Institute for Sanitary Engineering, Water Quality and Solid Waste ...

Chair of Waste Management and Emissions
Analytical benchmark of two optimised industrial
scale waste air treatment plants for treatment
of sewage sludge emissions during sludge dehydration
In cooperation with the responsible engineers of the
industrial project partner an industrial scale procedure
for treatment of emissions out of the drying of sewage
sludges as well as wood residues was developed and
realized. Analytical evaluation of the waste air situation
in the inlet and outlet of each treatment step
was one of the main topics of the department in this
assignment. The results worked out were the base for
further development and optimisation procedures.
fluidized bed dryers or drum dryers to reduce water
content to a maximum of 10 %. Afterwards, a thermal
use is possible. Similar to a water extraction procedure
highly volatile organic compounds as well as well soluble
and well water extractable compounds are transferred
into the air flow for drying. These air streams
posses total carbon concentrations of 200 – 300 mg C/
m³, but efficient treatment to fulfil limit values of the
TA-Luft is not possible.
In cooperation with the industrial partner the main
topic to deal with was an optimization of the drying
procedure in dependency of the material to be dryed
to achieve a minimization of waste gas concentrations
and carbon freights in the waste air flow.
Advisor: Dr.-Ing. D. Dobslaw
Advisor: Dr.-Ing. D. Dobslaw
Optimisation of belt dryers’ drying procedures
under aspects of minimization of emissions and
fulfillment of TA-Luft 2002 limit values
Related to German laws the deposition of municipal
and industrial sewage sludges in landfills is no longer
and deposition on agricultural fields is only possible
under strict conditions. Furthermore, the depostion of
saw dust, residues of pressboard and paper production
or similar wastes is hardly restricted. Because of their
high heating value, in most cases these waste compounds
are thermal used in waste incineration plants,
cement plants or biomass power plants. However, the
sludges’ high water content shows negative effects in
production efficiency and product quality, especially
in case of clinker brick production. Therefore, these
waste compounds have to be pretreated in belt dryers,
Study of feasibility for chemical cleavage of
organic peroxides
Caused by a non efficient biological degradation of the
described peroxides, experiments for chemical and
physical mineralisation of organic peroxides focusing
on DTBP (di-tert-butylperoxide) and DTAP (di-tertamylperoxide)
were proceeded. In a second approach
the focus lied on an efficient chemical or physical cleavage
of these peroxides combined with a biological
stage for treatment of the resulting intermediates afterwards.
In these tests both peroxides showed high
stability towards UV irradiation and katalytical cleavage
at ambient temperature, poor adsorption characteristics,
stability against absorption and oxidation
by oxidising or reducing agents using aqueous and
organic solvents as absorbent. Furthermore no cleavage
occurred in presence of all basic and mostly all
acidic compounds tested. Only using sulphuric acid in
concentrations higher than 75 % an efficient cleavage
of these peroxides was observed. Based on these experiments
a test reactor for complete mineralisation
of these peroxides using a combination of sulphuric
scrubber, aqueous scrubber and biotrickling filter was
designed, constructed and operated to get further information
for a later industrial size scale-up.
Advisor: Dr.-Ing. D. Dobslaw
Study of feasibility for biological degradation of
organic peroxides
Belt dryer with a water evaporation capacity of 8 t /h.
Organic peroxides in general are highly reactive and
thus show poor stability. However, a group of chemical
high-stable peroxides exists, also used in chemical
industry and in the production of polymers. Benzoylperoxide,
dilaurylperoxide, di-tert-amylperoxide,
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