- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Characterization and toxicity of pulp and paper mill...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Characterization and toxicity of pulp and paper mill sludge leachates Perera, Dharshini Marian
Abstract
The main objective of this study was to investigate the characteristics of pulp and paper mill sludge leachates and to assess their toxicity. Sludges from three mills in British Columbia were subjected to aqueous leaching in laboratory columns at different pH levels to evaluate the relationship between leachability of the contaminants and pH. Leachates were fractionated by ultrafiltration into different molecular size fractions and the leachable contaminants were characterized for carbon content, colour and fluorescence properties, chlorinated phenolics, resin acids, metals and AOX content. The toxicity of the leachates was assessed by conducting laboratory bioassays on Daphnia magna and using the Microtox bioassay. The bioconcentration potential of the chlorinated phenolic compounds was measured using fresh water leeches. Leachates were also collected from sludge previously applied to a test site and analyzed for characteristics and toxicity to investigate the feasibility of applying pulp and paper mill sludge to forest land as an organic fertilizer. Leachability of carbon varied considerably between sludge leachates from different mills. The soluble carbon content of subsamples of the same sludge leachate varied between one to another, indicating the highly variable nature of these sludge leachates. Leachates of different molecular size fractions had different colour and fluorescence properties. No consistent relationship was found between the carbon distribution in the fractions and colour or fluorescence suggesting that colour or fluorescence cannot be used as an estimate of the total dissolved carbon or the predominance of any molecular size fraction in a sludge leachate. Leachability of contaminants was affected by pH. Generally the total concentration of chlorinated phenolics and resin acids increased with increasing pH for sludge leachates for all the mills. At higher pH’s, there was a tendency for the chlorinated phenolics with the lower chlorination number to leach out more. The identifiable chlorinated phenolics were a very small percentage (<0.5 %) of the adsorbable organic halides (AOX) in the leachates. The chlorinated phenolic concentrations in the sludge leachates were low when compared to concentrations found in treated effluents. Analysis of individual molecular fractions revealed the presence of low molecular weight chlorinated phenolics and resin acids (<1000 Daltons) in the high molecular (>1000 Daltons) weight fraction which indicated adsorption to these larger molecules. Toxicity studies with the two bioassays revealed different sensitivities. Generally the Microtox bioassay was more sensitive than the D.magna bioassay. The bioavailability of the chlorinated compounds in the sludge leachates was confirmed by some high bioconcentration factors in freshwater leeches.
Item Metadata
Title |
Characterization and toxicity of pulp and paper mill sludge leachates
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
1993
|
Description |
The main objective of this study was to investigate the characteristics of pulp and paper
mill sludge leachates and to assess their toxicity. Sludges from three mills in British Columbia
were subjected to aqueous leaching in laboratory columns at different pH levels to evaluate the
relationship between leachability of the contaminants and pH. Leachates were fractionated by
ultrafiltration into different molecular size fractions and the leachable contaminants were
characterized for carbon content, colour and fluorescence properties, chlorinated phenolics, resin
acids, metals and AOX content. The toxicity of the leachates was assessed by conducting
laboratory bioassays on Daphnia magna and using the Microtox bioassay. The bioconcentration
potential of the chlorinated phenolic compounds was measured using fresh water leeches.
Leachates were also collected from sludge previously applied to a test site and analyzed for
characteristics and toxicity to investigate the feasibility of applying pulp and paper mill sludge
to forest land as an organic fertilizer.
Leachability of carbon varied considerably between sludge leachates from different mills.
The soluble carbon content of subsamples of the same sludge leachate varied between one to
another, indicating the highly variable nature of these sludge leachates. Leachates of different
molecular size fractions had different colour and fluorescence properties. No consistent
relationship was found between the carbon distribution in the fractions and colour or
fluorescence suggesting that colour or fluorescence cannot be used as an estimate of the total
dissolved carbon or the predominance of any molecular size fraction in a sludge leachate. Leachability of contaminants was affected by pH. Generally the total concentration of
chlorinated phenolics and resin acids increased with increasing pH for sludge leachates for all
the mills. At higher pH’s, there was a tendency for the chlorinated phenolics with the lower
chlorination number to leach out more. The identifiable chlorinated phenolics were a very small
percentage (<0.5 %) of the adsorbable organic halides (AOX) in the leachates. The chlorinated
phenolic concentrations in the sludge leachates were low when compared to concentrations found
in treated effluents. Analysis of individual molecular fractions revealed the presence of low
molecular weight chlorinated phenolics and resin acids (<1000 Daltons) in the high molecular
(>1000 Daltons) weight fraction which indicated adsorption to these larger molecules.
Toxicity studies with the two bioassays revealed different sensitivities. Generally the
Microtox bioassay was more sensitive than the D.magna bioassay. The bioavailability of the
chlorinated compounds in the sludge leachates was confirmed by some high bioconcentration
factors in freshwater leeches.
|
Extent |
3230408 bytes
|
Genre | |
Type | |
File Format |
application/pdf
|
Language |
eng
|
Date Available |
2009-02-20
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0050436
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
1994-05
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.