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Current Mine Water and Environment Remediation and Rehabilitation research.
Microcosm experiments for
remediation of acid pit lakes with bulk organic materials
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| In collaboration with
Collinsville Coal Project, this project aims to evaluate
municipal sewage and green waste as organic substrates for
bacterially-mediated sulfate reduction at an entire-lake
scale.
We have conducted both onsite and Perth-based laboratory microcosm trials. We are now executing a field-scale experiment (with controls) involving the treatment of an entire acid coal pit lake in North Queensland, Australia with municipal treated sewage and green waste. Raw sewage and green waste have been introduced into an acid mine void lake (150 ML, pH 2.2) since July 2006. Monitoring of the biology and chemistry of this and three control lakes will continue for the next 18 months. As a direct result of this project's inception, Collinsville won the "Ergon Energy, Environmental Innovation Award" in July, 2006. For a recent "COHESION" article on the project click here Output(s): McCullough, C. D.; Lund, M. A. & May, J. M. (2006). Microcosm testing of municipal sewage and green waste for full-scale remediation of an acid coal pit lake, in semi-arid tropical Australia. Proceedings of the 7th International Conference on Acid Rock Drainage (ICARD). St Louis, Massachusetts, USA. 1,177-1,197.McCullough, C. D.; Lund, M. A. & May, J. M. (2008). Field scale trials treating acidity in coal pit lakes using sewage and green waste. Proceedings of the 10th International Mine Water Association (IMWA) Congress. International Mine Water Association (IMWA) Congress. Karlovy Vary, Czech Republic. 599-602 pp.
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Garrick East pit lake | ||||||||||||||||||||||||||||||||||||
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Microcosm core trial of organic materials |
Microcosm pH remediation results
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| Workshop Evaporation Pond
2 (WEP2) is a water body used to reduce low pH and/or high
salinity surface water volumes through evaporation.
Approximately 4 ML of acid dewatering water from WEP2 was
introduced into the 60 ML Workshop Evaporation Pond 1 (WEP1)
in late May 2003. WEP1 is a hyper-eutrophic water body into
which raw sewage and CCP workshop vehicle washdown and waste
waters are continuously fed. In situ sulfate reduction processes produced alkalinity and removed heavy metals from WEP2 waters. It appears that the WEP1 wetland has fulfilled an example of a site-specific, medium-scale evaluation of the proposed in-void remediation technology. This conclusion is further borne out by the large number of macroinvertebrates and high phytoplankton abundances present again, and by the many species of waterfowl also now making use of this previously inhospitable water body. |
Workshop Evaporation Ponds 2 (WEP2) and 1 (WEP1) | ||||||||||||||||||||||||||||||||||||
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Output(s): |
Changes in WEP1 pH and EC over time |
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Twelve 1,200 L mesocosms at ECU have been filled with a 40 mm layer of lake sediment from the bottom of the river fast-filled Lake Kepwari. This representative sediment layer has then been covered with Lake Kepwari water. Treatments have been allocated in a randomised two-way factorial design to test the effects of liming, phosphorus enrichment and combined liming and phosphorus amendment on different aspects of the AMD water chemistry, ecotoxicity and ecology.
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Collecting sediment from Lake Kepwari | |||||||||
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The mesocosms back @ ECU |
The Edith Cowan University team is examining water chemistry, sediment and periphyton dynamics, including the effect of liming and enhanced primary production upon dissolved heavy metal and nutrient concentrations, alkalinity and pH. Acid pit lake waters are typically low in P due to sorption by Al and Fe and liming appears to further remove this essential nutrient. Amendment by P may required to stimulate primary productivity, in turn raising pH through nitrate assimilation and also scavenging some heavy metals. Output(s): |
Research team: Mark Lund (MiWER), Clint McCullough (MiWER), Yuden (MiWER)
Can the environmental values of Collie pit lakes be enhanced with refractory organic matter and nutrients?
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Low sulfate concentrations prevent microbial sulfate reduction from reducing acidity in these lakes. However, stimulation of primary and secondary production may produce alkalinity help establish a more natural ecosystem providing a cost effective and sustainable solution to the acidity problems. A field-scale experiment (with control) involving the treatment of in-situ macrocosms (~600 m3) with municipal mulch and phosphorus additions to enhance primary production has been established in a small south-west, Western Australian coal mine lake.
