Lab-Scale Constructed Wetland.

Constructed wetlands are often described as marshes that have been created and designed for the treatment of waste water.  Through the duplication of natural processes, constructed wetlands are able to remediate livestock effluent, human waste, and drainage water of excess nutrients and harmful pathogens.  A lab-scale constructed wetland was designed and built to measure the overall ability of the constructed wetland to remove phosphorus and pathogens from wastewater.  The constructed wetland is comprised of 75 L aquariums equipped for wastewater residence and treatment.  Each aquarium contains a substrate of 30 cm of gravel and 15 cm of organic soil in which native wetland plants are grown.  Total phosphorus, pH, and E. coli measurements were made on the wastewater before and after treatment by the wetland.  Initial experiments compare a native cattail to a non-native reed canary grass in their ability to treat wastewater.  Nutrient uptake efficiency of water treatment residuals (WTRs) were also tested to explore the utility of the WTRs for treating wetland influent.  Initial phosphorus isotherm data on WTRs from Milwaukee Water Works indicates a relatively high P sorption maximum.  Engineering an additional way to remove P from wastewater using WTRs in conjunction with constructed wetland treatment could help meet new P water quality standards and allow beneficial reuse of materials.