In situ biomethanation: Inoculum origin influences acetate consumption rate during hydrogen addition

2021 ◽  
Vol 14 ◽  
pp. 100656
Author(s):  
Nathalia Thygesen Vechi ◽  
Laura Mia Agneessens ◽  
Anders Feilberg ◽  
Lars Ditlev Mørck Ottosen ◽  
Michael Vedel Wegener Kofoed
Keyword(s):  
Consumption Rate ◽  
Hydrogen Addition

Ship Drag Reduction by Microalgal Biopolymers: A Feasibility Analysis

2007 ◽  
Vol 51 (04) ◽  
pp. 326-337
Author(s):  
K. Gasljevic ◽  
E. F. Matthys
Keyword(s):  
Drag Reduction ◽  
Consumption Rate ◽  
Synthetic Polymers ◽  
Point Of View ◽  
Technical Issues ◽  
Fuel Costs ◽  
Propulsion Power ◽  
Ship Speed ◽  
In Situ Production

We have investigated the feasibility of using high-molecular-weight polysaccharides produced by marine microalgae to reduce the drag on ships and therefore to be able to reduce the needed propulsion power and fuel costs or, alternatively, to increase the ship speed. Experimental and analytical studies were used to answer four critical questions:How suitable are the biopolymers for drag reduction on ships?What is the needed polymer consumption rate at a given level of drag reduction?What is the achievable polymer production rate that can be achieved by the microalgae?What are possible modes of implementation of the proposed technology? It is seen that in situ production of biopolymers by microalgae growing on the hull may be a possible approach to polymeric ship drag reduction. Production of biopolysaccharide off the ship and even harvesting it from the ocean are other possibilities. The use of biopolymers is naturally advantageous from an environmental point of view as well. Some comparison of biopolymers and synthetic polymers is also presented. Several technical issues remain to be investigated, but the information available suggests that biopolymers may be the best additives for drag reduction on ships.

Kinetic and metabolic aspects of Defluviicoccus vanus-related organisms as competitors in EBPR systems

2008 ◽  
Vol 58 (8) ◽  
pp. 1693-1697 ◽  
Author(s):  
A. B. Lanham ◽  
M. A. M Reis ◽  
P. C. Lemos
Keyword(s):  
In Situ Hybridization ◽  
Volatile Fatty Acid ◽  
Consumption Rate ◽  
Carbon Sources ◽  
Aerobic Conditions ◽  
Initial Batch ◽  
Batch Tests ◽  
Consumption Rates ◽  
Pha Production

A reactor was successfully enriched (90% as shown by Fluorescence in situ Hybridization) in Defluviicoccus vanus-related organisms presenting a Glycogen Accumulating Organisms (GAO) phenotype. Initial batch tests were performed using anaerobic/aerobic conditions to assess the capacity of different carbon sources utilization frequently abundant in wastewater: acetate, propionate, butyrate, valerate and glucose. Acetate and propionate were totally consumed in the anaerobic phase as well as butyrate and valerate, though these last ones with a very low consumption rate. All substrates were converted to polyhydroxyalkanoates (PHA). Glucose had a very slight anaerobic consumption but failed to disclose a typical GAO phenotype. In aerobic conditions, again all carbon sources were readily consumed except for glucose, with acetate and propionate having the higher consumption rates. Therefore, glucose seems not be used by this type of organisms. Acetate and propionate consumption rates indicated that these GAOs could reveal good competition advantages in EBPR systems where these carbon sources are available, especially propionate. Volatile Fatty Acid (VFA) uptake in aerobic phase and consequential PHA production indicate these organisms as possible candidates for PHA production.

scholarly journals Sulfide may directly modify cytoplasmic hemoglobin deoxygenation in Solemya reidi gills

1996 ◽  
Vol 199 (6) ◽  
pp. 1343-1352 ◽  
Author(s):  
D Kraus ◽  
J Doeller ◽  
C Powell
Keyword(s):  
Oxygen Consumption ◽  
Hydrogen Sulfide ◽  
Intracellular Ph ◽  
Oxygen Consumption Rate ◽  
Optical Spectrum ◽  
Consumption Rate ◽  
Dissociation Rate ◽  
High Concentration ◽  
Dissociation Rate Constants

The clam Solemya reidi, which survives in sulfide-rich sediments, houses intracellular sulfide-oxidizing bacteria as symbionts in its gills. The gill bacteriocytes also contain a high concentration of cytoplasmic hemoglobin. Although the in situ hemoglobin optical spectrum was not altered in the presence of hydrogen sulfide, hemoglobin deoxygenation was significantly slowed and incomplete when sulfide was present. A sulfide-mediated decrease in oxygen consumption rate, a shift in intracellular pH or the conversion of hemoglobin to an unusual derivative could all slow in situ hemoglobin deoxygenation. However, under low sulfide levels at which deoxygenation is incomplete, oxygen consumption rate was not inhibited, intracellular pH decreased by less than 0.1 units and the only hemoglobin derivatives present were deoxyhemoglobin and oxyhemoglobin. These results and preliminary measurements of the isolated gill hemoglobin dissociation rate constants suggest that sulfide or a rapidly formed oxidation product may directly influence the rate of Solemya reidi gill hemoglobin deoxygenation.

