Commercialization of a Kenaf-Based Biosorptive Process for Use in the Treatment of Contaminated Aqueous Streams

Conventional wastewater and groundwater cleanup technologies all have inherent limitations associated with costs, performance, and operational protocols. Clearly, new processes that can reduce costs, maintain or even improve treatment, and reduce technical complexity will be a great asset to the environmental engineering community. The KenGro Corporation proposes to develop an innovative process for the treatment of contaminated waters that involves adsorption of contaminants onto kenaf fibers that are loaded within a packed column. Kenaf, a plant in the same family as okra, was selected because recent research by members of the project team has determined that kenaf has a high sorptive capacity for several organic compounds. Additionally, there is evidence indicating that kenaf may have an appreciable adsorption capacity for heavy metals. After the sorptive capacity of the kenaf is expended, the spent kenaf fibers will be disposed via composting. The composting step will not only reduce more than 75 percent of the fiber volume, but this step also will biologically degrade the adsorbates that are present on the spent kenaf fibers and concentrate the heavy metals. This process is viewed as a direct competitor to activated carbon; however, processed kenaf costs approximately one order of magnitude less than activated carbon. Processing techniques for converting raw kenaf into various fiber types are well developed and inexpensive. Stability testing of kenaf fiber has found this material to be stable under high handling stresses and saturated column with minimal changes in column pressure drop noted. This Phase I research project will determine key adsorption characteristics of kenaf for the removal of two petroleum products and two heavy metals from wastewater effluents. Planned development includes evaluation of various candidate kenaf fibers for removal of the four test adsorbates, performance of dynamic column testing for optimizing kenaf processing in terms of column hydrodynamics, composting of the spent kenaf, evaluation of product surface condition techniques to increase adsorptive capacity, and estimation of process economics. Although only four test absorbates are to be tested in Phase I, this process has potential to be used for many pollutants, including biodegradable organics and heavy metals.