A COMPARATIVE LIFE CYCLE ASSESSMENT OF ROCK BASED AND RECYCLED P - PDF document

A COMPARATIVE LIFE CYCLE ASSESSMENT OF ROCK BASED AND RECYCLED P FERTILISERS Fabian Kraus, Kompetenzzentrum Wasser Berlin gGmbH fabian.kraus@kompetenz-wasser.de www.kompetenz-wasser.de www.kompetenz-wasser.de 1 1 1 Overview  Conventional fertilizer production  Recovery from wastewater path and comparison  Outlook www.kompetenz-wasser.de 2 2 2 1

Overview  Conventional fertilizer production  Recovery from wastewater path and comparison  Outlook www.kompetenz-wasser.de 3 3 3 Conventional fertilizer production Raw materials Intermediates Final products/fertilizer Phosphate rock, 2 % Calcium phosphates 0-36-0* 0-36-0* Sulfuric acid SSP: 0.5 % Single super phosphate Electricity (SSP) and PK-fertilizer Heat PK: 7.5 % Potassium salts 0-21-0*/* 0-21-0*/* Phosphate ore Triple super phosphate Electricity (TSP) 5 % Heat 0-48-0* 0-48-0* Electricity Water Phosphate rock Heat beneficiated Mono ammonium Diesel Electricity 5 % Additives Heat phosphate (MAP) + Calcination Ammonia 11-52-0 11-52-0 Sulfuric acid Electricity Phosphoric acid (and Water Electricity Di ammonium phosphogypsum) Heat Heat phosphate (DAP) 56.5 % Additives Ammonia + Solvent-extraction 18-46-0 18-46-0 Electricity Heat NP-, NPK-fertilizer NP: 4 % Ammonia via ‚mixed acid route‘ also AP NPK: 7.5 % AN/ Nitric acid * Potassium salts Electricity Nitric acid NP-, NPK-fertilizer NP: 4.5 % Electricity Nitro phosphoric Heat via ‚nitro phosphate route‘ Water acid and by-products NPK: 7.5 % Heat Ammonia * Additives Potassium salts * Variable nutrient concentrations www.kompetenz-wasser.de 4 4 4 2

Goal and scope of LCA Goal: Environmental impact assessment of conventional P- fertilizer production and application Function: Provisioning of conventional P-fertilizers and their agricultural application Functional unit: Functional equivalency is derived via nutrient content, meaning functional unit is „ per kg P 2 O 5 in the fertilizers (total phosphate content)“ In case of multi nutrient fertilizers, efforts for other nutrients (N, K) are allocated www.kompetenz-wasser.de 5 5 5 Scope, System boundaries Emissions to air Energy Materials, Chemicals Fossil fuels Transportation (Electricity & Infrastructure Heat) Heavy fuel oil/ Ammonia, Acid and fertilizer production Natural gas Nitric acid Crude oil/ Natural gas Sulfuric acid Sulfur H 3 PO 4 AP Fertilizer Phosphate Mining & application Phosphate rock SP/PK ore beneficiation NP/NPK Nitro-P Sylvinite Potassium chloride System boundaries Emissions to water Waste and emissions to soil www.kompetenz-wasser.de 6 6 6 3

Relevant countries of origin for phosphate rock and transportation routes [1] Google [1] Google Maps 2018 www.kompetenz-wasser.de 7 7 7 Non-renewable cumulative energy demand (CED) coal, oil, natural gas, uranium net effort for P net effort for K gross effort for P and K Take home messages: #1 Sulfuric acid production and potential by-product valorization are important #2 Valorization of by-products (CAN) reduces energy footprint www.kompetenz-wasser.de 8 8 8 4

Global warming potential (GWP) fossil CO 2 , CH 4 , N 2 O 1 kg P 2 O 5 & 1 kg N Take home messages: #3 GWP of 1 kg N production and application 6-fold higher than for 1 kg P 2 O 5 #4 GWP for N in half equally related to production and to application www.kompetenz-wasser.de 9 9 9 Human toxicity potential (HTP) heavy metals in agricultural soils average Cd-polluted sedimentary rock igneous rock sedimentary rock with high Cd-content Take home messages: #5 Fertilizer application dominates human toxicity potential #6 Extreme variation of HTP depends on Cd-content of phosphate rock www.kompetenz-wasser.de 10 10 10 5

