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Superfund Innovative Technology Evaluation (SITE)


Note: EPA no longer updates this information, but it may be useful as a reference or resource.


CWM PO*WW*ER™ Evaporation-Catalytic Oxidation Technology
September 1993

This report evaluates the Chemical Waste Management, Inc. (CWM), PO*WW*ERTM technology's ability to remove volatile organic compounds (VOC), semivolatile organic compounds (SVOC), ammonia, cyanide, metals, and other inorganic contaminants from aqueous wastes. This evaluation is based on treatment performance and cost data obtained from the Super-fund Innovative Technology Evaluation (SITE) demonstration and 11 case studies conducted by CWM.

The PO*WW*ERTM system reduces the volume of an aqueous waste and catalytically oxidizes volatile contaminants. The PO*WW*ERTM system consists primarily of (1) an evaporator that reduces influent wastewater volume, (2) a catalytic oxidizer that oxidizes the volatile contaminants in the vapor stream from the evaporator, (3) a scrubber that removes acid gases formed during oxidation, and (4) a condenser that condenses the vapor stream leaving the scrubber.

The PO*WW*ERTM system demonstration was conducted under the SITE program at CWM's Lake Charles Treatment Center (LCTC) site in Lake Charles, Louisiana. The SITE demonstration was conducted in September 1992. During the demonstration, the PO*WW*ERTM system treated landfill leachate, an F039 hazardous waste, contaminated with VOCs, SVOCs, ammonia, cyanide, metals, and other inorganic contaminants. During the development of the PO*WW*ERTM system, CWM conducted bench- and pilot-scale tests and collected treatability data for the following aqueous wastes: (1) landfill leachate, (2) contaminated well water, (3) contaminated lagoon water, (4) fuels decant water, (5) oil emulsion wastewater, and (6) wastewater contaminated with nitrogen-containing organic compounds and cyanide. During these tests, the PO*WW*ERTM system processed aqueous wastes containing VOCs, SVOCs, pesticides, herbicides, solvents, heavy metals, cyanide, ammonia, nitrate, chloride, and sulfide.

Based on the results of the SITE demonstration and other case studies, the following conclusions can be drawn:

  • The PO*WW*ERTM system can process a wide variety of aqueous wastes with differing contaminant concentrations.
  • During the SITE demonstration, the PO*WW*ERTM system achieved a total solids (TS) concentration ratio of about 32 to 1. During other case studies conducted by CWM, a TS concentration ratio ranging from 35 to 1 to 50 to 1 was achieved.
  • During the SITE demonstration, the TS concentration in the brine ranged from 50 percent to 56 percent. During other case studies conducted by CWM, the TS concentration in the brine ranged from 28 to 80 percent.
  • Concentrations of VOCs and SVOCs in the product condensate exiting the PO*WW*ERTM system condenser were below their respective detection limits of 5 to 10 ug/L and 10 to 130 ug/L.
  • During the SITE demonstration, ammonia and cyanide concentrations in the product condensate samples were below the detection limits of 0.1 and 0.01 mg/L, respectively. Results from other case studies show that the product condensate contained ammonia and cyanide at similar low concentrations.
  • The product condensate contained trace levels of metals.
  • The product condensate may contain nitrate resulting from the hydrolysis of nitrogen dioxide.
  • During the SITE demonstration, the brine, which is an FO3Pderived hazardous waste, was also found to be hazardous based on toxicity characteristic leaching procedure (TCLP) test results. The brine also had relatively high levels of cyanide. Under acidic conditions, the brine could exhibit the hazardous waste characteristic of reactivity.
  • During the SITE demonstration, the noncondensible gas stream met proposed regulatory requirements for the LCTC site. The noncondensible gas emissions may contain VOCs, SVOCs, ammonia, cyanide, nitrogen oxides (NOx), sulfur dioxide (SO,), carbon monoxide (CO), and carbon dioxide (CO,), generally at low concentrations determined by treatment conditions and the type of contaminants present in the feed waste.
  • The PO*WW*ERTM system removes sources of feed waste toxicity, such as VOCs, SVOCs, ammonia, and cyanide. The feed waste was acutely toxic, with LC5Os consistently below 10 percent. The product condensate was nontoxic, with LC5Os consistently greater than 100 percent, but only after the product condensate was cooled and its pH, dissolved oxygen level, and hardness or salinity were increased to meet demonstration objectives and as allowed in EPA acute toxicity testing procedures.
  • Economic data indicate that the capital cost for a 50-gallon per minute PO*WW*ERTM system is approximately $4 million on a turnkey basis. The capital cost includes treatability study costs; design costs; all necessary components of aPO*WW*ERTM system; all interconnecting piping, controls, and monitoring equipment; and assembly and installation costs. Annual operating and maintenance (O&M) costs, including labor, consumables, utilities, analytical services, and waste disposal costs at a Superfund site are estimated to be about $3.3 million. Waste disposal costs account for about 70 percent of the annual cost. The total cost of a project lasting 15 years was estimated to be about $100 per 1 000 gallons of aqueous waste treated; and the total cost of a project lasting 30 years was estimated to be about $73 per 1,000 gallons of aqueous waste treated.

This report also discusses the applicability of the PO*WW*ERTM system based on compliance with regulatory requirements, implementability, short-term impact, and long-term effectiveness. In addition, factors influencing the technology's performance in meeting these criteria and evaluation limitations are discussed.


Randy Parker

Risk Mangement Research | Air and Climate Change Research | Water Research | Ecosystems Restoration Research | Land Risk Management Research | Technology: Sustainable Technologies Research, Environmental Technology Verification Program (ETV), and Technology Assessments

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