High Rate Anaerobic Digestion of High Strength Acidic Wastewater at
Demonstration Scale
Dr. Michael Cooney
Hawaii Natural Energy Institute
University of Hawaii
http://www.hnei.hawaii.edu
Value of Wastewater
http://www.hnei.hawaii.edu
WWTP
Biogas (CO2, CH4)
Biomass (CHaNbOc)
Cl-1,NO3-1,PO4
-2,SO4-2
Na+,K+,Mg+2,Ca+2
Steroid hormones,
Alkylphenolic compounds,
Perfluorinated chemicals
Electricity
Treated Water
Relative mass ratios of outputs depends greatly upon the process technology
used, including the form of electron acceptor.
Wastewater (3 to 10 MGD)
Water
Carbon
Electrons
Ions
Pharmaceuticals
Energy
Air
Anaerobic Wastewater Treatment
http://www.hnei.hawaii.edu
WWTP
Outputs
Water – High
Biogas – Medium to High
Ions – Low to Medium
Electricity – low
Pharmaceuticals – low
Biomass - Low
Inputs
Water – High
Air - Low
Energy - Low
Aerobic Wastewater Treatment
http://www.hnei.hawaii.edu
WWTP
Inputs
Water - High
Air - High
Energy - High
Outputs
Water – High
Biomass – Medium High
Ions – Low
Pharmaceuticals – Low
Electricity – Nil
Biogas - Nil
Wastewater Products
http://www.hnei.hawaii.edu
The principal product exiting a wastewater treatment plant, in terms
of any logical productivity metric, is treated wastewater.
Historically, treated wastewater has been given little to no positive value,
instead being treated as a negative emission that requires treatment with
high-energy and high chemical inputs prior to its discharge.
Recently, efforts have been made to find “heretofore” undiscovered value
in wastewater in terms of energy as electrons, energy as biogas, high
value chemicals, and even macronutrients.
These efforts, however, are hindered by their low densities – they are
byproducts.
The treatment of wastewater, therefore, remains driven by regulatory
implementation of fines and not the recovery of value added byproducts.
http://www.hnei.hawaii.edu
"There are parts of the bay where you are literally inside a
latrine where hundreds of thousands of people defecate daily,"
according to Mario Moscatelli, an independent biologist who
closely monitors pollution in Rio's waterways. Moscatelli says in
addition to sewage, he has documented cadavers, hospital
waste, home electronics and tires in the water” – Taylor Barnes,
Special for USA Today, 2/24/2015http://www.usatoday.com/story/sports/olympics/2015/02/24/rio-de-janeiro-olympic-legacy-
promises/23942105/
With a resident population of over 900,000, and more than
485,500 visitors a month, Honolulu is the largest U.S. city that
does not provide secondary sewage treatment.
Under the 2010 consent decree, the Honouliuli wastewater
treatment plant must be upgraded to secondary treatment by
2024, the Sand Island Plant by 2035.
Lawsuit brought by Sierra Club, Hawai’is Thousand Friends,
and Our Children’s Earth Foundation
Application of Anaerobic Digestion for High-Rate Treatment of
GTW Wastewater
A collaborative research cooperative between
Hawaii Natural Energy Institute
& Pacific Biodiesel
http://www.hnei.hawaii.edu
Acknowledgements
Robert King Sam Millington
Kevin Harris Ken Lewis
Ryan Lopez Scott Higgins
Application of Anaerobic Digestion for High-Rate Treatment of
GTW Wastewater
MISSION STATEMENT
To evaluate the application of anaerobic digestion to the treatment of
waste trap grease wastewater as a means to reduce discharge costs
and to produce methane gas for on-site energy use.
RATIONAL
The business of producing biodiesel from waste oil is marginal. The
key merit to this project, therefore, is the application of AD to treat a
pre-existing waste stream (i.e. GTW wastewater) as a means to
reduce the cost of wastewater discharge to sewage and thus improve
the profit margin of biodiesel production.
