Solvent recovery from hazardous wastes

Olexsey RA, Blaney BL, Turner RJ, et al. 1988. Technologies for the recovery of solvents from hazardous wastes. Hazard Waste Hazard Mater 5 365-377. 

The recovery and recycling of waste solvents has some similarities to the recycling of waste oil and is also an important enterprise. Among the many solvents listed as hazardous wastes and recoverable from wastes are dichloromethane, tetra-chloroethylene, trichloroethylene, 1,1,1-trichloroethane, benzene, liquid alkanes, 2-nitropropane, methylisobutyl ketone, and cyclohexanone. For reasons of both economics and pollution control, many industrial processes that use solvents are equipped for solvent recycle. The basic scheme for solvent reclamation and reuse is shown in Figure 22.4. 

U.S. Environmental Protection Agency modified flic hazardous waste management regulations under the Resource Conservation and Recovery Act (RCRA) to conditionally exclude solvent-contaminated wipes from hazardous waste regulations provided fliat businesses clean or dispose of them properly. The rule is based on EPA s final risk analysis, which was peer reviewed in 2008 and published for public comment in 2009, that concluded wipes contaminated with certain hazardous solvents do not pose significant risk to human health and the environment when managed properly. EPA estimates that the final rule will result in a net savings of between 21.7 million and 27.8 million per year. ... 

Fischer and co-workers undertook a LCA of the 26 organic solvents which they had already assessed in terms of EHS criteria (see above).They used the Eco-solvent software tool (http //www.sust-chem.ethz.ch/tools/ecosolvent/), which on the basis of industrial data considers the birth of the solvent (its petrochemical production) and its death by either a distillation process or treatment in a hazardous waste incineration plant. For both types of end-of-life treatment, environmental credits were granted where appropriate, e.g. solvent recovery and reuse upon distillation. The results of this assessment are shown in Figure 1.2. From an LCA perspective, tetrahydrofuran (THF), butyl acetate, cyclohexanone and 1-propanol are not good solvents. This is primarily due to the environmental... 

Listed as toxic waste from nonspecific sources spent nonhalogenated solvents such as carbon disulfide spent solvent mixtures containing a total of at least 10% (by volume) of carbon disulfide before use and still bottoms from the recovery of above nonhalogenated solvent and solvent mixtures this item was listed as a hazardous waste due to its toxicity and ignitability Yes EPA 1995h (46 FR 4618)... 

Hazardous wastes from nonspecific sources - Examples of laboratory wastes that would fall in this category would be spent solvents, the residue resulting from distillation recovery of used solvents, materials left over from silk screening and electroplating procedures in electronic laboratories, and other sources of used chemicals. 

An electric company uses a water-based electrostatic paint system instead of a conventional organic solvent paint system. This has resulted in improved quality of application, decrease of downtime from 3 percent to 1 percent, reduction in the generation of aromatic waste solvent by 95 percent, reduction in paint sludge by 97 percent, and increase of efficiency with up to 95 percent recovery and reuse of paint. The new system reduced hazardous waste disposal costs and decreased personnel and maintenance costs by 40 percent. 

To satisfy the Resource Conservation and Recovery Act (1977) and its amendment for hazardous and solid waste (1984), the 80(K) Series Methods have been designed to analyze solid waste, soUs, and groundwater. In particular, methods 8240/8260 require the use of a purge-and-trap device in conjunction with packed or capillary GC/MS, respectively, for the analysis of purgeable organic compounds. Methods 8250/8270 concern analyses for the less-volatile bases, neutrals, and acids by GC/MS after extraction from the matrix by an organic solvent. 

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