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HomeMy WebLinkAboutNCD980602163_19830216_Warren County PCB Landfill_SERB C_The PPM Process - Chemical Destruction of PCBs-OCRTHE PPM PROCESS CHEMICAL DESTRUCTION OF PCBs February 16, 1983 By Dr. Louis Centofanti President PPM, INC. Presented to the 1983 APPA ENGINEERING & OPERATIONS WORKSHOP BACKGROUND PPM, INC is a waste management firm specializing in PCB handling, chemical destruction and testing. PPM has offices in Kansas Cityi Missouri, and Atlanta, Georgia. PPM's laboratory is located in Atlanta and is equipped with the most modern equipment available to measure PCBs and other hazardous contaminants in oil, air, and water. PCB and organic analysis are performed using a Perkin-Elmer Sigma IIIB Gas Chromatograph. Trace metal analysis is performed using a Perkin-Elmer Atomic Absorption Spectrophotometer. PPM, INC. has licensed its present PCB chemical destruction process from Southeastern Technologies, Inc., a chemical development firm in Atlanta. PPM has incorporated the process into a mobile decontamination unit. The mobile unit underwent its first commercial operation early in November 1981, treating over 17,000 gallons of PCB-contaminated mineral oil owned by Kansas City Power & Light. This clean-up was observed by EPA Region VII. Analysis by both an independent laboratory and EPA's laboratory indicated that PCB levels had been reduced to undetectable levels in the oil. In May of 1982, PPM demonstrated the process again to EPA and State of Missouri Officials at higher PCB levels. At that time PPM treated 500 gallons of a kerosene based flushing oil that contained 1100 ppm of PCB. Again the mobile unit reduced PCB levels in the oil to undetectable levels. PCB's were first controlled by the Toxic Substance Control Act. This law was passed by Congress in 1976, and took effect January 1, 1977. The Environmental Protection Agency has issued since 1977 a variety of PCB regulations. These regulations are now firmly in place and cover all aspects of record keeping, handling, and disposal. All PCB disposal must be done with EPA approved process or at an approved facility. The three methods of disposal that have been approved by the EPA are landfilling, incineration, and chemical destruction. PPM, INC. views landfills as nothing more than long-term storage. Although it is legal to utilize landfills for the dis- posal of PCB contaminated wastes, we recommend to our clients that only destruction options be used since the generator may be required in the future to pay to have the landfill cleaned. Incineration is permitted for a variety of materials. Incin- eration may include specially permitted incinertors or, for contam- inated oils, high efficiency boilers that would meet these EPA criteria. Initial cost estimates indicate that burning in these boilers is most economical method of disposal; however, most utilities have avoided this option. Public opposition to power plants becoming hazardous waste disposal facilities is intense. Many utilities that have attempted taking this route have found that public opposition and ensuing expenses to defend the burning rapidly make the project economically unfeasible. Chemical destructions are usually sodium based processes that dechlorinate the PCB molecule. Although sodium processes are relatively new methods of dealing with PCB disposal, they are a known technology in the chemical industry and used in a variety of other processes. In fact, a sodium process was used for some time in the oil industry to purify virgin transformer oil. The process was later replaced by less expensive sulfuric acid, solvent extraction and hydrogenation processes. The first semi-commercial sodium PCB destruction process was proposed by Goodyear. Goodyear did not commercialize the process, but it made the technology available to any firm interested in commercializing the technology. The initial "Goodyear Process" had serious economic and safety problems associated with it. The most serious problem was the use of a highly flammable solvent, tetrahydrofuran, to dissolve the metallic sodium. Independently, several firms, including PPM, INC. have developed their own proprietary processes. An advantage of chemical treatment using the PPM process rather than incineration is that the process avoids conditions forming highly toxic chlorinated and non-chlorinated benzofurans and benzodioxins. These materials require oxygen and heat for their formation. However, the PPM process is done in an oxygen-free atmosphere and at room temperature. Moreover, the sodium reagent chemically destroys these materials so that the formation of these compounds is avoided. The PPM process has no emissions or effluent, allowing it to be performed at any location safely. THE PPM PROCESS The PPM process was independently developed to meet three important criteria: l. It must be safely and simply operated in the field, 2. It must produce an acceptable product ( i.e, transformer oil), and 3. It must be economical. For simplicity and safety, the PPM process operates at ambient temperature and does not use flammable solvents. The reducing agent used in the PPM process is a highly complex organo-sodium reagent. Due to propriatary consideration, the exact nature of the agent cannot be disclosed. The reagent is air and water sensitive and therefore the process must be blanketed with nitrogen. The process can tolerate small amounts of water, but every effort is made to minimize water levels. The reagent reacts immediately with PCB's and chlorinated hydrocarbons forming sodium chloride and a polyphenylene polymer. Transformer oil is a complex blend of organic materials. To determine the reusability of transformer oil, the reaction of the organo-sodium reagent with various components must be examined. Chemically, the material is a potent reducing agent and produces reactions similiar to the hydrogenation step used in transformer oil refineries. The sodium reagent immediately reacts with inhibitors, acids, thiols, and chlorides forming the appropriate sodium salts. These materials are then present in the oil as an insoluble sludge. This solid sludge is composed of a variety of reaction materials and products and includes the following: polyphenylene unreacted reagent NaCl NaOH NaOR (inhibtor) Na02R (acids) After complete destruction of all PCB's, the reagent has also converted inhibitors and acids into insoluble sludge. Polyaromatic nature of the