http://www.hnei.hawaii.edu
Anaerobic Digestion of
GTW Wastewater
http://www.hnei.hawaii.edu
Gas Box
GTW wastewater Feed
Solids Recycle
A
2X
B
4X
C
4X
Treated Effluent
pH, Temperature
controller
Acid catalyzed DT
Biodiesel
FOG
GTW
Anaerobic Digestion of
GTW Wastewater
Synthetic media GTW Wastewater
pH 7 4.0 - 4.4
Total COD (g L-1) 16.1 15.9 – 21.2
Soluble COD(g L-1) 16.1 13.4 -17.3
Total N (g L-1) 0.66 0.15 - 0.43
Soluble TN (g L-1) 0.66 0.14 - 0.37
TP (g L-1) 2.01 0.24 - 0.97
Soluble TP(g L-1) 2.01 0.19 -0 .79
Soluble TVOA (g L-1) 390 2.9 - 4.3
TSS (g L-1) - 1.8 – 2.8
Total COD/TN 24.4 55.4 – 73.3
Soluble COD/TN 24.4 62.2 - 83.6
Total COD:N:P 100:4.1:12.5 100:0.71:1.13 - 100:2.70:6.10
Soluble COD:N:P 100:4.1:12.5 100:0.81:1.10 - 100:2.76:5.90
http://www.hnei.hawaii.edu
Table 1: Characteristics of GTW wastewater.
Anaerobic Digestion of
GTW Wastewater
Packing density (g L-1), System HRT (d), OLR (kg COD m-3 d-1)
25, 3.0; 5.53 25, 2.0, 9.75 25, 1.0, 21.2
HYD R1 R2 HYD R1 R2 HYD R1 R2
pH 5.96 6.95 7.17 6.01 6.89 7.21 5.95 6.97 7.24
TSS (g L-1) 2.75 1.4 0.45 4.8 3.8 0.7 2.6 3.6 2
TSS reduction (g L-1) -45 26 76 -71 -36 75 -8 -50 13
COD (g L-1) 8.6, 3.6(s) 3.0,
0.6(s)
1.0,
0.4(s)
18.5,
10.8(s)
8.5,
2.4(s)
1.6,
0.7(s)
11.7,
8.4(s)
7.8,
2.7(s)
4.0,
1.1(s)
COD reduction (%) 48, 73(s) 82, 96(s) 94, 97(s) 5, 28(s) 56, 84(s) 92, 95(s) 45, 51(s) 63, 84(s) 81, 94(s)
COD reduction (kg
COD m-3 d-1)
2.67;
3.27(s)
4.53,
4.27(s)
5.2,
4.56(s)
0.5,
2.15(s)
5.5,
6.35(s)
8.95,
8.1(s)
9.5,
8.9(s)
13.4,
14.6(s)
17.2,
16.2(s)
TVOA (mg L-1) 1.275 (s) 0.149 (s) 0.044 (s) 2.798(s) 0.498(s) 0.080(s) 2.834(s) 0.980(s) 0.313(s)
TVOA reduced (%) 57 95 99 34 88 98 15 71 91
TGPR (m3 m-3 d-1) 1.77 0.852 0.177 2.49 1.38 0.918 5.77 3.12 1.2
CO2 (%) 42 23 22 36 23 22 44 22 19
CH4 (%) 55 77 70 61 77 78 55 78 81
CH4 (m3 m-3 d-1) 0.974 0.656 0.124 1.52 1.06 0.72 3.17 2.43 0.97
CH4 per CODred (m3
kgCOD-1)
0.34 0.39 0.38
http://www.hnei.hawaii.edu
Characteristics of up flow anaerobic fixed film reactor modules on synthetic and GTW wastewater on corn
cob biochar as a function of packing density and organic loading rate at 37ºC.
Anaerobic Digestion of
GTW Wastewater
http://www.hnei.hawaii.edu
Figure 3. SEM images of native and biofilm covered corn cob biochar. Graphs: (LHS) 800x
magnification; (RHS) 2000 times magnification.
