Biosolids-derived fertilisers: A review of challenges and opportunities

• Published in: The Science of the total environment 2023-06, Vol.875, p.162555-162555, Article 162555
• Main Authors: Marchuk, Serhiy, Tait, Stephan, Sinha, Payel, Harris, Peter, Antille, Diogenes L., McCabe, Bernadette K.
• Format: Article
• Language: English
• Subjects: Agriculture; Agronomic value; Biosolids; Fertilizers; Land application; Microplastics; Nutrients recycling; Plastics; Regulation; Sewage; Soil; Sustainable management
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.162555

Soil application of biosolids as an organic fertiliser continues to be a cost-effective way to beneficially utilise its carbon and nutrient contents to maintain soil fertility. However, ongoing concerns over microplastics and persistent organic contaminants means that land-application of biosolids has come under increased scrutiny. To identify a way forward for the ongoing future use of biosolids-derived fertilisers in agriculture, the current work presents a critical review of: (1) contaminants of concern in biosolids and how regulatory approaches can address these to enable on-going beneficial reuse, (2) nutrient contents and bioavailability in biosolids to understand agronomic potential, (3) developments in extractive technologies to preserve and recover nutrients from biosolids before destructive dissipation when the biosolids are thermally processed to deal with persistent contaminants of concern (e.g. microplastics), and (4) use of the recovered nutrients, and the biochar produced by thermal processing, in novel organomineral fertilisers that match specific equipment, crop and soil requirements of broad-acre cropping. Several challenges were identified and recommendations for prioritisation of future research and development are provided to enable safe beneficial reuse of biosolids-derived fertilisers. Opportunities include more efficient technologies to preserve, extract and reuse nutrients from sewage sludge and biosolids, and the production of organomineral fertiliser products with characteristics that enable reliable widespread use across broad-acre agriculture. [Display omitted] •Land application of biosolids is a cost effective way to reuse nutrient in soils.•Ever changing nature of biosolids contaminants dictates regulatory guidelines.•Nutrient content in biosolids provides an understanding of baseline agronomic value.•Extractive technologies can recover and purify valuable constituents from biosolids.•Prospects for novel granulated fertilisers derived from biosolids are significant.