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PASSIVE TREATMENT OF ACIDIC HIGH-METAL
DISCHARGES PART 1
Co-Conspirators: S. Busler, T. Danehy, M. Dunn, D. Guy, R.Mahony, C. Neely
Presenter: Cliff Denholm
<300 publicly funded PTS in PA1
>77 billion gal/yr of AMD treated in PA alone1
>16 Million Pounds of Iron removed/year >3 Million Pounds of Aluminum removed/year
Pennsylvania PTS: A Brief Background
1www.datashed.org
Growing Concern
We all know that Passive Systems Don’t Work Passive Systems require too much
maintenance Vertical Flow Ponds Don’t Work You can’t passively treat High Aluminum AMD You can’t passively treat High Iron AMD Active Treatment is the only answer Watershed Groups are failing Watershed Groups are not maintaining
systems
PTS Concerns, Myths, & Legends
Absolute Statements are ALWAYS Wrong
Treatment Technology ~30 years old◦ Developed over time◦ Still developing
Mistakes had to be made to learn Early excitement & funding availability allowed for
experimentation◦ Sometimes it worked, Sometimes it didn’t
Do something or do nothing
Are these concerns real? Why? Yes and No
Jennings – A Tale of Trial & Error
Mine Seal Blowout ~1984
Original Wetlands System Constructed ~1988
PointFlow(GPM) pH
Alk mg/L
Acidmg/L
T. Femg/L
T. Almg/L
T. Mnmg/L
SO4 mg/L
In 34 2.9 0 258 22 19 6 516
Out NA 3.3 0 154 15 14 6 519
ALD – Installed 1993
PointFlow(GPM) pH
Alk mg/L
Acidmg/L
T. Femg/L
T. Almg/L
T. Mnmg/L
SO4 mg/L
In NA 3.3 0 NA 81 21 9 691
Out 24 6.3 177 NA 62 <1 9 680
Plugged with Al within ~9 months
Vertical Flow Pond
PointFlow(GPM) pH
Alk mg/L
Acidmg/L
T. Femg/L
T. Almg/L
T. Mnmg/L
SO4 mg/L
Raw 20 3.0 NA 261 34 14 14 693
WL4 33 6.5 48 -2 <1 <1 6 642
Need to use the right tool for the job
VFPs
Tools In the Tool Box Chemical
Plants
Refuse Removal & CFB Plants
Land Reclamation
Aquafix
Coal Ash
ALDs
Wetlands
Lime dosers TIFs
HFLBs
Why Do Passive Systems “Fail”?
• Design - undersized, wrong application/developing technology,
etc.
• Construction - sloppiness, short-cuts, accidental errors
• Site conditions - not enough room, something vs. nothing
• Unanticipated issues - water quality or quantity changes
• Design life met and/or treatment media spent
• Lack of O&M
Passive Treatment Systems
Are LOW Maintenance
Not NO Maintenance
Risk Analysis Matrix
De Sale Phase 1Flow
pH Acid Alk Fe Mn Al
Raw 36 4.1 319 NA 82 55 12
De Sale Phase 1
Constructed 1999 (16 Years Old)Cost $391,000Upgrades Cost ~$10,000 O&M Costs ~$8,000Volunteer = $?O&M Annualized ~$500
Flow pH Acid Alk Fe Mn Al
Raw 36 4.1 319 NA 82 55 12
Treated 44 6.6 -2 81 1 31 <1
De Sale Phase 1
Flow
pH Acid Alk Fe Mn Al
Raw 36 4.1 319 NA 82 55 12
Forbay N
10 3.3 201 NA 20 40 11
Forbay S
21 3.4 228 NA 48 42 10
Upgrades◦ Installed Forebay◦ Replaced VFP Outlet Pipes to adjustable peri-pipes◦ Inlet & Outlet pools in HFLB
O&M Flushing/Backflushing Cleaning out low pH iron from pipes Removed low pH iron from top of VFPs Stirred top layer of VFP treatment media Stir HFLB
Remaining O&M Needs◦ Stir HFLB
De Sale 1 O&M & Upgrades
Dents Run 3895- Elk Country!!
One of the worst water quality discharges passively treated in PA
162-2162-8
162-3
CC1
162-6 & 162-10
OPC
Moat
VFP1
SB1
ALD
CC1CC1CC1
162-6 & 162-10
CC1
SB1
162-6 & 162-10
CC1
Moat
SB1
162-6 & 162-10
CC1
VFP1
Moat
SB1
162-6 & 162-10
CC1
VFP1
Moat
SB1
162-6 & 162-10
CC1
OPC
VFP1
Moat
SB1
162-6 & 162-10
CC1
ALD
OPC
VFP1
Moat
SB1
162-6 & 162-10
CC1
ALD
OPC
VFP1
Moat
SB1
162-6 & 162-10
CC1
162-8
ALD
OPC
VFP1
Moat
SB1
162-6 & 162-10
CC1
162-2162-8
ALD
OPC
Moat
SB1
162-6 & 162-10
CC1
162-3
162-2162-8
ALD
OPC
Moat
SB1
162-6 & 162-10
CC1
Forebay162-3162-2
162-8
ALD
OPC
VFP1
Moat SB1
162-6 & 162-10
CC1
Aka TIFs
HFLB
SP/WL
VFP2B
OPC3
SB1
Forebay
FlowGPM pH
Alk mg/L
Acidmg/L
T. Femg/L
T. Almg/L
T. Mnmg/L
SO4 mg/L
5-10 2.67 0 1385 304 142 20 2620
OPC2
FlowGPM pH
Alk mg/L
Acidmg/L
T. Femg/L
T. Almg/L
T. Mnmg/L
SO4 mg/L
3.12 0 512 28 83 26 2130
OPC2A
Avg 80% Fe Loading Removed
In ~600 Feet!!!
