The Sunohio PCBX process has been approved in all US EPA Regions, with ppm limitations as shown below:
- Region I--No limitation.
- Region II--No limitation; 500 ppm limit in reactor loop.
- Region III--No limitation; 500 ppm limit in reactor loop.
- Region IV--No limitation.
- Region V--No limitation; 500 ppm limit in reactor loop.
- Region VI--1 000 ppm with 500 ppm limit in reactor loop.
- Region VII--10 000 ppm.
- Region VIII--2 000 ppm, subject to some volume limitation.
- Region IX--No limitation.
- Region X--No limitation. 1 500 ppm in reactor loop.
In those Regions where 500 ppm reactor feed limitations have been stipulated, a higher limit will be set upon demonstration of ability. Such a demonstration has been made under the auspices of Sunohio's home Region V, and the upgrading procedure is now in progress.
Sunohio has been operating its process commercially since mid-1981. As of late May, 1982, it reports a roster of 20 large and satisfied customers and nearly 500 000 gallons of contaminated oil having been treated and returned to service free of PCB. There are presently (late May, 1982) five rigs in operation, and the company has the capability of constructing and fielding several new rigs each month.
The PCBX process claims the capability of returning electrical insulating oil to like-new condition, and this claim has been confirmed by exhaustive tests conducted by utility customers, the Electric Power Research Institute, and the Doble Testing Laboratories. This oil quality enables PCBX to be tied directly to a transformer in order to detoxify the transformer as well as the oil. This process, however, does meet the requirements of the PCB regulations.
Little information is forthcoming on the various components of the system and even less on the exact nature of the reagent itself. Sunohio has been notified by the US Patent Office that the claims on its process have been allowed. Identical patent applications are entered in Canada and all other major industrial nations.
This mobile system is available on a quantity/ppm/price basis. The current price for treatment of contaminated oils in the US ranges from $80 to $1.30 per litre for bulk oil, depending upon the degree of contamination. In making price comparisons with other methods of destruction of PCB, the reuse value of the oil is an important factor. Transformers are priced on a per-unit basis and the system is readily available.
The Sunohio unit is completely enclosed and should not impact the workers on-site providing that adequate care in handling wastes and reagents is taken. The units are mobile and can be used to treat PCBs on-site; therefore, the public attitude towards treating PCBs by this method should not be adverse. The process does not yield any air emissions or by-products that would be harmful.
In addition to the environmental stability and full reusability of the treated oil, toxicological studies of the by-products conducted by Sunohio for US EPA revealed no harmful qualities.
Sunohio, the developer of PCBX, is a partnership of Sun Company and Ohio Transformer Corporation.
References: (EPRI, 1981; Annual Conference of the Southern Electric Excharge, 1981; Sworzyn and Ackerman, 1981).
4.4.1.3 Acurex Process
Head Office: Acurex Waste Technologies, Inc.
485 Clyde Avenue
Mountain View, California 94042
General Manager: Don Fraser,
(415) 964-3200
Research Manager: Leo Weitzman
Acurex Waste Technologies, Inc.
074 Beechmont Avenue
Cincinnati, OH 45230
(513) 474-4420
The Acurex dechlorination process is a modification of the original Goodyear sodium naphthalide process. The Acurex system uses a mobile batch process for treating PCBs and PCB-contaminated oil with a sodium reagent at a rate of 0.9 m3/h.
The company has changed the original sodium naphthalide reagent by replacing naphthalene, a priority pollutant, with another constituent (proprietary) which is a non-priority pollutant. The PCBs or PCB-contaminated transformer oil enters the system at one end where it is filtered and batch sized. As the oil is transferred downstream, the sodium reagent is added and the mixture is allowed to react. After complete destruction of PCBs is shown by gas chromatographic analysis of a batch sample, the excess reagent is quenched. The PCB-free oil is then filtered and returned for reprocessing or for use as a fuel oil. The Acurex process is run under an inert atmosphere at ambient temperature with slight excess amounts of sodium reagent.
It is stated in manufacturers' literature that the Acurex process produces treated oil containing no PCBs and a sodium hydroxide effluent. Although no specific reference is made concerning the fate of the chlorine in the PCB molecule, it is likely that it leaves the process as NaCI in the NaOH effluent. The only air emissions released are small amounts of nitrogen and hydrogen containing less than 1 g/min total hydrocarbon, no measurable PCBs and no particulates.
Waste transformer oil containing up to 1062 ppm PCBs can be treated using the Acurex system. In September 1981 tests were conducted for the EPA. Oil containing up to 1062 ppm PCBs was treated and the PCBs were completely destroyed. The process routinely reduces the PCB level to <2 ppm. As in all sodium processes the Acurex system cannot be used to treat PCBs in aqueous solution.
The Acurex system was developed in 1980 and Acurex currently has one mobile PCB destruction unit in operation. They expect to have 6-12 units in operation by the end of 1982 depending on user demand. The mobile unit has been thoroughly tested for capability in destroying PCBs and is pending EPA approval before commercial development of the process.
This process lends itself well to a micro-processing control system. Monitoring of the contaminated oil through each stage can be attained, while at the same time, optimizing the flow.
The cost of PCB destruction using this process would be approximately $2.40/gallon of oil treated. This is approximately $0.70 (US) per kilogram of oil treated. The system is designed to destroy PCBs up to a concentration of 1000 pm in contaminated oil, well below capabilities of other technologies which handle 10 per cent or higher PCB concentrations. Oils with PCB concentrations of 10 000 ppm have been treated using this process and it is currently being demonstrated at this level.
