Phosphorus recovery processes in Germany Fabian Kraus IWA Sweden Seminar Phosphorus recovery from wastewater Malmö, 11 April 2018

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1 Phosphorus recovery processes in Germany Fabian Kraus IWA Sweden Seminar Phosphorus recovery from wastewater Malmö, 11 April

2 Legal regulations in Germany Düngeverordnung (national interpretation of EU nitrates directive) Upper limit of 170 kg N/hectare for biosolids (farm gate balance) Different qualifying factors regarding N for manure/digestates/sludge Result: dramatic decrease in agricultural sludge valorization Result: dramatic increase of sludge disposal costs Klärschlammverordnung (sewage sludge ordinance) Agricultural sludge valorization is partly prohibited (2029/32) Requirement regarding incineration and phosphorus recovery (2029/32) Mono-incineration and recovery from ash or mono-disposal of ash Co-incineration in cement works, lignite power plants or municipal waste incineration plants is only allowed if P concentration is reduced by 50 % or below 20 mg/kg DM sludge Result: mono-incineration is preferred options for most wastewater associations, P recovery will be done later 2 2

3 Legal regulations in Germany sewage sludge ordinance 3a phosphorus recovery from sludge for recovery of phosphorus from sewage sludge [ ], a process shall be used which reduces the phosphorus content in treated sewage sludge [ ] [ ] 1. By at least 50 percent or 2. To less than 20 g P/kg DM The phosphorus content depends not only on the amount of recovered phosphorus, it depends also on the amount of DM (efficiency of digester), energy recovery is counterproductive regarding this paragraph The paragraph contradicts with the waste hierarchy (efficient digester = waste reduction) A 50 percent reduction of the phosphorus content in sludge or a phosphorus content below 20 g P/kg DM does not mean that a defined recovery rate (mass balance!, e.g. 50 %) will be achieved 3 3

4 Phosphorus recovery processes Starting point modules for P release from sludge modules for P harvesting integrated recovery from water phase of sewage sludge onsite WWTP: (digested sludge or centrate) without forced P release forced Polyphosphaterelease before digestion P-release by thermal hydrolysis P-release by chemcial treatment Wasstrip Lysotherm Pondus Stuttgart CalPrex Haarslev ExtraPhos & Precipitation in water phase of digested sludge Precipitation in centrate AirPrex EloPhos Pearl NuReSys Phospaq PhorWater Stuttgart ExtraPhos Brushite CalPrex Brushite Sludge disposal P recovery processes end-of-pipe recovery from solid phase of sewage sludge decoupled from WWTP (dewatered/ dried sludge or ash) From ash via monoincineration From sludge/ alternative sludge disposal to monoincineration Wet chemical thermal thermal Conv. Fertilizer industry SSP/TSP/NP/NPK/PK Ash2Phos Calciumphosphate AshDec Treated sludge ash RecoPhos (InduCarb) P 4 Pyreg Pyrolysat traditional sludge recycling in agriculture TetraPhos techn. grade H 3 PO 4 EcoPhos (H 3 PO 4 ) techn. grade H 3 PO 4 Thermphos P 4 Mephrec P slag Full-scale Pilot-scale 4 4

5 Recovery of struvite in Europe (inventory from 2016) Word-wide full-scale operating systems: 14 x PEARL 9 x AirPrex 9 x NuReSys 3 x PHOSPAQ TM 10 x other struvite processes Approx t struvite in Europe recovered and recyceld (ca t P, 750 t N) 5 5

6 Struvit recovery from sludge (EBPR plants!) 6 6

7 Full-scale implementations of AirPrex in Germany Berlin-Waßmannsdorf Operating since 2011 Harvest: 2.5 t struvite/day Mönchengladbach Operating since 2010 Harvest: 1.5 t struvite/day Uelzen Salzgitter Wolfsburg 7 7

8 Combination of enhanced energy and nutrient recovery in Braunschweig, Germany (currently in construction) 8 8

9 Recovery from sewage sludge ash (TetraPhos) in Hamburg, Germany (currently in construction) 9 9

10 Conclusions Legislation An P recovery obligation with many restrictions may not be the best way to foster P recovery in practice; A green-deal (Netherlands) might be better?! Other legal boundaries towards P recycling are still existing Status-quo There are around 10 full-scale P recovery facilities in Germany (due to good economic business cases) although the legislation does not requires them yet. Processes P recovery from sludge (EBPR) is economically feasible due to operational benefits (e.g. reduction of sludge volume for disposal) P recovery from ash may be/ will be economically feasible In any case: the local boundary conditions are decisive! P recovery is part of a wider circular economy model! P recovery should be economically and environmentally feasible in a system-perspective (Energy-, N- and S-recovery, Sludge disposal, Polymer and coagulant consumption, coagulant recovery etc.)

11 Thank you for your attention