Chemical Remediation Services

Chemical Remediation Services

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Chemical Neutralisation of Potential Acid Sulfate Soils (PASS) and Acid Sulfate Soils (ASS)

New Soil has investigated and treated PASS and ASS for over 25 years, during which we have successfully treated more than 115,000 m3 of acid sulfate soil with different techniques suited to the site and excavation rate. This can include our Mobile Unit for Soil Treatment (MUST) or using a larger scale paddock as a treatment site, which is suitable for higher excavation rates. Our staff are trained in soil sampling and validation to reduce time by not relying on external consultants.

Depending on the size of the area available for treatment and your individual objectives, we utilise a variety of treatment technologies to either maximise daily treatment volumes, or to treat soils with the smallest environmental footprint possible, for example by utilising our Mobile Unit for Soil Treatment (MUST).

Treatment using MUST and Screen

Chemical Immobilisation/Stabilisation

Our team has extensive experience in producing field trials and accelerating the application process for obtaining Specific Immobilisation Approvals (SIAs) for a proposed chemical stabilisation. Utilising our proven methodology and technology, our team has performed a wide range of lead stabilisation remediation, including sludge stabilisation from metal manufacturing plants and shooting range soil stabilisation.

By performing on–site immobilisation, contamination disposal can be performed at a lower waste classification, thereby reducing disposal fees significantly.

Chemical immobilisation is typically undertaken to treat the leachability and bioavailability of elements, particularly metals. Whilst elements in soil cannot be destroyed, their level of toxicity can be minimised by manipulating that element’s state.

For most elements, level of toxicity relate to the level of solubility of the element. To change the solubility of a metal, it needs to be ensured that all soluble and ongoing soluble components of that metal can be altered to an insoluble mineral. This involves adding chemicals to create insoluble minerals; binding the metals as part of a non–dissolvable crystal lattice. Here the nature of the additives varies according to the mineral that requires immobilisation.

Compounds treated by chemical immobilisation include:

  • Barium
  • Lead
  • Zinc
  • Copper
  • Arsenic
  • Antimony

Chemical Reduction

The opposite chemical reaction to oxidation, Chemical Reduction uses powerful reducing compounds to chemically treat contaminated soil and groundwater.

During this process, a reductant solution such as zerovalent iron, or in the case of Hexavalent Chromium (CrVI), organic matter, is inserted into the contaminated soil or groundwater, where it reacts with the contaminants.

The contaminants are destroyed chemically through a process that breaks them down and converts them into less toxic compounds and harmless byproducts.

Compounds treated by chemical reduction include:

  • Hexavalent Chromium In-situ Chlorinated solvents (together with biostimulation)
  • Chlorinated Pesticides

Chemical Oxidation

Through chemical oxidation, organic pollutants can be converted into less hazardous or harmless substances. In the best case scenario, complete oxidisation of organic substances
will result in carbon dioxide and water. This technique can also be used to remove inorganic components (e.g. oxidisation of cyanide).

Chemical oxidation is undertaken on chlorinated or chloflourinated solvents. The solvents can be treated on client site or excavated and treated off–site and can involve a variety of oxidants. Whilst ex-situ treatment often involves sodium percarbonate, calcium persulfate or Condy’s crystals, in-situ treatment tends to involve Fenton’s reagent or Condy’s crystals.

Compounds treated by chemical oxidation include:

  • Chlorinated solvents

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