abstractOurworkwas focusedon invest

abstract
Ourworkwas focusedon investigationof different treatmentprocedures for theremoval of toxic fractions
from a landfill leachate, because sometimes the existing treatment inbiological sequencing batch reactor
(SBR) is not efficient enough, leading to a hazardous environmental impact of the present persistent and
toxic compounds. The efficiency of the procedures used was monitored by chemical analyses and two
toxicity tests (activated sludge andVibrio fischeri). The existing SBR (HRT=1.9 days) removed 46–78% of
CODand96–73%ofNH4
+
-N. Experimentswere conductedwith three landfill leachate samples expressing
significant difference in concentrations of pollutants and with low BOD5/COD ratio (0.06/0.01/0.03). The
applied methods were air stripping, adsorption to activated carbon and zeolite clinoptilolite and Fenton
oxidation. Air stripping at pH 11 was a viable treatment option for the removal of ammonia nitrogen (up
to 94%) and reduction of toxicity to microorganisms. In the adsorption experiments in batch systemwith
different concentration of PAC the most effective was the highest addition (50.0gL
−1
) where 63–92% of
COD was removed followed by significant reduction in toxicity toV. fischeri. In the column experiments
with clinoptilolite 45/93/100%of NH4
+
-Naswell as 25/32/39%of COD removalwas attained. The removal
efficiency for metals followed the sequence Cr >Zn>Cd>Ni. The procedure with zeolite was the second
most efficient one regarding reduction of toxicity to both organisms. Fenton oxidation at molar ratio
Fe
2+:H2O2=1.0:10.0 assured 70–85% removal of COD but it only slightly reduced the toxicity.
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