Normalized results Take home messages: #7 P and heavy metal emissions into environment of importance #8 Minor efforts for decadmiation technologies compared to benefits www.kompetenz-wasser.de 11 11 11 Summary NP-/NPK-production via nitro phosphate route shows lower efforts for  almost all impact categories related to P 2 O 5 Production route and origin of sulfuric acid is very important for energy-  and SO 2 -footprint (+/- 40 %) P-fertilizer application shows high normalized shares regarding the  freshwater eutrophication potential and the human toxicity potential Decadmiation of sedimentary phosphate rock reduces human toxicity  potential significantly, while the additional increase in energy demand and CO 2 -footprint are moderate (Long term-)emissions from gypsum stacks may be problematic  (potential local environmental drawbacks for the aquatic environment) www.kompetenz-wasser.de 12 12 12 6

Overview  Conventional fertilizer production  Recovery from wastewater path and comparison  Outlook www.kompetenz-wasser.de 13 13 13 Goal and scope of LCA Goal: Environmental impact assessment of P-fertilizer recovery from wastewater path and its application Function: Treatment and disposal of primary and excess sludge of a typical large scale WWTP in Germany Functional unit: All efforts/ benefits of an additional P recovery technology are related to the system and its function, the functional unit is „changes on sludge treatment and disposal per p.e. and year “ www.kompetenz-wasser.de 14 14 14 7

Scope, System boundaries Emissions to air Energy Materials, Chemicals (Electricity & Fossil fuels Transportation Infrastructure Heat) Primary sludge Static thickening Mono- Digestion Dewatering T T Ash disposal incineration Excess sludge Mechanical 3x Struvite precipiation 4x Recovery thickening from digested sludge from ash Recovered P- Recovered P- Fertilizer 5x Struvite precipitation fertilizers fertilizers application from centrate WWTP (simplified) Substitution of conventional Substitution of conventional fertilizers (Average German P) fertilizers (Average German P) System boundaries Emissions to water Waste and emissions to soil www.kompetenz-wasser.de 15 15 15 Non-renewable cumulative energy demand (CED) coal, oil, natural gas, uranium Trade-off: electric efficiency of CHP vs. mono-incineration Considering technical P-acid as product Take home messages: #1 Reduced sludge volume and gas production improve energetic efficiency #2 High-value (by-)products from ash improve energetic profile of processes www.kompetenz-wasser.de 16 16 16 8

Global warming potential (GWP) fossil CO 2 , CH 4 , N 2 O approx. + 13 kg CO 2 -Eq/(pe a) if co-incineration is status-quo approx. + 9 kg CO 2 -Eq/(pe a) for N 2 O-emissions mitigation Take home messages: #3 Direct emissions of mono-incineration (N 2 O) of importance #4 Quitting lignite incineration (and co-incineration) reduces GWP severely www.kompetenz-wasser.de 17 17 17 Human toxicity potential (HTP) heavy metals in agricultural soils Reduction Cd-Input sedimentary igneous Metals from rock with rock high Cd-content sludge/ ash Take home messages: #5 Struvite and technical P-acid are products with negligible contaminant-level #6 Sludge ash contains high HM-loads, HM removal recommended www.kompetenz-wasser.de 18 18 18 9

Summary Integrated P recovery in WWTP (struvite recovery) reveals  environmental benefits (for EBPR WWTP), it is accompanied by operational benefits (e.g. reduced sludge volume due to improved dewatering) End-of-pipe P recovery from sludge ash can be energetically and GWP-  related more or less equal to a conventional P fertilizer production, if chemical consumption can be reduced via internal recycling and high value products and by-products are recovered Strong differences regarding toxicity indicators for products derived  from sludge ash dependent on the fate of heavy metals in the process Consideration of local boundary condition (EBPR/ sludge disposal route)  necessary for an environmental friendly P-recovery scheme www.kompetenz-wasser.de 19 19 19 Overview  Conventional fertilizer production  Recovery from wastewater path and comparison  Outlook www.kompetenz-wasser.de 20 20 20 10

Outlook Products Precipitates (struvite and Conventional Sludge ash and thermal other salts) from sludge intermediates (H 3 PO 4 , recycled phosphates or and centrate Ca 3 (PO 4 ) 2 ) from sludge ash processes mixing ash with acids Outlook and Processes with 50 % P- Full-scale implementation Full-scale implementation further recovery rate in pending, first plant under pending development development construction Product quality Heavy metals negligible, Heavy metals relevant, Heavy metals and organic regarding organic pollutants organic pollutants pollutants negligible contaminants destroyed by incineration destroyed by incineration Main market, implementation of Niche market, costs for Niche market, costs can be products in conventional recovery have to be Market justified via operational production processes financed via product sales potential benefits, marketing can possible, costs for or via sewage fees, end-of- create additional income recovery have to be waste status depends on financed via product sales conformity with new FPR or via sewage fees www.kompetenz-wasser.de 21 21 21 Thanks for your attention!  Conventional fertilizer production  Recovery from wastewater path and comparison  Outlook  Questions? www.kompetenz-wasser.de 22 22 22 11