Solvents water contamination

Pervaporation has been commercialized for two appHcations. The first and most developed is the separation of water from concentrated alcohol solutions. GFT of Neunkirchen, Germany, the leader in this field, installed their first important plant in 1982. More than 100 plants have been installed by GFT for this appHcation (90). The second appHcation is the separation of small amounts of organic solvents from contaminated water (91). In both of these apphcations, organics are separated from water. This separation is relatively easy, because organic compounds and water, due to their difference in polarity, exhibit distinct membrane permeation properties. The separation is also amenable to membrane pervaporation because the feed solutions are relatively nonaggressive and do not chemically degrade the membrane. 

Insecticide methomyl is a very toxic pesticide and is highly soluble in water (57.9 g/1). It has a low sorption affinity to soil and can cause groundwater and surface water contamination in agricultural areas. Solubilities of methomyl in different solvents are in methanol 1000 g/1, in aceton 730 g/1, in ethanol 420 g/1, in isopropanol 220 g/1, in toluene 30 g/1. 

Reproductive Toxicity. Increased miscarriages were reported in one study of nurse-anesthetists exposed to trichloroethylene and other solvents (Corbett et al. 1974). A retrospective case-control study has should an approximate 3-fold increase in spontaneous abortion in women exposed to trichloroethylene and other solvents (Windham et al. 1991). Significant effects on sperm parameters were not observed in men occupationally exposed to trichloroethylene (Rasmussen et al. 1988). Adverse reproductive effects were not noted in humans that ingested water contaminated with trichloroethylene and other solvents (Byers et al. 

The aniline was being phosgenated in toluene as solvent, the reaction ran wild and ejected more than 3 tonnes of reactor contents. This is believed to have been due to water contamination, possibly as ice. An initial charge of only part of the phosgene failed to show the exotherm anticipated if water was present, however this may not have been enough, nor was the thermocouple immersed in the solvent. See Diprotium monoxide... 

Jackson, R. E., 1999, Anticipating Ground-Water Contamination by New Technologies and Chemicals The Case of Chlorinated Solvents in California Environmental Engineering Geoscience, Fall, Vol. V, No. 3, pp. 331-338. 

It is not surprising that the data produced as total petroleum hydrocarbons (EPA 418.1) suffer from several shortcomings as an index of potential ground-water contamination or health risk. In fact, it does not actually measure the total petroleum hydrocarbons in the sample but rather, measures a specific range of hydrocarbon compounds. This is caused by limitations of the extraction process (solvents used and the concentration steps) and the reference standards used for instrumental analysis. The method specifically states that it does not accurately measure the lighter fractions of gasoline [benzene-toluene-ethylbenzene-xylenes fraction (BTEX)], which should include the benzene-toluene-ethylbenzene-xylenes fraction. Further, the method was originally a method for water samples that has been modified for solids, and it is subject to bias. 

The sorption of a nonpolar organic contaminant on a solid phase is derived by enthalpy and entropy related forces. Hasset and Banwart (1989) suggested that sorption occurs when the free energy of the reaction is negative due to enthalpy or entropy. The enthalpy is primarily a function of the changes in the bonding between the adsorbing surface and the sorbate (solute) and between the solvent (water) and the solute. The entropy is related to the increase or decrease in the order of the system on sorption. 

Recently investigated methods of treating waste waters contaminated with 1,3-DNB or 1,3,5-TNB and related products include biological treatment, stripping, solvent extraction, and activated carbon adsorption (HSDB 1994). 

Minor admixtures of water to nonaqueous electrolytes are often harmful, for example in batteries with inorganic solvents such as POCI3, SOCI2, SO2CI2, where it is important that the electrolyte be free of water contamination because of the possible formation of oxychloride cements ... 

Oliveira DP, Sitar N. 1985. Ground water contamination from underground solvent storage tanks, Santa Clara, California. In Proceedings of the Fifth National Symposium on Aquifer Restoration and Ground Water Monitoring, 691- 708. 

The CleanSoil process is an ex situ treatment technology that uses steam to remove hydrocarbons and chlorinated solvents from contaminated soils. The steam vaporizes the contaminants from the soil and carries them to a condenser for recovery. The water is converted back into steam and reused in the system. The remaining vapors pass through an activated carbon filter and are released into the atmosphere. The technology has been applied full-scale at multiple sites and is commercially available. 

Constructed wetlands are commercially available through a number of vendors and have been used to treat water contaminated with acid mine drainage, explosives, hydrocarbons, chlorinated solvents, phenols, agricnltnral wastes, and sewage. The RIMS2000 database discusses constructed wetlands for the treatment of acid mine drainage in summary number T0179. 

Micro-Flo has been used at many sites throughout Canada to treat wastewater and surface water contaminated with polychlorinated biphenyls (PCBs), chlorophenols, polycyclic aromatic hydrocarbons (PAHs), phenols, dioxins, furans, hydrocarbons, metals, oil, and grease. The technology has also been used to treat water contaminated with paint, paint thinner, and paint solvents. 

Puls, R.W., Powell, R.M., and Paul, C.J., In situ remediation of ground water contaminated with chromate and chlorinated solvents using zero-valent iron a field study, The 209th ACS National Meeting, Division of Environmental Chemistry, 35(1), 788-791, 1995. 

PCB organic compounds found as soil and water contaminants continue to grow each year. They include polychlorinated biphenyls (PCBs), phenols, cyanides, plasticizers, solvents, and numerous industrial chemicals. PCBs were historically used as coolants in electrical transformers and are also known by-products of the plastic, lubricant, rubber, and paper industries. They are stable, lipophilic, and break down only slowly in tissues. Because of these properties they accumulate to high concentrations in fish and waterfowl in 1969 PCBs were responsible for the death of thousands of birds in the Irish Sea. 

---