What are biosolids used for?

Biosolids can be applied as a fertiliser to improve and maintain productive soils and stimulate plant growth. They are also used to fertilise gardens and parks and reclaim mining sites.

In Australia and New Zealand, biosolids have been used for:

• Co-generation/power production/energy recover
• Land application in agriculture (vine, cereal, pasture, olive)
• Road base
• Land application in forestry operations
• Land rehabilitation (including landfill capping)
• Landscaping and topsoil
• Composting
• Incineration
• Landfill
• Oil from sludge (experimental)

Other uses overseas include:

• Bricks and construction material
• Vitrification (glass manufacture)
• Bio-fuel
• Fuel substitute (cement works)
• Additive to road base
• Jewellery

Biosolids are graded according to chemical composition and the level of pathogens remaining after production. Not all biosolids can be used for all applications. Lower qualities are typically used for road based and mine site rehabilitation. Only the highest grade of biosolids can be used to grow crops for human consumption. Regulators, such as State departments of Health and Environment strictly control the application, production and quality of biosolids.