TCLP test

However, rotary furnaces tend to produce more exhaust gas and fumes, require more skill fill manipulation, and are more labor intensive. Also, the slags produced in the rotary furnaces, soda or fayaUte [13918-37-1] slags, normally do not pass the toxic characteristic leach procedure (TCLP) test and pose a disposal problem. 

The TCLP tests are performed by subjecting samples to a much harsher environment than would be encountered in natural surroundings. The samples of concrete are pulverized to maximize exposure to the acid used. Next, a particularly harsh solution of acetic acid is... 

A concrete made from Southdown cement is called a Southdown concrete. Even under the TCLP testing extreme conditions, the amount of metals that leached out of the Southdown concrete were many orders of magnitude below the standards set by USEPA. In many cases the levels were, in fact, below the limits of detection for the test. One historical use of Southdown concrete has been for pipes used to transport drinking water. Drinking water is routinely tested to... 

These metal leachate limitations are extremely difficult to meet with the Best Demonstrated Available Technology (BDAT) which is chemical stabilization technology proposed by the Federal EPA. The fact that no limit was proposed for cyanide adds uncertainty to chemical stabilization. TSD facilities do not want to put mixed wastes containing cyanides into their secure landfills which may have to be removed at a later date. Note that a 1972 U.S. silver dollar fails the TCLP test due to nickel. 

To test the effectiveness of the CHEMFIX process as a treatment option, the solidified samples were subjected to the TCLP test and a comparison made with the TCLP results on a raw sample. This test was designed to determine the mobility of contaminants present in liquid, solid and multiphasic wastes. If the TCLP extract from a representative sample contained any of the listed contaminants above the regulatory levels it would be considered a hazardous waste and should adhere to the strict disposal requirements. )... 

The Clean Air Act of 1990 has made trace metal content in fuels and wastes the final ash-related compositional characteristic of significance. Considerable attention is paid (ca 1993) to emissions of such metals as arsenic, cadmium, chromium, lead, mercury, silver, and zinc. The concentration of these metals in both grate ash and flyash is of significance as a result of federal and state requirements of particular importance is the mobility of metals. This mobility, and the consequent toxicity of the ash product, is determined by the Toxic Characteristic Leaching Procedure (tclp) test. Tables 8—10 present trace metal contents for wood wastes and agricultural wastes, municipal waste, and refuse-derived fuel, respectively. In Table 8, the specific concentration of various components in the RDF governs the expected average concentration of trace metals. 

Toxic Characteristic Leaching Protocol (TCLP) testing of this material indicates it to be nonhazardous. After drying, this material is sent to a solid waste landfill. The average annual quantity of wastewater residue landfilled per facility is approximately 1.1 tons. 

The EPA regulates both lead and hexavalent chromium in its hazardous waste regulation. Solid waste containing lead chromate or lead molybdate should be tested for toxicity prior to disposal via the TCLP test. 

Limits on Leaching (mg/1) as the Disposal Criteria in the TCLP Test. 

The samples were stored for 3 weeks for curing. Each sample was then crushed and was subjected to the TCLP test. The TCLP test results on both the waste stream and the treated CBPC waste form are given in Table 16.6. The results on the untreated waste streams show that the leaching levels far exceed the regulatory limits. The results for the waste forms, on the other hand, are an order of magnitude below the EPA limit. These results indicate superior stabilization of Hg in the phosphate ceramic waste forms coupled with sulfide immobilization. 

Ash can be liquefied info a slag fhat passes toxicity characteristic leaching procedure (also known as TCLP) testing in most instances. 

Previously, the U.S. EPA had specifically promulgated regulations that exempted used lead acid batteries from the regulatory burdens of RCRA in order to facilitate the already well-established recycling of automotive batteries. As a result, lead acid batteries enjoyed a recycling rate of better than 95%. NiCd batteries, however, were not included in this earlier scheme, and at the time the TCLP test was initiated, its potential impact on NiCd batteries was not recognized and no provisions were made to facilitate their recycling. 

The situation became even more complicated because of a change in the U.S. hazardous waste management law. In 1990, the U.S. EPA changed its test protocol for determining what wastes should be classified as hazardous. The new toxicity test, called the TCLP test, required that materials be crushed or cut up to a small particle size and exposed to an acetic acid solution. The constituents of the leachate were then measured against standards for (among other elements) cadmium and lead. The idea was to simulate the release of the battery s contents into a landfill environment over a protracted period of time. If excessive quantities of the hazardous constituents of concern were measured, the waste material was to be regulated as hazardous. 

Five years later, however, when the TCLP test was finalized, its potential adverse impact on Ni-Cd battery recycling was not recognized. Consequently, no parallel exemption was adopted. 

The use of the slag product is unaffected by battery additions. The slag produced during battery recycling in the USA passes US EPA, TCLP tests. Slag produced while recyeling batteries in Europe continues to be sold as construction material. 

A specification was drawn up for a pilot recycling plant (250 tons/year) that would meet German safety and environmental standards, but the plant was not constructed because the quantity of returned batteries was insufficient to support it. Analyses of solution from laboratory-scale recycling were carried out for chromium, which is regulated for toxieity, and levels were found to be below EPA limits. TCLP tests on cells also show amounts of leachable chromium that are within EPA standards. 

The mechanism of extraction of metal ions such as actinides and heavy metals is well understood at the molecular level. For extraction of metals from environmental systems, water content is found to be an in rtant parameter in the reaction scheme. Extraction from soils and other solid matrices was demonstrated at a small scale witii similar efficiency to tiiat of the US EPA TCLP test. The main areas for future development in this technology are the issues surrounding process scale up. 

EP toxicity and TCLP tests are described in the Code of Federal Regulations, 40, Part 261, Appendix II and Part 268, Appendix I, respectively. 

In the sludge material, the lead is present in the feed solution as lead sulfate. With a solubility of 0.029 g/1 in cold water (5), most of the lead is in the precipitated form but an amount far exceeding the TCLP test limits is in solution. Figure 5 shows the species of lead in solution as a function of pH (6). The diagram shows that lead is highly soluble at very low pH values as the divalent cation and at high pH values as the monovalent anion. 

Results of the leaching tests for a an incinerator sludge (7) are shown in Figure 6. The sludge was tested at different pFI levels in the TCLP test. The sludge contained 7300 mg/kg of lead. This is much lower than the smelter sludge under consideration in the present discussion. 

Initial laboratory tests aimed at stabilizing the arsenic at pH 5 and 8 showed a lead solubility of 30 an 32 ppm. These tests were carried out without excess lime addition. During the TCLP test, acetic acid is added so that the pH of the leach solution is not controlled at any particular value. This explains the relatively high Pb solubility. Phosphate was then added during the arsenic precipitation stage, again without excess alkaline material. The results of the TCLP tests with phosphate additions showed a Pb leachate concentration of 40 to 60 mg/1. These data indicate that phosphate alone is not able to control the leaching of the lead. 

Finally the arsenic stabilization tests were repeated with the addition of phosphate and sufficient limestone so that the pH during the TCLP test would remain above pH 8. This test gave a result of 2.7 mg/L Pb, a value which passes the TCLP test. 

Table II - TCLP Test Results Obtained Using Portland Cement...

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