Modified Soybean Hulls for Heavy Metal Removal

A major problem facing the metals products and machinery (MP&M)industry are the recently proposed effluent limits for heavy metals set by the US Environmental Protection Agency under Rule 66 FR 423. Current technology cannot consistently meet these effluent limits. This has forced the MP&M industry to search for new and innovative treatment technologies designed to polish their effluents to the new limits. Recently completed laboratory studies conducted by the USDA-ARS, Southern Regional Research Center (SRRC) New Orleans, LA have shown that soybean hulls modified with citric acid can effectively remove toxic and heavy metals from wastewater streams and may effectively meet these newly proposed limits. Indications are that this new product will have ion-exchange performance approaching conventional ion-exchange resins but at a significantly lower cost. However, the technology is only available at the laboratory-scale level. The proposed program, which will be carried out in close cooperation with the SRRC, is specifically directed at scaling-up their modified soybean hull manufacturing technology and designing a modular treatment system for implementation at several electroplating facilities in Phase II. This will demonstrate the use of the new technology under actual operating conditions, providing ultimate evaluations of system metal removal efficacy.