C H NOL E O T G • Y E • C R N E S E 147 E I A C R S C • H S H NOISIV•STHGI L H GI Sustainable algal biomass products by cultivation in waste water flows VTT TECHNOLOGY 147 Sustainable algal biomass products by cultivation in waste water flows Mona Arnold (Ed.) ISBN 978-951-38-8084-2 (URL: http://www.vtt.fi/publications/index.jsp) VTT Technology 147 ISSN-L 2242-1211 ISSN 2242-122X (Online) Copyright © VTT 2013 JULKAISIJA – UTGIVARE – PUBLISHER VTT PL 1000 (Tekniikantie 4 A, Espoo) 02044 VTT Puh. 020 722 111, faksi 020 722 7001 VTT PB 1000 (Teknikvägen 4 A, Esbo) FI-02044 VTT Tfn +358 20 722 111, telefax +358 20 722 7001 VTT Technical Research Centre of Finland P.O. Box 1000 (Tekniikantie 4 A, Espoo) FI-02044 VTT, Finland Tel. +358 20 722 111, fax +358 20 722 7001 Sustainable algal biomass products by cultivation in waste water flows Mona Arnold (Ed.).Espoo 2013. VTT Technology 147. 84 p. Abstract Algae are predicted to play an important role in tomorrow’s bioeconomy. The technical goal of the project was to develop enhanced algal cultivation processes utilising waste flows and to increase the overall material and energy efficiency of algal processing for biodiesel and biogas production. The project produced new knowledge on the boundary conditions for cost effi- cient algal cultivation and productivity. The use of algae as a tertiary treatment of municipal waste water, such as the utilisation of waste water flows from biowaste handling, was assessed with positive results. Process concepts based both on CO uptake and (waste) organic carbon were assessed. In a Nordic climate the 2 utilisation of spill heat is requisite and with restricted available daylight in the winter time, an alga’s ability to shift from autotrophic to heterotrophic growth provides a potential strategy for algal cultivation in Nordic circumstances. The fractionation of algal residuals for biopolymers is a new research area with potential long term impact in the bioeconomy sector. Cost efficient Integrated production concepts still need to be developed, as premises to successful business models. It is apparent that an economically viable algae-to-biodiesel commercialization will initially depend on government subsidies and the future price of oil, in addition to optimized biomass yields. However, algae to biofuels is globally a topical sector with a high interest from several stakeholders. The markets are likewise global. From the biofuel point of view, air traffic is particularly interesting, as this sector will probably need to rely on liquid fuel still during the next decade. Keywords microalgae, biofuels, waste, biorefinery 3 Preface This publication gives the overview of the results from the Tekes Biorefine pro- gramme project Algae from Waste for Combined Biodiesel and Biogas Production – ALDIGA coordinated by VTT and executed 02/2010–12/2012. The project was carried out as an extensive collaboration between five Finnish research organisation and eight international laboratories. The research partners in addition to VTT were: University of Helsinki (Prof. M. Romantschuk), Finnish Environment Institute (Senior Scientist Dr K. Spilling), HAMK University of Applied Sciences (Principal lecturer Dr M. Kymäläinen), LAMK Lahti University of Applied Sciences (Dean Dr S. Kostia). The international co-operators were Waterloo University (CA), Aalborg University (DK), DTU (DK), Lawrence Berkeley Natl. Lab (US), San Diego Center for Algae Biotechnology, UCSD (US), Ludwig Maximilian University (DE),University of Lon- don, Imperial College (UK) and Hamburg University of Applied Sciences (DE). The steering group consisted of representatives for the companies participating in the project: Neste Oil Oyj (chair), Kemira Oyj, Gasum Oy, Ekokem Oy, Wärtsilä Finland Oy, Bioste Oy, Biovakka Suomi Oy, PHJ Oy, Kujalan komposti Oy, Clewer Ltd, Sybimar Oy, Envor Group Oy, LHJ Group, the main funding organisation, Tekes, and the responsible leader of the coordinating organisation, professor Merja Penttilä at VTT. The following chapters give an overview of the results obtained in the project. Due to the large number of research question and tasks involved in the project the overviews are focussed on the results, whereas detailed information on research methods can be found in publications i.e. articles and theses, that have been produced by the participating organisations during and after the project. Espoo 12.12.2013 Mona Arnold, VTT Project manager 4 Contents Abstract ........................................................................................................... 3 Preface ............................................................................................................. 4 Terms and abbreviations ................................................................................. 7 1. Introduction ............................................................................................... 9 1.1 Cultivation and processing .................................................................. 9 1.2 Microalgal cultivation ........................................................................ 10 1.3 Sustainability and utilisation of waste streams.................................... 11 1.4 CO absorption or utilising carbon containing waste streams? ............ 12 2 1.5 Algae for biofuel production. .............................................................. 12 1.6 Residual valorisation. ........................................................................ 14 2. Goal ......................................................................................................... 15 3. Algal cultivation for lipid production in waste water .............................. 16 3.1 Selection of algal species for feasibility testing. .................................. 16 3.2 Algal growth in various waste waters ................................................. 16 3.3 Bacterial contamination of algal cultivations ....................................... 19 3.4 Biomass production in waste water ................................................... 