1. Welcome European visitors ! Februari 7, 2013, Site Houthalen Centrum

2. What are we going to do today? Who is Aquafin ? Energy management Wastewater treatment plant (WWTP) Thermal Sludge dryer Field trip on site

4. Wastewater treatment in Flanders

5. Who is Aquafin ? 1990 : Established by the Flemish government 1995 : exploitation of the infrastructure 2004 : owner of all WWTP 265 WWTP 1315 pumping stations 5096 km sewer pipeline 1000 employees 2.000.000.000 liters/day

6. Energy management

7. Energy consumption in Flanders 0,7% of the industrial energyconsumption in Flanders

8. Energy consumption Aquafin Budget : 112 million EUR

9. “Trias Energetica” concept Energy report, Energy audit, Aeration energy

10. Method -Monitoring -Simple performance indicator : kWh/IE NkJ -Compare model with reality  Awareness !!! Model Influentload Volumes Head (pumps) Aeration power Efficiency Pumping power Mixing power

11. Energy audit WWTP 11 Via voettekst kan je hier je titel toevoegen © Aquafin NV 2005 OPERA OD TOOO&PO Energy- Management - TOP 5 : audit by means of a multidisciplinairy team

12. Resultaat 2010 - 2011 - Besparing na uitvoering alle energieprojecten : 20102011 7 miljoen kWh e 7,5 miljoen kWhe 746.500 EUR/jaar755.000 EUR/jaar

13. “Trias Energetica” concept Sludge digestion Codigestion Heatpumps

14. Sludge digestion +40%

15. Resultaat 2012 - Besparing door opwekking groene stroom 9.500.000 kWhe  1.805.000 EUR (+14,5%) In 2010: 1 RWZI > 1 miljoen kWhe In 2011: 2 RWZI’s> 1 miljoen kWhe In 2012: 5 RWZI’s > 1miljoen kWhe

16. “Trias Energetica” concept Efficient processes ( Annamox, A/B Verfahren) Efficiënt equipment (bv. screwblowers) Efficient dewatering (bv bucher)

17. Efficient tools Incorporate Energy in everything we do : - ‘Knowledge’ projects (multidisciplinair !) -Propellors, mixers, et al. - Purchasing pumps, compressors : Energy as important parameter -Total Cost of Ownership !!!! - Experiments in tendering vb. Leuven, Burcht -Aim : use the knowledge of providers to think along with us. To provide us with a solution - Researchprojects -Heatpumps -Glycerol dosing -Screwcompressor - Bucher press

18. Total Cost of Ownership

19. Conclusion -Think Energy !

20. How do we do it ? Wastewater cycle and sludge cycle Sludge treatment

22. How do we do it ? Wastewater cycle and sludge cycle Stap 1: Mechanical treatment Stap 2: Biological treatment Stap 3: Final treatment (separation by sedimentation)

24. How do we do it ? Sludge treatment -Anaerobe sludge digestion -(sludge reduction, methane production) - Sludge dewatering (up to 35 %DS) - (thickener, thickening table, filter beltpress, chamber filterpress, centrifuge) - Drying (thermal sludge dryer) (up to 90 %DS) - (Energy production by burning as fuel, major reduction of sludge mass)

25. Thermal Sludge Dryer

26. Dryer To reduce sludge volume A consisted and manageable product To reduce transportation cost Energy value by burning as lower fuel Capacity = 10.000 tons/year at 90 %DS (3,7 m3/h water evaporation) Or 150 m3/d dewatered sludge transformed into 30 ton of pellets Why should we dry sludge ? Digested and active dewatered sludge

27. Dryer Air Fan Sludge drying The dryer is for 50 % filled up with pellets Air fans are started and create an air flow throughout the pellets (max. airflow = 24.000 m3/h) The air flow is used to absorb dust and moister coming out of dewatered sludge, it also forms the pellets Air flow is inert to prevent explosion Inert gasses are mainly produced during the process (extra nitrogen injection during start up or when necessary)

28. Dryer SteamWater Heat Exchanger Inside dryer Steam temperature = 200 °C Steam pressure = 12 bar Water temperature = 100 °C Under-pressure on top of dryer Top temperature is regulated at 85°C mainly by controlling the sludge flow Heating up the dryer Steam is used to heat up the dryer The steam is produced by a neighbor factory Condensed water (100 °C) coming out of the heat exchanger is returned to the steam producer

29. Cyclone Dust Separator Condenser Drip Collector Dryer WWTP Effluent Fully closed inert air circulation Remove dust (drying process) Remove water out of sludge Condensation by sprinkling 60 °C SteamWater Heat Exchanger Inside dryer 15 °C 85 °C 60 °C The condenser 89 m³/day

30. Sludge- Daily based buffering SteamWater Heat Exchanger Inside dryer Dryer Sludge Bunker (500 m3) Sludge flow at 150 m3/d DS = 25 - 30 % DS = 60 % Feeding sludge

31. SteamWater Pellet Silo Pellet Cooler Heat Exchanger Inside dryer Dryer 85 °C 40 °C WWTP 40 °C Pellets at 90 % DS Daily 30 tons of pellets Silo is kept inert to prevent explosion Removing the pellets 180 tons

32. SteamWater Pellet Silo Pellet Cooler Heat Exchanger Inside dryer Dryer SLUGE DRYER Air Fan Cyclone Dust Separator Condenser Drip Collector WWTP 60 °C 15 °C 85 °C 60 °C 89 m³/day Effluent Sludge- Daily based buffering Sludge Bunker (500 m3) DS = 60 % 85 °C 40 °C WWTP 40 °C 180 tons