Recharge systems for protecting and enhancing groundwate

696
TOPIC 6
Case studies / Region issues and artificial recharge case studies
was determined for the coconut fibres only shortly and lower compared to the other materials. In the effluents of
the recycled crushed glass and the sand the concentrations of nitrites were about two times higher as in the effluent
of the coconut fibres. This effect was also determined at the pilot scale test plant. In contrast to the recycled crushed
glass and the sand the coconut fibre filter showed a much lower accumulation of nitrate.
DOC C/C 0
DOC
1.4
1.2
5 - 10˚C
1.0
0.8
0.6
0.4
0.2
0.0
0 10 20 30 40
ammonium C/C 0
ammonium
1.4
1.2
5 - 10˚C
1.0
0.8
0.6
0.4
0.2 no dosing
0.0
0 10 20 30 40
DOC C/C 0
1.4
1.2
1.0
0.8
0.6
0.4
20˚C
0.2
0.0
0 10 20 30 40
50
ammonium C/C 0
1.4
1.2
1.0
20˚C
0.8
0.6
0.4
0.2
0.0
0 10 20 30 40 50
DOC C/C 0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
1.4
30˚C
1.2
30˚C
1.0
0.8
0.6
0.4
0.2
0.0
0 10 20 30 40 50 0 10 20 30 40 50
filter operation time [d]
ammonium C/C 0
filter operation time [d]
coconut fibre recycled crushed glass sand
Figure 3. Relative concentrations of DOC and ammonium in the effluent of the filter columns
Coconut fibres and sand showed a comparable reduction efficiency concerning the removal of iron and zinc. For
the recycled crushed glass a distinct lower elimination for zinc in general and for iron at the temperature 5–10°C
was detected. The results of the investigations proved in all a slightly better reduction efficiency with increasing
temperatures.
Especially in the start-up stages the filtrate of the coconut fibre was characterized by a pH value below 7. This
organic filter material also showed at higher temperatures a higher oxygen reduction during the filtration process
compared to the other filter materials.
ISMAR 2005 ■ AQUIFER RECHARGE ■ 5th International Symposium ■ 10 –16 June 2005, Berlin