Phosphogreen™ technology Nätverksträff för fosfor och andra avloppsresurser Stockholm, December 2017

Presentation Peter Balslev, wastewater specialist Suez Water A/S

Phosphorus is a limited ressource

Phosphorus means problems at sludge handling Piping Digester wall 50 m3 "sand" in digester

Mass balance, 0% recovery - “before situation" Pct. of inlet total-P FeCl3 inlet 100 141 outlet 4 WWTP 4% 137 Return sludge 41 Pre-dewater Digester 132 5 rejekt 36 Sludge 96 Final dewat. 96% 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 PO4 weekly NaOH is dosed into the reactor controlled by pH measurement – to keep pH value around 7.5, Air lift pump secures internal recirculation as well as CO2 stripping Internal recirculation pump secures up-flow velocity air water outlet inlet (centrates) struvite extraction washing drying packaging NaOH MgCl2 water recirculation

The bio-P circle for P-recovery Better conditions for bio-P process Chemical precipitation Me:P <1 Include Bio-P Using process control More P-release from digester sludge Higher internal P-load -> but recovered! Lower chemical bound P-content in sludge 40% of P in fertilizer 55% of P in sludge

Improved results: 45% recovery –, Aarhus case - feasible Pct. of inlet total-P FeCl3 inlet 100 115 outlet 4 WWTP 4% 10-20 111 SSH bio-sludge Digester Magnesium 93 15-22 reject 33-43 sludge 50-60 P-recovery Decanter 51% 35-45 45% 8

Quality of struvite and sludge, Aarhus plant 3 samples Land application in DK. DM % 23,7 N % of DM 5,4 P 3,22 % of sample 5,8 12,3 Mg 10,3 Cd mg/kg 0,9 <0,02 0.8 Hg 0,5 <0,1 Pb 23 <0,2 120 Ni 24,4 0,3 30 Cr 17,1 100 Zn 580 2,7 4000 Cu 230 0,7 1000 mg/kgP 28 <0,16 16 <0,8 200 714 <1,67 10000 758 2500 no heavy metals!

Financial Sustainability of P recovery Value creation (Herning case) Cost Unit Value Electricity Euro/year 6 100 MgCl2 ” 50 700 NaOH 6 700 O&M 12 100 Total costs to operate 75 600 Savings Ferric chloride (P removal) 53 300 Polymer(sludge dewatering) 2 000 Electricity (less nitrification) 3 900 Sludge disposal (less volume) 16 000 Biogas (more production) 5 600 Less struvit fighting (O&M costs) 20 700 Total Saving for WWTP 101 500 Income Sales of struvit/ MAP (350€/t) 49 100 Financial balance at 45 % P recovery (in €/y) Operational costs are approx.: 75 600 Savings are calculated/estimated to: 101 500 Income from sales of struvite is: 49 100 The resulting net income is 75 000 Return of investment? The investment cost (as sales price) for the P recovery plant was €465 000 ROI of approx. 6.2 years when operating on both sources of reject waters, and reaching 45 % total P recovery With ROI approx. 7 years - P recovery is a sustainable investment for many water utilities

Front view of reactors and plant

Drying of struvite product, test plant Åby

Silo and bagging of final product

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 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 The product is approx. 2 mm pellets ready for use as fertilizer P=12,5% N=5,5% Mg= 10%

Case for Phosphogreen™ Marselisborg WWTP Reject water treatment project (220 000 PE) Largest P-recovery plant in Scandinavia

Marselisborg WWTP – New building

Existing technology – ready to use fertilizer

Vi ses ved speed-dating  Suez Water A/S Rugaardsvej 5, 8680 Ry, Denmark Tel: +4569156600 Mobile/Direct: +45 40577390 mail; peb@aarhusvand.dk Phosphorgreen™