A HYBRID AIR STRIPPER/MEMBRANE VAPOR SEPARATION SYSTEM FOR VOLATILE ORGANIC COMPOUNDS RECOVERY FROM INDUSTRIAL WASTEWATER

CONTAMINATION OF INDUSTRIAL WASTEWATER WITH VOLATILE ORGANIC COMPOUNDS (VOCS) IS A COMMON PROBLEM THROUGHOUT U.S. INDUSTRY. CURRENTLY, MOST OF THE VOC CONTENT OF WASTEWATERS IS LOST. COMMON WASTEWATER TREATMENT METHODS INCLUDE BIOLOGICAL TREATMENT, INCINERATION, AND DEEP-WELL INJECTION. THESE METHODS ARE USUALLY EXPENSIVE, ENVIRONMENTALLY QUESTIONABLE, OR OPERATIONALLY DIFFICULT. VOC-CONTAINING WASTEWATERS ALSO REPRESENT AN ENORMOUS UNTAPPED RECOVERY OPPORTUNITY SPANNING THE BREADTH OF INDUSTRIAL ACTIVITY. THE TOTAL ENERGY VALUE OF THE VOCS CONTAINED IN WASTEWATERS PRODUCED BY U.S. INDUSTRY IS AT LEAST 200 TO 300 TRILLION BTU/YEAR, AND MAY BE AS HIGH AS 1,000 TRILLION BTU/YEAR. THIS PROJECT IS STUDYING THE TREATMENT OF WASTEWATER TO REMOVE AND RECOVER VOCS USING A COMBINATION OF AIR STRIPPING AND MEMBRANE SEPARATION. THE TECHNOLOGY HAS ALREADY BEEN DEMONSTRATED ON CONTAMINATED GROUNDWATER FEEDS CONTAINING 1 TO 10 PPM VOCS. IN THIS PROJECT, THE APPLICATION TO MUCH MORE HEAVILY CONTAMINATED FEEDS, REPRESENTATIVE OF MANY INDUSTRIAL WASTE STREAMS (IN THE RANGE OF 1,000 TO 20,000 PPM VOCS), IS BEING EVALUATED. IN PHASE I, AN EXISTING STRIPPER/MEMBRANE SYSTEM WILL BE OPERATED TO DEMONSTRATE THE FEASIBILITY OF THIS APPROACH. THE RESULTS WILL BE USED TO DESIGN A SMALLER, HIGHLY EFFICIENT, COST-EFFECTIVE AIR STRIPPER/MEMBRANE VAPOR SEPARATION SYSTEM APPROPRIATE TO RECOVERY OF VOCS FROM INDUSTRIAL WASTEWATER. PRELIMINARY COST CALCULATIONS SHOW THAT THE TECHNOLOGY PROMISES SIGNIFICANT COST AND ENERGY SAVING BENEFITS COMPARED WITH ALTERNATIVE TECHNIQUES. THE MEMBRANE SYSTEM IS EXPECTED TO RECOVER AT LEAST 90% OF THE VOCS AS PURE CONDENSED LIQUID. SECONDARY WASTE STREAMS ARE ELIMINATED.