removing trace organic contaminants using biofiltration in...
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Removing Trace Organic Contaminants Using Biofiltration in
Potable Reuse Systems
Marco Velarde, Mandu Inyang, Daniel Gerrity, Jacimaria Batista,
Ben Stanford, Eric Wert, Eric Dickenson
∗ WateReuse-13-10: Controlling Trace Organic Contaminants Using Alternative, Non-FAT Technology for Indirect Potable Water Reuse
∗ Principal Investigators: Benjamin Stanford and Eric Dickenson
∗ WRRF Project Manager: Kristan Cwalina
∗ Southern Nevada Water Authority Team: Douglas D. Drury, Brett Vanderford, Beck Trenholm, Oscar Quiñones, Janie Ziegler, Josephine Chu, Brianna Enright, Brittney Stipanov, Ashley Selvy, Paige Pruisner
WateReuse-13-10
■ Growing demand for scarce water supplies
■ Drawbacks in fully advanced treatment technology (FAT)
● RO membrane: Expensive, brine disposal
● AOPs: Energy-intensive
■ Potential benefits of Biofiltration (Non-FAT):
● Sustainably-sourced media
● Operations cost savings
● Post-AOP polishing step for trace organic contaminants (TOrC)
Motivation
Fres
h G
AC
Exha
uste
d G
AC
Anth
raci
te
Conventional media Alternative media vs.
Bioc
har
Tri-P
ack
Biof
ill
Floa
ting
bead
sObjective
∗ Low density plastic support for biomass growth
∗ Acts as fixed-bed bioreactor ∗ No filtration action – biodegradation only∗ Lower headloss than granular filters∗ Lower backwash requirements – cost savings∗ Proven for AOC and aldehyde removal
Jaeger Tri-PackBioscience Biofill
Hollow Plastic Media
∗ Fresh or virgin GAC∗ Provides baseline for comparison with other media
∗ “Exhausted” GAC (Biologically active media)∗ Used in full-scale treatment for >10 years∗ Adsorptive capacity used up∗ Assumed that all treatment due to biodegradation
∗ Anthracite∗ Assumed that there is no adsorptive capacity∗ All treatment due to biodegradation
GAC and Anthracite
∗ Adsorbent charcoal product
∗ Produced from pyrolysis of biomass in limited oxygen∗ Agricultural waste product – sustainable∗ Cost savings - $0.076/kg biochar vs. $1.44-2.93/kg GAC
∗ Proven potential for removing organic contaminants (Inyang and Dickenson 2015, Chemosphere)
Biochar
Biochar
∗ Low density media similar to plastic media.
∗ Typically used in aquaculture for physical filtration and to achieve nitrification.
∗ Limited knowledge on use as a biofiltration media.
∗ Significant removal (70 – 90 %) of BOD reported in a recirculation system.
Floating plastic beads
Floating Beads
Full-scale tertiary treatment
SNWA Pilot-scale treatment
Secondary Treatment
Dual media filtration
Ozone treatment Biofiltration
Wastewater Treatment Train
∗ 6 Columns∗ Height – 15’∗ Diameter – 6”∗ Individual pumps∗ 7 Sampling ports spaced 10 feet∗ Hydraulic Loading Rate (HLR) – 9 GPM/ft2
∗ Empty Bed Contact Time (EBCT) – 8 min∗ Flow Rate – 1.77 GPM∗ Bed Volume – 14.16 gal∗ Bed Height – 9.6 ft
Intuitech biofiltration skid
Biofiltration Skid
Analyticalmeasurements
Frequency Analyte/Parameter
Biomass AcclimationMonitoring
Weekly – 32x(Aug 2014 –March 2015
Turbidity, pH, tempATP assay, DO, DOCUV254, NO3, Total N and P
Fluorescence
TOrC Performance Monitoring
Monthly – 7x(Aug 2014 –March 2015)
Indicator TOrCs16 PPCPs11 Perfluoroalkyl acids9 Nitrosamines
Headloss/Backwash Monitoring
Continuous since startup (May 2014 –March 2015)
Online flow and turbidityHead loss buildupBackwash frequency
Methods
∗ Head loss used for backwash schedule control
∗ Backwash flow different for each granular media filter
∗ Plastic media systems did not require any backwash
Methods
Classification
Group 1:Low-Sorbing / Biodegradable
Naproxen, Atenolol, Meprobamate
Group 2:Sorbing / Biodegradable
Triclosan
Group 3:Low-Sorbing /
Non-biodegradable
Carbamazepine
Group 4:Sorbing /
Non-biodegradable
TriclocarbanFluoxetine
Results – Tri- Pack Plastic Media
-20
0
20
40
60
80
100
0 100 200 300 400 500
% Re
mov
al
