Decentralised Water and Energy Recycling from Low Polluted Greywater in a Residential Passive House for 41 Flats

Transcription

1 Decentralised Water and Energy Recycling from Low Polluted Greywater in a Residential Passive House for 41 Flats Dipl.-Ing. Erwin Nolde mail@nolde-partner.de IFAT 2014: EWA 17th International Symposium WatE nergy R essources 1

2 Outline Introduction Wastewater is a resource; water saving = energy saving Project presentation Berlin-Arnimplatz Client/owner goals and requirements Data on systems engineering Results Water and energy data Maintenance, costs and benefits Summary and conclusion 2

3 Water supply and wastewater treatment sectors require much energy! The Berliner Wasserbetriebe require for the water sector as much electrical energy as the household electrical energy demand for a city with inhabitants. (*) Augsburg population (2011) Economical use of drinking water = Energy saving Example: Berlin and Hamburg approx. 2 kwh/m³ for drinking water and wastewater (*) 3

4 Household solid wastes are a resource that should be separated inside the building! In 2011 municipal solid wastes generation in Germany amounted to 597 kg/p/a. In Germany, Austria and Belgium about 50% of the household solid wastes had been recycled or composted. Source: 4

5 Household wastewater is a resource that should be separated inside the building! Amounts per person and year Greywater (Bath, kitchen, laundry) (1 kg COD = 0.25 kg Methane = 3.47 kwh). Blackwater (Urine, faeces) Volume Litres Nitrogen kg 0,153 4,9 Phosphorus kg 0,073 0,66 Potassium kg 0,62 1,08 COD kg 12,7 18,3 Bacteria Usable energy 15K = 436 kwh thermic kwh (Biogas) Instead of gaining 400 kwh/p/a, 250 kwh/p/a are wasted as a result of heat dissipation and loss of fertiliser potential! Link: sendung/grauwasser-102.html Utilisable energy potential from greywater at a specific living space of 40 m²/p: approx. 10 kwh/m²/a. 5

6 Decentralised greywater recycling combined with heat recovery Pilot project: First Berliner passive house with 41 dwellings and 4 commercial units Goals and requirements of the investor: Ressource efficiency in a decentralised setting no health risks, comfort loss or restrictions of any kind to the tenant maintenance-poor, easily accessible system little space requirement little energy consumption good system monitoring guaranteed manufacturer s service and maintenance. Lokus GmbH Projekt: Arnimplatz Bauherr: Dr. Grunow Inbetriebnahme: März

7 Centralised heat recovery from wastewater? 3.2 kwh heat energy per 1 kwh electrical = 2.55 kwh primary energy corresponding to a primary energy gain of 25% Source: Beat Kobel (2008) 7

8 V-2 V-2 V-2 V-2 Warm greywater (showers and bathtubs) Pre-heated cold water (ca C) Heat Buffer tank Heat recovery m³ Buffer + pretreatment Air Biological/ mechanical treatment UV m³ Service water tank Booster pump m³ Service water (Toilet flushing) Drinking water cold (ca. 10 C) Cold water pre-heating before entry into boiler (CHP) Greywater inflow, mechanical pre-treatment and heat recovery Buffer and biological pre-treatment Biological/mechanical treatment and UV-disinfection Service water and backup water supplies Lokus GmbH Projekt: Arnimplatz Bauherr: Dr. Grunow Operation startup: March

9 Cumulative frequency in % Greywater inflow temperatures Passive house Arnimplatz (plastic pipes) KfW-40 house Marienburgerstr. (cast iron) Plastic pipe: Cast iron: Temperature in C 9

10 Jan 13 Feb 13 Mrz 13 Apr 13 Mai 13 Jun 13 Jul 13 Aug 13 Sep 13 Okt 13 Nov 13 Dez 13 kwh/d Water and energy input and output (Monthly median values for 2013) Greywater recycling and heat recovery in Arnimplatz 2013 (monthly median values) total energy demand kwh/d thermal energy savings kwh/d greywater litres/d warm water litres/d service water litres/d Litres/d

