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Where disturbance of ASS is unavoidable, the most common way to manage the disturbance is to neutralise the soils with alkaline materials.

Section 2.5 of pdfTreatment and management of soils and water in acid sulfate soil landscapes 1.59 MB  (Published July 2011, Revised June 2015) outlines methods for soil neutralisation.

Calculator

Weight basis lime requirement - calculates the mass (in kg) of lime required to neutralise a mass (in tonnes) of ASS materials.

Lime (kg /tonne soil) = (Net acidity1 (%S x 30.59) x 1.022 x Safety Factor3) / ENV4
Net acidity (% S)
enter net acidity of ASS as %S5
Safety factor
enter adopted safety factor (DER default value is 1.5)
ENV (%)
enter ENV of neutralising material as a percentage
Lime required (kg/tonne) :

Volume basis lime requirement - calculates the mass (in kg) of lime required to neutralise a volume (in cubic metres) of ASS materials

Lime (kg /m3 soil) = Soil bulk density x (Net acidity (%S x 30.59) x 1.02 x Safety Factor) / ENV
Soil bulk density (tonne/m3)
enter bulk density of ASS material in tonne/m3
Net acidity (% S)
enter net acidity of ASS as %S
Safety factor
enter adopted safety factor (DER default value is 1.5)
ENV (%)
enter ENV of neutralising material as a percentage
Lime required (kg/m3) :
  1. Net acidity = potential acidity + existing acidity*
  2. The factor 1.02 is used to stoichiometrically convert units of sulfuric acid (H2SO4) to units of calcium carbonate (CaCO3)
  3. A minimum safety factor of 1.5 should be used
  4. The actual rate of application of neutralising materials required must be corrected for the effective neutralising value (ENV) (see Section 2.5.2 of pdfTreatment and management of soils and water in acid sulfate soil landscapes1.59 MB (Published July, 2011, Revised June 2015)
  5. For linear and non-linear disturbances involving soil volumes less than 1000m3, the highest net acidity detected at the site should be used to calculate the amount of neutralising material required. When the volume of soil to be disturbed is greater than 1000m3, the mean net acidity plus the standard deviation may be used to calculate the amount of neutralising material required, provided a statistically sufficient number of laboratory analyses have been performed to satisfactorily characterise the soil profile and ASS at the site. Detrimental environmental impacts may occur if incorrect liming rates are used.

*Due to the particular characteristics of the soil and groundwater regime in WA, DER does not recognise the validity of ANC values without confirmatory kinetic testing or modified laboratory methods to provide a more accurate estimate of the neutralising capacity available under real field conditions. For further information, refer to

pdfIdentification and investigation of acid sulfate soils and acidic landscapes823.39KB (Published March 2013, Revised June 2015).

 

Default bulk density values for soil types (to be used in the absence of site-specific data)

Sand 1.6
Loamy sand 1.5
Sandy loam 1.4
Loam 1.3
Silty loam

1.2
Clay loam 1.1
Clay 1.05
Peat 1
Textural class Natural (in-situ) bulk density (tonne/m3)