Mine Drainage Treatment Alternatives Analysis
West Virginia
Evaluation of alternatives to the existing use of caustic soda by a mining company to treat acid
mine drainage from multiple abandoned coal mine sources to meet NPDES limits. AMD
sources were monitored to develop design ranges for contaminant loading and flow, which
were then used to conceptually size hydrated lime delivery systems using silo or manual feed
with aerators and a choice of clarifiers or settling basins. Alternative sites and collection plans
were developed to prepare comparative cost estimates for construction and operation with
sludge cleaning and pumping.
Sustainable Water Management for a Changing WorldSM
Representative Water Treatment
Passive Fly Ash Leachate Treatment Concept Design
West Virginia
Development of a conceptual design to combine three sedimentation ponds receiving leachate
from active and closed fly ash disposal areas into a common passive treatment system. The
parameters of most concern on this site are selenium, arsenic, and hexavalent chromium.
Discharges from the ponds were monitored for flow and loading, and a passive treatment plan
was developed using vertical flow organic beds and surface flow wetlands to provide long-
term, low cost removal. A collection plan was developed to evaluate options of gravity flow,
pumping, and horizontal drilling to convey treated waters from existing headwaters stream
discharge to the Monongahela River, where discharge standards are less restrictive.
Boron Treatment Evaluation Using Resin Ion Exchange
Pennsylvania
Design and operation of a pilot-scale study to test the use of a resin ion exchange product for
removal of boron from fly ash leachate that is currently treated by a passive wetland system.
A resin column from a commercial vendor was installed on site to receive a portion of the flow
from the passive system and operated through steady-state and breakthrough testing to
determine the capacity of the resin under field conditions. Results were used to size a full-
scale concept system for which construction and operation costs were estimated, including
various disposal options for waste products.
Passive Flue Gas Desulfurization Wastewater Treatment
North Carolina
Design of a pilot study and full-scale system retrofit to use vertical flow organic beds to remove
selenium and mercury from FGD wastewater at a coal-fired utility’s existing wetland treatment
system. The pilot test was conducted because the existing surface flow wetlands had low
selenium removal rates. Site-specific sizing criteria were developed for vertical flow organic
beds, the first large-scale application of this technology to FGD wastewater. A full-scale
system was designed to include six vertical flow cells operating in parallel and sized such that
any one could be taken off line for maintenance while the remaining cells continued treatment.
The system readily achieved target selenium and mercury removal rates after construction.
