Waste leachability

Vaajasaari, K., Ahtiainen, J., Nakari, T. and Dahlbo, H. (2000) Hazard assessment of industrial waste leachability chemical characterization and biotesting by routine effluent tests, in G. Persoone, C. Janssen and W. M. De Coen (eds.), New Microbiotests for Routine Toxicity Screening and Biomonitoring, Kluwer Academic / Plenum Publishers, New York, pp. 413-423. 

Sulfur Polymer Cement. SPC has been proven effective in reducing leach rates of reactive heavy metals to the extent that some wastes can be managed solely as low level waste (LLW). When SPC is combined with mercury and lead oxides (both toxic metals), it interacts chemically to form mercury sulfide, HgS, and lead sulfide, PbS, both of which are insoluble in water. A dried sulfur residue from petroleum refining that contained 600-ppm vanadium (a carcinogen) was chemically modified using dicyclopentadiene and oligomer of cyclopentadiene and used to make SC (58). This material was examined by the California Department of Health Services (Cal EPA) and the leachable level of vanadium had been reduced to 8.3 ppm, well below the soluble threshold limit concentration of 24 ppm (59). 

Allard, B. Andersson, K. "The Influence of Groundwater Chemistry on the Leachability of Bitumenized Waste" Nordisk Kontakt-organ for Atomenergisporsmal in press. 

Wbter, extracts or digests of waste Filtration or digestion as appropriate (depends on matrix, dissolved or total, acid leachable, etc.) ICP/MS (EPA Method 6020) No data 71-137% (11-23% RSD) for aqueous solutions 90-104% (6-28% RSD) for solid samples EPA 1994e... 

Mundell JA, Hill KR, Weaver JW II. 1989. In situ case history Leachable lead required precipitation immobilization. Hazardous Waste Management 23-27. 

Example Optimization of an Eleven Component Glass Formulation. Piepel (6) discussed the generation and analysis of a mixture design consisting of eleven oxides used to prepare glasses for waste vitrification. Although many responses must be considered for the end use of this composition, the intent of Piepel s study was to minimize the response of leachability subject to the compositional constraints of ... 

Plasma gasification is a generic-type process that can accommodate virtually any input waste material in as-received condition, including liquids, gases, and solids in any form or combination. Also, moisture content is not a problem. Liquids, gases, and small particle-size waste materials are very easily and efficiently processed. Bulky items, such as household appliances, tires, and bedsprings, can also be readily accommodated without loss of destruction efficiency. The reactor vessel and waste feed mechanism are designed for the physical characteristics of the input waste stream. Even waste materials such as low-level radioactive waste can be processed to reduce the bulk and encapsulate the radioactive constituents to reduce leachability. 

The CSIRO Division of Mineral Products, Port Melbourne, Victoria, Australia, is conducting research to develop a process to recover fluoride and aluminum from spent pot lining ash with concurrent production of an environmentally safe residue that is suitable for disposal. The proposed method involves initial calcination which thermally decomposes the cyanide in the spent pot lining. Successful completion of this research would reduce the amount of hazardous wastes that contain potentially harmful leachable cyanides that can enter the groundwater during open air storage. 

Pintail Systems, Inc. s, spent-ore bioremediation technology includes two main treatment processes. The first process involves the biological treatment of cyanide wastes using indigenous bacteria, which are isolated from contaminated sites and cultured in large quantities for full-scale applications. The second process involves metal biomineralization in which biological processes are adapted to immobilize soluble and leachable metals. 

At Kirtland Air Force Base in New Mexico, an in situ application of MAECTITE was used to treat 2000 yd of soil contaminated with lead and cadmium. Following MAECTITE treatment, leachable lead and cadmium levels in soils were less than residential human health standards. In addition, contaminant levels were low enough that the treated waste could be categorized as nonhazardous by Resource Conservation and Recovery Act (RCRA) standards. Total costs for the project were 125,000, which was almost 40% less than alternative stabilization techniques considered at the site (D21483F, p. 3). 

Solucorp Industries molecular bonding system (MBS) is a patented process that stabilizes heavy metals. The technology uses proprietary mixtures of nonhazardous chemicals to convert heavy-metal contaminants from existing reactive/leachable forms (usually oxides) into stable, insoluble, metal-sulfide compounds. The vendor states that MBS is a mobile technology that quickly treats large volumes of waste on site. 

Reduces leachability through the chemical fixation of the organic component of the waste. 

The vendor claims that the CCBA process can be used on a variety of wastes, including sludges, sediments, and soils, contaminated with mixed organics and heavy-metal wastes. The process reduces the contaminated material to a nonleachable product composed of particles of sand to aggregate sizes. The treated wastes pass required leachability tests, and organic compounds are destroyed. The treated material can be disposed of on-site. 

Hassett, D. J. Hassett, D. F. 1988. Fixation of leachable elements in composite waste forms from North Dakota lignite coal conversion ash. Materials Research Society Symposium Proceedings, 113, 333-340. 

Chemical stabilization of waste materials offers the potential to reduce the leachability of contaminants present in the waste. As shown in Fig. 1, it involves the conversion of the available fraction (or soluble species) of an element in a waste to an unavailable fraction (insoluble... 

A solid waste is considered hazardous if it is either a listed waste or a characteristic waste. Listed wastes include a list of specific processes that generate a waste and a list of discarded commercial chemical products. There are four hazardous waste characteristics ignitability, corrosivity, reactivity, and toxicity. The last refers to the leachability of a waste and the resultant toxicity in the groundwater using the analytical method referred to as toxicity characteristic leaching procedure (TCLP). A list of substances included under TCLP is shown in Table 1. 

Paige, B. E., "Leachability of Glass Prepared from Highly Radioactive Calcined Alumina Waste," National Reactor Testing Station, Rept. IDO-14672, (February, 1966). 

Mendel, J. E., "A Review of Leaching Test Methods and Leachability of Various Solid Media Containing Radioactive Wastes," Battelle Northwest Laboratory, Rept. BNWL-1765, (1973). 

Leaching onto Ion-Exchange Resins. A more sophisticated procedure for determining leachabilities of radioactive waste forms has been developed(7). Flowing deionized water is continuously circulated across the sample surface and then through ion-exchange resins where the leached ions are adsorbed. The adsorbed ions are subsequently eluted from the resin columns for atomic absorption analyses. Leachabilities measured by this procedure are claimed to be lower and more consistent than those made in stagnant water in the absence of continuous ionic control (7 ). 

During development, evaluation of the consolidated materials was based primarily on two criteria, leachability and the concentration factor, i.e., the concentration of waste oxides on a volume basis. The concentration factor is directly affected by the residual porosity in a consolidated waste as well as by the dilution caused by the addition of consolidation aids. This factor can be as high as 1.2 g/cm3 for a fully dense ( 5 g/cm ) titanate waste prepared from the projected Barnwell plant solution composition. The factor is slightly lower for a titanate waste containing silicon and zeolite additions, which has a typical density of U.2 g/cm3. The leachability was determined by an "instantaneous leach test developed for fast, comparative evaluations of materials, the details of which are described elsewhere (l6). 

The solidified SSM sample at the optimum reagent ratio was tested for metal leachability by the Toxic Characteristic Leaching Procedure as per 51 FR 21685-21693.(7) The target metals were analyzed by atomic absorption spectrometer using USEPA SW-846 "Test Methods for Evaluating Solid Wastes," 1986(8) as required by 40 CFR Part 261.( ... 

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