- Principal pullutant linkages associated with acid
tar lagoons
| Label |
Environmental risks |
Examples of contaminants involved (anticipated) |
Receptor |
| 1 |
Volatiles from liquid tar (significantly exacerbated if
tar is disturbed) |
Benzene, sulphur dioxide |
Site users, residents of adjacent properties |
| 2 |
Dust blowoff from exposed and weathered tar surfaces |
PAHs, heavy metals |
Site users, residents of adjacent properties |
| 3 |
Subsurface contaminant leaching from tar into groundwater |
Sulphuric acid, heavy metals, phenol, BTEX |
Groundwater, major/minor aquifer |
| 4 |
Leaching from tar into surface water (e.g. water ponding
over tar body, or migration of tar into a stream) |
Sulphuric acid, heavy metals, phenol, BTEX |
Nearby water course |
| 5 |
Direct contact with tar migrating out of contained area(e.g.
fenced or capped) |
Sulphuric acid, PAHs, heavy metals |
Site users, residents of adjacent properties |
From Talbot et al. 2004
- Restoration methods used or attempted
The restoration/remediation techniques of acid tar lagoons
can be summarized into two categories:
- Pathway control, which break the contamination
linkages between the source and
receptors. The most common pathway control techniques applied
to acid tar
lagoons is capping. Unengineered capping in the past has typically
suffered
from significant stability issues.
- Source control, techniques that achieve
remediation of acid tar lagoons by
rendering the acid tars inert or completely removing the acid
tars for other
use. A highly significant challenge faced by source control
techniques is
emission control of sulfur dioxide and other volatiles given
off during the
excavation or treatment of acid tars.
Recent full site remediations:
| Technique |
Site |
Reference |
| Excavation and ex-situ treatment to form a fuel substitute |
Chemnitz |
Gruss, D, 2005 |
| Stabilisation and solidification |
Rieme, Belgium |
Pensaert 2005 |
| Stabilisation and solidification |
Sandsprings |
Grajczak 1995 |
Small scale field trials/laboratory scale demonstrations:
| Technique |
Site |
Reference |
| Stabilisation |
(lab scale) |
Slater 2003 |
All information herein is provided in
good faith. It is not intended to be, and should not be relied
on as, a substitute for professional advice. See disclaimer.
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