oil is either unchanged or slightly increased due to the coupling nature of the reagent. The increase is insignificant and if anything should improve the properties of the oil. To reuse the oil as transformer oil, the above described sludge is removed. After cleanup, sodium levels in the oil have been reduced to undetectable levels and the oil passes or excedes transformer oil spec- ifications. MOBILE UNIT PPM has incorporated the sodium process into a mobile decontamination unit. The unit is on a trailer towed to the site where the hazardous material is stored. By taking the unit to the site, problems associated with transportation, handling and public and worker exposure of the contaminated oil are greatly reduced. The need for a permanant disposal site is also eliminated by cleaning the oil so that it can be reused. TRAILER The unit has been constructed in a forty foot trailer. All lines and equipment on the trailer are within a large spill pan. The pan holds approximately 1,200 gallons which is more than the combined volume of all tanks on the unit. The trailer is connected to the holding tank using two-inch chemical transfer lines. The lines are fitted with male/female quick disconnects. During storage and transportation, all of these lines are plugged or capped to prevent spills. Drip pans are placed under all connections. Areas leading to sewers or open water are diked. Valves are opened slowly and all connections are checked for leaks. SUPPORT VAN Chemicals, laboratory equipment, water filters, and miscellaneous equipment and tools are brought to the site in a twenty foot enclosed panel truck. . . CHEMICAL DECONTAMINATION The PPM Chemical Process consists of three parts: Pretreatment, Decontamination and Clarification. In the Pretreatment portion of the process, water is reduced to acceptable levels by draining the water off the bottom of the tank and using water filters. In the second step, Decontamination, PCB's are destroyed. PCB's in the oil are reduced to undetectable levels. After PCB destruction, the sludge and solids in the oil are removed using a variety of filters. PRETREATMENT In the first step of the process the oil is pretreated to remove water, air, and a variety of impurities that interfere with the decontamination. DECONTAMINATION After pretreatment the oil is decontaminated. The sodium reagent is added directly to the oil. The amount of reagent added is determined before cleanup by sampling the oil and running laboratory tests to determine PCB, chlorinated hydrocarbon, sulfur and other impuity levels. As the PCBs react, they are monitored on site with a gas chromatograph (GC). Reaction is rapid as PCB levels are reduced to undetectable levels. Because PPM tests the oil on site, the destruction of the PCBs in the oil is guaranteed and PPM does not leave the site until total destruction has occured. CLARIFICATION After decontamination the oil is cleaned of salts and solids in the seperator. During this stage, small amounts of water are added to destroy excess reagent and to assist in the seperation of the byproducts. The soilds, salts, and small amounts of water solution of sodium hydroxide are removed in this step. The volume of waste removed is a minimal amount of the original volume (usually less than 2 percent of that volume). These waste materials become the responsibility of PPM, INC. They are collected and properly disposed. The oil leaving the unit is measured for PCBs, which are below detection limits. If the level is not below 2ppm, the oil is retreated. At this point the oil is deregulated, and the owner can reuse the oil. WASTE STREAMS Prior to treatment the oil is inspected, and any free water held at the bottom of the tank is drained and disposed according to regu- lations. During operation, clothing, rags and disposable equipment that come in contact with PCB-contaminated oil are placed in a container and disposed as necessary for PCB-contaminated materials. The process itself produces solids and small amounts of sludge and aqueous waste that are removed from the process and disposed according to regulation. The chemical destruction process produces a polymeric material that is filtered from the oil. This material is disposed in an "Annex III Landfill". The process does not produce any emmissions. There are no dis- charges into the environment. This makes the PPM process inherently safer than the disposal options of landfilling or incineration. The PPM process can be performed at any location without fear of discharges into the environment. PROCESS SAFETY The PPM process is designed for worker and environmental safety. The process itself operates at room temperature and does not use flammable solvents. Equipment construction conforms to industrial safety codes, and equipment hazards are minimized. The equipment is blanketed with nitrogen to avoid reaction side products and to eliminate fire hazards. Employees are trained in process controls and operational safety. Each unit is operated by qualified personnel. In general, worker exposure to PCB oil is minimized and, under normal operating coaditions, should never occur. This becomes the PPM process is a closed-system process. Once the PPM mobile unit has been connected to the source of contaminated oil, all contaminated material is confined to the PPM unit and the original container. At the end of the PPM process, the oil, the original container, and the PPM unit have all been decontam- inated. Each unit contains spill cleanup equipment, and necessary work protection clothing including gloves, goggles, and full-body garments. On-site fire extinguishers and sodium carbonate are located near the unit for fire protection. An oil absorbant is also available for minor spills and cleanup. SAMPLING AND ANALYSIS Prior to treatment, the storage site is inspected by PPM, INC. personnel. The inspection team examines the oil storage layout to look for potential problems and to evaluate the safety of the site. During this visit, the oil is sampled and carefully examined by PPM's laboratory to determine the amount of materials needed to clean the oil. When the mobile unit arrives at the site, the oil is again analyzed for PCB. PPM uses an AID portable gas chromatograph (GC) for site work. As the oil is treated, it is continually monitored for PCBs by the on-site CC. PCB levels are usually undetectable and at least less than 2 ppm as required •. The PCB analytical technique is an approved EPA method.