11 Water and energy input and output during March

12 Greywater recycling combined with energy recovery (Arnimplatz) per m² of living space or 430 /P 0.1 m²/person = A4 paper size Savings: approx. 5,000 /a Savings: approx. 1,000 /a Electricity demand can be covered by: 16 m² PV (water recycling) 2 m² PV (heat recovery) Investment costs for greywater recycling and energy recovery (prototype): 53,000 (25% für energy recovery) incl. assembly and 19% VAT Space requirement (prototype): floor space 9 m² Water savings: approx ,200 m³/a of high quality drinking water (better than the EU Guidelines for Bathing Water) Energy recovery from greywater: approx. 12,000 kwh/a ; corresponding to 33 m² of solar energy Maintenance and operation: Electricity: approx. 1,800 kwh/a Following 2 years of operation, no maintenance works were necessary. CO 2 reduction from energy recovery = 3.3 t/a. CO 2 reduction from water-saving measures and water recyling approx. 1.5 t/a (own electricity consumption considered). 12

13 Greywater Recycling with Heat Recovery Individual Benefits 1,000 litres greywater kwh elec. energy (Photovoltaics) = kwh thermal energy for pre-heating of cold water Environmental benefits heat recovery 0.25 kwh greywater treatment 0.8 kwh service water distribution 0.35 kwh (1) kwh less city warming (2) 1,000 litres of groundwater saved (3) 1-3 kwh saved from drinking water and wastewater treatment including pumping (4) saving on chemicals for drinking water and wastewater treatment (5) less concrete corrosion in the sewer (6) CO 2 reductions: 2.51 kg CO 2 per 10 kwh recycled thermal energy plus 0.6 kg CO 2 per 1 kwh elec. saved in the water cycle COP = ,000 litres of high quality service water for toilet flushing, laundry, etc. + Credit points in buildings certification (BREEAM, LEED, DGNB, etc.) 13

14 kwh/m²/a Hot water production from fossil energy vs. Energy recycling from greywater (without distribution losses) Thermal output Wärmeabgabe Primary energy demand Greywater cooling: down to 8 C Greywater generation: 50 instead of 23 L/P/d Energiebedarf Energy demand for WW-Bereitung hot water production (minus distribution ohne V-Verluste losses ) Only nur greywter Duschund showers Bade- and from abwasser bathtubs Wärmetauscher Tested heat erprobt exchanger Wärmetauscher Optimised heat optimiert exchanger Wärmepumpe Heat pump JAZ COP

15 Neighbourhood 2015 Arnimplatz 2013 Cost savings Conventional (centralised) Water saving devices, GW-Recycling and heat recovery Cost savings Goal 2012: maintenance-poor, reliable greywater recycling system combined with energy recovery Demand for DW 122 L/P/d 44,5 m³/p/a 76 L/P/d 27,7 m³/p/a Service water -- L/P/d m³/p/a 20 L/P/d 7,3 m³/p/a 4.489,50 Electricity 2 kwh/m³ 89,1 kwh/p/a 2 kwh/m³ 55,5 kwh/p/a 1,4 kwh/m³ 10,2 kwh/p/a -314,27 65,7 kwh/p/a Heat recovery -97,6 kwh/p/a 960,00 Primary energy demand total 231,6 kwh 73,3 kwh/p/a Total yearly saving potential: ,59 Goal 2015: include other greywater resources with a new heat exchanger and buffer systems Demand for DW 56 L/P/d 20,4 m³/p/a Service water 40 L/P/d 14,6 m³/p/a 8.979,00 Electricity 2 kwh/m³ 40,9 kwh/p/a 1,4 kwh/m³ 20,4 kwh/p/a -628,53 61,3 kwh/p/a Heat recovery -195,1 kwh/p/a 1.920,00 Primary energy demand total -35,7 kwh/p/a Total yearly saving potential: ,

16 Summary and conclusion Separation of greywater and blackwater inside the building is past due The project Arnimplatz is running since 2012: with high acceptance of the owner and tenants with very low maintenance, which is undertaken by professionals much more energy is recovered than required for the whole process significant savings in water and energy costs significant reductions in CO 2 emissions The above decentralised water and energy recycling system can be optimised by including all greywater resources (also the high load greywater from laundry and kitchen) The decentralised system has positive impacts on the existing centralised system (reduction of fats and solids, less corrosion in sewer). 16

17 Thank you for your interest. Es ist nicht genug, zu wissen, man muss auch anwenden; es ist nicht genug, zu wollen, man muss auch tun. Johann Wolfgang von Goethe (Werk: Wilhelm Meisters Wanderjahre) Contact: 17