text: In 2003, the Ministry for the Environment and the New Zealand Water & Wastes Association produced the document Guidelines for the safe application of biosolids to land in New Zealand. In the document, biosolids were defined as "sewage sludges or sewage sludges mixed with other materials that have been treated and/or stabilised to the extent that they are able to be safely and beneficially applied to land... [and noted that they] have significant fertilising and soil conditioning properties as a result of the nutrients and organic materials they contain."
  A New Zealand scientist, Jacqui Horswell later led collaborative research by the Institute of Environmental Science and Research, Scion, Landcare Research and the Cawthron Institute into the management of waste, in particular biosolids, and this has informed the development of frameworks for engaging local communities in the process. In 2016 the project developed a Community Engagement Framework for Biowastes to provide guidelines in effective consultation with communities about the discharge of biowastes to land, and in 2017 another collaborative three-year project with councils aimed to develop a collective biosolids strategy and use the programme in the lower North Island. When the project was reviewed in 2020, the conclusion was that it had shown biosolids can be beneficially reused. 
  A research paper in 2019, reported on the management considerations around using biosolids as a fertilizer, specifically to account for the complexity of the nutrients reducing the availability for plant uptake, and noted that  stakeholders need to "factor in the expected plant availability of the nutrients when
  assessing the risk and benefits of these biological materials."