scholarly journals Differences of methanogenesis between mesophilic and thermophilic in situ biogas-upgrading systems by hydrogen addition

2019 ◽  
Vol 46 (11) ◽  
pp. 1569-1581 ◽  
Author(s):  
Xianpu Zhu ◽  
Liumeng Chen ◽  
Yichao Chen ◽  
Qin Cao ◽  
Xiaofeng Liu ◽  
...  
Keyword(s):  
Biogas Upgrading ◽  
Hydrogen Addition

Improvement of Gas Turbine Combustion Reactivity Under Flue Gas Recirculation Condition With In-Situ Hydrogen Addition

2009 ◽  
Author(s):  
Dieter Winkler ◽  
Pascal Mu¨ller ◽  
Simon Reimer ◽  
Timothy Griffin ◽  
Andre´ Burdet ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Co2 Capture ◽  
Flue Gas ◽  
Co2 Concentration ◽  
Oxygen Depletion ◽  
Hydrogen Addition ◽  
Flue Gas Recirculation ◽  
Combustion Reactivity ◽  
Gas Recirculation

Carbon Capture and Storage (CCS) solutions are currently being assessed in order to address appropriately the climate change challenge. Post-combustion CO2 capture is one of the technologies proposed for both coal-fired and gas-fired power plants. In Natural Gas Combined Cycle (NGCC), the flue gas is treated after the Heat Recovery Steam Generator (HRSG) in a so-called post-combustion CO2 capture module through use of solvents. The size of systems envisaged for the capture of CO2 scales with volumetric flow to be treated together with the CO2 concentration contained in the flue gas. Flue Gas Recirculation (FGR) is proposed as a means to increase CO2 concentration in the flue gas together with a net reduction of volumetric flow to be treated by the CO2 capture module. One of the limiting factors of this technology is the vitiation of air within gas turbine combustor and the associated reduction in oxygen concentration. This paper analyses the influence of air vitiation upon combustion in a generic premix lean industrial burner. Tests are carried out under representative inlet pressure and temperature levels. Variation of inlet oxidizer composition is simulated with the addition of nitrogen and carbon dioxide to the inlet air. It is observed that CO emission increases with oxygen depletion at a fixed residence time, signaling a reduction of combustion reactivity. In addition, NOx emission is shown to be sensitive to oxygen depletion. In order to mitigate reduction of combustion reactivity, hydrogen is added to the fuel, up to 20% in volume. As another alternative, a Catalytic Partial Oxidation (CPO) reactor is used in-situ in order to reform the fuel to different syngas blends. These syngas is then used as fuel, which enables the enhancement of the combustion reactivity counter-acting the impact of FGR conditions. The hydrogen addition appears to help improving the reactivity of the flame, making this concept relevant for operation under vitiated air condition.

An in situ biofouling monitor for membrane systems

2003 ◽  
Vol 3 (5-6) ◽  
pp. 205-210 ◽  
Author(s):  
J.W.N.M. Kappelhof ◽  
H.S. Vrouwenvelder ◽  
M. Schaap ◽  
J.C. Kruithof ◽  
D. van der Kooij ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Early Stage ◽  
Membrane Systems ◽  
Active Biomass ◽  
Ongoing Research ◽  
Rate Of Oxygen Consumption ◽  
Non Destructive

Biofouling is a frequently occurring fouling mechanism in membrane applications. Controlling this phenomenon is a challenge due to the difficulty of cleaning biofouling in spiral wound membrane elements. It is assumed that cleaning can be more efficient when biofouling is in an early stage of colonisation. Therefore a sensitive method has to be available for an early identification of biofouling. The present method, the measurement of the normalised pressure drop (NPD) is not specific for biofouling and is not very sensitive. In this research the feasibility of the specific oxygen consumption rate for detection of the activity of biofilms was investigated in membrane systems. The method has the advantages to be specific for active biomass, applicable in situ, non-destructive and more sensitive than NPD. Three experiments demonstrated that the measurement of the rate of oxygen consumption is potentially a simple, reliable method for the measurement of the active biomass in membrane systems. During one of the experiments the method illustrated the effect of cleaning and the regrowth of bacteria afterwards. The method will be further evaluated and standardized. The relation between the specific oxygen consumption rate and the condition of the biofilm, measured by autopsy of membrane elements, will be further explored. The ongoing research will result in an apparatus and procedure, to be used for biofouling identification during the operation of full-scale and pilot plants.

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