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Steve Skill Plymouth Marine Laboratory [email protected]
Energy from Waste and Biomass11 Mar 2009, IOM3, London, UK
Energy from Algae
Plymouth Marine Laboratory
PML brings together:100+ Professionals in biology, chemistry, maths and physics
using the latest approaches in: novel technology, modelling, earth observations, virology, biogeochemistry, ecotoxicology, microbiology and molecular science.
Multidisciplinary science
Innovation & Partnership
Delivering pioneering marine research for 30 years.
A Collaborative Centre of the
PML- Bioenergy Research Focus
• IPCC advisers on Carbon Capture & Storage• Pioneers of ocean fertilisation experiments• Algal physiology and biochemistry • Photobioreactor design & engineering• Metabolomics, Biochemical Identification, Bio-refineries and healthcare
products• Molecular Biology and Transgenics• Algal virology• Biogas analysis and identification• Marine Microbiology• Photosynthetic wastewater treatment system design
Supported by:
Why Microalgae ?- Superior productivity per hectare.
Algae50,000 l/ha
Palm oil6,000 l/ha
Rapeseed1,400 l/ha
Sunflower1000 l/ha
Soya
Corn
50,000
5,000
500
100
Litresper
hectareperyear
Vegetable OilYield
172l/ha
450l/ha
Bioenergy
Landfill GasMethane/CO2
Sewage Sludge
Secondary SewageEffluent
Flue Gas CO2
Algal Consortia
Methane/CO2
Liquid fuel/gas
Methane/O2
PBRMicroalgae
Hydrothermalliquifaction
Anaerobic digestionMethane/O2PBR
Microalgae
Algal BiomassAlgal Biofilm
Mixed biomass Methane/CO2AnaerobicDigestion
Methane/O2PBR Microalgae
Lipid storingMicroAlgaePBR
PBR
Hydrocarbons BiodeiselTrans-Esterification
MSW-OrganicFraction
High HydrocarbonBiomassNutrient
limitationLipid
Extraction
Ligno- cellulose
Hydrogen
Lignin / OrganicAcids
Hydrolysis
PBRPhotosynthetic
Anaerobes
PBR=Photobioreactor (including ponds)MSW=Municipal solid waste
Green CrudeNutrients (N &P)
FertiliserN & P
AqueousFraction
Green DeiselCatalyticConversion
HydrothermalLiquifaction
Bioenergy (& Fertiliser) from Photosynthetic Microbes
• “The energy required to treat sewage is high and the water industry is the fourth most energy intensive sector in the UK”. (Parliamentary Office of Science and Technology, Postnote No. 282 April 2007).
A schematic diagram of the activated sludge process
Bioenergy from Sewage
INFLUENT
ORGANICMATTER
ORGANICSLUDGES
BACTERIALOXIDATION
AMMONIAPHOSPHATE
CARBON DIOXIDE
DISSOLVEDOXYGEN
SOLUBLEORGANICMATTER
ENERGY
NUTRIENTDISCHARGE
ACTIVATED SLUDGE PROCESS CO2
EMISSIONS
CO2
EMISSIONS
SEWAGESLUDGE
BIOGAS(AD)
HAZARDOUSWASTE
What a waste! • Nutrients (N & P)• Fixed C component [oxidised to CO2]• Heavy metals (Au, Pt, Cu, Zn, Cd etc)
What a load of problems!• CO2 emissions
• Nutrient discharges• Sewage sludge (hazardous waste)• Hormone disrupting chemicals (hermaphrodite fish!)
R. J. Diaz et al., Science 321, 926 -929 (2008)
Global distribution of 400-plus systems that have scientifically reported accounts of being
eutrophication-associated dead zones
Global Nature of Eutrophication-Induced Hypoxia
ORGANICMATTER
ORGANICSLUDGES
BACTERIALOXIDATION
AMMONIAPHOSPHATE
CARBON DIOXIDE
DISSOLVEDOXYGEN
ALGALPHOTOSYNTHESIS
ALGALBIOMASS
SOLUBLEORGANICMATTER
ALGAL/BACTERIAL BIOFILM PROCESS
SUNLIGHTINFLUENT
How do you reduce CO2 emissions and energy use, and recover nutrients during sewage treatment?