Phylogentic analysis revealed broad spectrum populations of anaerobic bacteria
that ferment organic substrates to produce acetate, ethanol, and hydrogen as
major end products as well as archaeal populations that produce methane gas
Biofilm Communities
http://www.hnei.hawaii.edu
Band Top match (accession number) Identitya Phylum Domain
1 Thermotogaceae strain SulfLac1 (FR850164) 99% Thermotogae Bacteria
2 Spirochaetes clone DhR^2/LM-B02 (HQ012843) 92% Spirochaetes Bacteria
3 Thermotogaceae clone B3112 (HQ133023) 91% Thermotogae Bacteria
4 Pelotomaculum sp. FP (AB159558) 95% Firmicutes (Clostridia) Bacteria
5 Clostridium sp. clone K13-19 (HE862234) 91% Firmicutes (Clostridia) Bacteria
6 Desulfotomaculum thermobenzoicum (AJ294430) 93% Firmicutes (Clostridia) Bacteria
7 Clostridium thermocellum (CP002416) 90% Firmicutes (Clostidia) Bacteria
8 Symbiobacterium sp. clone BL1_11 (JX101989) 99% Firmicutes (Clostridia) Bacteria
9 Symbiobacterium sp. clone BL1_11 (JX101989) 94% Firmicutes (Clostridia) Bacteria
10 Methanobacterium formicicum strain KOR-1
(JX042445)
100% Euryarchaeota
(Methanobacteriales)
Archaea
11 Methanobacteriaceae clone B11-A-115 (JN836424) 100% Euryarchaeota
(Methanobacteriales)
Archaea
12 Methanosaeta sp. clone BUH10-1 (JQ282391) 100% Euryarchaeota
(Methanomicrobia)
Archaea
13 Methanoculleus bourgensis MS2 (HE964772) 97% Euryarchaeota
(Methanomicrobia)
Archaea
A B
DGGE gels showing microbial community profiles for the
bacteria (panel A) and archaea (panel B) in the anaerobic
reactors (R1 and R2) based on 16S rRNA genes. DNA
sequence information was obtained for the numbered
DGGE bands. Lanes i and iii are replicate samples for
Reactor 1, and Lanes ii and iv are for Reactor 2.
Design and Fabrication of
Demonstration Scale HRAD Reactors
http://www.hnei.hawaii.edu
http://www.hnei.hawaii.edu
Installation of Demonstration Scale
HRAD System
Evaluation of HRAD System
at Demonstration Scale
http://www.hnei.hawaii.edu
Total 5-Jul 17-Jul 24-Jul 1-Aug 7-Aug 14-Aug 21-Aug 24-Jun Ave std
COD 12.60 17.00 17.30 16.50 13.60 15.40 15.10
STA
RT
UP
15.36 1.76
N 0.24 0.34 0.42 0.34 0.38 0.33 0.32 0.34 0.06
P 0.15 0.27 0.28 0.24 0.21 0.22 0.15 0.22 0.05
HEM 3.28 1.64 1.86 2.00 3.41 6.84 5.17 3.46 1.93
TSS 1.08 1.04 1.20 1.19 0.89 0.83 1.07 1.04 0.14
pH 4.49 4.58 4.62 4.63 4.61 4.60 4.33 4.55 0.11
COD/N 52.50 42.50 41.20 49.10 35.40 46.40 47.90 45.00 5.72
Table 1. Total characteristics of waste grease trap wastewater feedstock. Total values represents
measurements made on samples without filtering. Units are in g L-1.
Soluble 17-Jul 24-Jul 1-Aug 7-Aug 14-Aug 21-Aug 24-Jun Ave std
COD 12.50 15.20 14.70 12.40 12.80 10.52
STA
RT
UP
13.02 1.70
N 0.28 0.31 0.28 0.31 0.22 0.20 0.27 0.05
P 0.20 0.22 0.16 0.16 0.12 0.09 0.16 0.05
VOA 4.32 4.32 4.50 4.35 3.59 4.68 4.29 0.37
HEM 1.65 2.12 2.17 6.46 4.69 4.74 3.64 1.93
COD/N 44.00 48.70 53.30 39.70 59.30 51.60 49.43 6.95
Table 2. Soluble characteristics of waste grease trap wastewater feedstock. Soluble values represent
measurements made on samples after they were filtered through 1.8 micron Whatman filters. Units
are in g L-1.
Application of Anaerobic Digestion for Treatment of
GTW Wastewater
http://www.hnei.hawaii.edu
Figure 3. Performance of packed bed anaerobic reactor as a function of location at day fifty nine after innoculation. Symbols: Open triangles, total COD; open squares, soluble COD; open triangles, total volatile organic acids; crosses, pH.
0
1
2
3
4
5
6
7
8
0
2
4
6
8
10
12
14
16
pHg
L-1
Sample Location
Figure 4: PH profile as a function of location at various times after inoculation. Symbols: Open diamonds, fifty nine days after innoculation; open squares, fifty three days after innoculation; open triangles, twenty eight days after innoculation.
