There have been many studies on the use of organically derived fertilizer on soils.This research has focused on both the efficacy and safety of the use of organically derived fertilizer as a soil amendment and a soil conditioner.Here is a selection of relevant research studies:
Global Atlas of Excreta, Wastewater Sludge, and Management: Moving Forward the Sustainable and Welcome uses of a Global Resource
Biosolids – A Fuel or a Waste
Assessing the Fate and Significance of Microconstituents and Pathogens in Sewage Sludge
Examples of Scientific Studies Relating to the Use of Biosolids
Surveys, Literature Review and Analytical Results for Biosolids