A: PHOTOSYNTHESIS (Algae)
ORGANICMATTER
ORGANICSLUDGES
BACTERIALOXIDATION
AMMONIAPHOSPHATE
CARBON DIOXIDE
DISSOLVEDOXYGEN
ALGALPHOTOSYNTHESIS
ALGALBIOMASS
SOLUBLEORGANICMATTER
ALGAL/BACTERIAL BIOFILM PROCESS
SUNLIGHTINFLUENT BIOFUEL
INFLUENT
ORGANICMATTER
ORGANICSLUDGES
BACTERIALOXIDATION
AMMONIAPHOSPHATE
CARBON DIOXIDE
DISSOLVEDOXYGEN
SOLUBLEORGANICMATTER
ENERGY
NUTRIENTDISCHARGE
ACTIVATED SLUDGE PROCESS CO2
EMISSIONS
CO2
EMISSIONS
SEWAGESLUDGE
BIOGAS(AD)
HAZARDOUSWASTE
William J. OswaldProfessor of Civil and Environmental Engineering, Emeritus
Professor of Public Health, EmeritusBerkeley
1919 – 2005
Algae/bacterial wastewater treatment- Current Practice
Tertiary Treatment Biocoil PBR – Severn Trent, Stoke Bardolph, Nottingham (1993)
BIOCOIL MIXTANK SETTLING
INFLUENT
DISCHARGE
Wastewater treatment photobioreactors and direct fuelling of diesel engines with powdered algal biomass (1993)
Algal Biofilm wastewater treatment system applied to water recycling in intensive fish farming. (S. Skill 1999)
Carbon Dioxide, Soluble Organic and Nitrogenous Material
Suspended Solids Algal/Bacterial Biofilm Clear PlasticOxygen
ORGANICMATTER
ORGANICSLUDGES
BACTERIALOXIDATION
AMMONIAPHOSPHATE
CARBON DIOXIDE
DISSOLVEDOXYGEN
ALGALPHOTOSYNTHESIS
ALGAE
SOLUBLEORGANICMATTER
Wastewater
CleanWater
Algal Biofilm Wastewater Treatment
Advantages• Low C footprint sewage treatment (Energy in v Sunlight)• Low carbon emission (oxidation v photosynthesis)• Single stage 2o, 3o & 4o treatment (inc.hormone
degradation)• No sludge disposal• Not susceptible to biomass washout (flooding, extreme
storm)• Simple dry biomass recovery (Biofuel + nutrient feedstock)
Land area•Algal/bacterial ~0.25 – 0.4 kg/m2/day BOD•Activated Sludge ~3kg/m2/day BOD
Algal/bacterial/PBR systems will require 5-10 times the land area compared to activated sludge (excluding settling tanks). May be less!
Drawbacks
Algae Biofilm Sewage treatment
Liquifaction in supercritical water (<300oC, Pressure + catalyst [H donor additives])
BiocrudeO content of 12-20%
30-35MJ/kgLong chain hydrocarbons
Aqueous phaseOrganic acids and ketones
Anions- Cl-, PO43-
Cations- K+, Ca2+, Na+, NH4+
Gascous phase(CO2)
Compared to fast pyrolysis oil: Lower oxygen conten, Higher heating value, Lower carbon in char, Easier to upgrade, Tolerate high moisture content, Tolerate high ash content
Algal biomass conversion to fuels and chemicals
4 - 6kg of nitrogen per person per year.
Bioenergy (& Fertiliser) from Algae
Bioenergy
Landfill GasMethane/CO2
Sewage Sludge
Secondary SewageEffluent
Flue Gas CO2
Algal Consortia
Methane/CO2
Liquid fuel/gas
Methane/O2
PBRMicroalgae
Hydrothermalliquifaction
Anaerobic digestionMethane/O2PBR
Microalgae
Algal BiomassAlgal Biofilm
Mixed biomass Methane/CO2AnaerobicDigestion
Methane/O2PBR Microalgae
Lipid storingMicroAlgaePBR
PBR
Hydrocarbons BiodeiselTrans-Esterification
MSW-OrganicFraction
High HydrocarbonBiomassNutrient
limitationLipid
Extraction
Ligno- cellulose
Hydrogen
Lignin / OrganicAcids
Hydrolysis
PBRPhotosynthetic
Anaerobes
PBR=Photobioreactor (including ponds)MSW=Municipal solid waste
Green CrudeNutrients (N &P)
FertiliserN & P
AqueousFraction
Green DeiselCatalyticConversion
HydrothermalLiquifaction
PhotobioreactorsPond and raceway algae cultivation
Disadvantages
•Ponds and raceways have lower productivity compared to closed PBRs.•Open to the atmosphere and therefore susceptible to contamination.•Successful cultivation limited to a few extremophile strains•Low culture density
Advantages
•Low capital cost•Low running costs (paddle wheel or passive wind mixing•Atmospheric CO2
Closed Photobioreactors
Biocoil Photobioreactor 1993 (S. Skill)
PhotobioreactorEngineering
Technology Obstacles
• Leakage• Fouling• Oxygen removal• Contamination• Temperature control• High Capital Cost• Operating costs• Gas Injection• Robustness
R&D required
BiocoilPhotobioreactors
1994
Algae strains with:
• Robustness• High Growth rate• Thermophilic capability• High Lipid content at max growth rate• Resistance to invasion• Self harvesting
• NOx, SOx and High [CO2] tolerannce
• Amenable to transgenics
Wanted!
>5 years R&D required
Algal Microbiology - Biochemistry
R&D Focus
Lipid Synthesis in Microalgae(biodiesel feedstock)
Light (photons)
Microalgae(photosynthetic CO2
fixation)
Gene mediated enzyme control
O2CO2
Nutients(N, P, K, Si)
Lipid storage Carbohydrate storage
(CH) (CHO)
• Engineer strains to produce to produce and accumulate high levels of lipids during exponential growth.
• Focus on non-oleagenous microalgal strains with high temp, NOx, SOX, High CO2 tolerant strains exhibiting autoflocculation.
• Reduce heat dissipation• Low sunlight utilization efficiency due to light harvesting complexes• Modify photosynthetic antennae• Increase photosynthetic efficiency to > 10%
Bright Sunlight
Heat Dissipation
Bright Sunlight
Heat Dissipation
FixedCarbon
FixedCarbon
Increasing Photosynthetic Efficiency
R&D Focus
Commercially important metabolic pathways in microalgae.
PML Roof Mounted PBR
