Post on 27-Jan-2016
description
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
Horizontal Subsurface Flow Horizontal Subsurface Flow WetlandWetland
Wildflower Meadows: 90-person treatment system
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
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
Casper Benzene Data 2004 - 2006
Benzene effluent at Outfall 001consistently below detection levels
<0.01 mg/L
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