Anaerobic Process Schematic of Hydrolysis, Fermentation, and Methanogenesis
Theoretical
Stages
POLYSACCHARIDES
NUCLEIC ACIDS
PROTEIN
Hydrolysis
LIPIDS
Methanogenesis
Fermentation (acidogenesis)
FATTY ACIDS
MONOSACCHARIDES AMINO ACIDS
PURINES & PYRIMIDINES
SIMPLE AROMATICS
Other fermentation products
(e.g., Propionate, Butyrate,
Succinate, Lactate, ethanol, etc.)
Methanogenic substrates H2, CO2,
formate, methanol, methylamines,
acetate
Methane + carbon dioxide
Figure by MIT OCW.
Adapted from: G. Tchobanoglous, F. L. Burton, and H. D. Stensel. Wastewater Engineering: Treatment
and Reuse. 4th ed. Metcalf & Eddy Inc., New York, NY: McGraw-Hill, 2003, 631.
100
80
S=
Percentage
H2S
60
40
20
HS-
0
5
6
7
8
9
10
11
pH
Variation of the proportions of hydrogen sulphide, bisulphide and sulphide with pH in aqueous solutions.
Figure by MIT OCW.
Adapted from: Mara, D. Domestic Wastewater Treatment in Developing Countries. London, UK:
Earthscan, 2003, p. 107.
Diurnal Variation of Dissolved Oxygen in a Facultative Pond
DO Concentration (mg/l)
15
10
5
0
0400
1000
1600
2200
0400
TIME (h)
Top 200 mm of pound
800 mm below surface
Figure by MIT OCW.
Adapted from: Mara, D. Domestic Wastewater Treatment in Developing Countries. London, UK:
Earthscan, 2003, p. 115.
DIURNAL VARIATION IN FACULTATIVE POND EFFLUENT QUALITY
pH
26
5.0
24
22
0
Total and Soluble P (mg/l)
7.0
28
10.0
30.0
10.0
20.0
8.0
Ammonia
Total Phosphorus
6.0
10.0
4.0
2.0
Soluble Phosphorus
BOD5 (mg/l)
0.0
Chlorophyl a (µg/l)
Temperature (oC)
7.5
Temperature
Ammonia (mg/l)
8.0
30
15.0
600
150
100
Suspended
Solids
BODS
50
400
200
0
0
10,000
Faecal Coliforms
8000
6.50
6000
6.00
5.50
4000
Chlorophyll a
2000
5.00
0
4.50
08.00
08.00
14.00
20.00
Time of Day (hr)
02.00
Suspended Solids (mg/l)
8.5
Dissolved Oxygen
Faecal Coliforms (log cells/100ml)
pH
9.0
20.0
Dissolved Oxygen (mg/l)
9.5
Figure by MIT OCW.
Adapted from: Mara, D. Domestic Wastewater Treatment in Developing Countries. London, UK:
Earthscan, 2003, p. 122.
Thirumurthi Chart for the Wehner-Wilhelm Equation
∞
2
4
0.5
PLE
COM
1
IXIN
TE M
0.1
5
G
Dimensionless Product (k1θ) Ktres
7
0.25
0
3
PLU
GF
2
5
LO
W
10
20
40
BOD Remaining (Percentage)
(Note: The numbers adjacent to each curve are the corresponding dispersion numbers.)
Figure by MIT OCW.
Adapted from: Mara, D. Domestic Wastewater Treatment in Developing Countries. London, UK:
Earthscan, 2003, p. 62.