dbp control strategies: source water, treatment, and distribution system
DESCRIPTION
DBP Control Strategies: Source Water, Treatment, and Distribution System. Philip A. Tangorra NYC WATERSHED / TIFFT SYMPOSIUM September 17, 2013 West Point, NY. Source water characteristics Traditional Treatment Disinfection Distribution. Spatial/Temporal levels of TTHM that are “high”. - PowerPoint PPT PresentationTRANSCRIPT
DBP Control Strategies: Source Water, Treatment, and Distribution System
Philip A. Tangorra
NYC WATERSHED / TIFFT SYMPOSIUM
September 17, 2013West Point, NY
TOC & DBPs
Source water characteristics Traditional Treatment Disinfection Distribution
Spatial/Temporal levels of TTHM that are “high”.
Long Term exposures - Large dataset on carcinogenicity of THM.
Stage 2 Compliance
TTHM REGULATIONS
1979 - Total Trihalomethanes Rule 0.100 mg/L MCL
1998 - Stage 1 D/DBP Rule 0.080 mg/L RAA MCL for TTHM 0.060 mg/L RAA MCL for HAA5
2006 - Stage 2 D/DBP Rule 0.080 mg/L LRAA MCL for TTHM 0.060 mg/L LRAA MCL for HAA5
19811982
19831984
19851986
19871988
19891990
19911992
19931995
19961997
19981999
20002001
20022003
20042005
20062007
20082009
20102011
2012
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.140
0.160
0.180
0.200
Annual Mean TTHM Concentrations(Compliance)1981-present
Mea
n C
on
c (u
g/L
)
2007
History of Recent MVWA Studies
1999 2002
Stage 2 D/DBP Rule Proposed
2003
Promulgation of Stage 2 D/DBP and LT2ESWTR
2004 2005
Stage 1 D/DBPCompliance
2012
DBP Control Study
TANCS Project
Nitrification Control Study
2001 2008 2010
GAC Pilot and Full Scale Demos
Cl-NH3 Conversion & Pipe Loop
2006
Stage 2 D/DBPCompliance
MVWA Studies for Stage 2 D/DBP Rule Compliance DBP Control Options Study – 2001 TANCS study – 2003 Nitrification Control Study – 2004 Chloramines System Pre-Design – 2005 Chloramines Conversion Master Plan – 2005 Corrosion Pipe Loop Testing – 2006 GAC Pilot scale testing – 2007 GAC Demonstration Scale Testing – 2008 Ongoing
Alternative coagulants DS corrosion chemistry modifications GAC Pilot Scale Testing
GAC Implementation Complete media change
out (63”) Timing Operational Issues
Flow/Demand Raw Water Quality Backwash frequency Staffing
Logistics Facilities Deliveries Noise
2011 – Full scale comparison of 8*30 GAC Wood Virgin Bituminous Reactivated
Bituminous 2012 - 8*20 Lignite 2013 - 8*20 Lignite
+ Underdrain Rehab
ANNUAL BUDGET $1,000,000
Apr-99
Apr-00
Apr-01
Apr-02
Apr-03
Apr-04
Apr-05
Apr-06
Apr-07
Apr-08
Apr-09
Apr-10
Apr-11
Apr-12
Apr-13
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
TOTAL ORGANIC CARBONMonthly Means
Raw TOC
Filtered TOC
Co
nc
en
tra
tio
n (
mg
/L)
Apr-99
Apr-00
Apr-01
Apr-02
Apr-03
Apr-04
Apr-05
Apr-06
Apr-07
Apr-08
Apr-09
Apr-10
Apr-11
Apr-12
Apr-13
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
TOC Percent RemovalMonthly Means
% R
em
ov
al
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.002011 -2013 WTP TOC
Raw
Clarified
Filtered
TO
C (
mg/L
)
May-11
Aug-11
Nov-11
Feb-12
May-12
Aug-12
Nov-12
Feb-13
May-13
Aug-13
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90C/Co
02/01/03
02/01/04
02/01/05
02/01/06
02/01/07
02/01/08
02/01/09
02/01/10
02/01/11
02/01/12
02/01/13
02/01/14
0
20
40
60
80
100
120
140
160
180
200
TTHMStage 1 & 2 Compliance
Endpoint
Co
nc
(u
g/L
)
02/01/03
02/01/04
02/01/05
02/01/06
02/01/07
02/01/08
02/01/09
02/01/10
02/01/11
02/01/12
02/01/13
02/01/14
0
20
40
60
80
100
120 TTHM - LRAA
Endpoint
Co
nc
(u
g/L
)
02/01/12
05/01/12
08/01/12
11/01/12
02/01/13
05/01/13
08/01/13
11/01/13
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0TTHM - Stage 2 Compliance
BELL HILL ROAD, DEERFIELD
LRAA
Co
nc
(u
g/L
)
MVWA Studies for Stage 2 D/DBP Rule Compliance DBP Control Options Study – 2001 TANCS study – 2003 Nitrification Control Study – 2004 Chloramines System Pre-Design – 2005 Chloramines Conversion Master Plan – 2005 Corrosion Pipe Loop Testing – 2006 GAC Pilot scale testing – 2007 GAC Demonstration Scale Testing – 2008 Ongoing
Alternative coagulants DS corrosion chemistry modifications GAC Pilot Scale Testing
OngoingAlternative coagulantsDS corrosion chemistry modifications
GAC Pilot Scale Testing
Alternative Coagulants
Applied Specialtie
s
Holland Chemical Delta Chemical
AS-4070 PCH180 GLP39 DeltaFloc1123
AS-4071 PCH182 GLP24 DeltaFloc1124
AS-3026 DelPac1525 DeltaFloc1173
AS-3027 DelPac2450 DeltaFloc842
AS-3032 DelPac2000 DeltaFloc807
AS-3034 DelPac2020 GLP23
AS-3036 DelPac2950 AL4P
AS-3003 DeltaPacXP GLP17
AS-3023
Distribution System
Recent DS Conditions pH 9.4 Alkalinity ~40mg
CaCO3/L PO4 0mg/L Optimized Corrosion UFWR offline
Experimental (CDM Smith) pH 7.8 Alkalinity ~40mg
CaCO3/L PO4 0.8 mg/L Cost Savings? TTHM Reduction?
