298 94 307/02 Untersuchungen zum Stand der Umsetzung des ...

Teil 3 Seite 8-32
The installed stripping plant consists of 2 filling body columns which are dimensioned as
follows:
Influent to the stripping plant: 75 m 3 /d
Filling body height: approx. 8 m
Throughput of column 1: 2.100 l/h
Throughput of column 2: 3.000 l/h
Column entry temperature: approx. 60 °C
Recirculation air stream: 5.100 Nm 3 /h
NaOH demand: approx. 4,5 kg/kg N el.
Ammonium nitrogen (influent): approx. 2.000 mg/l
Guaranteed value (effluent): 150 mg/l.
The exhaust vapour condensates, which are 60 to 80°C hot, are conveyed at first into a
container of 3 m 3 . Into the following stripping input pipeline for the feeding of the columns,
a defoaming agent on silicone basis is dosed in order to prevent the emergence of foams,
and pH-value controlled soda lye is added to increase the pH-value. In the counter-
current, air saturated with steam is fed from the press room at a temperature of approx. 30
°C and with a wastewater:air ratio of 1:1000. Any neutralisation of the stripping effluent is
not done immediately after the stripping, but only after the reconvergence with the other
wastewater part-streams. The exhaust air from the stripping with a maximum of 122.400
m 3 /d is conveyed through the existing bio-filter system.
BK Alkalisierung
sonst.
Abw.
Ammoniak-
Strippung
Fettabscheider
Trommelsieb
MB Flotation Neutralisation AB
BK Brüdenkondensate MB Misch- und Ausgleichsbecken
sonst. Abw. sonstiges Abwasser AB Anaerobbiologie
Figure 8-1: Block diagram of a mechanical/physical-chemical preliminary wastewater plant
Table 8-3 shows the performance data achieved in 14-day-long examination periods in
winter and summer, respectively (average values from daily mixed samples). According to
these data, the stripping plant did fully achieve the targeted capacity. Operation experi-
ences show that the target values can be kept also in cases of increased influent concen-
trations of ammonium nitrogen.