Because of the extent of AMD impacts in Pennsylvania, the Commonwealth has become, by necessity, a leader in the development of passive treatment technology. People from around the world travel to Pennsylvania to learn about the successes we have collectively achieved, including the installation of over 300 passive treatment systems. In recent years, the capabilities of passive systems to treat highly acidic mine discharges with high concentrations of dissolved metals has been questioned. It is important to remember that with any treatment system, whether passive or active, proper design, suitable land characteristics, quality construction, proper maintenance and sufficient funding, are needed to provide a long-term, cost-effective approach for watershed restoration. This presentation will provide mini case studies that demonstrate, by example, that passive systems can and are effectively treating acidic, high-metal, discharges in Pennsylvania.
2. <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
1www.datashed.org
3.
4. 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
5.
6.
7. 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
Yes and No
15. 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
18. Flow pH Acid Alk Fe Mn Al
Raw 36 4.1 319 NA 82 55 12
19.
20. Constructed 1999 (16 Years Old)
Cost $391,000
Upgrades Cost ~$10,000
O&M Costs ~$8,000
Volunteer = $?
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
21. 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
22.
23. 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
24.
25.
26. 162-
2162-8
162-
3
CC
1
162-6
& 162-
10
OPC
Moa
t
VFP
1
SB1
AL
D
CC
1
CC
1
CC
1
162-6
& 162-
10
CC
1
SB1
162-6
& 162-
10
CC
1
Moa
t
SB1
162-6
& 162-
10
CC
1
VFP
1
Moa
t
SB1
162-6
& 162-
10
CC
1
VFP
1
Moa
t
SB1
162-6
& 162-
10
CC
1
OPC
VFP
1
Moa
t
SB1
162-6
& 162-
10
CC
1
AL
D
OPC
VFP
1
Moa
t
SB1
162-6
& 162-
10
CC
1
AL
D
OPC
VFP
1
Moa
t
SB1
162-6
& 162-
10
CC
1
162-8
AL
D
OPC
VFP
1
Moa
t
SB1
162-6
& 162-
10
CC
1
162-
2162-8
AL
D
OPC
Moa
t
SB1
162-6
& 162-
10
CC
1
162-
3
162-
2162-8
AL
D
OPC
Moa
t
SB1
162-6
& 162-
10
CC
1
Forebay
162-3162-2
162-8
ALD
OPC
VFP1
Moat SB1
162-6 &
162-10
CC1
Aka TIFs
45. Flow 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
46.
47. 2000-Site constructed
2012- decreased
treatment performance
noted
VFP East Stir
Forebay inlet and
outlet cleaned
48. WL outlet cleared of
vegetation
HFLB stone re-leveled
VFP outlet spillway
cleared of vegetation
buildup
49. Multiple issues noted
during site visit by SRWC
Forebay pipe inlet clogged
VFP performance
decreased
50.
51.
52.
53. Pre- and Post- O&M Effluent
Field Water Quality Data
Parameter Pre-
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
54. Flow 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
55.
56.
57.
58.
59. Replace baffle curtains
Removed Fe off of VFP & stirred VFP
Backflushed & Stirred HFLB
Fixed access road entry
60. 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
61. Construction Cost = $200,000
Annual O&M = 1%
Need = ~$40,000 to invest
Replacement Cost every 20 Years
Need = ~$60,000 to invest
If provide an extra $100,000 at time of grant
to the watershed group, they could maintain
treatment for “perpetuity”
62. High Risk (High Metal) AMD can be
passively treated IF
◦ Good Design
◦ Sufficient Site Conditions
Area
Elevation Change
◦ Proper Construction
◦ Maintained
64. 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
65. 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;
66. 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;
67.
68.
69.
70. Most sites require
maintenance over time
Regular site visits and
observations allow
many problems to be
addressed quickly and
efficiently
PA PTS Snapshot
71. 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
72. 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)
73. BEFORE
Flow
GPM pH
Alk
mg/L
Acid
mg/L
T. Fe
mg/L
T. Al
mg/L
T. Mn
mg/L
SO4
mg/L
69 3.0 0 498 51 26 21 1340
AFTER
Flow
GPM pH
Alk
mg/L
Acid
mg/L
T. Fe
mg/L
T. Al
mg/L
T. Mn
mg/L
SO4
mg/L
319 6.0 22 12 4 4 13 830
74. Don’t let the perfect get in the way of the
good
75. Need to fund maintenance not just the design
& construction to ensure long-term treatment