MVWA HISTORICAL LEAD MONITORING DATA LCR Monitoring Period Lead Percentiles
50th 75th 90th
Initial Monitoring
1992 - 1st 6 Months 0.038 0.070 0.100
1992 - 2nd 6 Months 0.063 0.092 0.165
Follow-Up Monitoring
1993 - 1st 6 Months 0.021 0.040 0.055
1993 - 2nd 6 Months 0.014 0.024 0.043
1994 - 1st 6 Months 0.009 0.016 0.027
1994 - 2nd 6 Months 0.010 0.018 0.029
1995 - 1st 6 Months 0.003 0.006 0.010
1995- 2nd 6 months 0.003 0.007 0.011
1996 – 1st 6 months 0.003 0.005 0.009
1996- 2nd 6 months 0.004 0.008 0.012
Reduced Monitoring 1997 0.005 0.008 0.014
2000 0.005 0.008 0.013
2003 0.007 0.012 0.014
2006 0.005 0.008 0.011
2009 0.005 0.008 0.011
2012 0.003 0.005 0.008
0
20
40
60
80
100
120
140
160
0 2 4 6 8 10 12
TTHM
(ug/
L)
Holding Time (days)
pH 9.4
pH 7.8
MCL
Distribution Considerations
Unidirectional Flush Timeframe Lime / Soda Ash / Bicarb Pb/Cu compliance TTHM reductions
GAC Options Siemens Coconut shell Calgon Carbsorb 820 Factors
Cost RSSCT and pilot scale testing
EBCT at 20MGD 63” GAC = 14.5 min 55” GAC = 12.7 min
Regeneration??
In Situ GAC Regeneration
Dr. Paul Westerhoff at Arizona State University has developed a technique that may allow for in situ GAC regeneration
Iron nanoparticles (<100 nm) are combined with H2O2 to form hydroxyl radicals, which can oxidize adsorbed organic compounds, converting them to CO2 and H2O
Objectives
Determine if the in situ regeneration technique is suitable for recovering TOC adsorption capacity
Evaluate the effectiveness of the method under “more realistic” conditions Commercially available GAC
Full size GAC grains
Typical (full scale) GAC bed depth
Iron Nanoparticle Production
Commercial grade FeCl3 resulted in larger NPs than those produced from reagent grade FeCl3 (200 nm vs. 80-90 nm)
Methylene blue dye oxidation tests were used to gauge NP reactivity
Multiple batches of NPs appeared non-reactive
It was discovered that dye oxidation only occurred in a pH range of 2.6-2.8
Methylene Blue Oxidation Tests
Pilot Scale Filter Columns
Pilot Scale Recirculation System
Regeneration Results
Wood-based GAC - Three 1-hour regeneration cycles
No measureable change in effluent TOC
Lignite-based GAC One 1-hour regeneration cycle
No measureable change in effluent TOC
Regeneration Results
Coconut-based GAC Three 1-hour regeneration cycles
Effluent TOC reduced after each cycle First round: 1.25 mg/L → 0.85 mg/L
Second round: 0.65 mg/L
Third round: 0.55 mg/L
Effluent TOC Profile – Coconut GAC
Regeneration Considerations
Reagent v. Commercial FeCl3 pH control Peroxide measurement Biofilm?
Summary
In situ regeneration using Fe NPs and peroxide has been shown to be effective for recovering phenol adsorption capacity in bench scale tests
Pilot scale testing has demonstrated that recovering NOM adsorption capacity in full size GAC grains is possible
Achieving greater recovery may require further modifications, or simply more time
THE LAST SLIDE
Thanks Connie Schreppel, PhD
MVWA Director of Water Quality Kim Hoffman CDM Smith Kirk Nowack, PhD - Arcadis
Questions?