Mass & Energy balances around full scale plants for food waste anaerobic digestion Franco Cecchi, David Bolzonella, Francesco Fatone, Franco Cecchi, David Bolzonella, Francesco Fatone, Veronica Facchin, Nicola Frison University of Verona, Department of Biotechnology Valorgas (ENERGY-2009-3.2.2) workshop ADSW&EC Vienna 2011 1
Mass and energy balances around plants operating the mesophilic and thermophilic AD of food waste In the Valorgas project we are considering not only the global …. Biogas Solid Pre- S/L Food AD treatments Separation waste Liquid Rejects ADSW&EC Vienna 2011 2
…. mass and energy balance, but also …… Biogas Solid Pre- S/L Food AD treatments Separation waste Liquid Rejects ADSW&EC Vienna 2011 3
… the balance for single parts of the train of processes for food waste treatment …. Biogas Solid Pre- S/L Food AD treatments Separation waste Liquid Rejects ADSW&EC Vienna 2011 4
Biogas Solid Pre- S/L Food AD treatments Separation waste Liquid Rejects ADSW&EC Vienna 2011 5
Biogas Solid Pre- S/L Food AD treatments Separation waste Liquid Rejects ADSW&EC Vienna 2011 6
Biogas Solid Pre- S/L Food AD treatments Separation waste Liquid Rejects ADSW&EC Vienna 2011 7
Biogas Solid Pre- S/L Food AD treatments Separation waste Liquid Rejects Post- treatments ? ADSW&EC Vienna 2011 8
We decided, together with the plant managers at Valorsul (P) and Biogen Greenfinch (UK), to collect data on samples from the following points (wherever possible) Biogas post- Condensate solid phase treatments water (if any) (recycle) pre- separation anaerobic digester anaerobic digester raw raw treatments treatments food waste post- liquid phase treatments inert / reject (if any) sampling point ADSW&EC Vienna 2011 9
And determine the following parameters (minimal set) Solid/liquid streams Parameter Abbreviation Units kg day -1 Flowrate, Q g kg -1 or % on wet weight Total solids TS g kg -1 ,%TS Total volatile solids TVS gO 2 kgTS -1 Total COD TCOD g kgTS -1 Total Kjeldahl Nitrogen TKN (as N) g kgTS -1 Total phosphorous TP (as P) Biogas Parameter Abbreviation Units Nm 3 day -1 Flowrate, Q kg day -1 Mass flowrate CH4 content CH4 % CO2 content CO2 % ADSW&EC Vienna 2011 10
Then, also the energetic balance, as a global figure, and for different parts of the treatment plants, will be determined considering: a) the heat and power production from biogas b) the overall power consumption of the plant (kWh per day) c) the heat and power supply from nets (if any) On the other hand, the specific energy consumption for any single unit (e.g., pre-treatment – and its parts, if possible - , digester, solid/liquid separation ....) is of fundamental interest for the study and comparison of different processes/technologies/substrates. ADSW&EC Vienna 2011 11
Two different treatment plants are considered in the research project a) The Biogen Greenfinch plant in Ludlow (UK) - MESOPHILIC AD of food waste from separate collection b) The Valorsul plant in Almadora-Lisbon (P) – THERMOPHILIC AD of both food waste from separate collection and residues from restaurants /markets ADSW&EC Vienna 2011 12
Biogen Greenfinch plant in Ludlow (UK) Courtesy of Paolo Pavan ADSW&EC Vienna 2011 13
Courtesy of Michael Chesshire ADSW&EC Vienna 2011 14
Courtesy of Michael Chesshire ADSW&EC Vienna 2011 15
Courtesy of Michael Chesshire ADSW&EC Vienna 2011 16
Courtesy of Michael Chesshire ADSW&EC Vienna 2011 17
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Courtesy of Michael Chesshire ADSW&EC Vienna 2011 19
Courtesy of Michael Chesshire ADSW&EC Vienna 2011 20
Courtesy of Michael Chesshire ADSW&EC Vienna 2011 21
Courtesy of Michael Chesshire ADSW&EC Vienna 2011 22
Courtesy of Michael Chesshire ADSW&EC Vienna 2011 23
MASS BALANCE Preliminary figures from Greenfinch (tonnes/year) Biogas 2.249 (Condensate 20) Inputs (total) 15.487 Meso Meso AD AD Outputs (total) 12.051 Biowaste 11.959 Liquid biofertiliser 11.982 of of Industrial water 3.370 Solid biofertiliser Solid biofertiliser 69 69 Domestic water Domestic water 158 158 food food waste food food waste waste waste Rejects 122 Key figures Specific biogas production 160 Nm 3 /tonne or 0.65 Nm 3 /kgVS VS removal up to 84% ADSW&EC Vienna 2011 24
ENERGY BALANCE The average yearly data for Biogen Greenfinch in Ludlow (UK) are Electricity Generated 2.329 MWh Parasitic 782 MWh 90% digester mix & CHP 10% fans and S/L separation Imported Electricity Imported Electricity 211 211 MWh MWh Net Electricity Output 1.547 MWh Generated 194kWh/tonne Consumed 23kWh/tonne Energy Index (Gen/Cons) 8,5 ADSW&EC Vienna 2011 25
Valorsul treatment plant in Lisbon Metro area (P) - thermophilic treatment of households and restaurants food waste Courtesy of Paolo Pavan ADSW&EC Vienna 2011 26
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Collection from large producers (restaurants, canteens, supermarkets ….) #�"�����$������������%�� ��������������"������� �&�����%���������������� �&�����%���������������� ������������������������'� ���������"�����'����� ADSW&EC Vienna 2011 29
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68�!���� Composting Digesters and gas holder Reception and pre-treatment Water treatment ADSW&EC Vienna 2011 33
68�!���� Composting Digesters and gas holder Reception and pre-treatment Water treatment ADSW&EC Vienna 2011 34
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Collected bags from restaurants and canteens Courtesy of Paolo Pavan Up to 18% contaminants in large producers waste…. ADSW&EC Vienna 2011 36
Courtesy of Paolo Pavan ADSW&EC Vienna 2011 37
“Inert” output of the trommel screen Courtesy of Paolo Pavan Jyvaskyla Summer School 2011 38
Manual sorting Courtesy of Paolo Pavan Jyvaskyla Summer School 2011 39
Wet rafination for heavy (glass, stones…) and light (plastic) light (plastic) inerts by means of a hydro- pulper Hydro-pulper (Linde) Courtesy of Paolo Pavan Jyvaskyla Summer School 2011 40
Hydropulper (internal view) From BTA website Jyvaskyla Summer School 2011 41
Inert material from the pulper (bottom) …. Courtesy of Paolo Pavan Jyvaskyla Summer School 2011 42
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