Thursday 4:25 Ron Neufeld, DEE., Dept Environmental Engineering,University of Pittsburgh
Acelerated Ferrous Oxidation with a Multiple Oriface Spray Reactor
Dr. Ronald D. Neufeld, P.E., DEE
This project focuses on an innovative active treatment technique for the management of acid mine drainage. Wet lands, lagoons and other passive systems are quite suitable for many abandoned mine applications or locations with large land space. However, numerous AMD discharges exist where active systems must be employed. Such sites include mine mouth applications, and underground mine pools from recently abandoned formerly active mine sites that are predicted to have “water blow outs” (and become new AMD discharges) in the next few years. In addition, some AMD sites are generators of potentially valuable quantities of relatively pure metals which can be reclaimed and marketed if managed suitably. A bench scale experiment using a multiple orifice spray reactor (MOSR) is investigated as a potential remediation technology for the rapid oxidation of ferrous iron from the St. Michaels (PA) acidic mine discharge. The MOSR makes use of flow through multiple orifices to enhance aqueous aeration and oxidation rates. The reactor consists of two concentric cylinders, the inner cylinder having a series of orifices which act in a manner similar to a venturi. In this fashion neutralization and aeration are combined into a single step due to the aspiration of air as a result of a pressure gradient across the reactor which allows for the introduction of an alkaline agent into a reaction chamber with detention time of seconds. Results show ferrous iron oxidation rates at pH values between 6 and 7 can be increased by four orders of magnitude as compared to theoretical oxidation rates. Under certain conditions the MOSR oxidizes more ferrous iron than can be simply attributed to the measured oxygen transfer capabilities of the system. It is suggested that the oxidation capability in excess of oxygen transfer is due to, or initiated by, the chemical effects of hydrodynamic cavitation. In addition, a relatively pure iron hydroxide product is rapidly generated from the St. Michaels AMD discharge which has reclamation potential. Field Applications of the MOSR: PPC Corporation has demonstrated the “Turbojett”, a field scale prototype version of the OSR at several abandoned AMD sites at the 200 gpm to 400 gpm scale. Knowledge gained at the bench scale is being used by PPC to enhance future applications of multiple orifice type aerator-oxidizers.
Dr. Ronald D. Neufeld is Professor of Civil and Environmental
Engineering at the University of Pittsburgh where he teaches and
conducts research in the area of biological and physical/chemical
processes for water and wastewater management. Dr. Neufeld holds
a BE (Ch.E.) from Cooper Union; a MS (Ch.E.) from Northwestern University;
and a Ph.D. in Civil/Environmental Engineering from Northwestern
University. Dr. Neufeld is a registered engineer in Pennsylvania
and holds Diplomate certification from the American Academy of Environmental
Engineers. He has over 100 Journal publications and technical contributions
to the environmental engineering literature.