CeraMem Ceramic Membrane Technology Advanced Heavy Metals Removal System WATER TECHNOLOGIES
Key System Features CeraMem UF membranes act as an absolute barrier to oils, suspended solids, and precipitated metals Process combines oil, suspended solids, and metals removal into one system in a compact footprint Produces reliable, high-quality effluent regardless of influent upsets Fully automated, requiring minimal staffing Utilization of efficient precipitation seed recycle, improving metal co-precipitation to greatly reduce chemical consumption Flexibility to incorporate chemical treatment for handling Cr6+ or cyanide removal as well as precipitation of Cr3+, Zn, Ni, Cd, Cu, Ag, Hg, Pb, etc. Heavy Metals in Wastewater Surface coating of steel products is commonly used to extend its service life. Coating with streams rich in chrome, nickel, zinc, and other metals is widely used in the steel industry. These coating processes present an environmental challenge. Residual metals from coating processes and uncoated steel surfaces, combined with oils from uncoated steel surfaces, find their way into process wastewaters. These challenges also exist in the semiconductor, mining, and other industries involving the presence of oils and metals in subsequent waste streams. These heavy metals and oils must be removed from the wastewaters to a very low level prior to disposal or water reuse. Conventional methods to solve this problem rely on gravity and traditional separation approaches that may not achieve the removal efficiency required for water discharge limits or reuse. Advanced Heavy Metals Treatment System Veolia Water Technologies has developed a complete wastewater treatment plant (WWTP) specifically for the metals industry for a simple, effective, and robust process that provides combined solids, metals, and oil & grease removal from wastewater. The key process steps include pre-treatment (e.g. for cyanide or chromate containing streams), precipitation of the metals, followed by ultrafiltration (UF) and sludge handling. A block diagram of the process is shown above (sludge recycle is internal to the UF system). A typical WWTP has a treatment capacity range of 200-400 gpm and a footprint of 70 x 80 including nearly 30% free floor space for integration of post-treatment and controls equipment. Smaller capacity designs are also available, often as fully skidded systems.
Process Equipment The FMS Series UF systems are pre-engineered systems that are flexible, easily expandable, and offer the performance of CeraMem ceramic membranes in a compact footprint. Each system provides the following features and options: Wetted materials include stainless steel, CPVC, Viton, PTFE, Polyethylene, FRP, Polypropylene, ceramic, and other suitable materials All required valves are pre-installed. Automated valves are pneumatic and require 80-100 psi dry, oil-free instrument air to operate Reactor Tanks and Dosing Stations FRP, SS, PE, and/or PP tanks are available and sized with the appropriate residence time to meet reaction requirements. The reaction vessels are fitted with agitators enhanced with Turbomix technology for improved reactor efficiency, required ph, ORP and other analytical probes, as well as dosing stations as a complete reactor system for coupling to the membrane filtration system. CeraMem ceramic membranes are pre-installed A NEMA4/IP64 electrical cabinet installed on the unit with all instruments factory wired into the cabinet Various process controls available, depending on specific application Clean-In-Place (CIP) System Backpulsing System A CIP system can be furnished with acid and caustic dosing pumps to transfer chemicals into the CIP tank from a chemical storage tote. CIP is typically performed every one to two weeks depending on the application. An automated, intermittent, pumped backpulse system is included with the UF system. Backpulse operation utilizes clean permeate in the opposite direction of the production flow to remove materials from the membrane surface to restore production efficiency. Hydrex chemicals are available from Veolia and can be supplied in chemical totes (200-330 gallons). These volumes are typically large enough to be used directly for dosing into the CIP tank for months of operation. Backpulsing can improve overall operation of the membrane plant and reduce the frequency of chemical cleaning. CeraMem ceramic membranes can withstand repeated, aggressive, and effective backflush over several years. Viton is a registered trademark of DuPont Performance Elastomers Filter Press A properly sized filter press is provided to dewater the UF concentrate and recycle a portion of the filtrate to the WWTP. The filter press is smaller in Veolia s WWTP as compared to conventional processes due to less need for oil removal and associated filter aid. Sizing will typically range from 2 ft² to 40 ft² and will depend on the metals concentration and influent flow rate.
Combined Metals, Oil & Grease, and Solids Removal Membrane Specification All-ceramic membrane support structure with chemical, thermal, and thermal shock resistance. Capable of operating in a ph range as wide as 0 to 14. Attributes enable handling the toughest feed streams and most demanding cleaning regimes with long membrane life. Asymmetric pore structure allows retention of TSS and soils reliably to provide efficient backflush through the open membrane support structure. UF membrane pore size in the range of 10 to 50 nanometers, depending on type of membrane selected is fine enough to retain dispersed oils and greases as well as suspended solids and precipitated metals. The fine pore structure, 10 times finer than typical MF membranes, improves contaminant removal. Finer pore structure also increases carbon filter and RO performance downstream of the WWTP. Compact structure with about 400 to 800 square meters of membrane area per cubic meter of membrane volume, resulting in a very small membrane system footprint.
Performance Data Field Trial Exceptional Removal and Effluent Results Pilot testing of the process at a coating and finishing plant resulted in achievement of highquality metals removal from a feed stream containing oil, solids, and dissolved metals in one process. Solids and oils were removed to <2 NTU turbidity and metals removal typically exceeded disposal limits, regardless of influent variability. The UF system operated smoothly and reliably in a one week trial requiring little cleaning, using backpulses to maintain production rates. Chemical cleaning was a simple process and restored the membranes to nameplate performance within a short two-hour cleaning cycle. Typical Effluent Properties Influent from Coating & Finishing Mill Parameter Results (mg/l) Reportable Detection Limit (mg/l) Methodology Silver BRL* 0.0050 EPA 200.7 Barium BRL* 0.0050 EPA 200.7 Cadmium BRL* 0.0025 EPA 200.7 Chromium BRL* 0.0050 EPA200.7 Copper 0.0074 0.0050 EPA 200.7 Iron 0.0277 0.0150 EPA 200.7 Mercury BRL* 0.00020 EPA 245.1/7470A Potassium 6.22 0.500 EPA 200.7 Sodium 547 5.00 EPA 200.7 Nickel BRL* 0.0050 EPA 200.7 Lead BRL* 0.0075 EPA 200.7 Strontium 2.17 0.0050 EPA 200.7 Zinc BRL* 0.0155 EPA 200.7 Total Alkalinity 539 20.0 SM2320B Hexavalent Chromium BRL* 0.005 SW846 7196A/SM3500CrD Ferrous Iron BRL* 0.500 SM3500-Fe-D 19TH Ed Hardness 68.0 2.00 SM2340C Total Dissolved Solids 1,400 20.0 SM2540C Total Organic Carbon 23.5 2.00 SM5310B *Note: BRL (Below Reportable Limit) indicates that the specific parameter tested was lower than the lowest, accurate concentration detectable by the equipment utilized in the analysis.
CeraMem-BR-Heavy Metals removal - 09/2014 Veolia Water Technologies CeraMem Ceramic Membrane Systems 12 Clematis Avenue Waltham, MA 02453 USA tel. +1 (781) 810-7701 ceramem.info@veolia.com www.veoliawatertechnologies.com/ceramem