Flexible Platform Technologies for Resource Recovery from Food Waste Kartik Chandran Columbia University Rutgers University April 27 th, 2016
Brief overview of biological sewage treatment Solids, inerts separation Aerobic C &N removal Recycle of bacteria Disinfection and discharge A high fraction of WWT energy goes to aeration $MM in organic chemical purchase Bacteria could produce unwanted products (N 2 O)
Shifting to Engineered Resource Recovery from Waste Streams K. Chandran, 2014, in Water Reclamation and Sustainability, Elsevier
Energy self-sufficiency for wastewater treatment plants? Energy present Energy needed ~ 2500 kwh/mg ~2500 kwh/mg Assuming 34% conversion of organic matter to methane and electricity Assuming conventional BNR Can import carbon EBMUD Not at the expense of excessive N discharges
Think beyond CH 4 All based on anaerobic (+) technologies Biofuels Biodiesel from food waste at $0.71/L Commercial chemicals Fertilizer
This presentation focuses on Options for carbon recovery to fuels and chemicals Nitrite Water AMMONIA OXIDIZING BACTERIA Oxidation of ammonia as the primary energy source for energy metabolism Ammonia Methanol Resource efficient options for biological N-removal O 2 Oxidation of methane via cometabolism, without net energy synthesis Methane
Fecal sludge to biodiesel Biodiesel Lipids Lipids in feces
Biodiesel process agnostic to waste stream?
?? Our approach Domestic and Food waste Faecal sludge Municipal solid waste Animal byproduct waste Channel through fermentation platform Commodity chemicals, lipids, biodiesel
Complex organic polymers Sugars, amino acids VFA Acetic acid HRT > 10 d Methane Hydrolysis Anaerobic Digestion Acidogenesis Acetogenesis Methanogenesis
Complex organic polymers HRT ~ 2 d Sugars, amino acids VFA Acetic acid Hydrolysis Anaerobic Fermentation Acidogenesis Acetogenesis Fermentation is more advantageous than just anaerobic digestion Fermentation can be incorporated into existing digestion processes
Overview of our process Organic waste Anaerobic fermentation to produce volatile fatty acids (VFA) Convert VFA to lipids Harvest and extract lipids Convert lipids to biodiesel
Conversion of VFA to Lipids Different COD sources VFA from food waste fermentation Synthetic VFA Glucose Different initial VFA concentrations 6:1:3 acetate, propionate, butyrate. 2 day HRT Lipid content of C. albidus Different initial N concentrations Excess N: COD:N = 5:1 Limiting N: COD:N = 25:1, 50:1, 125:1, 250:1 Stoichiometric COD:N supply =33:1 Batch reactor Chemostat
Concentration (g/l) 1.6 1.2 0.8 0.4 0 Effect of feedstock composition Biomass (g/l) Lipid conc. (g/l) %Lipid content(w/w) Constant 5:1 25:1 50:1 125:1 250:1 35 30 25 20 15 10 5 0 Content (%w/w) Excess Nitrogen Limiting Nitrogen COD:N COD: N μ m (h -1 ) Limiting Nitrogen 5:1 0.041 25:1 0.043 50:1 0.039 125:1 0.036 250:1 0.023 Process can handle variability in influent feedstock
Lipid Composition Relative % of FAME 70 60 50 40 30 20 10 0 26 mgn/l 52 mgn/l 130 mgn/l 260 mgn/l 1300 mgn/l Fermenter VFA Glucose C 14:0 C 16:0 C 16:1 C 18:0 C 18:1 C 18:2 C 18:3 C 20:1 Major fatty acids accumulated are palmitic (C16:0), oleic (C18:1), and linoleic acid (C18:2) Similar to soybean oil and jatropha oil, which are used as feedstock for biodiesel production in the US and the EU
Gaining fundamental insights into lipid production through genome sequencing Vajpeyi and Chandran, 2016
Pathway elucidation Lipid Metabolism Nitrogen metabolism Citric acid cycle Vajpeyi and Chandran, 2015 unpublished
Conclusions and implications Municipal solid waste Faecal sludge Domestic and Food waste Fermentation to produce VFA Agricultural waste Animal byproduct waste Novel and flexible platform to convert a variety of organic waste streams to biodiesel or other lipid based commodity chemicals Not reliant upon inherent lipid content- other organic classes can be converted to lipids Biodiesel and other commodity chemicals For biodiesel as the preferred end point, reliance upon agricultural outputs is reduced or eliminated Links clean water production with energy and chemical recovery
Water Quality-Energy Org-N and NH 3 Org-N and NH 3 Org-N and NH 3
Biodiesel is not the only endpoint Dual-Phase Digestion and Fermentation of AS PDS fermentation and storage at 26 th Ward WPCP in New York City, 2002 Fermentation of PDS to produce VFA Used mainly for denitrification Kinetics higher than MeOH Biorefining for Chemical Recovery
