Application of Kenaf to Biofiltration of Wastewater and Contaminated Water for Removal of Heavy Metals - 11349

Kenaf (Hibiscus cannabinus L.) is a warm-season, annual, fiber crop. Two distinct fibers from kenaf stalks (long, jute-like bast fibers from the bark and short and balsawood-like fiber from the stem core) have been extensively used in various applications for remediation. Bast fibers are used to manufacture products such as burlap, carpet padding, and pulp, while the short-fibered core is processed into animal house bedding, packing materials, and oil-adsorbent mats. With the increase in demand for energy consumption, the US coal-fueled electric power industry annually produces 72 million tons of fly ash and 55 million tons of other coal combustion products (CCP) with a total production of 131 million tons in 2007. These by-products include mainly fly ash, bottom ash, boiler slag, flue gas desulphurization (FGD) gypsum, and FGD material dry/wet scrubbers. Moreover, the total CCP production increased linearly from 1966 through the early 21 st century. In 1966, the total CCP production generated by the US coal-fueled electric power industry was about 25 million tons; it reached about 130 million in 2007. At the same time, a vast amount of processing water from power plants has been discharged into ponds or rivers. This waste water requires a cost-effective remediation technology. The current study was to explore the potential of kenaf materials to remove heavy metals from waste water. Both batch and column experiments were designed to remove heavy metals such as Cr(VI), Pb, U, Cd, Ni, Hg, Sr, Ni, and metalloids As and Se. The column study results indicate that kenaf fibers can effectively remove the majority of Cr (VI) (84%), Pb (96%), U (93%) and almost all Hg (98%) from contaminated water. Current and previous studies suggest that that kenaf biofiltration could be incorporated into the early stages of wastewater processing to remove heavy metals from wastewater ponds and/or other water bodies. Adsorption mechanisms and methodology(s) to enhance filtration efficiency warrant further systematic studies. We are working toward development of a field-deployable biofiltration system that meets the remediation requirements for CCP-related and other relevant wastewater. In addition to cost saving for power plants, benefits will include creating new revenues for farmers and businesses that grow and process kenaf.