Phosphogreen technology. IWA Sweden Seminar Phosphorus recovery from wastewater Malmö, 11 April 2018 Peter Balslev

Transcription

1 Phosphogreen technology IWA Sweden Seminar Phosphorus recovery from wastewater Malmö, 11 April 2018 Peter Balslev

2 Presentation Principles of struvite precipitation Potential in struvite-method PhosphoGreen Benefits Experiences CO 2 and energy

3 3 Chemistry of struvite precipitation Mg 2+ + NH 4+ + HPO H 2 O magnesium + ammonium + phosphate MgNH 4 PO 4 :6H 2 O + H + struvite and acid

4 Advanced process control Includes: ph-control CO 2 stripping from biogas production in digester NaOH dosing to adjust ph at setpoint Fluid bed pelletizing Selection of larger particles at bottom of reactor for harvest Dilution of incoming reject to avoid fines And more

5 Phosphogreen Functionality Process control Magnesium chloride is dosed flow proportional into the reactor inlet together with inlet reject water, dosing is regulated based on analysis of PO 4 weekly water outlet NaOH is dosed into the reactor controlled by ph measurement to keep ph value around 7.5, water recirculation Air lift pump secures internal recirculation as well as CO 2 stripping NaOH Internal recirculation pump secures up-flow velocity air inlet (centrates) MgCl 2 struvite extraction washing drying packaging

6 Application of Phosphogreen TM in the process line primary and/or secondary sludge anaerobic digestion dewatering sludge cake for disposal/ land application water back to the headworks application field: WWTP capacity > 40,000 PE biological phosphorus removal anaerobic digestion phosphorus conc. in digested sludge centrates 70 mg/l THP-processes - Cambi Phosphogreen TM struvite

7 Combined pre-dewatering and final dewatering reject primary sludge sludge cake for disposal anaerobic digestion dewatering secondary sludge from P-stripping tank dewatering water back to the headworks struvite Phosphogreen TM

8 8 Benefit: Phosphorus means problems at sludge handling Piping Digester wall 50 m 3 "sand" in digester

9 Mass balance EBPR plant with no recovery Pct. of total-p inlet FeCl 3 inlet 100 Prim. 80 outlet Biol. 4 4% Dewater Digester 30 5 reject Dewater sludge 96 ~96% 9

10 Mass balance with potentially up to 50% recovery Pct. of total-p inlet FeCl 3 (Reduceret) inlet 100 Prim. 80 outlet Secondary + Tertiary 4 4% 20 Strip. PO 4 76 Magnesium Dewater Digester PhosphoGreen reject Dewater sludge ~46% ~50% 10

11 Quality of struvite and sludge, Aarhus plant Sludge Struvite 3 samples DM % 23,7 N % of DM 5,4 P % of DM 3,22 N % of sample 5,8 P % of sample 12,3 Mg % of sample 10,3 Land application in DK. Cd mg/kg 0,9 <0, Hg mg/kg 0,5 <0,1 0.8 Pb mg/kg 23 <0,2 120 Ni mg/kg 24,4 0,3 30 Cr mg/kg 17,1 <0,1 100 Zn mg/kg 580 2, Cu mg/kg 230 0, no heavy metals! Cd mg/kgp 28 <0, Hg mg/kgp 16 <0,8 200 Pb mg/kgp 714 <1, Ni mg/kgp 758 2,7 2500

12 Energy and CO 2 60 kgp/day recovered exstra energy, Saved energy, kwh/year kwh/year Pumping Drying low temp. waste (12.000) Diverse internal transportation 600 Saved nitrification Extra biogas from carbon saved Saved energy for dewatering Saved transportation of sudge Sum total energy sawing kwh/year kwh/kgp recovered 9,0

13 Energy and CO 2 60 kgp/day recoved Ton/year extra CO2 pumping 13,7 (drying) 4,4 transport and prod. of MgCl 2 40,0 saved CO2 Saved FeCl3 for P-precip. -69,6 Saved aeration for Nitrification -18,5 Saved carbon for DN-process -77,0 Saved N2O from N-removal. -3,0 Saved sludgedewatering + polyme -6,4 Saved transportation of sludge -5,9 total change -126,7 kgco2/kgp recovered -5,8

14 Front view of reactors and plant

15 Quality of struvite, Aarhus plant

16 Existing technology ready to use fertilizer

17 19 Existing technology ready to use fertilizer

18 Phosphogreen Summary Advantages of investment Innovative & effective reject water treatment solution Overall OPEX Cost advantage Green Image phosphorus recovery and reuse ROI ~7 years depending on plant The product is approx. 2 mm pellets ready for use as fertilizer P=12,5% N=5,5% Mg= 10% Value creation No or very reduced scaling problems Reduced chemical use for chemical P removal Reduced costs for sludge dewatering Reduced energy uptake for nitrification Less sludge produced A fertilizer with high value: Struvite Residual sludge with better N:P balance CO 2 -benefits from process

19 Phosphogreen references: Size struvite Finished notes PE recovery % production Aaby WWTP* % kg/d 2013 test plant Herning WWTP % kg/d 2015 no EBPR Marselisborg WWTP % kg/d 2018 partly EBPR

20 Thank you for your attention! Suez Water A/S Rugaardsvej 5, 8680 Ry, Denmark Phosphorgreen Tel: Mobile/Direct: mail; 22