Biosolids have been used in Australia in a range of landscape rehabilitation projects, agriculture and forestry research, with positive results.
Biosolids are rich in nitrogen and phosphorous. These nutrients are released into the soil very slowly. Approximately 30-40% of the nutrients in biosolids is released in the first year, with declining rates over the next two to four years.
However the spoil material from the biosolids, often has unfavourable characteristics such as high pH, low CEC and can be sodic or saline. The spoil material generally means that the treated paddock or site will require a further application of a another product such as gypsum to balance the soil properties.
In the Hunter region, green waste, fly ash, bottom ash, lime and gypsum have all been blended with biosolids to improve pasture growth around disused open-cut mining sites. Pasture dry matter yields from these sites have been up to 100 times greater than on those areas left untreated (Bio-Recycle 2003). In addition, those areas receiving processed organics sustained pastures with a much greater legume content, thereby establishing a much more viable soil-plant ecosystem.