The Influence of Dissolved Oxygen Concentration on the Toxicity of Potassium Cyanide to Rainbow Trout

1954 ◽  
Vol 31 (2) ◽  
pp. 161-164
Author(s):  
KATHLEEN M. DOWNING
Keyword(s):  
Rainbow Trout ◽  
Dissolved Oxygen ◽  
Survival Time ◽  
Oxygen Concentration ◽  
Potassium Cyanide ◽  
Dissolved Oxygen Concentration ◽  
Survival Times ◽  
Rate Of Increase ◽  
Log Normal

1. Survival times of rainbow trout in concentrations of potassium cyanide in the range 0.105-0.155 p.p.m. cyanide increased with increase in dissolved oxygen concentration between 10 and 100 % of air saturation value, the effect being most marked with the lowest concentration of cyanide. 2. The rate of increase of survival time with increasing concentration of oxygen did not appear to fall off as air saturation value was approached. 3. The distributions of survival times which had median values of 3.3 min. or less were approximately normal, and those with median values of 13.0 min. or more were approximately log-normal.

scholarly journals The Toxicity of Potassium Cyanide to Trout

1952 ◽  
Vol 29 (4) ◽  
pp. 632-649
Author(s):  
D. W. M. HERBERT ◽  
J. C. MERKENS
Keyword(s):  
Rainbow Trout ◽  
Survival Time ◽  
Potassium Cyanide ◽  
Survival Times ◽  
Constant Concentration ◽  
Equilibrium Control ◽  
Test Fish ◽  
The Times ◽  
Cyanide Solutions ◽  
Turn Over

1. An apparatus is described in which fifty yearling rainbow trout can be tested in a stream of water at a constant temperature and containing a constant concentration of poison. 2. Exposure to cyanide causes the fish to lose equilibrium control and to turn over. Resistance is measured as survival time, by which is meant the time taken to overturn the fish. 3. When the experimental temperature is higher than that of the water in the stock aquaria the resistance of yearling rainbow trout to cyanide increases with increasing time of acclimatization to the temperature of the experiment. 4. Small yearling rainbow trout tend to be more resistant to cyanide than larger fish of the same age. 5. The distribution of the logarithms of the survival times of the test fish in cyanide solutions, though not precisely normal, is sufficiently close to a normal distribution to justify the application of standard statistical techniques. Neither the distribution of the survival times nor that of the reciprocals of the times provide a suitable basis. 6. At 17.5°C. in the range 2.5 parts to 0.07 part CN per million it has been found that (i) mean log survival time decreases linearly with log concentration, (ii) the variance of log survival time is approximately constant, and (iii) the distribution of log survival time is approximately normal. At higher concentrations these conclusions are not true. 7. The resistance of an individual rainbow trout to cyanide is mainly determined by inherent properties which persist for at least three weeks.

Effect of Dissolved Oxygen Concentrations on the Toxicity of Several Poisons to Rainbow Trout (Salmo Gairdnerii Richardson)

1961 ◽  
Vol 38 (2) ◽  
pp. 447-455
Author(s):  
R. LLOYD
Keyword(s):  
Rainbow Trout ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Ph Value ◽  
Dissolved Oxygen Concentration ◽  
Low Oxygen ◽  
Copper Salts ◽  
Respiratory Flow ◽  
The Difference ◽  
Oxygen Concentrations

1. A given reduction in the dissolved oxygen concentration of the water from the air-saturation value to a lower level increases the toxicity to rainbow trout of zinc, lead and copper salts, and of a mixture of monohydric phenols, to about the same extent. 2. The effect of a reduced oxygen concentration on the toxicity of ammonia solutions is greater than that found for the other four poisons; the extra increase can be accounted for by a theoretical calculation of the difference between the pH value of the bulk of the solution and that at the gill surface. 3. An hypothesis is presented to account for the effect of low oxygen concentrations on the toxicity of poisons to fish. It assumes that a given toxic effect is produced by a specified concentration of poison at the gill surface, and suggests that this concentration is governed not only by the concentration of poison in the bulk of the solution but also by the velocity of respiratory flow.

Effect of Physicochemical Variables on Algal Autoflotation

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1769-1778 ◽  
Author(s):  
S.-I. Lee ◽  
B. Koopman ◽  
E. P. Lincoln
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Retention Time ◽  
Contact Time ◽  
Pilot Scale ◽  
Dissolved Oxygen Concentration ◽  
Physicochemical Variables ◽  
Rise Rate ◽  
Mixing Intensity ◽  
Maximum Rise

Combined chemical flocculation and autoflotation were examined using pilot scale process with chitosan and alum as flocculants. Positive correlation was observed between dissolved oxygen concentration and rise rate. Rise rate depended entirely on the autoflotation parameters: mixing intensity, retention time, and flocculant contact time. Also, rise rate was influenced by the type of flocculant used. The maximum rise rate with alum was observed to be 70 m/h, whereas that with chitosan was approximately 420 m/h. The efficiency of the flocculation-autoflotation process was superior to that of the flocculation-sedimentation process.

scholarly journals Gas–liquid mass transfer characteristics of aviation fuel scrubbing in an aircraft fuel tank

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Chaoyue ◽  
Feng Shiyu ◽  
Xu Lei ◽  
Peng Xiaotian ◽  
Yan Yan
Keyword(s):  
Mass Transfer ◽  
Dissolved Oxygen ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Oxygen Concentration ◽  
Gas Holdup ◽  
Aviation Fuel ◽  
Volumetric Mass Transfer Coefficient ◽  
Dissolved Oxygen Concentration ◽  
Liquid Mass Transfer

AbstractDissolved oxygen evolving from aviation fuel leads to an increase in the oxygen concentration in an inert aircraft fuel tank ullage that may increase the flammability of the tank. Aviation fuel scrubbing with nitrogen-enriched air (NEA) can largely reduce the amount of dissolved oxygen and counteract the adverse effect of oxygen evolution. The gas–liquid mass transfer characteristics of aviation fuel scrubbing are investigated using the computational fluid dynamics method, which is verified experimentally. The effects of the NEA bubble diameter, NEA superficial velocity and fuel load on oxygen transfer between NEA and aviation fuel are discussed. Findings from this work indicate that the descent rate of the average dissolved oxygen concentration, gas holdup distribution and volumetric mass transfer coefficient increase with increasing NEA superficial velocity but decrease with increasing bubble diameter and fuel load. When the bubble diameter varies from 1 to 4 mm, the maximum change of descent rate of dissolved oxygen concentration is 18.46%, the gas holdup is 8.73%, the oxygen volumetric mass transfer coefficient is 81.45%. When the NEA superficial velocities varies from 0.04 to 0.10 m/s, the maximum change of descent rate of dissolved oxygen concentration is 146.77%, the gas holdup is 77.14%, the oxygen volumetric mass transfer coefficient is 175.38%. When the fuel load varies from 35 to 80%, the maximum change of descent rate of dissolved oxygen concentration is 21.15%, the gas holdup is 49.54%, the oxygen volumetric mass transfer coefficient is 44.57%. These results provide a better understanding of the gas and liquid mass transfer characteristics of aviation fuel scrubbing in aircraft fuel tanks and can promote the optimal design of fuel scrubbing inerting systems.

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