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WRRCTR No.16 Effects of Soluble Organics on Flow through Thin Cracks of Basaltic Lava
|Title:||WRRCTR No.16 Effects of Soluble Organics on Flow through Thin Cracks of Basaltic Lava|
Burbank, Nathan C Jr.
Lau, L. Stephen
|LC Subject Headings:||Basalt -- Hawaii -- Oahu.|
Groundwater -- Pollution -- Hawaii -- Oahu.
Hydrogeology -- Hawaii -- Oahu.
Rocks -- Permeability -- Hawaii -- Oahu.
|Date Issued:||Aug 1967|
|Publisher:||Water Resources Research Center, University of Hawaii at Manoa|
|Citation:||Ishizaki K, Burbank NC, Lau LS. 1967. Effects of soluble organics on flow through thin cracks of basaltic lava. Honolulu (HI): Water Resources Research Center, University of Hawaii at Manoa. WRRC technical report, 16.|
|Series:||WRRC Technical Report|
|Abstract:||The source of most of Oahu's domestic water supply is from ground water occurring in the permeable materials of volcanic rock. Movement of the ground water is intrinsically through thin cracks in basaltic
lavas. This project studied passage of an organic-rich liquid through cracks in basalt.
Permeability of "blue rock" portions of aa basalt was determined as 2.6 x 10^-4 gallons/day/ft^2 of water, classing the rock as impervious. A range of 7.7 to 10.4 per cent in porosity values was obtained from
the "blue rock" portion; the clinker portion yielded a value of 50 per cent. Difficulties in experimental verification of the Hagen-Poiseuille derivation of radial flow through thin cracks were encountered in measuring
flow at low gradients and aligning crack surfaces absolutely parallel. These discrepancies caused some variation in the determination. The flow rate is proportional to the 0.9 power of the head. Flow rates are less than theorized by Hagen-Poiseuille's derivation with the flow rate of clarified sewage being less than tap water under
identical conditions. The greatest retardation in flow of non-biodegradable liquids through thin cracks occurred in the initial hours followed by a systematic
reduction of flow to a terminal and nearly constant flow of 7/8 to 1/100 of the initial flow rate. Flow rates through aa basalt
decrease faster than through a similated thin crack made of lucite plastic.
Flow of organic-rich liquids through such cracks, similar to non-biodegradable liquids, exhibits a decrease in flow initially and continues this trend for as long as 220 hours. The terminal flow velocity
of tap water is much greater than that of sewage which appears to proceed to a no-flow condition. The clogging phenomenon was dependent upon microbial activity and food supply in sewage. Retardation of flow of organic-rich liquid is attributed to presence of microbial cells and their biochemically synthesized products in the cracks. The products are primarily polysaccharides and slimes along with ferrous
sulfide, a common material found in septic sewage in contact with soil or rock.
|Pages/Duration:||vii + 56 pages|
|Appears in Collections:||
WRRC Technical Reports|
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