Chemical compatibility testing

Chemical compatibility tests using U.S. EPA Method 909040 should always be performed for hazardous waste sites, but some municipal waste sites also contain hazardous, nondegradable materials. U.S. EPA conducted a 5-year study of the impact of municipal refuse on commercially available liner materials and found no evidence of deterioration within that period. However, in a current study of leachate quality in municipal landfills, the Agency has discovered some organic chemical constituents normally found in hazardous waste landfill facilities. Apparently, small quantities of household hazardous waste enter municipal sites or are disposed of as small quantity generator wastes. As a result of these findings, U.S. EPA developed a position on the need for chemical compatibility tests for thousands of municipal waste disposal sites. 

A primary objective of chemical compatibility testing is to ensure that liner materials will remain intact not just during a landfill s operation but also through the postclosure period, and preferably longer. It is difficult, however, to predict future chemical impacts. There is no guarantee that liner materials selected for a site today will be the same as materials manufactured 20 years from now. For example, the quality of basic resins has improved considerably over the last few years. 

A designer should consult with experts to interpret data from chemical compatibility tests. To meet this need, U.S. EPA developed a software system called Flexible Membrane Liner Advisory Expert System (FLEX) to assist in evaluating test data. FLEX is an expert system that is based on data from many chemical compatibility tests and contains interpretations from experts in the field. 

Chemical compatibility tests. These tests are used to determine the behavior of various materials when they are in contact with oil. For example, specific tests are conducted to ensure the compatibility of a lubricant with seals. 

Because of the number of chemicals and subsequent multiple number of potential reactions, it is impractical and (perhaps impossible) to list all potential reactions. Several systems exist for determining the reactions between classes of chemicals, however, none of them is definitive. Because all of the potential reactions for individual chemicals are not cataloged and because there are no (or very few), pure solutions of waste materials, laboratory compatibility testing is recommended for most materials. An appropriate protocol for compatibility testing would involve the following steps ... 

Chemical compatibility studies with hydraulic conductivity tests must be performed over a long enough period of time to determine the full effects of the waste liquid. Termination criteria include equal inflow and outflow of liquid, steady hydraulic conductivity, and influent/effluent equilibrium. At least two pore volumes of liquid must be passed through the soil to flush out the soil water and bring the waste leachate into the soil in significant quantities. Reasonable equilibrations of the influent and effluent liquids occur when the pH values of the waste influent and effluent liquids are similar and the key organic and inorganic ions are at full concentrations in the effluent liquid. 

Chemical compatibility and U.S. EPA Method 9090 tests must be performed on the synthetics that will be used to construct FMLs. Unfortunately, there is usually a lag period between the time these tests are performed and the actual construction of a facility. It is very rare that at the time of the 9090 test, enough material is purchased to construct the liner. This means that the material used for testing is not typically from the same production lot as the synthetics installed in the field. The molecular structure of different polymers can be analyzed through differential scanning calorimeter... 

The American Society for Testing and Materials (ASTM) is a not-for-profit organization that provides a forum for the development and publication of voluntary consensus standards for materials, products, systems, and services.67 One ASTM committee (E27) develops standardized physical and chemical test methods on the hazard potential of chemicals, including but not limited to reactive hazards. The committee has developed standard analytical methods for calorimetry studies in addition to a standard guide for determining binary chemical compatibility (ASTM, 2000). 

Five of nine respondents to the CSB survey frequently use both screening and more sophisticated approaches, including adiabatic calorimetry, to determine the thermal stability or compatibility of process materials. Seven of nine respondents use screening alone for chemical reactivity testing. The most often used testing objectives are ... 

Costs likely to be incurred in the design and installation of a standard soil-bentonite wall in soft to medium soil range from 540 to 750/m ( 5 to 7/tf) (1991 dollars). These costs do not include variable costs required for chemical analyses, feasibility, or compatibility testing. Testing costs depend heavily on site-specific factors (D109308, p. 2). The installation cost of a cement-based slurry wall ranges from 10 to 20 per vertical square foot for a 2-ft-wide barrier of less than 100 ft in depth (D18976I, p. 6). 

The modulus of elasticity (MOE) is related to the strength and can be used as a nondestructive quality control test on high cost special refractory shapes such as slide gate valves employed in the pouring of steel (qv). The slide gate type must be selected to ensure chemical compatibility and it must be used in a way to reduce thermal shock. The performance of a properly selected and used slide gate is direcdy related to its strength and therefore predicted by its MOE. 

Characterization, Chemical Compatibility, Storability, and Hazard Testing of Liquid Propellants... 

When introducing binders or plasticizers into intimate contact with explosives, it is critical that there is no chemical incompatibility either initially or later on, as munitions are expected to have in-service life-spans of up to 30 years. Nitramines for example, have been found to be chemically incompatible with amines which are used for fast-curing epoxy resins. Therefore, all materials that might be used as part of an explosive formulation are carefully tested for their chemical compatibility with each other and also with the explosive, prior to their use for explosive formulations. 

Compatibility of TATB PBX with Weapons Materials , PlastOtherMaterExplosProplntsSymp, IIIA (1976) CA 87,87227 (1977) [Reported is the use of Viton-A, Kel-F 800 and Estane 5702-F1 as a binder for TATB contg expl compns. Compatibility tests (the object of the study with stainless steel, V, polyamide film and several sealant/adhesives at 120° for 1 to 4 months revealed no definite reaction. However, it was concluded that the major cause of gas evoln and chemical interaction between expl and test materials is the presence of w]... 

PDLCOM William Andrew, Inc., Plastics Design Library test data on the chemical compatibility and the environmental stress crack resistance of plastics... 

Standard tests are utilized early in the evaluation phase to evaluate flammability, ignition and explosive characteristics. These include differential thermal analysis, thermo gravometric analysis, drop weight tests, friction tests, card gap (shock initiation) tests, and materials compatibility tests. Information derived from the above tests serve as a basis to establish safe procedures and techniques to handle and process the chemicals into propellants. 

PP, PVDF, and PE are not jointed using solvent cements, but the weld regions contain relatively high levels of intrinsic stress caused by the thermal fusion process. Chemical stress cracking could occur at these welds if exposed to certain chemicals. When performing material compatibility tests for any... 

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