5.5
6
6.5
7
7.5
8
Hydrolysis R1P2 R2P2 Effluent
pH
Sample Location
BIOFILM COMMUNITIES DIFFER FROM
PLANKTONIC COMMUNITIES
Taxa Aqueous (MC 01-05) and Biochar (MC 06-09) samples
Kindom Class Genus MC01 MC02 MC03 MC04 MC05 MC06 MC07 MC08 MC09
Archaea
Methanobacteria
Methanobacteriu
m 0.02 0.19 0.37 0.92 0.68 20.86 19.28 31.08 24.42
Methanobacteria
Methanobrevibact
er 0.00 0.08 0.43 0.49 0.21 3.12 6.79 1.23 1.29
Methanobacteria Methanosarcina 0.00 0.27 1.92 2.22 1.10 1.77 5.97 2.95 3.08
Bacteria
Bacteroidia 0.06 6.99 7.14 3.75 2.39 1.59 4.98 1.09 2.18
Bacteroidia 0.05 12.33 10.06 2.87 3.70 0.00 0.02 0.01 0.04
Bacteroidia 0.00 1.77 5.58 9.74 6.06 0.06 0.30 0.00 0.00
Bacteroidia Prevotella 63.22 20.11 8.27 5.95 7.43 0.00 0.02 0.00 0.00
Bacteroidia 0.00 14.14 7.06 2.83 2.47 0.00 0.00 0.00 0.00
Bacteroidia 0.12 10.93 12.93 9.58 13.80 0.11 0.64 0.08 0.18
Anaerolineae SHD-231 0.00 0.00 0.04 0.16 0.09 7.26 4.66 3.84 2.50
Bacilli Lactobacillus 6.23 0.24 0.05 0.00 0.02 0.00 0.00 0.00 0.00
Clostridia Sporanaerobacter 0.00 0.04 0.13 1.95 2.20 10.48 4.29 2.53 1.97
Clostridia Other 0.00 0.92 5.32 7.20 7.02 0.90 0.83 1.06 0.87
Clostridia Syntrophomonas 0.00 0.10 0.46 3.12 4.53 6.40 8.46 12.31 11.68
Clostridia Megasphaera 7.19 2.73 2.30 0.66 0.57 0.01 0.00 0.00 0.01
Deltaproteobacteria Desulfovibrio 0.01 11.17 8.51 7.73 7.98 0.26 1.60 0.33 0.28
Gammaproteobacte
ria Escherichia 0.06 0.01 0.01 0.06 0.06 9.96 4.19 5.09 1.03
WWE1 W22 0.01 0.00 0.05 0.59 0.91 2.14 6.01 4.53 11.76
Synergistia Aminobacterium 0.00 0.08 0.37 1.53 1.48 11.09 6.87 8.82 10.16
http://www.hnei.hawaii.edu
MC01: Feedstock; MC02: Mixing Tank; MC03: Column B WW; MC04: Column C WW; MC05: Treated effluent; MC06: Column
B biochar top; MC07: Column B biochar bottom; MC08: Column C biochar top; MC09: Column C biochar bottom.
Summary
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Methanogenic archea grow much slower than acido and acetogenic bacteria; these
differences can be amplified by any number of process variables such as temperature,
pH, and organic loading rate.
The start-up phase is critical to long-term operation of anaerobic digesters. In
particular, failure to achieve a properly balanced methanogenic microbial community
during start up can lead to inefficient operation, indefinite delays or failure.
At lab scale biochar served as an excellent packing material to support the growth
and retention of biofilms rich in active and properly balanced methanogenic microbial
communities.
In this presentation biochar was been shown to excel at demonstration scale under
commercial operating conditions.
Specifically, in the relatively short time of only fifty nine days, the system
achieved excellent performance and developed biofilms that were populated with
active methanogenic microbial communities.
