Post on 12-Aug-2015
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Two Passive Treatment Systems that are Community Assets
Bob HedinHedin Environmental
Two Passive Treatment Systems that are Community Assets
(Form Follows Function)
Bob HedinHedin Environmental
Mine Drainage
Treatment System
Clean Water
Mine Drainage
Treatment System
Clean Water
2o ValuesValue Adding Form?
Primary Functions
– Reliable production of effluent that meets chemical targets
– Reliable production of effluent that can support biological life
– Contribution to restoration and/or maintenance of functional stream ecosystem
Secondary Functions
• Products that offset treatment costs– Marketable solids– Water– Energy
• Ecological benefits of treatment system• Educational benefits• Aesthetic benefits
Form Follows Functions Observations
• Effective Form Can Follow Good Function• Effective Form Rarely Follows Disfunction• Good Function Rarely Follows Form
Form Follows Function Process
1. Design the system to be functional2. Involve form-adding ideas during design
process3. Set the table for form to be applied after
function is established
Presentation Goal
Present the design process for two functional passive systems in Allegheny County that have become regional assets
• Wingfield Pines (Allegheny Land Trust)• Woodlands Passive System (Pittsburgh Botanic
Garden)
Wingfield PinesPassive System
Wingfield Pines
• Discharge from abandoned underground coal mine to Chartiers Creek
• Pittsburgh Coal seam• Located on land purchased and conserved by
Allegheny Land Trust
Anoxic Limestone Drain
Ponds Vertical Flow Pond
Oxic Limestone Bed
Wetland Ponds Ponds
Oxic Limestone Bed (drainable)
NetAlkaline
Net alkaline Net acid
Net acid
DO, Fe3+, Al all < 1 mg/L(high Fe2+)
Characterize Mine Water
Wetland
Final Discharge
Mn
DO, Fe3+, Al any > 1 mg/L DO, Fe3+, Al any > 1 mg/LFe < 10 mg/L
High Fe2+
Ponds
Repeat As Needed
Mn
Flow pH Alk Acid Fe Al Mn SO4
gpm s.u. mg/L CaCO3 -------- mg/L --------- 1,446 6.6 390 -360 14.6 <0.1 0.3 315
Wingfield Pines AMD
Anoxic Limestone Drain
Ponds Vertical Flow Pond
Oxic Limestone Bed
Wetland Ponds Ponds
Oxic Limestone Bed (drainable)
NetAlkaline
Net alkaline Net acid
Net acid
DO, Fe3+, Al all < 1 mg/L(high Fe2+)
Characterize Mine Water
Wetland
Final Discharge
Mn
DO, Fe3+, Al any > 1 mg/L DO, Fe3+, Al any > 1 mg/LFe < 10 mg/L
High Fe2+
Ponds
Repeat As Needed
Mn
Net Alkaline Water
• No need for alkalinity generation• Contaminants are Fe (and Mn)• Goals:
1. Promote aeration and metal oxidation2. Promote settling of solids3. Promote filtration of solids
Sizing of Wingfield Pines System
• Design for 1,500 gpm flow• Sizing calculations– 7 acres of ponds and wetlands– Available area: 10 acres
• Enough room for creative design• Final Design:– 3.7 acres of ponds– 3.6 acres of wetland
Pond 1 Design Considerations
• Avoid short-circuiting flow• Aerate water to promote iron oxidation• Minimize O&M
Ponds 2-5 Design Considerations
• Avoid short-circuiting• Minimize O&M• Allow observer to easily observe remediation
Wetland Design Considerations
• Avoid short-circuiting flows• Promote vegetation
Miscellaneous Design Considerations
• Minimize earthwork• Shallow groundwater: limit excavation of all
ponds to 825 ft• Account for sewer line through middle of site• Minimize impacts to existing wetlands
