Potential Environmental Benefits from Blending Biosolids with Other Organic Amendments before Application to Land

• Published in: Journal of environmental quality 2017-05, Vol.46 (3), p.481-489
• Main Authors: Paramashivam, Dharini, Dickinson, Nicholas M., Clough, Timothy J., Horswell, Jacqui, Robinson, Brett H.
• Format: Article
• Language: English
• Subjects: Coal; Metals, Heavy - analysis; Plants; Soil; Soil Pollutants
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2016.10.0421

Biosolids disposal to landfill or through incineration is wasteful of a resource that is rich in organic matter and plant nutrients. Land application can improve soil fertility and enhance crop production but may result in excessive nitrate N (NO3−–N) leaching and residual contamination from pathogens, heavy metals, and xenobiotics. This paper evaluates evidence that these concerns can be reduced significantly by blending biosolids with organic materials to reduce the environmental impact of biosolids application to soils. It appears feasible to combine organic waste streams for use as a resource to build or amend degraded soils. Sawdust and partially pyrolyzed biochars provide an opportunity to reduce the environmental impact of biosolids application, with studies showing reductions of NO3−–N leaching of 40 to 80%. However, other organic amendments including lignite coal waste may result in excessive NO3−–N leaching. Field trials combining biosolids and biochars for rehabilitation of degraded forest and ecological restoration are recommended. Core Ideas Landfilling or burning biosolids is an expensive waste of a valuable resource. High rates of biosolids restore degraded soil but cause excessive nitrate leaching. Combining biosolids with other biowastes can mitigate nitrate leaching. Dried, but not wet, wood waste effectively mitigates nitrate leaching. Partial pyrolysis of wood waste may provide energy‐neutral drying.