Wetland Assimilation of Treated Municipal Effluent: Wetland

Restoration & Improved Water Quality in Louisiana

Dr. Rachael Hunter 1,2, Dr. John W. Day1,2,

Dr. Robert R. Lane1,2, Joel Lindsey1.

Montgomery Hunter1 & Jason Day1

1Comite Resources, Inc., Zachary, LA2School of the Coast & Environment,

LSU, Baton Rouge, LA

Criteria for the use of Wetlands for Municipal Effluent Assimilation

• Effluent is treated, disinfected, and no toxic inputs.• Sheet-flow hydrology (minimal channels and no

short-circuits).• Appropriately sized wetlands: low nitrogen and

phosphorus loading rates.• Monitoring ecosystem response in receiving

wetlands, as well as non-impacted reference sites.

Monitoring

• Water level and hydrology.• Water quality: NOx, NHx, TN, PO4, TP, TSS,

D.O., salinity, BOD, and fecal coliform.• Vegetation species composition and productivity

– Stem growth (tree diameter)– Leaf fall (litter boxes)

• Soils: bulk density and heavy metal concentrations– Benthos is no longer monitored due to high seasonal

and spatial variability, and lack of statistically significant trends in past monitoring and research.

• Assimilation wetlands have typical benthic species composition found throughout coastal Louisiana.

ConclusionsWetland assimilation of municipal effluent is a

proven method of wetland restoration, as well as water quality improvement.

Municipal effluent positively effects wetlands by:• Increasing vegetative productivity• Increasing organic matter deposition• Increasing wetland surface elevation,

counteracting high regional subsidence