Presented by:Scott Wallace, P.E.

Scott.Wallace@naturallywallace.com(612) 802-2329

Treatment Wetlands

References for Wetland DesignReferences for Wetland Design

Water Environment Research Foundation (WERF)

• Small Scale Constructed Wetland Systems (Wallace & Knight, 2006)

Treatment Wetlands 2nd Edition• (Kadlec & Wallace, 2009)

Types of Treatment Wetlands Types of Treatment Wetlands • Surface Flow (SF) • Horizontal Subsurface Flow (HSSF)• Vertical Flow (VF)• Sludge Dewatering Reed Beds• Intensified Wetlands

– Aerated (cold climates)– fill-and-drain (warm climates)– reactive media (ammonia, phosphorus, etc)– industrial wastewaters

Surface Flow WetlandsSurface Flow Wetlands

Kadlec & Wallace, 2008

Surface Flow WetlandsSurface Flow Wetlands

Champion Paper, Pensacola Florida

Horizontal Subsurface Flow Horizontal Subsurface Flow WetlandsWetlands

Wallace & Knight, 2006

Horizontal Subsurface Flow Horizontal Subsurface Flow WetlandWetland

Wildflower Meadows: 90-person treatment system

Vertical Flow WetlandVertical Flow Wetland

IWA, 2000

Vertical Flow WetlandVertical Flow Wetland

Rousillon, France

Sludge Dewatering Reed BedSludge Dewatering Reed Bed

Kadlec & Wallace, 2008

Skovby, Denmark: 8000-person treatment wetland

Main Treatment MechanismsMain Treatment Mechanisms• Adsorption of dissolved-phase hydrocarbons• Microbial degradation of organic compounds• Settling of particulate compounds• Oxidation and reduction of nitrogen

compounds• Precipitation of metals• Use of intensification methods (aeration and

reactive medias to accelerate treatment)

Natural vs. Mechanical Systems

LEAST MOST

Natural SystemsIntensified Wetlands

Mechanical Treatment Systems

Area RequirementsMOST LEAST

Energy and O&M Needs

Climate Range of Climate Range of Treatment WetlandsTreatment Wetlands

Wellsville, New York Northern Sahara,Libya

Casper, WyomingCasper, Wyoming

Casper

BP – Casper, Wyoming RefineryBP – Casper, Wyoming Refinery• Operated 1912 to 1991

• 37,000 m3 of LNAPL recovered to date

• Extensive smear zone due to river flooding

• 50 to 100 years to remediate site

• High mountain west: -35oC

BP – Casper Wyoming RefineryBP – Casper Wyoming Refinery

Casper Reuse PlanCasper Reuse Plan

SF Wetlands

HSSF Wetlands

Full-Size System from Pilot DataFull-Size System from Pilot DataWallace & Kadlec, 2005

Casper Intensified Wetland CellCasper Intensified Wetland Cell

Casper System ConstructionCasper System Construction

Casper Wetland ConstructionCasper Wetland Construction

Casper Benzene Data 2004 - 2006

Benzene effluent at Outfall 001consistently below detection levels

<0.01 mg/L

Rosebel Gold MineRosebel Gold Mine

Project Site

Cyanide RemovalCyanide Removal

Iron RemovalIron Removal

Multi-Stage Treatment ProcessesMulti-Stage Treatment Processes• Wetlands are typically multi-stage

treatment systems– Process Chemistry– Site Topography

Compania Minera Antamina, Peru

ConclusionsConclusions

• Treatment wetlands are already being used in North America, South America, Europe, Asia and Australia

• Surface flow, horizontal subsurface flow, vertical flow, and intensified wetlands are all being used

• Use of wetlands for treatment wetlands is increasing on two major fronts:– Range of applications in different industries– Construction of wetlands in different geographic regions

Thank you for your timeThank you for your time

Treatment Wetlands