Glossary
Lit.
Lit. (liter) = 1,000cc = 1,000mLit. = 1,000cm3
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μm
μm (micrometer) = 1/1,000mm (*'μ' is a unit prefix representing 10-6[-6 power of 10])
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Mesh
Number of meshes in an inch (2.54cm). Tyler mesh of America is generally used.
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pH
pH is a measure of the concentration of dissolved hydrogen ions in a solution. The value is obtained by taking the common logarithm of the reciprocal of the number of gram ions of hydrogen per liter solution. 0~14 is used as a scale. Neutral = pH 7, less than 7 = acidic and greater than 7 = alkaline.
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ppm
ppm is a unit to express the quantity of substances contained in a volume.
It is commonly used as a measure of pollutant rate in air or water. 10,000ppm = 1%1ppm≒1mg/Lit. (based on the assumption of 1Lit.≒1kg)
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Å
1Å(angstrom) = 10-4 [-4 power of 10]μm-4μm
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Concentration
The rate of a substance dissolved in a certain volume of solution. In the field of separation and filtration, it often refers to SS Concentration or water content rate of cake.
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Disposal (Treatment) Volume
The volume of Raw Material disposed of (treated, fed) by a separator/filtrator. It is expressed both as slurry volume and as dried solid volume. Slurry volume is expressed as: m³/Hr, Lit./Hr, m³/B. Dried solid volume means the volume of solid matter after drying. Dried solid volume is expressed as: kgDSS/Hr, kgDS/Hr.
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SS Concentration
The rate of insoluble solids that float in slurry.
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Water Content Rate of Cake
The quantity rate of water contained in cakes after the separation/filtration. The water content rate of cake, after a normal sludge disposal by a decanter, is 83~85% (W.B.).
The water content rate is expressed in two ways :
W.B. (wet base) = W/(W+S), or D.B. (dry base) = W/S [W=water, S =solid]. When referring to filtration, W.B. is often used.
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SS Recovery Rate
Expresses how much of the fed solids is recovered. When normal sludge is treated with flocculant by a decanter, SS Recovery Rate is 95% or higher.
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Flocculant Supply Rate
The rate of flocculant supplied. IHI uses this term to express how much flocculant powder is normally needed for the disposal volume of dried solids. We express it as the Polymer Addition Ratio for Dry Solid. In the case of treating organic sludge, generally, if you add 1.5 Polymer Addition Ratio for Dry Solid of ationic polymer flocculant, you can obtain the optimum flocculation conditions.
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Dissolving Concentration
Expresses how much flocculant of filter aid is dissolved into liquid. The dissolving concentration of cationic polymer flocculant is approximately 0.2%.
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Particle Size Distribution
Distribution of particle sizes. (Particle diameter distribution as for Spherical Particles.)
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BOD
BOD measures the amount of oxygen consumed by aerobic bacteria that dissolve and purify organic matter in water during a specified period of time (5 days at 20℃), expressed by ppm or mg/Lit. The dirtier the water, the more organic matter there is, therefore the amount of oxygen bacteria need to dissolve and purify organic matter increases. The larger the BOD rate, the more organic decomposing matter there is, which means the water is dirty. When the rate reaches 5ppm or higher, it is impossible to purify the water. When the rate is more than 10ppm, a stench is produced.
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COD
COD measures the amount of oxygen needed to oxidize the dirt in the water and render it harmless. The lower the rate, the cleaner the water. Expressed by ppm or mg/Lit.
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Viscosity
Viscosity measures the resistance of a fluid.
Expressed by P(poise), cP(centipoise) [1P = 100cP *The use of CGS unit is admitted] and Pa･s(pascal-second) [1Pa･s = 1,000cP *SI unit : kgf･s/m21kgf･s/m2≒9807cP].
Example : 1cP (water at20℃),
2.5cP (milk at15℃),
5~6cP (soy sauce at17℃),
450cP (tonkatsu sauce)
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Centrifugal efficiency
A measure of the centrifugal force of a rotator. The larger the rate, the greater the force.
Z = rω2/g = r×(2πN/60) 2/g = r×N2/894
Z : Centrifugal efficiency (G), r : rotation radius = radius inside the bowl (m),
N : rotational speed (1/min.), g : gravitational acceleration (9.8m/sec2)
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SI Units
Prefixes that represent integer power of 10.
giga （G） 109
mega （M） 106
kilo （k） 103
hecto （h） 102
deca （da） 101
deci （d） 10-1
centi （c） 10-2
milli （m） 10-3
micro（μ） 10-6
nano （n） 10-9
pico （p） 10-12
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