FS Characterization Extreme Variability Average ± SD Total COD (mg/l) 22,951 ± 19,499 Total VFA (mgcod/l) 1,417 ± 1,074 ph 8.01 ± 0.27 Total Suspended Solids (mg/l) Volatile Suspended Solids (mg/l) 15,663 ± 16,867 12,617 ± 13,328 Need to characterize beyond conventional parameters
Approach: Comprehensive Pilot Operations with Modelling Analysis Pilot Scale Field Operations Process Modeling
Sewage sludge to methanol Nitrite Water Oxidation of ammonia as the primary energy source for energy metabolism AMMONIA OXIDIZING BACTERIA Ammonia Methanol O 2 Oxidation of methane via cometabolism, without net energy synthesis Methane Concomitant oxidation of CH 4 and CO 2 fixation Prospect of combining C &N cycles WERF Paul Busch Award, 2010 Taher and Chandran, ES&T, 2013
25 Biological production of methanol A MMO MDH FLD FDH CH 4 CH 3 OH HCHO HCOOH CO 2 Type I methanotroph Type II methanotroph Phylogeny Gamma proteobacteria Alpha-proteobacteria CH4 oxidation and carbon assimilation Ribulose mono-phosphate Serine Monooxygenase pmmo smmo
26 Biological production of methanol B AMO CH 4 CH 3 OH Type I methanotroph Type II methanotroph Ammonia oxidizing bacteria Phylogeny Gamma proteobacteria Alpha-proteobacteria Beta-proteobacteria CH4 oxidation and carbon assimilation Ribulose monophosphate Serine Fortuitous, no assimilation known Monooxygenase pmmo smmo AMO
Maximum CH 3 OH production rate mg CH 3 OH COD mg biomass COD-d Peak CH 3 OH concentration (mg COD/L) 0.21 23.47 ± 0.50 0.30 27.50 ± 0.78 Microbial system used Mixed nitrifying cultures NH 3 only feed (FS1) Mixed nitrifying cultures NH 2 OH only feed (FS2) Reference 0.22 31.52 ± 1.19 0.20 40.71 ± 0.16 Mixed nitrifying cultures NH 3 and NH 2 OH co-feed (FS3) Mixed nitrifying cultures NH 3 and NH 2 OH alternating feed (FS4) Taher and Chandran, 2013 0.82 59.89 ± 1.12 Mixed nitrifying cultures NH 2 OH only feed with biomass replenishment (high rate) 0.37 28.8 0.31-0.54 NA Pure suspended cultures of Nitrosomonas europaea Hyman and Wood, 1983 Pure suspended cultures of N. europaea Hyman et al.,, 1988 0.02-0.1 6.2 ± 4.9 Pure immobilized cultures of N. europaea Thorn, 2007
C P N Possible flowsheet for C, N and P recovery
Few examples of resource recovery from food waste wide spectrum of endpoints possible Disrupting conventional pathways to biofuels Nitrite Water AMMONIA OXIDIZING BACTERIA Oxidation of ammonia as the primary energy source for energy metabolism Ammonia Methanol Links to other applications needed and possible O 2 Oxidation of methane via cometabolism, without net energy synthesis Methane Resource efficient options for biological N-removal
Discussion Kartik Chandran Professor Director Wastewater Treatment and Climate Change Program Director, Columbia University Biomolecular Environmental Sciences Email: kc2288@columbia.edu Phone: (212) 854 9027 URL: www.columbia.edu/~kc2288/ccr 30
Greenhouse Gas Management Energy Recovery Future City Sustainable Design & Operation Biorefining for Chemical Recovery Microconstituents Removal 6 Engineering Microbial Pathways and Technologies Water Quality & Reuse 7
The water cycle today
METABOLIC EFFECT OF NITROGEN CONCENTRATION Acetyl-CoA Key step in nitrogen assimilation, active at non-limiting nitrogen concentrations High N Higher metabolic activity and higher growth rate. Citrate Citric Acid Cycle Isocitrate α-ketoglutarate Isocitr ate Isocitrate is transported outside the mitochondria Low N Low metabolic activity and lower growth rate. Isocitrate converted to Acetyl-CoA Mitochondria Excess Acetyl co-a assimilated and stored as lipids.
Organics to biodiesel Using the fat content of biosolids Using MeOH for fuel production instead of N- removal
Cumulative CH 3 OH production Switching between NH 3 and NH 2 OH supply gave the highest CH 3 OH yield Taher & Chandran, 2013, ES&T
Rate of CH 3 OH production Taher & Chandran, 2013, ES&T
EFFECT OF NITROGEN CONCENTRATION ON YIELD COEFFICIENTS 0.3 Y X/COD, (g/g) 0.2 0.1 0 0 100 200 300 Initial COD/N Cultures become more efficient in carbon uptake and storage (as lipids) with increasing N- limitation Y X/N, (g/g) 40 20 0 0 100 200 300 Initial COD/N Vajpeyi and Chandran, 2015 BRT
Chemicals from sludge or biomass Chemical Platform technology Application Succinic acid Fermentation Nutraceutical Ethyl acetate Fermentation Solvent Methyl acetate Fermentation Solvent!,3 propanediol Fermentation Industrial monomer Butyric acid and butanol Fermentation Biofuel Challenges remain Separation and purification (although sometimes not needed) Price of co-substrates (methanol, ethanol, glycerol) Biorefining for Chemical Recovery
Provision of reducing equivalents (electrons) is crucial for converting methane to methanol