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DEMONSTRATION BULLETIN: COLLOID POLISHING FILTER METHOD - FILTER FLOW TECHNOLOGY, INC.
Citation:
Ball, T. DEMONSTRATION BULLETIN: COLLOID POLISHING FILTER METHOD - FILTER FLOW TECHNOLOGY, INC. EPA/540/MR-94/501, 1994.
Impact/Purpose:
information
Description:
The Filter Flow Technology, Inc. (FFT) Colloid Polishing Filter Method (CPFM) was tested as a transportable, trailer mounted, system that uses sorption and chemical complexing phenomena to remove heavy metals and nontritium radionuclides from water. Contaminated waters can be processed by the CPFM system either as batch (using several thousand gallons/cycle) or continuous (5 to 100-gallon per minute (gpm)) modes. Contaminated water to be treated by the system is either pretreated to adjust chemical oxidation state and acidity (pH) in mixing tanks or processed directly. After chemical pretreatment, total suspended solids (TSS) are removed in a small, parallel plate separator or mini-clarifier, and bag filters to prolong colloid filter pack life. Effluent from the bag filter is routed to the colloid filter units. Sludge from the mini-clarifier is pumped through a small filter press and the filtered water is returned to the mini-clarifier. The sorption unit consisted of four horizontal polypropylene filter plates that house three colloid filter packs. Each filter pack contains a coprietary, inorganic, insoluble, oxide-based, filter bed material in particle and bead form. Operationally, the filter packs are pneumatically pressure sealed between each set of plates. The influent contaminated water is evenly dispensed throughout the filter packs where contaminants are removed by sorption, chemical mechanisms, chemical complexing, adsorption, and physical filtration. Water traversing through the filter packs is collected and directed to a final pH adjustment tank. If necessary, effluent from the colloid filter unit is treated with acid in this tank to reduce the effluent pH to 8.0 to 8.3 before discharge. Once treatment is complete, air blow-down is used to dewater the filter bed, then the hydraulic pressure on the support plates is released, the plates are separated, and the filter packs are removed. Alternatively, the filter media can be regenerated and reused. Spent filter media is then mixed with solids from the mini-clarifier and bag filters and stabilized to meet EPA land disposal restrictions.