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Regards from Flanders Greet De Gueldre Manager strategic innovation and climate Conférence Charleroi - Gestion innovante des boues d’épuration à l’échelle européenne - 22 Oct 2013 Content • Aquafin in brief • Drivers innovation sludge management • Sludge treatment infrastructure • Examples research and innovation for different sludge treatment steps 2 Mission for the Flemish government Finance Design Build Operate 3 Non-regulated activities Flemish municipalities Products and services for the expansion and management of the local municipal system Other clients Projects for industry in Flanders and foreign partners by the subsidiary Aquaplus 4 Key figures – 31st December 2012 Infrastructure managed on behalf of the Flemish government 5.172 km supra-municipal collectors 1.332 pumpiung stations and detention basins 266 wastewater treatment plants 96,5% of the treatment plants met all standards in 2012 5 Key figures – 31st December 2012 Projects in portfolio for the Flemish region delivered: 2,416 3.1 billion Euros in design phase or awarded: 1,176 • 1.2 billion Euros 6 6 Drivers innovation sludge management • Need to dispose volume of 110 229 tonnes dry solids (TDS) (2012) • Agriculture not allowed since end 1999 • Landfill prohibited in 1997 Incineration Co-incineration • Costs of chemicals and sludge disposal: EUR 29 million Other operating costs 13% 0% 5% 5% Transport by truck Chemicals dewatering Co-incineration after drying 77% Incineration 7 Drivers innovation sludge management Energy policy declaration: by 2020 Save 20% primary energy Save 20% on transportation Generate 13% green electricity as compared to 2010 8 Innovations in sludge management are mainly driven by aim to further optimise process and reduce operational costs aim to recover and produce energy from sludge aim to reduce transportation of liquid sludge aim to exploit raw materials from sludge 9 Current sludge treatment Aquafin • As is situation 2012 54 856 TDS Seed sludge: 45 TDS 50% Co-incineration of pellets: 32 216 TDS - 12 579 TDS 266 WWTPs 17 digesters 110 229 TDS 3 sludge dryers 43 dewatering sites 33% 1100 PS 32 381 TDS Incineration: 62 999 TDS Sealing landfills: 1 609 TDS 97 825 TDS Results 2012 10 Sludge digestion • Situation digestion in 2012 • Reduction of sludge volume -12 579 TDS • Production of 8.27 million m3 biogas • Green electricity (gas-engines, CHP): 9.5 million kWh • Used on own infrastructure • Green electricity certificates ± EUR 800 000 • Replacement of natural gas: heat production to dry sludge 11 Research and innovation digestion • Past optimisations of existing infrastructure and operations 120000 10 9 100000 7 80000 TDS 6 60000 5 4 40000 3 Million kWh 8 2 20000 1 0 0 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Total sludge production Digested sludge Electrical energy 12 Research and innovation digestion • Aquafin sludge mainly secundary sludge (< 50% ODS degraded) • Research on maximisation biogas production for more electricity, more continuous CHP generation, impact on dewatering • New processes before digestion: pretreatment with CAMBI, ultrasonic, electroporation • Co-digestion 13 Pretreatment with CAMBI thermal hydrolysis • Patented technology of CAMBI - Norway • Hydrolysis of organic material for 20-30 min at 160°C and 6-10 bar prior to digestion • Concept evaluated on pilot set-ups with and without CAMBI pretreatment (sludge WWTP Antwerp-South) 14 Pretreatment with CAMBI thermal hydrolysis • Pilot-scale research conclusions • Increase of VS degradation, 40-50% increase of biogas production • Increased dewaterability up to 40% DS (but more polymer usage) • Stable operations, decrease of foam risk • Pre-dewatering necessary to obtain 5%-16% DS • Financial feasibility • High investment costs • Payback in current situation digestors Aquafin > 7 years • Only interesting for large digesters with enough input of sludge and where dewaterability can be optimized • Option will now be considered for the renovation of the sludge treatment line with dryer of a large WWTP 15 Pretreatment with ultrasonic disintegration • Patented technology of VTA – Austria • Through periodical densification and expansion of the sludge finest gas bubbles are produced in which a pressure of up to 500 bar and temperatures of approximately 5,500 °Celsius prevail • Full-scale evaluation on thickened surplus sludge before secondary digester of WWTP Turnhout • At same time: solve massive operational problems • Foaming on digester (filamentous bacteria Microthrix and Nostocoïda) • Odor problems 16 Pretreatment with ultrasonic disintegration •Full-scale research conclusions •Significant improvement DS-disintegration and associated biogas production •primary sludge: 55% - 60% •secondary sludge : 30% - 40% •Increased DS content of dewatered sludge: 15% - 20% improvement •Considerable decrease of foaming and odor problem •Financial feasibility •pay-back 3 years •Full-scale application since 2007 17 Pretreatment with electroporation • BioCrack patented technology • Hydrolysis of organic material by electrical field (15-100kV/cm, 250mA) applied with electrodes in stream • Concept will be evaluated on 2 pilot-scale digestors (1.3 m3 each) • Just started 18 Co-digestion with glycerine • Co-digestion of secondary sludge to increase organic load of digestors • Full-scale test with crude glycerine 80% (up to 1 kg crude glycerine/m3 reactor) on WWTP Hoogstraten • Commercially available product • Side product of bio diesel 19 Co-digestion with glycerine • Full-scale research conclusions • Surplus methane production 34-66% • Degradability sludge up to 66% higher (synergistic effect) 3000 2500 Average Period III m³ /day 2000 1500 Average period II Total daily average 1000 Average Period I 500 Average without dosing 0 0 20 40 60 80 100 120 20 Co-digestion with glycerine • Operational aspects • No significant operational problems • Foaming problems at highest dosage • Return on investment: <1 year • Potential for Aquafin • 2 900 MWh extra electricity/year • with 870 tonnes of glycerine/year • dosed on 5 digesters • Not applied due to cost increases of crude glycerine 21 Co-digestion other • Pilot-scale (1 m3) evaluation co-digestion of WWTP sludge with kitchen waste and roadside grass mowings • Adding limited amounts of kitchen waste can increase both the biodegradebility and the methane propduction • However not possible for Aquafin due to legal restrictions • New concepts • Co-digestion of organic material and sludge in combination with anammox technology • Possibly efficient at smaller scale 22 Dewatering • Situation of dewatering in 2012 • Average DS: 20-36% = LOW • Cost chemicals EUR 5.5 million = HIGH • Transport dewatered sludge 270 000 tonnes, EUR 2.4 million • Research and innovation dewatering • To increase DS content • To decrease transport of dewatered sludge • 0,3% increase of DS in 2012 • = 2 000 shipments off the roads • To decrease energy consumption of subsequent incineration or drying 23 Dewatering with Kemicond • Patented sludge conditioning process of Kemira • Preliminary research good results in combination with Bücher press H2SO4 H2O2 Polymer Sludge 2 - 5% 20 - 38°C pH = 4.0 - 5.0 Filtrate 1. Conditioning (KemiCond) with H2SO4 (95%) and H2O2 (35%) 2. Flocculant addition polymer Filter cake 3. Dewatering with Bücher press 24 Dewatering with Kemicond • Pilot-scale evaluation on sludge WWTP Grimbergen Centrifuge Bücher press Bücher press + Kemicond DS dewatered % 33 33 43 PE consumption kg act. PE/TDS 20 15 10 • Financial feasibility • High investment costs compared to CEN • Equal after 5,2 years • Function of cost of chemicals • Will be applied in full-scale at WWTP 25 Drying • Situation of drying in 2012 • Capacity of about 200,000 tonnes dewatered sludge/year • 33% of the sludge dried • Pellets recognised as renewable energy if dried using biogas or renewable energy source • Dryer Houthalen: waste heat adjoining household waste incinerator (24 million kWhthermal supplied) • Dryer Antwerp - Deurne: biogas from digestors, replacing part of natural gas (17,7 million kWhthermal ) 26 Final disposal • Situation in 2012 • Incineration EUR 16.5 million • Co-incineration EUR 32,000 • Research new technologies in frame of future renovations • • • • • Impact on sludge treatment steps Disposal cost/benefit Gasification Supercritical water oxidation … 27 Resource recovery with struvite • Research on phosphorous recovery • 10 tonnes total phosphorous/day in influent • Operational problems with struvite formation after digestion • Dried sludge to cement kilns, P limiting • Phosphorous recovery with struvite (MgNH4PO4.6H2O) • Market ready concept • Concept proven on pilot-scale on sludge waters and concentrated effluent • Demonstration project on the recovery of phosphorus from digestate with struvite ongoing 28 Thank you. © 2010 Aquafin Disclaimer Lorem ipsum dolor sit amet, consectetur adipiscing elit. 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