1. PHOSPHORUS REMOVAL ON DAIRIES IN THE PACIFIC NORTHWEST Applying a Cone Shaped Fluidized Bed Phosphorus Crystallizer Ron Sheffield – U of Idaho Keith Bowers – Multiform Harvest Inc. Joe Harrison – U of Washington

2. Magnesium, Struvite Precipitation Magnesium ammonia phosphate crystal Similar to a Kidney Stone Equilimolar concentrations of Mg, NH 3 and PO 4 Naturally occurring in waste systems Overflow pipes, recycle elbows, pump impeller Very common in municipal and swine waste systems Historically produced slow release fertilizer

3. Magnesium, Struvite Precipitation Theory: Magnesium acts as a coagulant to settle out phosphorus. How it Works: Magnesium, ammonium and phosphate ions when at a pH of 7 to 11 will combine to form Struvite (MgNH 4 PO 4 *6 H 2 O) Removal Efficiency: 90% reduction in SP from a swine anaerobic treatment lagoon in NC

4. Laboratory Crystallizer

5. Crystallizer Cone Mg Dissolving Cone (optional) Anhydrous Ammonia Mg Wastewater In Harvested Struvite 4-20-0.25 Treated Effluent Fluidized-Bed Struvite (MgNH 4 PO 4 ) Crystallizer Pilot Scale Crystallizer 2 gpm

6. Si-Ellen Farm 4,000 cow open lot Flush feeding alleys Primary Solids Removal – Slope Screen Secondary Solids Removal – Gravity Basin 3 Wastewater Storage Ponds - 18M gallons

7. Werkhoven Dairy 600 cow freestall Flush manure handling Primary Solids Removal – Gravity Basin 3 Wastewater Storage Ponds - 18M gallons Wastewater Analysis TP = 85 mg/l PO 4 = 25.4 mg/l pH = 7.8

8. Results PARAMETER Bowers and Westerman, 2003 Idaho DairyWashington Dairy TP (ppm) 889383 OP (ppm) 422739 Mg (ppm) 60155241 TAN (ppm as N) 178332662 pH 7.77.57.8 TP removal (%) 66 19 (0 – 55) 6 (-41 – 63) PO4 removal (%) 80 56 (-59 – 89) 4 (-55 – 38)

9. Crystalline Product Advantages Non-sludgy Crystalline structure Easily dried and handled Concentrated Fertilizer - 4:20:0.25 Average ID analysis Organic Product??? Limitations Slow Release Low Nitrogen

10. Wastewater Solubility vs Equilibrium - Ohlinger et al. 1998

11. Conclusions Cone shaped fluidized bed crystallizer was successful in removing P from dairy wastewater TP removal was observed to be lower than as demonstrated with swine lagoon wastewater PNW dairies showed higher Mg and TAN: possibly reducing TP removal via struvite harvesting

12. Next Steps….. Struvite Crystallization Acidification Pre-Treatment pH, retention time Portable Struvite Crystallizer Trailer mounted Evaluate various wastewaters Full-Scale Crystallizer: >10M gallons/year Organic Certification Crop Response

13. Next Steps….. Anaerobic Digestion Phosphorus Pretreatment Digester not for energy production rather as P removal systems Investigate lowest Hydraulic Retention Time (HRT) to achieve highest PO 4 :TP Smaller & Cheaper digester Follow with Struvite Crystallization