Cliff Denholm, Stream Restoration Incorporated, "Passive Treatment of Acidic High-Metal...

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