CONSTRUCTED WETLAND TREATMENT SYSTEM DESIGN AND PERMITTING
Lockwood Hills LLC
Dresden, New York
(716) 773-6872 x201
The Lockwood Ash Disposal Site is an ash monofill in the Finger Lakes Region of New York. DE lead a team in the design and permitting of a constructed wetland treatment system (CWTS) as a very economical yet effective way to treat leachate from the landfill before on-site discharge to surface waters. The CWTS was selected as a sustainable, passive technology with many environmental benefits including simple operation and maintenance. DE demonstrated the CWTS provides for a significantly reduced carbon footprint and greenhouse gas emissions compared to the much more common store, haul, and treat options.
For this facility, the removal of iron to reliably achieve the permit limit drove the process selection to a hybrid secondary/tertiary treatment system. The recommended process train included a cascade aerator sized to provide sufficient oxygen to oxidize soluble iron to form a precipitate; a settling basin sized to provide residence time to gravity settle precipitates; and a free-surface wetland sized for solids filtering prior to discharge and to support atmospheric oxygen transfer, which provides supplemental iron removal capacity.