Biosolids in food production - phosphorus recycling and food safety (218901)

This project will improve the understanding of how biosolids can be a future phosphorus source in food production without compromising on food safety and environmental risks. There is a growing awareness of the limitations in global mineral P reserves, in creasing the need to create efficient P cycles in food production. Although a considerable amount of P is returned to Norwegian agriculture with biosolids, this mainly supplements P in mineral fertilizers instead of substituting it. The agricultural benef it of the biosolid-P is low, and instead implies a potential environmental risk as it increases the P concentration in the soil. Efficient utilization of biosolid-P calls for reliable tools to quantify the availability of P to plants in an agricultural sy stem in the short and long term. As the availability of P presumably is low in typical Norwegian biosolids, the potential for improving plant availability by adjustments in specific sewage treatment process-steps will be tested. Urban sewage, the raw mate rial for biosolids, contains compounds originating from various and complex sources, e.g. food, personal care products, cleaning, industries and road dust. Regarding food safety, the occurrence, availability and/or degradation of pollutants in biosolids n eed to be understood. The project will supplement the report from the Norwegian Scientific Committee on Food Safety on agricultural use of biosolids with more data on heavy metals and organic pollutans. The project is expected to contribute to a safe an d sustainable utilization of biosolids in agriculture. The findings are expected to give practical recommendations on how to improve the substitution of mineral P with biosolid-P in food production. It is also expected that the project will clarify the ne ed for limitations on use of biosolids on agricultural land situated near sensitive aquatic systems.