Sodic Soil Remediation for Pasture:

AGR is a technology development company with a special interest in beneficial reuse of waste materials and a strong focus on practical, cost-effective waste reuse solutions. It has been in operation since 2000 and has a wealth of experience in soil remediation processes and technologies.

As part of its beneficial reuse program, AGR develops and utilises patented technologies to process wastes into beneficial soil amendment agents suitable for the treatment of land affected by salinity and / or sodicity. The technologies have been proven to improve affected soils physical and chemical properties, and increase the carrying capacity of the land.

Specifically, AGR have developed proprietary products known as "Sodic Soil Amendment Agent" and "Humus Builder" for application to a heavily sodic soil on a trial property on the Downs (SEQ). These materials are derived from beneficially reused wastes and incorporate a balance of metals, organic carbon and nitrogen sources (such as from biosolids and related materials) to correct the degraded soil for its lack of soil nutrients and poor structure, to the extent that treated areas are now cultivating oats and barley. This indicates the potential for correcting the formerly degraded land, so as to now grow various crops that would not ordinarily grow in the area.

The organic materials are matched for their elemental balances, and blended to produce "Humus Builder". This product is applied under the land management program already in effect at the property, which dictates that the soil carbon content is to be gradually built up over successive applications. Under this program, the soil ecology is gradually modified to that of productive cropping or pasture land. In relation to the organic carbon sourced from biosolids, lignins and related byproducts, the nutrients are of immediate benefit as energy provisions for stimulating soil micro-flora and fauna. As the carbon is introduced to the soil, it is utilized in the re-establishment of the desired micro-ecosystems, and so rebuild the soil health.

Dredged Silt Enhancement for Civil Bulk Earthworks:

Presently, the use of dredged silts is limited because of their low load bearing capacity, and accepted consolidation processes for stabilising them are costly and time consuming. Improvements in the engineering properties through chemical treatments will turn this situation around and impart some value on the dredged silts, making them useful fill materials in a broad range of applications.

Furthermore, these treatments can be carried out using a select range of waste derived additives, with positive environmental outcomes in terms of the beneficial reuse of waste materials, while presenting no adverse environmental impact on their final placement.

By way of background, the engineering properties of a soil arise from a combination of its physical and chemical characteristics. How a soil compacts and the strength the soil attains are functions of the types, sizes and shapes of the mineral particles present. Clay minerals are able to absorb many times their volume of water and expand into loose structures. These expanded structures are very poor load bearers, so the silt has poor engineering properties. Therefore, the durability, deformability and moisture reactivity of the soil are also functions of the types and gradings of the minerals, but the clay contents generally dominate these properties.

By neutralising the reactivity of the clays, the silts will achieve better compaction. These same reactions which destroy the expansivity of the clays reduce their moisture holding capacity and consequently allow the silts to dewater more readily. The stabilised silts will as a result have lower swell and achieve better compaction and strength.

The AGR technology utilises two classes of stabilisers to treat clays:

* Highly positively charged ions (cations) adsorb onto negatively charged mineral surfaces to coagulate them and aggregate them into larger particles.
* Replacement Lime reacts with soil minerals to create cementitious materials, as well as having some cation exchange capability.