According to all available test data, the Acurex process gives off no effluents, or by-products that would be unduly hazardous to workers, the public, or the environment. Proper control of the unit and testing of the products and by-products must be maintained to ensure worker safety. The impact of the Acurex system on the public is diminished by the fact that the unit is mobile. PCB-contaminated fluid need not be transported off-site, thus diminishing the possibility of spills, and the problem of having a permanent facility which could be a hazard to a specific area is avoided.
The Acurex mobile PCB destruction process is currently approved in three EPA regions to destroy PCB transformer oil containing up to 1000 ppm PCB and the company is expecting approval from the other regions at any time.
References: (Weitzman, 1982; Miille, 1981; Acurex Corp., 1981).
4.4.1.4 PPM Process
Head Office: PPM Incorporated
8220 Travis
Overland Park, Kansas 66204
Contact: Dennis Tapsak
(913) 648-0448
PPM Incorporated has developed a mobile chemical process for destroying PCBs using a sodium reagent. The unit is hauled on a tractor trailer to the site of the PCB-contaminated oil. The proprietary sodium reagent is added to the contaminated oil and left to react. There is no adverse environmental impact resulting from the operation of the PPM, Inc. mobile PCB decontamination process. The unit emits no effluent, and emissions are limited to nitrogen and a small amount of hydrogen. The solid polymer which is filtered out of the oil by this process is a regulated substance in the United States, but does not contain PCBs and can be readily disposed. It generates about one 55 gallon barrel of polymer (US gallons) for approximately every 40 000 L of oil treated.
Testing conducted for the US EPA indicated acceptable destruction efficien-cies. In the testing 70 000 L of oil contaminated with 200 ppm PCB were treated with the sodium reagent. After reaction no PCBs were detectable in the treated oil.
Insufficient information was available on the PPM process to give an estimate of capital and operating costs. It may be considered that these costs would be in the same range as the other sodium processes.
The PPM process has currently been approved in EPA Regions I, IV and VIII to destroy oils contaminated with up to 10 000 ppm PCB and PPM expect to have approval in all EPA regions by this summer. PPM has one unit in operation as of January 1982. This process is being considered for application in Canada.
References: (Manufacturer's literature; Tapsak, pers. comm., 1982).
4.4.1.5 NaPEG Process
Head Office: Franklin Institute Inc.
Research Laboratories
The Benjamin Franklin Parkway
Philadelphia, Pa. 19103
Contact: Dr. Steve Osborn,
Technical Manager
(215) 448-1297
The NaPEG PCB destruction method uses a chemically modified sodium polyethylene glycol complex as its reagent. The composition of the reagent can be varied depending on the type of polyethylene glycol (PEG) that is used. PEG400, i.e. polyethylene glycol having a molecular weight of approximately 400 is normally combined with the sodium to form NaPEG400. Sodium polyethylene glycol is made by adding sodium to polyethylene glycol at an elevated temperature. The amber sodium polyethylene glycol is produced almost immediately with the evolution of heat and hydrogen.
The Franklin Institute manufactures the NaPEG at their facility in Philadelphia, and then ships the reagent to a location where PCBs are to be destroyed. When the reagent is manufactured, it is stable for more than 2 years; it is not sensitive to small quantities of air or water, and contains no metallic sodium. PCB can be destroyed using the NaPEG system in a mobile, or a permanent facility. The NaPEG reagent is added to the PCB-contaminated material on a batch basis at a temperature ranging from ambient to 150°C. The mixture is left to react; the reaction by-products are removed; and any excess reagent is neutralized after the PCBs are shown to be destroyed. The reaction by-products are sodium chloride; nontoxic organic compounds; and decontami-nated material.
The NaPEG reagent can be used to decontaminate PCB-containing oils. Use of the reagent to decontaminate solids, including soils, is presently being investigated under grants from the US EPA. The presence of water and air in small amounts does not appear to hinder the reaction.
The process is simple to run, and users are expected to be able to process their own oils for cleanup and reclamation on-site, using relatively simple equipment. A batch plant can be constructed from components that are normally available with some specially purchased equipment such as a stirrer, a controller, or a special duty pump. The Franklin Institute has constructed one process demonstration unit which is currently being used to test the process for the US EPA. In EPA monitored tests, contaminated oils containing up to 400 ppm of PCBs have been successfully treated.
The technology involved is not complex in nature, and would be relatively easy to operate. No such system is presently in operation to destroy PCBs. The process appears to comply with all of the current EPA regulations, including emissions from the process, which are below the limits of detectability.
Little information is available on the technology as far as flow rates, PCB concentrations, or costs are concerned. However, the costs are currently estimated at about $1.50/kg of PCB-contaminated liquid treated.
The process involves equipment normally available for batch operations: tanks, transfer pumps, mixing chambers, diaphragm control valves, piping construction of compatible material, etc.
The NaPEG reagent, after it has been produced, is not hazardous to persons using it, although it should be handled with the same caution given all potentially dangerous chemicals.
The public at large and the environment are not overly affected by the NaPEG system although the exact composition of the organic compound forms as by-product is not known.
The NaPEG process is currently being demonstrated to the US EPA Region III and is under review for approval. Final approval is expected during the early 3rd quarter of 1982.
References: (EPRI, 1981; Franklin Inst. Research, Lab. Inc.; Pytlewski et al.) |
