Skip to main content
Conference Proceedings

Sixth International Conference on Acid Rock Drainage (ICARD)

Conference Proceedings

Sixth International Conference on Acid Rock Drainage (ICARD)

PDF Add to cart

Application of an Active Treatment System for the Reduction of Acidity and Dissolved Metals From Acid Sulfate Soil Drainage Waters

The acidic and metal rich waters that are generated from acid sulfate soil (ASS) drainage can have damaging impacts upon ecosystems. The most obvious impact has been the discolouration of water and occasional fish kills. ASS's produce these acidic and metal rich waters when pyrite in soil is oxidised. Land management techniques are an essential long-term requirement to minimise the amount of pyrite oxidation. Acidic water that cannot be prevented through land management can be neutralised by other techniques. Powdered lime is the most common material in agriculture that is applied directly to soils and waters. Powdered lime can be expensive and if applied dry it may aggregate. Since the aggregated particles of lime are larger they could sink rapidly in the water column and not react. In waters with high concentrations of dissolved iron and aluminium the lime particles may become coated with a metal oxy-hydroxide precipitate, which will decrease its reactivity. A unique lime-dispensing machine, the Waterways Lime Spreader, has been developed to neutralise acidic waterways. The Waterways Lime Spreader can produce a solution rich in fine lime from larger limestone fragments. The current size of the machine means only 3.5 grams per second of limestone can be emitted. This output will neutralise low acidity waters, however, for high acidity waters the time for neutralisation can be long. More reactive chemicals such as hydrated lime or increasing the size of the machine will reduce this neutralisation time. The Waterways Lime Spreader is also capable of producing slurry mixtures if powdered materials are required. Trials with the Waterways Lime Spreader were undertaken in part of the Clothiers Creek catchment located in northeast NSW, Australia. A small drain with a water volume of 4 m3 was neutralised with crushed limestone to pH 6.9 from an initial pH of 2.6 and an acidity of 902 mg/L CaCO3 in 160 minutes. In comparison a drain with a slightly larger volume of 6 m3 that had an initial pH of 3.2 and an acidity of 753 mg/L CaCO3 was neutralised with hydrated lime to pH 11.8 in five minutes. The Waterways Lime Spreader has been used successfully to neutralise water from acid sulfate soils. It is expected that future applications of the machine may be for the neutralisation of acid rock drainage or acidified lakes.
Return to parent product
  • Application of an Active Treatment System for the Reduction of Acidity and Dissolved Metals From Acid Sulfate Soil Drainage Waters
    PDF
    This product is exclusive to Digital library subscription
  • Application of an Active Treatment System for the Reduction of Acidity and Dissolved Metals From Acid Sulfate Soil Drainage Waters
    PDF
    Normal price $22.00
    Member price from $0.00
    Add to cart

    Fees above are GST inclusive

PD Hours
Approved activity
  • Published: 2002
  • PDF Size: 0.172 Mb.
  • Unique ID: P200303070

Our site uses cookies

We use these to improve your browser experience. By continuing to use the website you agree to the use of cookies.