70% Iron Was Removed
Winter Solstice 12/21/09
<0°C
Vertical Flow Pond 1 (VFP1)
VFP1 Mixing with OPC2
pH ~3
pH ~ 5
pH ~~7
Settling Basin 1 (SB1)
OPC3
VFP2B
Settling Pond/Wetland
HFLB (Final Effluent)
FlowGPM pH
Alk mg/L
Acidmg/L
T. Femg/L
T. Almg/L
T. Mnmg/L
SO4 mg/L
46 7.51 214 -180 0.1 0.2 5.3 1097
Vegetation in Channels and Spillways
Dents Run 3895
Box outlet clogged Vegetation removed,
outlet depth increased
Dents Run 3895
Dents Run 3895
Dents Run 3895
2008-Site constructed Hydraulic issues noted
De Sale Phase 2Flow pH Acid Alk Fe Mn Al
Raw 135 3.2 257 NA 26 55 10
Treated 135 6.3 0 74 <1 25 <1
Source: www.datashed.org
De Sale II- History/Maintenance
2000-Site constructed 2012- decreased
treatment performance noted
VFP East Stir Forebay inlet and outlet
cleaned
De Sale II- History/Maintenance WL outlet cleared of
vegetation HFLB stone re-
leveled VFP outlet spillway
cleared of vegetation buildup
De Sale II- Recent Maintenance
Multiple issues noted during site visit by SRWC
Forebay pipe inlet clogged
VFP performance decreased
De Sale II-Forebay
De Sale II- Vertical Flow Pond
De Sale II- Vertical Flow Pond
O&M- De Sale II
Pre- and Post- O&M Effluent Field Water Quality DataParamet
erPre-O&M
Post-O&M
pH 6.0 6.9
alkalinity 20 ~70
Fe (mg/l) 4-8 0.5 - 1
Total metals mg/L, acidity and alkalinity as CaCO3 mg/L
De Sale Phase 3Flow pH Acid Alk Fe Mn Al
Forebay 12 3.1 509 NA 107 107 29
Treated 13 6.9 30 64 <1 53 <1
Source: www.datashed.org
De Sale Phase 3
Constructed 2003 (~12 Years Old)
VFP1 Maintenance
VFP1 Maintenance
Access Road Maintenance
Replace baffle curtains Removed Fe off of VFP & stirred VFP Backflushed & Stirred HFLB Fixed access road entry
De Sale 3 O&M
Assist PA watershed groups, non-profits, conservation districts, etc.
2011-Current (multiple grants) Technical assistance & water sampling Funding Sources
◦ PA DEP Growing Greener Program◦ Foundation for PA Watersheds◦ In-kind/match watershed groups
Operation & Maintenance Technical Assistance Program
Construction Cost = $200,000
Annual O&M = 1% Need = ~$40,000 to invest
Replacement Cost every 20 YearsNeed = ~$60,000 to invest
If provide an extra $100,000 at time of grant to the watershed group, they could maintain treatment for “perpetuity”
Passive Treatment Trust Fund
High Risk (High Metal) AMD can be passively treated IF◦Good Design◦Sufficient Site Conditions Area Elevation Change
◦Proper Construction◦Maintained
Take Home Message
Require Sufficient Funding At All Stages:◦Design◦Construction◦Monitoring◦Maintenance
Take Home Message
Watershed Groups Can and Should be part of the long-term plan to maintain treatment systems as they can do it cheaper but they need:
◦Support ◦Funding
Lab Samples Field Equipment Travel Expenses
◦Maintenance◦Technical Assistance like SRI’s O&M TAG
Take Home Message
Passive treatment is not maintenance free; Like a car, regular inspections and occasional
maintenance are needed for a treatment system to reach it’s design life;
Take Home Message
Poor water quality does not always mean the system is a failure or has reached its design life;
Treatment performance can often be restored through maintenance activities that rejuvenate the system instead of replacing the treatment media or rebuilding the system and thus saving money;
Take Home Message
Questions?
Questions???
Most sites require maintenance over time
Regular site visits and observations allow many problems to be addressed quickly and efficiently
PA PTS Snapshot
Site Assesment
Passive is the only answer All of our systems work 100%, 100% of the
time Passive systems don’t require maintenance All watershed groups are fine
I am not here to tell you
Slippery Rock Watershed Coalition 1994 Stream Restoration Incorporated 1996 BioMost, Inc 1998 Designed over 60 Passive Treatment Systems Designed/modified a handful of Active Systems Maintained/repaired numerous systems Inspected & evaluated >100 systems Managed Statewide AMD Treatment Snapshots
in 2009, 2010, 2012, 2015 Created & Manage Datashed
(www.datashed.org)
About Us
Porcupine Run 162-21
BEFORE
FlowGPM pH
Alk mg/L
Acidmg/L
T. Femg/L
T. Almg/L
T. Mnmg/L
SO4 mg/L
69 3.0 0 498 51 26 21 1340
AFTER
FlowGPM pH
Alk mg/L
Acidmg/L
T. Femg/L
T. Almg/L
T. Mnmg/L
SO4 mg/L
319 6.0 22 12 4 4 13 830
Don’t let the perfect get in the way of the good
Failure or Success?
Need to fund maintenance not just the design & construction to ensure long-term treatment
Is it a failure ?Or just needs maintenance?
De Sale II- Vertical Flow Pond