Beneficial reuse of biosolids

Biosolids are a nutrient- and energy-rich byproduct of the wastewater treatment process. They are predominantly a mix of water and organic materials.

The biosolids standard is based on the 2025 Guidelines for the Beneficial Reuse of Biosolids. The key aspects of the standard include:

• setting a grading system for processing biosolids, with corresponding activity status under the Resource Management Act 1991 (RMA) for how and when biosolids can be reused and stored

• imposing additional requirements where biosolids have a lower grade and greater risk profile

• requiring monitoring and reporting to reflect the grade of biosolids.

The 2025 Guidelines for Beneficial Reuse of Biosolidsoutbound provide additional detail about how to comply with the biosolids standard, including detail about how to discharge biosolids while managing the impacts on soils, water, plants, animals and people.