ◽

Water Column ◽

Suspended Solids ◽

Biomass Concentration ◽

Pilot Scale ◽

Controlling Factor ◽

Waste Stabilisation Ponds ◽

Nutrient Levels ◽

Complex Mechanisms

The effect of accumulated bottom sludge on water column characteristics was studied in two pilot-scale ponds. Parameters measured were ammonia, nitrate, phosphate, COD, suspended solids, dissolved oxygen (DO), temperature and light intensity. The de-sludged pond showed a stronger correlation between DO, light intensity, nutrients and suspended solids with the controlling factor being availability of nitrogen. This was less apparent in the pond with sludge where nutrient levels were higher and more complex mechanisms controlled biomass concentration. Water column characteristics in the two ponds converged rapidly in 7–10 weeks, however, due to accumulation of fresh sludge.

Download Full-text

Anaerobic treatment of low concentration waste water in an inverse fluidized bed reactor

Water Science & Technology ◽

10.2166/wst.2000.0452 ◽

2000 ◽

Vol 41 (4-5) ◽

pp. 245-251 ◽

Cited By ~ 17

Author(s):

P. Castilla ◽

M. Meraz ◽

O. Monroy ◽

A. Noyola

Keyword(s):

Fluidized Bed ◽

Removal Efficiency ◽

Suspended Solids ◽

Municipal Wastewater ◽

Specific Activity ◽

Biomass Concentration ◽

Fluidized Bed Reactor ◽

Anaerobic Treatment ◽

Low Concentration ◽

Inverse Fluidized Bed

Low concentration synthetic and municipal wastewaters were treated at HRT as short as 3 and 0.6 h respectively in an anaerobic inverse fluidized bed. Both bioreactors showed gas hold up due to the liquid downflow pattern of the prototype. The bioreactor operated at 3 h had a removal efficiency of 83%, specific activity of 4.5 kg CODremoved/kg IVS (d and the gas hold up varied from 23 to 55%. The reactor treating municipal wastewater had a removal efficiency of 44% when operating at 0.6 h, the specific activity was 4.2 kg CODremoved/kg IVS (d and no biogas was detected apparently because an important fraction was dissolved in the liquid phase. The biomass concentration was 13.8 and 1.1 kg IVS/m3 for synthetic and municipal wastewater and the SEM microphotographs showed a bacterial diversity for the first run and only cocci cells for the second run. The system does not remove suspended solids, so a polishing postreatment to improve water quality has to be implemented.

Download Full-text

Clofibric acid and gemfibrozil removal in membrane bioreactors

Water Science & Technology ◽

10.2166/wst.2015.079 ◽

2015 ◽

Vol 71 (8) ◽

pp. 1143-1150

Author(s):

Tania Gutierrez-Macias ◽

Petia Mijaylova Nacheva

Keyword(s):

Suspended Solids ◽

Biomass Concentration ◽

Total Suspended Solids ◽

Blood Lipid ◽

Membrane Bioreactors ◽

Clofibric Acid ◽

Operating Conditions ◽

Organic Load ◽

Hydraulic Residence Time ◽

Lipid Regulators

The removal of two blood lipid regulators, clofibric acid (CLA) and gemfibrozil (GFZ), was evaluated using two identical aerobic membrane bioreactors with 6.5 L effective volume each. Polysulfone ultrafiltration hollow fiber membranes were submerged in the reactors. Different operating conditions were tested varying the organic load (F/M), hydraulic residence time (HRT), biomass concentration measured as total suspended solids in the mixed liquor (MLTSS) and the sludge retention time (SRT). Complete GFZ removal was obtained with F/M of 0.21–0.48 kg COD kgTSS−1 d−1, HRT of 4–10 hours, SRT of 10–32 d and MLTSS of 6–10 g L−1. The GFZ removal can be attributed to biodegradation and there was no accumulation of the compound in the biomass. The CLA removals improved with the SRT and HRT increase and F/M decrease. Average removals of 78–79% were obtained with SRT 16–32 d, F/M of 0.21–0.34 kgCOD kgTSS−1 d−1, HRT of 7–10 hours and MLTSS of 6–10 g L−1. Biodegradation was found to be the main removal pathway.

Download Full-text

Modeling study for oscillatory reaction of chlorite – iodide – ethyl acetoacetate

Canadian Journal of Chemistry ◽

10.1139/cjc-2014-0072 ◽

2014 ◽

Vol 92 (5) ◽

pp. 417-425 ◽

Cited By ~ 1

Author(s):

Laishun Shi ◽

Jian Gao ◽

Jingjing Chen

Keyword(s):

Chlorine Dioxide ◽

Ethyl Acetoacetate ◽

Ph Value ◽

Great Influence ◽

Iodine Concentration ◽

Hydrogen Ion ◽

Initial Concentration ◽

Bifurcation Surface ◽

Concentration Changes ◽

Theoretical Evidence

Chlorine dioxide based chemical oscillating behavior was modeled by a simple scheme consisting of three component reactions. Furthermore, little is known about the influence of the pH value. In this study, four component reactions were used to model the chlorite – iodide – ethyl acetoacetate oscillating reaction by dynamic analysis software. The oscillatory phenomenon is observed for concentration changes of triiodide ion, chlorite ion, and hydrogen ion. The initial concentration of ethyl acetoacetate, chlorite ion, iodide ion, and hydrogen ion has great influence on oscillations. The amplitude and number of oscillations are associated with the initial reactant concentrations. The equation of the reaction rate of triiodide ion, chlorite ion, or hydrogen ion changing with reaction time and initial concentrations in the oscillation stage was obtained. The bifurcation surface between oscillatory and nonoscillatory behavior with different pH values was obtained. The spatial zone for the occurrence of oscillation is reduced with an increase in the pH value. The range of oscillation as concentrations of chlorine dioxide, iodine, and ethyl acetoacetate is well described by an equation. There is a lower limit on ethyl acetoacetate initial concentration for oscillation. However, there is a higher limit on chlorine dioxide and iodine concentration for oscillation. The concentrations of chlorine dioxide and iodine for oscillation decrease with an increase in the pH value. The results provide new theoretical evidence of the importance of pH value, which can affect the bifurcation surface between oscillatory and nonoscillatory behavior.

Download Full-text