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Macrocosm experiment in Ewington Lake |
 Changes in water quality of macrocosms and reference lakes over months |
Decomposition of mulch reduced nitrogen to low levels and necessitated supplementation with urea fertilizer. Phosphorus concentrations dropped rapidly after addition as it became bound to iron, organic matter and sediment. There was little difference between treatments and control for most physico-chemical parameters measured (including pH). However, a PCA of the data showed that the addition of mulch sent the macrocosms on a different trajectory to the control. This difference was reflected in observations of increased abundance and diversity of biofilms and macroinvertebrates within the treated macrocosms. The addition of mulch and phosphorus alone was not sufficient to increase the pH of Collie mine lakes, although it does provide a number of benefits for biota in the water. We recommend that liming be used to increase pH, followed by organic matter and nutrient additions to stimulate primary production. Output(s): |
Research team: Clint McCullough (MiWER), Mark Lund (MiWER), David Bills (Griffin Coal)
Does treatment with oxic liming and an aerobic wetland remediate mine waters from a new acid pit lake?
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A mine water treatment system was constructed at Griffin Coal Mining Company Limited in Collie Western Australia, to remediate acidified mine lake water from the nearby Chicken Creek pit lake (pH 3, containing approximately 8 million m3 of water) and make it suitable for cultivating plants or fish. The first part of pit water treatment is a two-stage liming system utilising a fluidised bed of limestone. At each stage of liming there is a settling pond to remove particulate iron- and aluminium oxyhydroxides. From here the limed water gravity-feeds back to the lake though 5 ha constructed aerobic "polishing" wetland. |
Fluidised liming of Chicken Creek pit lake water |
 Aerobic polishing of fluidised Chicken Creek pit lake water |
This study is evaluating the way in which fluidised liming and aerobic wetland treatment can remediate pH and elevated metal concentrations in water from a typical recently groundwater-filled acid pit lake of Collie. Both water chemistry analyses and toxicity teas are being undertaken to evaluate water quality at each stage of treatment in order to better understand the processes taking place in this treatment system. The conclusions and recommendations of this project will enable better design of such systems for this mining region.
Output(s):
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Research team: Clint McCullough (MiWER), Mark Lund (MiWER), Avijit Das (CUT), Ron Watkins (CUT)
Will liming treatment, followed by treatment by anaerobic organic reactors and an aerobic wetland remediate Acid Sulfate Soils groundwater quality?
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Urban development in the City of Stirling (WA) has led to exposure of Acid Sulfate Soils (ASS) causing acidification of groundwater and metal/metalloid (including arsenic) toxicity. This acidic and toxic groundwater flows through the Spoonbill Lakes causing environmental and health impacts on this wildlife reserve. This treatment of groundwater in an urban context poses a new and challenging problem for environmental managers. To treat this problem, an innovative modular treatment system, has been constructed and is being experimentally tested at the Lakes. The project will produce a design for a permanent treatment system at the Lake, and similar situations. |
Acid Sulfate Soil impacts at Spoonbill Lakes |
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Schematic of the modular treatment system |
The treatment sequence is as follows. Injection with either sodium hydroxide, calcium hydroxide or oxic lime chip liming remediates pH and reduce iron and aluminium concentrations. These metal precipitates are then removed in a settling tank. Organic bioreactors then reduces sulfate and precipitate heavy metals and arsenic. The north lake functions as a untreated, reference site. The northern half of the south lake has been enhanced with extra plantings and wood mulching to develop a final aerobic wetland polishing treatment for the neutral pH and low solute water product. Finally, treated water is left to travel through the remaining aerobic un-rehabilitated lake and percolate back into the groundwater system. Output(s): Lund, M. A.; McCullough, C. D. & Galeotti, D. (2008). Remediation of water quality and macroinvertebrate communities in an urban artificial lake affected by acid sulphate soils. Verhandlungen der Internationalen Vereinigung fur Limnologie 32: |
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