Long Term Full Scale Experience in Biogas Production from Brewery Yeast in an EGSB Reactor

Transcription

1 Long Term Full Scale Experience in Biogas Production from Brewery Yeast in an EGSB Reactor Gregor D. Zupančič, Center for development of sustainable technologies & University of Nova Gorica Green Capital of Europe: EWA Workshop Bio-energy and By-product Recovery in Integrated Water and Biosolids Management Ljubljana,

2 Brewery project SLO brewing industry - 2 breweries, each approx. 100,000,000 L of brew annually. The goal in 2006: achieving and surpassing 20% renewable by 2015, several directions: Solar photovoltaic, solar thermal, Biogas from waste. Ongoing project : Biogas productionfrom brewery waste substitution of natural gas for processing heat generation. Economic sustainability! 10 years of research

3 Starting conditions Efficient treatment of brewery wastewater since 2006 (approx m 3 annually). Usual No % recovery from wastewater. Available waste for biogas production: Waste yeast (quantity approx 3000 t (m 3 ) annually), resolved since 2012, additional 6 % recovery Spent brewery grain (quantity t annually), concept confirmed in 2015, potential recovery additional 50 % Conventional management: Yeast: drying and sold as a food supplement 1 /L Spent brewery grain: livestock feed 13 /ton

4 Renewable potential Wastewater m 3 /kg COD Waste yeast 0.78 m 3 /kg dry organic matter Spent brewery grains m 3 /ton Total usable biogas potential: 2,600,000-3,500,000 m 3 annually Methane 1,600,000-2,000,000 m 3 annually This adds up to % renewable

5 Biogas L/kg inserted Ammonia Nitrogen Yeast digestion L/kg VSS L/kg KPK Nitrogen-ammonia accumulation

6 Brewery wastewater Biothane s BIOBED reactor for wastewater treatment 750 m 3, design load 16 kg COD /m 3 day, fully operational 2007 Reactor is hydraulically appropriately loaded and organically underloaded average only 4 kg COD /m 3 day

7 YEAST research Yeast is a good substrate (organically): COD 277 g/l No significant additional volume load 0.7 % Significant additional COD load %, average 60 % Biogas yield m 3 /kg COD indicates minimum 40 % increase, average 60 % Enormous dillution no ammonia problem

8 Previous research: Considerations Biogas production from used brewery yeast (Diplomawork of Christian Herr: Biogas erzeugung aus Althefe in einer Breuerei, TU München, 1998) Conclusion: Solid portion of yeast not digestable Microbiological competition anaerobic biomas destruction Equipment producer warning: warranty void if yeast digested

9 Lab experiments 0,300 Biomethane potential (m 3 kg -1 COD) 0,250 0,200 0,150 0,100 0, % yeast 0.74 % yeast 1.85 % yeast 3.70 % yeast 0, No significant impacts, slight improvements Days

10 Pilot plant experiments Pilot experiments for feasibility determination Mixture of yeast and wastewater 0,7 2,8 % Trials at min. and max COD load Control wastewater only Biomass analysis

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13 Results pilot experiments Control wastewater only COD load 8.13 kg/m 3 day - COD removal 93.8 % Increasing load to 12.2 kg/m 3 day - COD removal 91.5 % Biogas yield m 3 /kg COD Wastewater + yeast - low COD load 8.75 kg/m 3 day COD removal 90.4 % Biogas yield m 3 /kg Wastewater + yeast - high COD load 14.9 kg/m 3 day COD removal 89.9 % Biogas yield m 3 /kg Absolutely no harmful change in biomass

14 Full Scale Operation

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16 Acomplishments Parameter Min. Max. Avg Change COD inf ww COD inf ww+y ,6 % COD eff ww COD eff ww+y ,9 % COD efficiency ww 67,8 92,9 82,6 COD efficiency ww+y 66,9 92,8 82,1-0,6 % Biogas production ww m 3 Biogas production ww+y m 3 +38,5 % SBP ww 0,023 0,730 0,461 SBP ww+y 0,220 0,788 0,502 +8,9 % COD (mg/l); SBP (m 3 /kg COD ); efficiency (%); Biogas production(m 3 /year)

17 5 year full-scale operation Constant monitoring Absolutely NO harmful effects

18 Biomass change a. Archael community pilot scale; b. Archael community full-scale c. Bacterial community full-scale

19 Substitite ratio (%) Increase (%) Natural gas substitute Substitute ratio wastewater Substitute ratio wastewater and yeast Increase JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER ANNUAL Using yeast double increase More biogas no yeast drying

20 Economic sustainability

21 Transport fuel

22 Scientific result: Patent: Brewery: Gregor D. Zupančič, Igor Škrjanec, Romana Marinšek Logar, Anaerobic co-digestion of excess brewery yeast in a granular biomass reactor to enhance the production of biomethane, Bioresource Technology, Volume 124, November 2012, Pages ZUPANČIČ, Gregor Drago, ROŠ, Milenko, KLEMENČIČ, Miran, OSET, Matej, MARINŠEK-LOGAR, Romana. Biogas production from brewery yeast in an EGSB reactor. Brauwelt international, ISSN , 2016, vol. 34, no. 2, Pages ZUPANČIČ, Gregor Drago, KLEMENČIČ, Miran, OSET, Matej, MARINŠEK-LOGAR, Romana, ROŠ, Milenko. Procedure for biogas production from brewery yeast. Slovene: Postopek za predelavo pivovarniške kvasine v bioplin : patent : SI A, Ljubljana: Slovenian intellectual property office, Annual savings of 150,000 ; added value of up to 0,2 /L of brew

23 Conclusions If the natural gas price is over 0,32 (including VAT).. ABSOLUTELY YES!!!!! There are NO harmful effects is such treatment. And the Economy is GOOD.