9.3.10 Landfill Leachate
Jeong et al. (1995, 1996) examined landfill leachate as a very minor pollutant
component of drainage and evaluated its influence on Daphnia magna in both a
single-species culture test and in a multiple-species microcosm test. Landfill leachate
(untreated), ozone-treated leachate, fluidized bed-treated leachate, and ozone +
fluidized bed-treated leachate were applied to the microcosm-WET test. The ratios
of the test drainage waters were set as 0 (control/no-addition system), 5, 10, 25, 50,
and 100%. At the beginning of microcosm cultivation, test drainage water, which
suction filtered using a 0.45 μm diameter membrane (ADVANTEC, GS-45), was
added to microcosm.
As a result of the untreated landfill leachate, the NOEC of the swimming
inhibition of Daphnia magna was 2.5%, and the half-influence concentration
(EC 50 ) was 6.0%. The NOEC for the populations of the constituent species in the
microcosm test were evaluated for the 1–5% addition of untreated landfill leachate.
All species in the microcosm survived and were coexisting on the 28th day in the 1%
addition system, and almost no influence of landfill leachate was observed. Meanwhile, for the 5% addition system, microbial species, except for bacteria and
Chlorella sp., became extinct after the seventh day, and biological interactions
among producers, consumers, and decomposers had collapsed. From these outcomes, it was estimated that there exists a boundary concentration for system
stability between 1% and 5% of landfill leachate. Cyclidium glaucoma, the most
sensitive species, exhibited growth similar to that in the control system until the
fourth day, and it was clearly influenced by the landfill leachate during the first
7 days.
9.3.11 Ozone-Treated Landfill Leachate
From the addition of ozone-treated landfill leachate, all microbial species except for
Aeolosoma hemprichi survived and coexisted, and almost no influence was observed
in the 1% addition system. Meanwhile, all species except for bacteria and Chlorella
sp. became extinct after the seventh day, and biological interaction collapsed in
systems with more than 5% addition. These results were very similar to those for the
addition of untreated landfill leachate. Two interpretations of these results were
considered, one in which hazardous materials in landfill leachate still remained
and influenced the microcosm in spite of ozone treatment and another in which
new hazardous materials were generated by ozone treatment. It has been reported
that humic in landfill leachate converts to aldehyde or carboxylic acid, which are
toxic mutagens, after ozone treatment. From this, the possibility of generating new
hazardous materials may be assumed. Furthermore, it was estimated that there exists
a boundary concentration for the stability of the ecosystem between 1% and 5% of
ozone-treated landfill leachate. Cyclidium glaucoma exhibited similar growth as in
9 Application to the Whole Effluent Toxicity Test
183
Jeong et al. (1995, 1996) examined landfill leachate as a very minor pollutant
component of drainage and evaluated its influence on Daphnia magna in both a
single-species culture test and in a multiple-species microcosm test. Landfill leachate
(untreated), ozone-treated leachate, fluidized bed-treated leachate, and ozone +
fluidized bed-treated leachate were applied to the microcosm-WET test. The ratios
of the test drainage waters were set as 0 (control/no-addition system), 5, 10, 25, 50,
and 100%. At the beginning of microcosm cultivation, test drainage water, which
suction filtered using a 0.45 μm diameter membrane (ADVANTEC, GS-45), was
added to microcosm.
As a result of the untreated landfill leachate, the NOEC of the swimming
inhibition of Daphnia magna was 2.5%, and the half-influence concentration
(EC 50 ) was 6.0%. The NOEC for the populations of the constituent species in the
microcosm test were evaluated for the 1–5% addition of untreated landfill leachate.
All species in the microcosm survived and were coexisting on the 28th day in the 1%
addition system, and almost no influence of landfill leachate was observed. Meanwhile, for the 5% addition system, microbial species, except for bacteria and
Chlorella sp., became extinct after the seventh day, and biological interactions
among producers, consumers, and decomposers had collapsed. From these outcomes, it was estimated that there exists a boundary concentration for system
stability between 1% and 5% of landfill leachate. Cyclidium glaucoma, the most
sensitive species, exhibited growth similar to that in the control system until the
fourth day, and it was clearly influenced by the landfill leachate during the first
7 days.
9.3.11 Ozone-Treated Landfill Leachate
From the addition of ozone-treated landfill leachate, all microbial species except for
Aeolosoma hemprichi survived and coexisted, and almost no influence was observed
in the 1% addition system. Meanwhile, all species except for bacteria and Chlorella
sp. became extinct after the seventh day, and biological interaction collapsed in
systems with more than 5% addition. These results were very similar to those for the
addition of untreated landfill leachate. Two interpretations of these results were
considered, one in which hazardous materials in landfill leachate still remained
and influenced the microcosm in spite of ozone treatment and another in which
new hazardous materials were generated by ozone treatment. It has been reported
that humic in landfill leachate converts to aldehyde or carboxylic acid, which are
toxic mutagens, after ozone treatment. From this, the possibility of generating new
hazardous materials may be assumed. Furthermore, it was estimated that there exists
a boundary concentration for the stability of the ecosystem between 1% and 5% of
ozone-treated landfill leachate. Cyclidium glaucoma exhibited similar growth as in
9 Application to the Whole Effluent Toxicity Test
183