Volume Treated (10^3 gallons)
Naproxen (G1)
Atenolol (G1)
Meprobamate (G1)
Triclosan (G2)
Fluoxetine (G2)
Carbamazepine (G3)
Triclocarban (G4)
Results – Biofill Plastic Media
-20
0
20
40
60
80
100
0 100 200 300 400
% Re
mov
al
Volume Treated (10^3 gallons)
Naproxen (G1)
Atenolol (G1)
Meprobamate (G1)
Triclosan (G2)
Fluoxetine (G2)
Carbamazepine (G3)
Triclocarban (G4)
Results – Floating Beads
-20
0
20
40
60
80
100
0 100 200 300 400 500
% Re
mov
al
Volume Treated (10^3 gallons)
Naproxen (G1)
Atenolol (G1)
Meprobamate (G1)
Triclosan (G2)
Fluoxetine (G2)
Carbamazepine (G3)
Triclocarban (G4)
Results - Anthracite
-20
0
20
40
60
80
100
0 100 200 300 400 500
% Re
mov
al
Volume Treated (10^3 gallons)
Group 2 and 4 - Sorbing
Triclosan (G2)
Fluoxetine (G2)
Triclocarban (G4)
Results - Biochar
-20
0
20
40
60
80
100
0 50 100 150 200 250 300
% Re
mov
al
Volume Treated (10^3 gallons)
Group 2 and 4 - Sorbing
Triclosan (G2)
Fluoxetine (G2)
Triclocarban (G4)
Results – Spent GAC
-20
0
20
40
60
80
100
0 100 200 300 400
% Re
mov
al
Volume Treated (10^3 gallons)
Group 2 and 4 - Sorbing
Triclosan (G2)
Fluoxetine (G2)
Triclocarban (G4)
Results – Fresh GAC
-20
0
20
40
60
80
100
0 100 200 300 400
% Re
mov
al
Volume Treated (10^3 gallons)
Group 2 and 4 - Sorbing
Triclosan (G2)
Fluoxetine (G2)
Triclocarban (G4)
Results - Anthracite
-20
0
20
40
60
80
100
0 100 200 300 400 500
% Re
mov
al
Volume Treated (10^3 gallons)
Group 1 and 3 – Low-sorbing
Naproxen (G1)
Atenolol (G1)
Meprobamate (G1)
Carbamazepine (G3)
Results - Biochar
-20
0
20
40
60
80
100
0 50 100 150 200 250 300
% Re
mov
al
Volume Treated (10^3 gallons)
Group 1 and 3 – Low-sorbing
Naproxen (G1)
Atenolol (G1)
Meprobamate (G1)
Carbamazepine (G3)
Results – Spent GAC
-20
0
20
40
60
80
100
0 100 200 300 400
% Re
mov
al
Volume Treated (10^3 gallons)
Group 1 and 3 – Low-sorbing
Naproxen (G1)
Atenolol (G1)
Meprobamate (G1)
Carbamazepine (G3)
Results – Fresh GAC
-20
0
20
40
60
80
100
0 100 200 300 400
% Re
mov
al
Volume Treated (10^3 gallons)
Group 1 and 3 – Low-sorbing
Naproxen (G1)
Atenolol (G1)
Meprobamate (G1)
Carbamazepine (G3)
∗ Non-conventional plastic media provide cost-savings, but show poor performance at reducing TOrCs, so far.
∗ Strongly “sorbing” compounds were consistently reduced in the anthracite, biochar, and spent and fresh GACcolumns.
∗ Several “low-sorbing” TOrCs were reduced across the floating beads, anthracite, biochar, and spent GAC packed media, indicating biodegradation occurrence. ∗ Increased removal versus time was observed for some TOrC !
∗ Biofiltration shows promise for reducing TOrC levels in potable reuse systems.
Conclusions
∗ Pre-Ozonation for biofilters(Ozone:TOC < 1.0 at different ranges)
∗ Microbial characterization will be determined for each column
∗ Toxicity assay of influent and effluent
Future
Preliminary Results - NDMA
-40
-20
0
20
40
60
80
100
0 20000 40000 60000 80000 100000
Rem
oval
(%)
Bed volume
NDMA
Tripack
Biofill
-40
-20
0
20
40
60
80
100
0 20000 40000 60000 80000 100000
Rem
oval
(%)
Bed volume
NDMA
Anthracite
Spent GAC
Fresh GAC
∗ Stratified samples of a column to look at TOrC removal at different contact times
∗ Stratified sampling of media to look at stratification of ATP and microorganisms
Future
Questions?
Marco VelardeGraduate Intern, Southern Nevada Water Authority
M.S. Candidate, University of Nevada Las Vegas
velardem@unlv.nevada.edu
∗ Air scour for each granular filter at 0.75 SCFM
∗ Backwash to fluidization for each filter (flows varied from 1.0 GPM to 3.0 GPM)
∗ Backwash time ranged from 10 mins – 30 mins
∗ Pressure head below 9.0 feet determined successful backwash
∗ Each granular filter was backwashed twice a week
Methods
∗ Solids ATP analysis done using LuminUltra testing∗ Columns drained to right below sampling port∗ Sterile devices used to retrieve media and transport
Methods
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