figure by mit ocw. · figure by mit ocw. adapted from: g. tchobanoglous, f. l. burton, and h. d....
TRANSCRIPT
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, p. 617.
Organic Nitrogen(proteins; urea)
Ammonia Nitrogen Nitrate (NO2) Nitrate (NO3)
Organic Nitrogen(bacterial cells)
Organic Nitrogen(net growth)
Nitrogen Gas (N2)
Denitrification
O2 O2
Nitrification
Lysis and AutooxidationAssimilation
- -
Bacterial Decompositionany hydrolysis
Organic Carbon
Cell wall
Short-chain
fatty acids
Facultative bacteria
Substrate
Fermentation Products
Phosphorus removing bacteria
Soluble COD
PHB
Carbon
storage
Carbon
storage
CO2 + H2O
Energ
y P
P
New cell production
O2
PHB
ANAEROBIC AEROBIC
Removal mechanisms for excess biological phosphorus (COD = chemical oxygen demand, PHB = poly-β-hydroxybuty-
rate).
+
Energy
Figure by MIT OCW.
Adapted from: Rittman, Bruce E., and Perry L. McCarty. Environmental Biotechnology: Principals
and Applications. New York, NY: McGraw-Hill, 2001.
Figure by MIT OCW.
Adapted from: Rittman, Bruce E., and Perry L. McCarty. Environmental Biotechnology: Principals
and Applications. New York, NY: McGraw-Hill, 2001.
15
10
10
20
30
40
50
5
1
0 05 10 15 20
Ortho Phosphorus
ADP + PO4
Bacteria absorb BOD byreleasing phosphorusATP ADP + PO4 + energy
Soluble BOD
Solu
ble
BO
D, m
g/L
Influent ortho phosphorusconcentration
Bacteria store phosphorusduring growth to competefor BOD when they getback to anaerobic zone
ATPenergy
First Anoxic Aerobic SecondAnoxic
Reaeration
Stored phosphorus in bacteria is removed in waste sludge
Anaerobic
Typical profile of soluble phosphorus concentrations in a biological nutrient removal process (ATP = adenosine triphosphate, ADP = adenosine diphosphate).
Nom
inal
ort
ho p
hosp
horu
s co
ncen
trat
ion,
mg/
L a
s P
Nominal Hydraulic Retention Time, Hours (Based on Influent Flow only)
Anaerobic Aerobic
OrthophosphorusSoluble BOD
TIME
CO
NC
EN
TR
AT
ION
Fate of soluble BOD and phosphorus in nutrient removal reactor.
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, p. 626.
Chemical
Inorganic Chemicals Used Most Commonly for Coagulation and Precipitation Processes in Wastewater Treatment
Formula Molecular Weight
Equivalent Weight Form Percent
Alum
594.4 114
Liquid
Lump
Liquid
Lump
8.5 (Al2O3)
17 (Al2O3)
8.5 (Al2O3)
17 (Al2O3)
63-73 as CaO
85-99
15-20
20 (Fe)
20 (Fe)
Al2(SO4)3.18H2O#
Aluminum Chloride
Calcium Hydroxide(lime)
Ferric Chloride
133.3
56.1 as CaO
162.2
44
40
91
Liquid
Lump
Powder
Slurry
Liquid
Lump
AlCl3
Ca(OH)2
FeCl3
18.5 (Fe)Ferric Sulfate 400 51.5 GranularFe2(SO4)3
20 (Fe)Ferrous Sulfate(copperas)
278.1 139 GranularFeSO4.7H2O
46 (Al2O3)Sodium Aluminate
# Number of bound water molecules will typically vary from 14 to 18
163.9
666.5
100 FlakeNa2Al2O4
Al2(SO4)3.14H2O#
AVAILABILITY
Figure by MIT OCW.
Adapted from : Metcalf, and Eddy. 2003
00
% C
OD
Rem
oval
20Ferric Chloride Sulfate Concentration (mg/l)
(no polymer)
North Budapest Wastewater Treatment PlantComparison of Influent vs. Pre-aeration Raw Water
Topolcany Wastewater Treatment PlantBOD and COD % Removal vs. Ferric Chloride Concentration
40 60 80 100
20
40
COD Influent Conc. = 515 mg/lCOD Pre-aeration Conc. = 594 mg/l
60
80
100
00
% R
emov
al
20Ferric Chloride Concentration (mg/l)
(no polymer)
40 30 40 50 60
20
10
30
40
50
60
70
Jar Test - Influent
Jar Test - Pre-aeration
Primary Effluent: Cin = 515 mg/l
Primary Effluent: Cin = 594 mg/l
BOD % Removal
COD % Removal
Figure by MIT OCW.
Adapted from: Murcott, and Hurleman. 1994, p. 24
Low dose
Fe/Al
Cationic
Polymer
Anionic
Polyme
r
High dose
Fe/Al
Possibly
Anionic
Polymer
a. Existing primary treatment plant
b. CEPT (left) and primary precipitation (right)
Fe/Al
c. Preprecipitation (or CEPT) followed by ASP
Fe/Al
Carbon
source
DD
d. Preprecipitation with ASP and postdenitrification
Multi-stage upgrading of an existing
primary treatment plant
Grit
chamber
Grit
chamber
Grit
chamber
Grit
chamber
Primary
Clarifier
Primary
Clarifier
Primary
ClarifierPrimary
Clarifier
Primary
Clarifier
Grit
chamber
Secondary
Clarifier
Secondary
Clarifier
AST
Aeration
AST
AerationMixer
Mixer
Optional
Mixer
Denitrification
020
40
6080
100Without Chemical Addition
0
Susp
ende
d So
lid R
emov
al (%
)
20
40
6080
100Ferric Chloride Addition
050
Overflow Rate
Overflow Rate Verses TSS Removal for Sarnia Treatment Plant
100150 cu m/sq.m/d
20
40
6080
100Ferric Chloride Plus Polymer Addition
Figure by MIT OCW.