1. A tool to evaluate the fertilizer value and the environmental impact of substrates from wastewater treatment Martina Hammer* and Joachim Clemens** *Hamburg University of Technology **University of Bonn

2. Introduction Wastewater systems generate new fertilizer products (used themselves or transferred to fertilizing product) Comparison of fertilizers regarding their potential use and pollutant fluxes Existing model was extended for urine and pharmaceuticals (antibiotics, hormones, others)

3. Material & methods Model developed by Rieß (2003) for sewage sludge and manure Based on nutrient equivalents (NE), necessary for sustainable agriculture Relevant data collected by literature review 18 Mg 20 S 1500 Humic substance (H.S.) 170 N 26.4 P 132.8 K 177.5 Ca Amount corresponding to 1 NE (kg ha -1 ) Nutrient

4. Material & methods Assumptions: Fertilization according to regulations - no overfertilization As no data for pharmaceuticals in urine available: Consumed dose (g/a) x Renal excretion (%) Annual amount of urine in Germany (m³/a) Concentration of pharmaceuticals in urine (g/m³) =

5. Nutrient equivalents

6. Amount of urine to be field applied: 19 m³ ha -1 a -1 → 25 m³ ha -1 a -1

7. Heavy metals

8. Antibiotics

9. Hormones

10. Other pharmaceuticals

11. Combinations of organic fertilizers Blend of urine and pig slurry not feasible »Phosphor surplus Only possible combination: »Urine added to cattle manure »Order is important!

12. Combinations of organic fertilizers

13. Conclusion I Urine can be field applied in a dosage of about 20 m³ ha -1 a -1. None single nor any combination can match soil requirements completely. Thus, mineral fertilizer application for all nutrients except N and humic substance is necessary. Best (and only) combination: urine added to cattle manure. Heavy metals’, hormones’ and antibiotics’ fluxes show higher values in animal manure than in urine.

14. Conclusion II Other pharmaceuticals are not comparable. Ecotoxicological studies needed to precise their hazardousness. Overall: model a suitable tool worth to extend.

15. Thanks to … members of DWA-Fachausschuss KA 1.3 … Prof. Otterpohl and his team … DBU … Linz AG Thank you!