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Maximizing Microorganism-BasedResources
Bruce E. Rittmann
Regents’ Professor of Environmental Engineering
Director of the Swette Center for EnvironmentalBiotechnology
Biodesign Institute at Arizona State University
[email protected] http://environmentalbiotechnology.org
My Context
• We know that many kinds of complexorganic residues – food processingwastes, animal wastes, sludges,microalgae, etc. – can be converted intorenewable, socially useful energy bydifferent anaerobic microbial systems.
• Why aren’t we doing more of it?
– So far, it is not economically valuable enough.
We Want to Improve the ValueProposition
1. Get more energy out of complex organicresidues
2. Produce a higher value energy outputthan methane
3. Capture nutrients into high value “mobile”stream
4. Get high value from the left-over solids
Our PARENS concept
PARENS = Profitable Agriculture through Recovered Energy, Nutrients, andSolids
1. Get more energy out ofcomplex organic residues
Pre-treatment
Sludge pre-treatment technologies
Technology Description/Scale Comments
Thermal •High-temperature treatment (150-220oC)
•Full-scale success
•Achieve solids reduction
•Capital intensive
•Energy neutral/negative
Mechanical(includingultrasound)
•Shear, pressure, homogenization,or ultrasonic physical attack ofmembrane
•Pilot scale success
•Achieve benefits of cell lysis at smallscale
•High energy consumption
•Restricted to WAS only
Chemical •Addition ofacids/bases/enzymes/oxidants toattack membrane
•Lab/pilot scale success
•Achieve benefits of lysis
•High chemical/capital costs
•Chemical removal/neutralization
Electrical •Generation of free radicals byelectrolysis of water
•Pilot scale demonstrations
•High energy consumption
•Discontinued technology
Electrical – PEF •Electroporation of cell membranesresulting in osmotic lysing;disruption and fragmentation
•Lab/pilot/full scale
•Demonstrated in multiple labs and atfull scale
•Energy positive
R&D Issues
• Reproducibility
Electromechanical – OpenCEL® FP• Focused Pulsed (FP) technology
uses pulsed electric fields (PEF) ofhigh voltage to permanently openpores and fragment flocs and cells:
– Voltage of 20 – 30 kV, Pulsingfrequency of > 2000 Hz, Treatmenttime <500 milliseconds
• Full-scale application (Mesa,Arizona) indicated that FP pre-treatment of the input primary andWAS demonstrated a biogasproduction increase of nearly 60%and reduced biosolids requiringdisposal by 30%
• FP treatment caused importantimprovements in the microbialcommunity structure
Up to 200% more CH4 from animal wastes!
2. Produce a higher valueenergy output than methane
Microbial ElectrochemicalCells (MXCs)
e- donor half reaction: - 0.29 V
e- acceptor half reaction: 2 O2 + 8H+ + 8e- → 4 H2O 0.81 V
The reaction potential drives all biological, chemical, and electrochemicalprocesses in MFC => typical recovered potentials are 0.3 - 0.6 V
Membrane
H2O
CH3COO-¼ O2
Air
e-H+ +
CH3COO- + 3 H2O → CO2 + HCO3- + 8H+ + 8e-
1.10 VNet reaction: CH3COO- + 2O2 → CO2 + HCO3- + H2O
Electrical powergeneration
Anode Cathode
Microbial Fuel Cell
Modifying the MXC to an MEC toProduce H2e- donor half reaction: - 0.29 V
e- acceptor half reaction: 8H+ + 8e- → 4 H2 - 0.41 V
In a Microbial Electrolysis Cell (MEC), we exclude O2 and addpower (applied voltage) to have a low enough cathode potential toproduce H2.
Membrane
H2
CH3COO-
e-
H+ +
CH3COO- + 3 H2O → CO2 + HCO3- + 8H+ + 8e-
- 0.12 VNet reaction: CH3COO- + 3H2O → CO2 + HCO3- + 4 H2
H2 gasproduction
CathodeAnode
2H+
H2 from an MEC or CH4?
• H2 can be used to power chemical fuel cells, sayto drive your car of the future.
• H2 is a major feedstock to the chemical industryfor reductions, or hydrogenations.
• H2 can be used for water-pollution control toreduce oxidized contaminants, like nitrate,perchlorate, selenate, and TCE The MBfRtechnology.
• The economic value of H2 is about 5 timesgreater than CH4 on an e- (or BOD) basis!
3. Capture nutrients into highvalue “mobile” stream
Selective Sorption Technology
P-recovery strategy (similar for N)
High P and BOD(animal waste)(40% of mined P)
Convert Org-P toInorg-Psimultaneouslywith anaerobicbioenergyproduction
Separate, concentrate, andrecover Inorg-P by selectiveadsorption or ion exchange
Low P and BOD(runoff)(46% of mined P)
Convert Org-P toInorg-P with anAOP
Recovered P for food crops orother uses
Sources Conversions Recovery and Use
Energy output, e.g., CH4 or H2
Water for reuse
Medium P andBOD (sewage)(16% of mined P)
Hybrid Ion-Exchange (HAIX)
Anion exchange resin beads impregnated with hydrated ferricoxide (HFO) nanoparticles
PhosXnp
4. Get high value from the left-over solids
High-value Soil Amendment
Partnering with Midwest BioAg
• Post anaerobic digestion, they
– Dry residual biomass
– Augment with N and P
– Pelletize
• Creates a high-value soil amendment forregional use.
Where is the Value?
EBT = earnings before taxes
North American Partnership for PhosphorusSustainability
NAPPS
The goal of NAPPS is to work actively with stakeholders to fosterthe implementation of sustainable P solutions in public and
private sectors.
Short introductory presentation anddiscussion today at 5:15pm.
Please join me!
Maximizing Microorganism-BasedResourcesBruce E. Rittmann
Regents’ Professor of Environmental Engineering
Director of the Swette Center for EnvironmentalBiotechnology
Biodesign Institute at Arizona State University
[email protected] http://environmentalbiotechnology.org
P-RCN: Coordinating PhosphorusResearch to Create a Sustainable
Food System
• Five-year effort funded by the US NationalScience Foundation (2012 – 2017)
• ASU as lead institution
– James Elser is PI; Helen Rowe is executive
• Goal: catalyze an international network ofresearchers and practitioners tosynthesize data, perspectives, andunderstanding about phosphorus toidentify and implement solutions for Psustainability.
~45 core participants.
International: USA, Canada, Australia, Japan,United Kingdom, Ireland, Switzerland, India,China, Argentina, Congo
From university, industry, NGO, and governmentagencies.
Includes NAPPS
Who is in the P-RCN?
North American Partnership for PhosphorusSustainability
NAPPS
The goal of NAPPS is to work actively with stakeholders to fosterthe implementation of sustainable P solutions in public and
private sectors.
• Monitor, collect, review and circulateinformation concerning key dimensions of Psustainability.
• Foster implementation of innovativetechnologies and solutions
• Coordinate position statements andcommunication
• NAPPS Stakeholders
Water Quality: governmentagencies, non-profits
Agriculture: producers,consultants, fertilizer industry
P Recycling: companies/startups
P Demand: bioenergy, foodindustry, food and detergentadditives
Phosphorus and WaterQuality
Phosphorus Efficiency inFood Production
PhosphorusRecycling
P DemandDrivers
Stage I Working Groups
It’s not just the P!
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