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CH3041
CAIRNS & QUEENSLAND
• The East Trinity inlet area was
drained in the 1970s for sugar cane
by pumping down the watertable.
• This exposed ASS & the generation
of acid started. In 2000 4 x 106 L/y of cH2SO4 was being generated on site.   (NSW 8 ML)
• 5kg H2SO4/1m3 soil (¯ 1.8m), pH soilav. 3.4
• This has liberated large amounts of Al3+ which has resulted in fish kills in the creeks
that drain the site. (10mg/Lav,. limit 5mg/L)
• QASSIT (Queensland A.S.S. Investigation Team) has  flooded the Firewood Creek area
® soil » pH neutral, creek flocculants gone.
• DNRM&E management (Mareeba) – 2006.
A lime assisted tidal exchange process has been chosen to address the problem because of its substantially reduced cost compared to conventional approaches. Tidal exchange will be the cornerstone of an Acid Sulfate Soil Remediation Action Plan (ASSRAP), which the State has funded over a 4-year period. A ‘Neutra-Mill’ capable of pumping large amounts of hydrated lime into surface waters has been purchased for this purpose. It will also be utilised during the tidal exchange phase to treat tidal exchange waters prior to release, should indicators such as pH reach unacceptable levels. In the Wet season in batches.
Department of Natural Resources, Mines and Energy (NRM&E)