19 3.5 Lipid production and characterization in waste water grown algae ...... 20 3.6 Light and temperature requirement. ................................................... 22 3.7 Pilot scale cultivation ........................................................................ 22 3.8 Case study – Kujalan Komposti Oy ................................................... 24 4. The productivity of algae in mixotrophic conditions .............................. 27 4.1 Phototrophic growth .......................................................................... 28 4.2 Mixotrophic and heterotrophic batch growth ....................................... 30 4.3 Mixotrophic and heterotrophic continuous growth............................... 32 4.4 Conclusions and recommendations ................................................... 33 5. Algal cultivation integrated into municipal waste water treatment ........ 34 5.1 Introduction ...................................................................................... 34 5.2 Screening for inhibitory effects of treated wastewater ......................... 36 5.3 Screening in untreated wastewater. ................................................... 36 5.4 The community effect........................................................................ 37 5 5.5 Potential algal biomass production in municipal wastewater. ..................... 39 5.6 Potential wastewater treatment using algae in Finland ....................... 39 6. Anaerobic digestion of algal biomass .................................................... 41 6.1 Introduction ...................................................................................... 41 6.2 Materials and methods. ..................................................................... 42 6.3 Methane production .......................................................................... 44 6.4 Biogas (AD) process performance ..................................................... 47 6.5 Combined biohydrogen and methane production ............................... 49 6.6 Conclusions...................................................................................... 50 7. Techno-economic feasibility of microalgae-based energy in Finland and globally. ............................................................................... 52 7.1 Introduction ...................................................................................... 52 7.1.1Objective ................................................................................. 53 7.1.2Algae based energy – processes .............................................. 53 7.2 Techno-economics and greenhouse gas emissions of selected microalgae-based biofuel concepts in Finnish conditions.................... 55 7.2.1Case study definition ................................................................ 55 7.2.2Assumptions ............................................................................ 55 7.2.3Techno-economic feasibility ..................................................... 56 7.2.4Environmental assessment....................................................... 58 7.3 Conclusions...................................................................................... 60 8. Fractionation of residual algal biomass – potential for value-added products .................................................................................................. 62 8.1 Introduction and motivation ............................................................... 62 8.2 Fractionation .................................................................................... 62 8.2.1Microscopy .............................................................................. 64 8.2.2FTIR spectroscopy ................................................................... 65 8.2.3SDS-PAGE and Mass spectroscopy ......................................... 66 8.3 Pyrolysis GC/MS analysis of fractionated algal biomass ..................... 68 8.4 Molar mass determination of polymers .............................................. 71 8.5 Conclusions...................................................................................... 73 9. General conclusions ............................................................................... 74 10. Summary ................................................................................................. 75 References ..................................................................................................... 78 6 Terms and abbreviations AD anaerobic digestion AMPTS automatic methane potential test system autotrophy being capable of synthesizing its own food from inorganic substances, using light or chemical energy (e.g. CO ) 2 axenic free of other organisms BOD Biological Oxygen Demand after 7 days, i.e. the quantity of 7 oxygen consumed over 7 days cetane number cetane number or CN is a measure of a fuel's ignition delay, the time period between the start of injection and the first identifiable pressure increase during combustion of the fuel CSTR completely stirred tank reactor FTIR-PAS Fourier transform infrared photoacoustic spectroscopy FVW fruit and vegetable waste HRAP high rate algal pond mixotrophy a mixotroph is an organism that can use a mix of different sources of energy and carbon. In mixotrophic culture both CO and organic carbons are supplied and both are as- 2 similated. Both respiratory and photosynthetic metabolism occur in the same population. OLR organic loading rate PBR photobioreactor qPCR quantitative real time polymerase chain reaction. A labora- tory technique based on the polymerase chain reaction, which is used to amplify and simultaneously quantify a targeted DNA molecule. reject water liquid generated in dewatering of digested sewage sludge 7 SCE supercritical fluid extraction SEM scanning electron microscopy tertiary wastewater advanced cleaning of wastewater during which nutrients treatment (such as phosphorous and nitrogen) and most suspended solids are removed VFA volatile fatty acid VS volatile solids 8