New Research Directions
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Hybrid systems that meet EPA discharge limits on BOD5 and TSS
Hybid systems for safe water reuse for food and energy production
New support materials that increase the accessible surface area of active
methanogenic biofilm communities per unit reactor volume
Application of High Rate Anaerobic – Aerobic
Digestion (HRAAD)
A collaborative research project between
Hawaii Natural Energy Institute
Hawaii American Waters
RealGreen Power
AECOM
http://www.hnei.hawaii.edu
Acknowledgements
Roger Babcock Rick Rocheleau
Lee Mansfield Rudy Mina,
Dennis Tulang Dennis Furukawa
HRAD Example 1: Treatment of primary clarifier
effluent
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FOG enriched Primary Clarifier Effluent
Bionest
Biochar
Bionest/Biochar
Effluent Rxr 1
Air
Effluent Rxr 2
Recycle
1 FT Bionest
Sludge bed Zone
4.5 FT
Bionest/Biochar
0.8 FT Biochar
1.5 FT Bionest
Clarifier Zone
Gas outlet
Recycle
Application of High Rate Anaerobic – Aerobic
Digestion (HRAAD)
http://www.hnei.hawaii.edu
BOD5 = ~ 13.3 g/l < 30 mg/l
TSS = ~ 8.5 g/l < 30 mg/l
EPA Discharge Requirements met at HRT of 7 hours & use of recycle
Application of High Rate Anaerobic – Aerobic
Digestion (HRAAD)
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VHRAD 25000.0 gallons
HRTHRAD 7.0 hours
Qo 3571.4 gph
Qo 85714.3 gpd
Qo 324.4 m3pd
Qo 13.5 m3ph
Qrec1 7142.9 gph
Qrec1 171428.6 gpd
Qrec1 648.9 m3pd
Qrec1 27.0 m3ph
Qrec2 14285.7 gph
Qrec2 342857.1 gpd
Qrec2 1297.7 m3pd
Qrec2 54.1 m3ph
HRTClarifier 2.0 hours
VClarifier 7142.9 gallons
ENERGY
Q Head Voltage Current Power Power
gph ft V Amps Watt kW
P1 (Qrecy1) 3571.4 5 115 2 230 0.23
P2 (Qrecy1) 3571.4 5 115 2 230 0.23
P3 (Qrecy2) 4761.9 20 115 2 230 0.23
P4 (Qrecy2) 4761.9 20 115 2 230 0.23
P5 (Qrecy2) 4761.9 20 115 2 230 0.23
P6 Grinder (Solids recycle) 230 9.8 31.1 0.0
Punit 1181.1 1.18
Energy Balance
Application of High Rate Anaerobic – Aerobic
Digestion (HRAAD)
http://www.hnei.hawaii.edu
PC
PC
PC
AERATION
AERATION
AERATION
CLARIFIERUV
P1
R1 R1 R1 R1R1 R1
R2 R2
R1 R1 R1 R1R1 R1
R2 R2 R2 R2 R2 R2 R2 R2 R2 R2
R1 R1 R1 R1R1 R1
R2 R2
R1 R1 R1 R1R1 R1
R2 R2 R2 R2 R2 R2 R2 R2 R2 R2
R1 R1 R1 R1R1 R1
R2 R2
R1 R1 R1 R1R1 R1
R2 R2 R2 R2 R2 R2 R2 R2 R2 R2
P1
P1
Pair
SANDFILTER
Pras
HEADWORKS
DISCHARGE
Q gpd kWh/day
Exist HKWWTP 3,085,714
Loading (gravity) -
Blower (air) 2,640
RAS 925,714 115
Exist HK total 2,755
RGP HNEI 3,085,714 1,438
Energy Savings 48%
Comparison against
existing activated
sludge plant treating
3.1 MGD
Water Reuse System for food and Energy
Production
http://www.hnei.hawaii.edu
COD = 19.8 g/l
Tss = 1.16 g/l
CODred > 90%
Tssred > 60%
CODred > 98%
Tssred > 97.5%
CODred > 99.2%
Tssred > 99.8%
NH4+ ~ 0.37 g/l
NO3- ~ 0.0 g/l
PO42- ~ 0.91 g/l
K+ ~ 0.16 g/l
NH4+ ~ 0.37 g/l
NO3- ~ 0.0 g/l
PO42- ~ 0.91 g/l
K+ ~ 0.16 g/l
NH4+ ~ 0.01 g/l
NO3- ~ 1.06 g/l
PO42- ~ 0.87 g/l
K+ ~ 0.17 g/l
NH4+ ~ 0.0 g/l
NO3- ~ 1.03 g/l
PO42- ~ 0.87 g/l
K+ ~ 0.16 g/l
http://www.hnei.hawaii.edu
min0 10 20 30 40 50
nRIU
-5000
0
5000
10000
15000
20000
25000
30000
8.8
34 8
.982
9.1
51 9
.843
12.
040
12.
960
13.
880
14.
966
17.
308
18.
836
19.
531
20.
627 2
2.48
7
26.
382
28.
837
29.
667
32.
197
36.
900
41.
146
44.
221
min0 10 20 30 40 50
nRIU
-5000
0
5000
10000
15000
20000
25000
30000
8.9
78 9
.144
12.
039
12.
970
22.
466
26.
366
29.
203
min0 10 20 30 40 50
nRIU
-5000
0
5000
10000
15000
20000
25000
30000
8.9
74 9
.164
12.
046
12.
968
29.
454
min0 10 20 30 40 50
nRIU
-5000
0
5000
10000
15000
20000
25000
30000
9.0
51
12.
020
12.
972
29.
450
Feed Tank
Hydrolysis reactor
Anaerobic reactor
Aerobic Reactor
Water Reuse System for food and Energy
Production
HPLC
Advanced Biofilm Supports:
Island Biofilms
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