Wingfield Pines SystemOctober 19, 2009
Photo provided by PADEP Bureau of Abandoned Mine Reclamation
Pond 1
Pond 2Pond 3
Pond 4Pond 5
Constructed wetland
effluent
Chartiers Creek
System PerformanceSept 2009 – Oct 2011
Flow pH Fe Mn SO4 TSS
gpm s.u. mg/L mg/L mg/L mg/L
Influent 1,446 6.6 14.6 0.3 315 24
P5 out na 7.8 2.6 0.2 301 12
Effluent na 7.9 0.5 <0.1 315 4
Pittsburgh Botanic GardenWoodlands Passive Treatment System
Pittsburgh Botanic GardenWoodlands Passive Treatment System
• Piped discharge from abandoned deep mine• Pittsburgh Coal seam• Primary water source to the Lotus Pond in the
Woodlands Exhibit
Flow pH Alk Acid Fe Al Mn SO4
gpm s.u. mg/L CaCO3 -------- mg/L --------- 8 3.3 0 177 1.3 26.0 1.0 699
PBG Woodlands Raw AMD
pH Alk Acid Fe Al Mn SO4
s.u. mg/L CaCO3 -------- mg/L --------- Woodlands 3.3 0 177 1.3 26.0 1.0 699Wingfield 6.6 390 -360 14.6 <0.1 0.3 315
Two discharges from the Pittsburgh Coal Seam, 5 miles apart
Anoxic Limestone Drain
Ponds Vertical Flow Pond
Oxic Limestone Bed
Wetland Ponds Ponds
Oxic Limestone Bed (drainable)
NetAlkaline
Net alkaline Net acid
Net acid
DO, Fe3+, Al all < 1 mg/L(high Fe2+)
Characterize Mine Water
Wetland
Final Discharge
Mn
DO, Fe3+, Al any > 1 mg/L DO, Fe3+, Al any > 1 mg/LFe < 10 mg/L
High Fe2+
Ponds
Repeat As Needed
Mn
Net Acid Water
• Generate alkalinity and raise pH• Remove metals
Net Acid Water
• Generate alkalinity and raise pH• Remove metals
• Drainable Limestone Bed
Drainable Limestone Bed
AMD
Polishing Pond
Flush Pond
Receiving Stream
Drainable Limestone Bed
AMD
Polishing Pond
Flush Pond
Receiving Stream
Moore DLB System, Somerset County
Sizing of System
Drainable Limestone Bed• Acid loading: 21 ppd acidity (9 kg/day)• DLB sizing calcuation: 225 tons limestone• PBG DLB: 450 tonsPolishing Pond• At least 24-48 hours• PBG Polishing Pond: > 200 hoursFlush Pond• At least twice the flush volume• PPG Flush Pond: 1.5 X flush volume
Secondary Design Concerns
• In Woodlands Exhibit: minimal tree impacts• Polishing Pond location and AMD discharge
location set prior to project– Topographic constraints– Available land constraints
• Planned to be major aquatic component of the Woodlands Exhibit
Drainable Limestone Bed
• 100 ft X 20 ft X 5 ft poured concrete tank• 4.5 ft of AASHTO 3 Vanport limestone• Distributed influent on top of stone• Effluent collection pipe at bottom of tank• Water level controlled by Agri Drain water
level control structure• Draining (once/week) activated by SDS
Concrete tank (filled with 450 tons of limestone)
Perforated influent pipe (4 inch dia)
Perforated drainage pipe (8 inch dia)
Agridrain box
Original terracotta pipe
To solids basin (during DLB drainage)
Riser (for influent sample collection)
Riser (for cleanout)
Riser (for influent pipe cleanout)
To channel and Asian pond (treated water)
Drainable Limestone Bed (Plan View)
Solar panel, battery and computer -to open and close valve in Agridrain box
Concrete tank
Polishing Pond
Flush Basin
Pittsburgh Botanic Garden DLBsolids basin during end of draining
71% of the Al retained in the DLB during routine operations released during draining
Flow pH Alk Acid Fe Al Mn SO4
gpm s.u. mg/L CaCO3 -------- mg/L ---------
Influent na 3.3 0 130 0.5 13.0 0.8 431Effluent 8.3 6.8 216 -188 0.1 0.7 0.2 456
Woodlands Passive Treatment System2013-2015
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