scholarly journals WATER FILTRATION RESEARCH. PART II. THE EFFECTS OF BACKWASH WATER TEMPERATURE ON FILTER BED EXPANSION.

1967 ◽  
Author(s):  
C.J. Touhill ◽  
R.L. Schmidt ◽  
B.L. Carlile ◽  
D.E. Olesen
Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3782
Author(s):  
Michał Zielina ◽  
Wojciech Dąbrowski

This paper describes an analysis of the effects of adjusting the intensity of filter backwash to the water temperature. The consequences of the lack of such adjustment for the life of filter beds, the amount of water used for backwashing, the amount of energy used for backwashing and the quality of the first filtrate are presented. In order to determine the losses and profits resulting from controlling the intensity of backwash water depending on its temperature, an analysis was carried out at a water treatment plant in southern Poland. Laboratory measurements were used to determine the granulation and specific gravity of sand grains filling the filtration beds. On the basis of measurements on a semi-technical scale, the magnitudes of filter bed expansion were determined for average monthly wash water temperatures. They were first calculated from the Richardson–Zaki equation, using different formulae for the value of the exponent of the power in this equation. Due to significant differences in the density and shape of grains covered with a permanent deposit after several years of filter operation, a satisfactory match between the formulae known from the literature and the results of expansion measurements was not obtained. Therefore, an new formula for the bed expansion was developed based on the Richardson–Zaki equation. A good fit of this formula to the experimental results was obtained. Monthly average values of water temperature were compiled, and on this basis the required amount of backwash water and energy was computed. The computations were made for 25% of fluidized bed expansion. Possible energy and water savings were estimated, as well as further gains from keeping the required expansion of the porous bed constant regardless of the wash water temperature.


Author(s):  
P. R. Walne

The rate of water filtration by bivalves has long excited interest, but it has in practice proved difficult to measure in conditions where the animal is relatively free from constraint. Its estimation is important from a number of aspects: feeding studies; as an indicator of the animal's reaction to its environment; and for predicting the flow of water required for the culture of economically important species. The work reported in this paper started as part of the general programme on shellfish culture in progress at this laboratory. During the development of a suitable method for studying the water requirements it became clear that one factor, water current, had a more important influence than has been generally recognized.


Waterlines ◽  
1983 ◽  
Vol 2 (2) ◽  
pp. 21-23 ◽  
Author(s):  
Barnes ◽  
Mampitiyarachichi

Author(s):  
Alexander G. Okhapkin ◽  
Tabet Hhedairia

The preliminary estimation of composition and structure of diatoms in the benthos of the Oka River allowed to determine the clear spatiotemporal confinedness of structure in such communities of them which has the most diverse composition in the low water period while water temperature decreasing.


2020 ◽  
Vol 3 (1) ◽  
pp. ACCEPTED
Author(s):  
Rho-Jeong Rae

This study investigated the boreal digging frog, Kaloula borealis, to determine the egg hatching period and whether the hatching period is affected by incubation temperature. The results of this study showed that all the eggs hatched within 48 h after spawning, with 28.1% (±10.8, n=52) hatching within 24 h and 99.9% (±0.23, n=49) within 48 h after spawning. A significant difference was noted in the mean hatching proportion of tadpoles at different water temperatures. The mean hatching rates between 15 and 24 h after spawning was higher at a water temperature of 21.1 (±0.2) °C than at 24.1 (±0.2) °C. These results suggest that incubation temperature affected the early life stages of the boreal digging frog, since they spawn in ponds or puddles that form during the rainy season.


2014 ◽  
Vol 134 (3) ◽  
pp. 411-417
Author(s):  
Teruichi Ogata ◽  
Shinichi Sugawara ◽  
Yoshinobu Maeda ◽  
Hideo Makino

2020 ◽  
Vol 46 (4) ◽  
pp. 382-394
Author(s):  
Holli C. Eskelinen ◽  
Jill L. Richardson ◽  
Juliana K. Wendt

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