David Stuckey
Imperial College London, Chemical Engineering, Faculty Member
Research Interests:
Research Interests:
Research Interests:
Research Interests: Environmental Engineering, Municipal Solid Waste Management, Municipal Solid Waste, Anaerobic Digestion, Biological Wastewater Treatment, and 7 more Enzymatic hydrolysis, Methane, Anaerobic digestion of organic wastes in relation to energy, Biological Wastewater Treatment, Anaerobic Digestion (Methanogenic and BSR), Activated Sludge Nutrient Removal and Integrated WWTP modelling, Environmental Science and Engineering, ENVIRONMENTAL SCIENCE AND MANAGEMENT, and Biochemical Methane Potential
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In this study, various methods were compared to reduce the Chemical Oxygen Demand (COD) content of stabilised leachate from a Submerged Anaerobic Membrane Bioreactor (SAMBR). It was found that Powdered Activated Carbon (PAC) resulted in... more
In this study, various methods were compared to reduce the Chemical Oxygen Demand (COD) content of stabilised leachate from a Submerged Anaerobic Membrane Bioreactor (SAMBR). It was found that Powdered Activated Carbon (PAC) resulted in greater COD removals (84 %) than Granular Activated Carbon (GAC-80 %), an ultrafiltration membrane of 1kDa (75 %), coagulation-flocculation with FeCl(3) and polyelectrolyte (45 %), FeCl(3) alone (32 %), and polymeric adsorbents such as XAD7HP (46 %) and XAD4 (32 %). Results obtained on the <1 kDa fraction showed that PAC and GAC had a similar adsorption efficiency of about 60 % COD removal, followed by XAD7HP (48 %), XAD4 (27 %) and then FeCl(3) (23 %). The post-treatment sequence UF+GAC would result in a final effluent with less than 100 mg COD/L. Size Exclusion Chromatography (SEC) revealed that the extent of adsorption of low MW compounds onto PAC was limited due to low MW hydrophilic compounds, whereas the kinetics of PAC adsorption depended mainly on the adsorption of high MW aromatics.
Research Interests: Kinetics, Water Purification, Multidisciplinary, Membrane Bioreactor Technology, Ultrafiltration, and 13 moreAdsorption, Charcoal, Flocculation, Bioreactors, Acrylic Resins, Chemical Oxygen Demand, Environmental, Landfill Leachate, Granular Activated Carbon, Iron Compounds, Size Exclusion Chromatography, Biological Oxygen Demand Analysis, and Polystyrenes
Research Interests: Carbon, Life Cycle Assessment, Environmental Impact Assessment, Energy Consumption, Starch, and 13 moreMultidisciplinary, Global Warming, Biofuels, Anaerobic Digestion, Methane, Proteins, Polyvinyl alcohol, Time Factors, Ozone layer depletion, Biological Assay, Environment, Product Packaging, and Environmental benefit
This study seeks to examine the ability of non-ionic/non-polar Colloidial Liquid Aphrons (CLAs) to preserve enzyme functionality upon immobilization and release. CLAs consisting of micron-sized oil droplets surrounded by a thin aqueous... more
This study seeks to examine the ability of non-ionic/non-polar Colloidial Liquid Aphrons (CLAs) to preserve enzyme functionality upon immobilization and release. CLAs consisting of micron-sized oil droplets surrounded by a thin aqueous layer stabilized by a mixture of surfactants, were formulated by direct addition (pre-manufacture addition) using 1% Tween 80/ mineral oil and 1% Tween 20 and the enzymes lipase, aprotinin and α-chymotrypsin. The results of activity assays for both lipase and α-chymotrypsin showed that kinetic activity increased upon immobilization by factors of 7 and 5.5, respectively, while aprotinin retained approximately 85% of its native activity. The conformation of the enzymes released through desorption showed no significant alterations compared to their native state. Changes in pH and temperature showed that optimum conditions did not change after immobilization, while analysis of activation energy for the immobilized enzyme showed an increase in activity at ...
