Characterization of Wastewaters and Sludges
2.2. Organic matter
Wastewater normally contains thousands of different organics. A measurement of
each individual organic matter would be impossible. Therefore different collective
analyses are used which comprise a greater or minor part of the organics. The
possibilities of collective analyses can be illustrated by an equation of reaction for
the oxidation of organic matter, here symbolized by the average composition
C1sH1909N /5/:
(2.3)
If organic matter is oxidized, the consumed amount of oxygen (the BOD-, COD-,
TOO-analyses) or the produced amount of carbon dioxide (the TOC-analysis) can
be measured.
The different measuring methods yield different results and therefore the individual
methods cannot replace each other indiscriminately. Table 2.1 shows an example of
analysis values for the different measuring methods for two different types of
wastewater.
Typical cone. (g 0:2/m 3 )
Element
Name
Bioi. treated
Raw wastewater
wastewater without
nitrification
Ccoop
Chemical oxygen demand
180
30
(with potassium permanganate in
alkaline solution)
CBoo
5-day biochemical oxygen demand
280
25
Coo07
7 -day biochemical oxygen demand
320
30
Cooo~
Total biochemical oxygen demand
400
35
Ccoo
Chemical oxygen demand
600
100
(with potassium dichromate)
Ss.coo
Easily biodegradable matter,
60
5
measured as COD
Xs,coo
Slowly biodegradable matter
200
10
CToD
Total oxygen demand (at 900 °C,
800
230
platinum catalyst)
Cmo (theoretical)
Theoretical total oxygen demand'
850
270
Cmc
Total organic carbon (at 8000 C)
200
..
35
..
C me( theoretical)
Theoretical TOC
200
..
..
35
• Calculated stoichiometrically, if the content of organic matter is assumed to be known
••
3
Unit: g C/m
Table 2.1
Analyses for organics in wastewater and their interrelationship
The choice of analysis parameters has been, and still is, the subject of discussion.
Generally, chemical analyses may be said to be fast, but they do not always measure
what is relevant. Biochemical analyses (Cscn Ss,ccn Xs,cm) are slow, but on the
other hand they measure, in many cases, the relevant sizes.
39
2.2. Organic matter
Wastewater normally contains thousands of different organics. A measurement of
each individual organic matter would be impossible. Therefore different collective
analyses are used which comprise a greater or minor part of the organics. The
possibilities of collective analyses can be illustrated by an equation of reaction for
the oxidation of organic matter, here symbolized by the average composition
C1sH1909N /5/:
(2.3)
If organic matter is oxidized, the consumed amount of oxygen (the BOD-, COD-,
TOO-analyses) or the produced amount of carbon dioxide (the TOC-analysis) can
be measured.
The different measuring methods yield different results and therefore the individual
methods cannot replace each other indiscriminately. Table 2.1 shows an example of
analysis values for the different measuring methods for two different types of
wastewater.
Typical cone. (g 0:2/m 3 )
Element
Name
Bioi. treated
Raw wastewater
wastewater without
nitrification
Ccoop
Chemical oxygen demand
180
30
(with potassium permanganate in
alkaline solution)
CBoo
5-day biochemical oxygen demand
280
25
Coo07
7 -day biochemical oxygen demand
320
30
Cooo~
Total biochemical oxygen demand
400
35
Ccoo
Chemical oxygen demand
600
100
(with potassium dichromate)
Ss.coo
Easily biodegradable matter,
60
5
measured as COD
Xs,coo
Slowly biodegradable matter
200
10
CToD
Total oxygen demand (at 900 °C,
800
230
platinum catalyst)
Cmo (theoretical)
Theoretical total oxygen demand'
850
270
Cmc
Total organic carbon (at 8000 C)
200
..
35
..
C me( theoretical)
Theoretical TOC
200
..
..
35
• Calculated stoichiometrically, if the content of organic matter is assumed to be known
••
3
Unit: g C/m
Table 2.1
Analyses for organics in wastewater and their interrelationship
The choice of analysis parameters has been, and still is, the subject of discussion.
Generally, chemical analyses may be said to be fast, but they do not always measure
what is relevant. Biochemical analyses (Cscn Ss,ccn Xs,cm) are slow, but on the
other hand they measure, in many cases, the relevant sizes.
39