NITROGEN FRACTIONS
1
NITROGEN FRACTIONS
• Ammonia makes up to 60% to
75% of TKN.
• For measurement the nitrogen
fractions directly, standard analysis
of TKN on both filtered and
unfiltered samples as well as
standard analyses of ammonia
need to be done.
• Nitrate/nitrite should be measured
in influent wastewater only if a
significant industrial source
present or in side stream.
2
NITROGEN FRACTIONS sON
• Soluble inorganic nitrogen = ammonia + nitrate/nitrite
• Soluble organic nitrogen =filtered TKN-ammonia
• Particulate organic nitrogen = TKN-filtered TKN
Influent
fTKN
3
NITROGEN FRACTIONS
NONBIODEGRADABLE PARTICULATE TKN
4
NITROGEN FRACTIONS
NONBIODEGRADABLE PARTICULATE TKN
Method-1
nbpON is associated with nbpCOD.
Calculate the fraction FupN
pTKN
FupN
pCOD
FupN= N:COD ratio for un-biodegradable particulate COD
pTKN TKN sON NH 4 _ N
nbpON pTKN
nbpCOD pCOD
pTKN
nbpON nbpCOD
pCOD
nbpON FupN nbpCOD
5
NITROGEN FRACTIONS
NONBIODEGRADABLE PARTICULATE TKN
Method-2
• nbpON is associated with nbVSS.
• nbpON can be estimated from VSS
and nbVSS
pTKN TKN sON NH 4 _ N
pTKN fN= fraction of organic nitrogen in
fN VSS , g N/g VSS
VSS
nbpON fN nbVSS
nbpON pTKN
nbVSS VSS
pTKN
nbpON nbVSS
VSS
6
NITROGEN FRACTIONS
NON-BIODEGRADABLE SOLUBLE TKN(nbsON)
7
NITROGEN FRACTIONS
NON-BIODEGRADABLE SOLUBLE TKN(nbsON)
• Passes through the plant untouched.
• Estimated as approximately 1.5-2% of the Influent TKN.Typically ranges from 1 to 2 mg/l.
• Assuming that all of the soluble biodegradable organic nitrogen is degraded within the
treatment process , then the effluent filtered TKN minus the effluent ammonia will equal
the nbsON.
nbsON fTKN NH 4 _ N
Effluent
fTKN
8
PHOSPHORUS FRACTIONS
• Knowing the phosphorus fractionation
is important for plants that provide
biological phosphorus removal.
• Orthophosphate(PO4) and soluble
biodegradable phosphorus are taken
up by PAOs in the aerobic zone.
• Orthophosphate(PO4) typically makes
up a large portion of TP in domestic
wastewater(50% to 80%).
• Almost all of the effluent soluble
phosphorus is orthophosphate.
• P fractions are simplified as follows:
– TP, total phosphorus .
– Orthophosphate (PO4) represents the two
reactive fractions.
9
WASTEWATER CONSTITUENT RELATIONSHIPS
The relationships between various constituents in raw influent establish a frame
of reference and are important for various process considerations. Established
relationships can also be relied upon when data is non-existent. The typical
wastewater constituent relationships are presented below.
10
RELATIONSHIP BETWEEN BOD,COD AND TSS
11
RELATIONSHIP BETWEEN BOD,COD,TSS, TN, & TP
12
EXAMPLE
SAMPLING RESULTS FOR WWTP IN JORDAN
13
EXAMPLE- ESTIMATION OF nbsCOD
14
EXAMPLE – ESTIMATION OF rbCOD
15
PARTICULATE COD/VSS RATIO(Fcv)
measured
16
EXAMPLE – ESTIMATION OF nbpCOD & sbCOD
17
RESULTS FOR COD FRACTIONS FOR
THE EXAMPLE
18
EXAMPLE – ESTIMATION OF nbVSS
nbpCOD
nbVSS VSS
pCOD
128 .1
nbVSS 418 .2 68 .3
657 128
128 .1
nbVSS 418 .2 68 .3
784 .8
19
EXAMPLE – ESTIMATION OF sON
20
EXAMPLE – ESTIMATION OF nbpON
21
EXAMPLE – ESTIMATION OF nbsON
22
EXAMPLE – CALCULATION OF PARTICULATE ORGANIC NITROGEN
FRACTION(Fnox) & AMMONIA FRACTION(Fna)
pON 33.5
Fnox 0.88
ON 37.9
NH 4 N 99.2
Fna 0.72
tTKN 137 .1
23
EXAMPLE – ESTIMATION OF FPO4
24
COD,BOD & TSS RELATIONSHIP IN THE EXAMPLE
25
MISCONCEPTION ON NITROGEN &
PHOSPHURUS LIMITS
What is the difference between?
NO3 and NO3-N
NH4 and NH4-N
NH3 and NH3-N
PO4 and PO4-N
26
MISCONCEPTION ON NITROGEN &
PHOSPHURUS LIMITS
There is a misunderstanding in the way the Nitrogen and Phosphorus
limits are expressed .
Wastewater test results and effluent quality for Nitrogen and Phosphorus
given in standards are expressed in one of the following methods :
• Elemental basis (i.e. NO3-N and NH4-N,PO4-P).
• Molecular basis (i.e. NO3 and NH4,PO4).
27
RECOMMENDED TYPICAL FRACTIONS
28
HOMEWORK
Estimate COD, N and P fractions for the sampling results given below
29
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Appendix
32
FLOCCULATED & FILTERED COD(ffCOD) ANALYSIS
• Procedure for filtered & flocculated COD (ffCOD) test :
1 mL of 100 g/L zinc sulfate solution is added to 100 mL of
wastewater
The sample is then mixed vigorously for approximately 1 minute
The sample pH is adjusted to approximately 10.5 using 6 M
sodium hydroxide solution(NaOH).
The sample then is allowed to settle, and a sample of the
supernatant is withdrawn
The supernatant sample is filtered using a 0.45 µm membrane
filter, and the filtrate COD is analyzed.
33
REFERENCES
1. Methods for Wastewater Characterization in Activated Sludge
Modeling, WERF
2. Nutrient Control Design Manual, EPA, August 2010
3. Wastewater Engineering Treatment & Reuse, Metcalf & Eddy, 2004
4. Standard Methods for Wastewater
5. User Manual for BioWin 3., EnviroSim Associates Ltd.
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WHY 5 DAY BOD?
The five day period was chosen for the test because the Thames
River (of England) requires five days from its origin to join sea,
and if oxygen demand for these five days is determined and
satisfied — the river’s water quality can be protected;
35
STANDARD METHODS FOR EXAMINATION OF WATER
& WASTEWATER
36
