|
Organic Matter in Water, Nonspecific Tests |
|
|
Test |
Description |
|
BOD |
Biochemical oxygen demand. Measures the ability of common bacteria to digest organic matter, usually in a 5-day incubation at 2O0C, by analyzing depletion of oxygen. This measures biodegradable organic matter. Expressed as O2. |
|
CCE |
Carbon-chloroform extract. Organics adsorbed on an activated carbon |
|
|
cartridge are extracted from the carbon by chloroform. The extract |
|
|
is weighed or further analyzed. |
|
CAE |
Carbon-alcohol extract. Organics adsorbed on an activated carbon |
|
|
cartridge are extracted from the carbon by ethyl alcohol. (This is |
|
|
performed after the chloroform extraction of the same column.) |
|
COD |
Chemical oxygen demand. Measures the ability of hot chromic acid |
|
|
solution to oxidize organic matter. This analyzes both |
|
|
biodegradable and nonbiodegradable (refractory) organic matter. |
|
|
Expressed as O2. |
|
Color |
Color. This is a rough measure of tannin, lignin, and other humic |
|
|
matter in surface waters and certain wastes, such as kraft pulping |
|
|
wastes. Reported in APHA units, related to platinum standard. |
|
IDOD |
Immediate dissolved oxygen demand. Measures the presence of strong reducing matter in wastes which would have an immediate |
|
|
effect in reducing the oxygen level of receiving streams. Determined by measuring reduction in oxygen 1 5 min after dilution of sample with an O2-saturated water. Expressed as O2 |
|
LOI |
Loss on ignition. In this determination, the water sample is first |
|
|
evaporated to dryness, then weighed. The solids are then heated to |
|
|
a dull red heat and reweighed. The difference in the two weights is |
|
|
loss on ignition. The firing step burns off organic matter, but it also |
|
|
affects mineral composition, as in the breakdown of carbonates to |
|
|
oxides, so the loss is not all organic. |
|
O2 consumed |
Oxygen consumed from permanganate. Measures the susceptibility of |
|
|
organic matter in sample to oxidation by KMnO4. Not as strongly |
|
|
oxidizing as chromic acid. Preceded the COD test and still a useful |
|
|
control test. Reported as O2. |
|
Solvent |
Extractables. Measures the organic matter directly extractable from |
|
extractables |
water, usually using hexane, although CCl4 and CHCl3 are also |
|
|
used. |
|
TOC |
Total organic carbon. Measures the CO2 produced from organics when a water sample is atomized into a combustion chamber. |
|
|
The CO2 equivalent to the alkalinity may be removed first, or this equivalent may be subtracted from the total CO2 to determine organic carbon reported as C |