Roux Associates was retained to evaluate the use of phytoremediation technologies for the on-site treatment and consumptive use of process wastewater generated at an active manufacturing site in South Carolina. The facility generates approximately 75,000 gallons of process wastewater daily and conveys this water to an off-site Publically Owned Treatment Works (POTW) for treatment and disposal. Wastestream contaminants included BOD, fluoride and trace levels of heavy metals. The client was interested in developing a sustainable, on-site alternative for process wastewater treatment and disposal.

Phytotechnology was evaluated for treatment of process lagoon water through consumptive use. Wastestream characterization was performed for the process lagoon water to determine the constituents of concern. Site soils were analyzed for agronomic parameters to determine their ability to support candidate phyto species and evaluate the need for nutrient amendments. Percolation testing was also performed for site soils. A comprehensive rooting test study was then performed to evaluate the ability of several tree and grass species to survive under site conditions (i.e., using various site soils and irrigation with process lagoon water). Four tree species were evaluated including three types of hybrid poplars and coyote willow. Four drought-resistant, low maintenance grasses were also evaluated as part of the rooting test. Two tree species and two grass species were selected for planting in the approximate 3-acre pilot study area as well as a soil moisture sensor system. Process lagoon water is spray irrigated onto the phyto plot at a rate that allows consumptive use by the trees and grasses and precludes any recharge of ground water. As a result of success of the pilot Phyto Plot, a full-scale 13-acre plot is currently designed and permitted and is scheduled for planting in spring 2010.