2. Composition of Domestic Wastewater
Parameter
mg/L
Total Solids
800
Total Volatile Solids
440
Suspended Solids
240
Volatile Suspended Solids
180
Biochemical O2 Demand (BOD5)
200
Inorganic N 22
Total N 35
Total Phosphorus 7

3. GRAYWATER:
Graywater includes all household wastewater that doesn't come from toilets. baths/showers, clothes washing, dishwashers and, optionally, kitchen sinks. Toilet wastewater, and often garbage disposal waste, is called blackwater. Graywater comprises about 60% of typical household wastewater flow.

4. Toilet 6.9-24 13-37 4.1-17 0.6-1.6 Garbage Disposal 11-31 16-44
Source
BOD5
TSS
Total N
Total P.
Toilet
6.9-24
13-37
4.1-17
Garbage Disposal
11-31
16-44
0.1
Graywater
25-39
11-23

6. C6H12O6 + 6 O2 6CO2 + 6 H2O Oxygen Demand of simple organic compound
This is equivalent to 1.06 grams O2 per gram of glucose. The concentration of glucose can then be represented as an “oxygen demand equivalent” referred to as Chemical Oxygen Demand (COD)

7. Biochemical Oxygen Demand (BOD) exerted by during bacterial oxidation
(25 %) C C
(75 %)
BOD is difficult to calculate so an experimental
procedure is used to measure it.

9. Time (days)
Oxygen
consumed 5 20
BODL
BOD5
BOD5 = 2/3 BODL

10. Microbial Nitrification
If nitrogen is present, as organic nitrogen or as ammonia
Microbial oxidation will occur as shown below.
Microbial Nitrification

11. Although some nitrogen is used for cell production the
amount is small and can be ignored. Since nitrogen can
be measured easily we can use the nitrification equation to predict nitrogen oxygen demand. This information is given by:
4.57 mg O2 per mg N

12. Besides BOD5 there are two other parameters generally used to chararacterize wastewater.
Solids
Bacterial Count – Coliforms

13. 1. volatile (organic) (measured by wt. loss @ 550oC)
Solids:
A. Total dissolved solids (TDS) (mg/L)
1. volatile (organic) (measured by wt. 550oC)
2. fixed (inorganic)
B . Suspended solids (TSS)
1. volatile (organic) (VSS)
C . Total solids

14. (Dissolved and suspended solids are “operationally” differentiated by passing the sample through a filter; typically mm.). This process is shown on the next slide.

16. How can we tell if water is contaminated by human activity?
One way to test this is the coliform test. Coliform bacteria are present in very large quantities in human intestines (and in other warm blooded mammals). Therefore they appear in human waste products.

17. The presence of coliform bacteria indicates the presence of human waste. They are indicator organisms.
Drinking water and wastewater treatment standards use coliform counts as a water quality parameter. For drinking water, in particular, coliform presence indicates the possible presence of water borne diseases such as typhoid, cholera, dysentery, hepatitis, poliomyelitis.

18. Coliform concentration is measured by:
MPN multiple tube fermentation
Membrane filter technique

19. It should be noted that coliforms are non-pathogenic (generally) but occur in great numbers.
Ex. 1/3 to 1/5 of weight of fecal matter = coliform bacteria. There is roughly
a 5 x 106 to 5 x 108 /1 ratio between coliforms
and pathogens such as those which cause typhoid (Salmonella typhosa).

20. ANALYSIS FOR COLIFORM BACTERIA
A test based on the ability of coliform bacteria to ferment lactose and produce gas.
ANALYSIS FOR COLIFORM BACTERIA
Two main ways:
I. Multiple tube Fermentation:
Goal = dilution to extinction; want a statistical likelihood that a 1 ml sample will not contain bacteria
Inverted tube
collects gas.
1 mL
1 mL
Typical dilutions
water: up to 10-4
waste water: up to 10-6
1 mL
dilute
1 ml
H2O
sample 10 10 10 10
1/ / / /10,000
1 mL
1 mL
inoculate
etc
etc
lactose broth
lactose broth
incubate
@ 35 oC
Gas found
in 24 hr. in any tube
Gas found
in any tube
in 48 hr.
No Gas found
in any tube
in 48 hr.
Doubtful
Presumptive Test
Presumptive Test
Positive
Presumptive Test
Negative
Presumptive Test

21. At this stage, the test for fecal coliform can be done
by inoculating a 2nd series
of tubes (containing EC
medium) and
44.5 oC for 48 hr.
Gas found in 24 hr. in any tube
Gas found in
48 hr. in any
tube
Note: overall, it takes 6 days to complete the test
48 hr.
48hr.
Doubtful
Presumptive Test
Presumptive Test
Positive
Presumptive Test
Transfer from all tubes showing gas
Production
Gas found in 48 hr. in any tube
No gas found in
48 hr. in any
tube
incubate
@ 35 oC
Confirmed Test
brilliant green
lactose bile broth
Positive
Confirmed Test
Negative Confirmed
Test
Completed
Test
Transfer from all tubes
Gram stain = Gram-negative
short straight rods
Gram-negative bacteria have thin cell walls and a higher lipid content.
showing gas production
No typical
coliform
colonies
Streak on
Endo agar
Streak on
Endo agar
Typical coliform
colonies
incubate
48 hr.
Negative Completed Test Positive Completed Test

22. Multiple tube Fermentation (cont.)
Results: From the original serial dilutions and the number
of positive tubes one can calculate using a
statistical procedure the most probable number
(MPN) of bacteria present in the original sample
Ex # Positive MPN per 100 ml of sample:

23. II. Membrane Filter Technique
This is now the preferred method for analysis. It’s faster and
can be used to analyze larger sample volumes but still has some
problems.
Procedure Summary:
1. Filter known volume of sample or sample
dilution through a membrane filter (0.45 µ)
2. Incubate filter for 24 hours on top of a pad with
appropriate medium at selected temperature.
Test Medium Temperature
Total Coliform M-Endo broth 35°C
Fecal Coliform M-FC broth 44.5°C
3. Identify coliform colonies by characteristic color and/or
metallic sheen & count them.
Coliform colonies are pink to red in color with a metallic sheen.

24. Testing for Coliform Bacteria: Membrane Filtration
Membrane filter
0.45 μm pores
47 mm in diameter
Filter 100 mL of water to be tested through the membrane filter

25. Membrane Filtration Add 2 mL of m-endo broth (selective media)
Place membrane filter in the petri dish on top of the nutrient pad
Petri dish with sterile absorbent nutrient pad

26. Membrane Filtration: Incubation and Results
Incubate for 24 hours at 35°C
Coliform bacteria grow into colonies with a metallic sheen
Non-coliform bacteria may grow into but will have a different sheen and/or color 1 2 3 4 5 6 7 8