2. Characterization of Wastewaters
and Sludges
by Mogens Henze
Different analytical methods of a mixed origin are used for the characterization of
wastewaters and sludges. Many of them have been specially developed for treatment plants and treatment processes. Below some of the analysis and characterization methods are described. Details on the subject can be found under the
references 111,121,131.
2.1. Suspended solids
The division of pollutants into dissolved and suspended solids is essential as many
of the treatment processes are only effective against one of these.
The division between dissolved and suspended solids is not well defined. In
Denmark, a filter of a pore size of 1.6j.lm (GF I A filter) is used. The filter holds the
major part of the bacteria and other particles in the water. In most other countries,
filters of a pore size of 1 11m (GF I C), or possibly 0.45 j.lm, are used. Of course these
filters remove even more suspended solids.
The solids passing aJilter are defined as the dissolved solids, S, whereas the solids
held by the filter are the suspended solids, X. See Fig 2.1.
Fig 2.1
Abbrev. Symbol
Total solids
TS
C
Suspended solids
ss
Dissolved solids
DS
Non-settleable solids }
TS
Settleable solids
Separation of dissolved and suspended solids, from Danish Standard /4/.
X
s
c
37