Environmental Engineering FOURTH EDITION

84 ENVIRONMENTAL ENGINEERING Microammeter PI Electrolyte solution 0 ring Membrane A LL Lead anod>l Silver cathode Figure 5-1. ...

Measurement of Water Quality 85 amount of oxygen required by bacteria and other microorganisms engaged in stabilizing decomposab ...

86 ENVIRONMENTALENGINEERING I I I I I I I I 0 1 2 3 4 5 Time (days) Figure 5-3. Typical oxygen uptake curves in a BOD test. Samp ...

Measurement of Water Quality 87 because only two-thirds of the bottle is seed water, and only the seed water has a BOD of 6 ma. ...

88 ENVIRONMENTALENGINEERING BOD concentration might be low. Engineers often talk of “pounds of BOD,” a value calculated by multi ...

Measurement of Water Quality 89 EXAMPLE 5.2. The BOD versus time data for the first 5 days of a BOD test are obtained as follows ...

90 ENVlRONMEN'IAL ENGINEERING BOD 0 5 10 15 20 Day Figure 5-5. Long-term BOD. Note that BODdt here includes both ultimate carbon ...

Measurement of Water Quality 91 CHEMICAL OXYGEN DEMAND One problem with the BOD test is that it takes 5 days to run. If the orga ...

92 ENVIRONMENTALENGINEERING TURBIDITY Water that is not clear but is “dirty,” in the sense that light transmission is inhibited, ...

Measurement of Water Quality 93 hydrogen and hydroxyl (OH-) ions: H20 H+ + OH-. (5.16) An excess of hydrogen ions makes a soluti ...

94 ENVIRONMENTAL ENGINEERING ALKALINITY Alkalinity measures the buffering capacity of the water against changes in pH. Water tha ...

Measurement of Water Quality 95 "."" 7.50 - 7.00 4 6.50 - 6.00 - 5.50 - 5.00 - 4.50 - HI=--=- 4.00 I I I I I I I I Added hydroge ...

96 ENVIRONMENTAL ENGINEERING Filter I I Holes 6 Figure 5-7. The Gooch crucible, with filter, for determining suspended solids, a ...

Measurement of Water Quality 97 NITROGEN AND PHOSPHORUS Recall from Chap. 4 that nitrogen and phosphorus are important nutrients ...

98 ENVIRONMENTAL ENGINEERING Light Filter Sample Photocell Ammeter source Figure 5-8. Elements of a filter photometer. where Po ...

Measurement of Water Quality 99 0.5 0.0 I I I I I I 0 50 100 150 200 250 300 350 Ammonia concentration (pg/L) Figure 5-9. Calcul ...

100 ENVIRONMENTAL, ENGINEERING Table 5-2. Examples of Common Waterborne Pathogens Microorganism Effects on humans Bacteria Campy ...

Measurement of Water Quality 101 pathogens. However, if a large number of fecal coliforms are present, there is a good chance of ...

102 ENVIRONMENTAL ENGINEERING A B D Figure 5-10, Millipore filter apparatus for coliform measurement. The procedure is illustrat ...

Measurement of Water Quality 103 Large test tube Lactose broth Gas from fermentation Small test tube Figure 5-11. Test tubes use ...