Research Interests:
Research Interests:
Research Interests: Water, Kinetics, Wastewater Treatment, Multidisciplinary, Energy Metabolism, and 19 moreMethane, Fulvic acid, Gel Permeation Chromatography, Enzyme, Biological treatment, Amino Acid Profile, Continuous stirred tank reactor, Chemical Oxygen Demand, Molecular weight, Hydraulic Retention Time, Process Parameters, Granular Activated Carbon, Organic Compound, Biochemical Oxygen Demand, Organic Loading Rate, Anaerobic Baffled Reactor, Product Modelling, Organic Acid, and Nucleic Acid
Acetic acid was used in abiotic experiments to adjust the solution pH and investigate its influence on the chemical hydrolysis of the Organic Fraction of Municipal Solid Waste (OFMSW). Soluble chemical oxygen demand (SCOD) was used to... more
Acetic acid was used in abiotic experiments to adjust the solution pH and investigate its influence on the chemical hydrolysis of the Organic Fraction of Municipal Solid Waste (OFMSW). Soluble chemical oxygen demand (SCOD) was used to measure the hydrolysis under oxidative conditions (positive oxidation-reduction potential values), and pH 4 allowed for 20% (±2%) of the COD added to be solubilized, whereas only 12% (±1%) was solubilized at pH7. Under reducing conditions (negative oxidation-reduction potential values) and pH 4, 32.3% (±3%) of the OFMSW was solubilized which shows that acidogenesis at pH 4 during the anaerobic digestion of solid waste can result in chemical hydrolysis. In comparison, bacterial hydrolysis resulted in 54% (±6%) solubilization.
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This paper focused on the factors affecting the respiration rate of the digestate taken from a continuous anaerobic two-stage process treating the organic fraction of municipal solid waste (OFMSW). The process involved a hydrolytic... more
This paper focused on the factors affecting the respiration rate of the digestate taken from a continuous anaerobic two-stage process treating the organic fraction of municipal solid waste (OFMSW). The process involved a hydrolytic reactor (HR) that produced a leachate fed to a submerged anaerobic membrane bioreactor (SAMBR). It was found that a volatile solids (VS) removal in the range 40-75% and an operating temperature in the HR between 21 and 35 °C resulted in digestates with similar respiration rates, with all digestates requiring 17 days of aeration before satisfying the British Standard Institution stability threshold of 16 mg CO(2) g VS(-1) day(-1). Sanitization of the digestate at 65 °C for 7 days allowed a mature digestate to be obtained. At 4 g VS L(-1) d(-1) and Solid Retention Times (SRT) greater than 70 days, all the digestates emitted CO(2) at a rate lower than 25 mg CO(2) g VS(-1) d(-1) after 3 days of aeration, while at SRT lower than 20 days all the digestates disp...
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Research Interests:
ABSTRACT The mass transfer characteristics of a non-porous silicone rubber membrane contacting an aqueous and an organic phase were determined using a shell and tube mass exchanger. Firstly, the stability of the liquid/membrane interfaces... more
ABSTRACT The mass transfer characteristics of a non-porous silicone rubber membrane contacting an aqueous and an organic phase were determined using a shell and tube mass exchanger. Firstly, the stability of the liquid/membrane interfaces was examined, and when positive aqueous phase transmembrane pressure differentials of up to 2 bar were applied, no bulk transmembrane flow of either liquid was observed. This result was not affected by the addition of surfactants or biomass to the aqueous phase, and therefore it seems that phase breakthrough, common with porous membranes, is avoided. Secondly, the mass transfer characteristics of a range of model solutes were investigated and explained with a resistances in series model. A high membrane/aqueous partition coefficient (Pmemaq) (approximately>25) resulted in the aqueous phase film resistance limiting, whilst a low Pmemaq (approximately<5) resulted in the membrane resistance limiting. In contact with organic solvents the silicone rubber swelled to various degrees, and this was solvent dependent. The degree of swelling, and the relative partitioning of the solute into the swelling solvent, impacted on Pmemaq and the membrane diffusion coefficient. These two parameters could be increased by using a highly swelling solvent (solvent constituting>50% of the swollen membrane volume) with a high organic/aqueous partition coefficient (Porgaq) for the solute. In this way the membrane resistance for some solutes was decreased, and therefore the overall mass transfer coefficient increased. Finally, the effect of the presence of other hydrophobic solutes on the rate of mass transfer was investigated, and in the case of geraniol and citronellol (two chemically similar solutes with low water solubilities, 0.7 and 0.35 g l−1, respectively) the effect was similar to a “salting out” phenomena. This resulted in an increase of Porgaq for both geraniol and citronellol, and therefore a decrease in flux of the solute transferring to the aqueous phase.