SBIR-STTR Award

This Small Business Innovative Research Phase I Project describes a study plan to develop sequential rhizosphere thin-film systems (RTF) and periphyton filters (PF) for removal of excess nutrients and trace elements from surface waters. It is hypothesized that the combination of high loading capacity and high contaminant tolerance of a wetland macrophyte (Hydrocotyle umbellata) with the higher affinity of periphyton for nutrients and trace elements will provide key components of a sequential process train that will effectively and economically treat large and variable volumes of water. The goal is to design and test a phytoremediation technology to remove trace elements from water to levels typical of natural ambient surface waters. Such treated waters would meet all permit stipulations for release to surface waters. It is proposed to optimize system design to take advantage of suspended particulate retention and pH mediated precipitation to enhance performance above that expected on the basis of bioaccumulation-binding mechanisms alone. The Phase I study will determine the highest water concentrations of P, Cu, Pb and As tolerated by the plants, the lowest routinely achievable contaminant concentrations in effluent water under reasonable contaminant inputs, and contaminant concentrations in biomass and associated solids. This effort will both characterize performance of the RTF and PF processes, and define acceptable strategies for handling harvested biomass. It is expected that successful development of this phytoremediation technology will provide a cost effective, rugged and broadly useful capability to remove trace element contaminants from moderately contaminated surface waters and stormwater from various sources, e.g. agricultural or urban runoff.Successful completion of Phase I and II research efforts will result in, for the first time, an operationally simple, reliable and relatively low maintenance technology to remove specific element contaminants fr om surface and ground waters. The sequential RTF-PF is a useful technology for government agencies (DOD, DOE, EPA). Private sector customers could employ them to treat effluent streams characterized by high or variable volumes and moderate metal contamination (~500 - 1000 microgram/L). This system may also be useful for reclamation/recycling efforts for metals.

This Small Business Innovation Research Phase II Project describes a study plan to optimize sequential thin-film rhizosphere systems (TFR) and periphyton filters (PF) for removal of excess nutrients and trace elements from surface and ground waters. Our Phase I research of this concept established the technical feasibility of using TFR-PF systems to remove phosphorus (P), lead (Pb) and copper (Cu) to low (ca. 10ug/L) levels. The combination of high loading capacity and high contaminant tolerance of wetland macrophytes cultured in a TFR configuration with the higher affinity of periphyton for nutrients and trace elements provide key components of a sequential process train that will effectively and economically treat large and variable volumes of water. Our Phase II research goal is to refine this phytoremediation technology to remove trace elements from contaminated waters (e.g, urban and agricultural runoff, eutropic lake waters) to levels typical of natural ambient surface waters. Optimization parameters to be studied include: appropriate hydraulic retention time (HRT) of the TFR and PF unit processes for effective removal of P, Cu, nickel (Ni) and cadmium (Cd); use of foliar nutritional sprays to support macrophyte growth in TFRs that are treating contaminated, but nutrient-deficient waters; and, investigation of appropriate sequencing of TFR-PF to maximize treatment efficiency. Macrophyte and algal biomass production rates and elemental composition will be measured routinely to define acceptable strategies for handling harvested biomass. We expect that successful development of this phytoremediation technology will provide a cost effective, rugged and broadly useful capability to remove trace element contaminants from moderately contaminated ground and surface waters. Successful completion of Phase II research efforts will result in, for the first time, an operationally simple, reliable and relatively low maintenance technology to remove specific element contami nants from surface and ground waters. Not only will we optimize our proposed phytoremediation process during the Phase II research, our strategic alliance with the one of the largest U.S. technology companies will permit us to quickly and cost-effectively penetrate existing and new water treatment markets