Aqueous waste environment

Heitkamp MA, V Camel, TJ Reuter, WJ Adams (1990) Biodegradation ofp-nitrophenol in an aqueous waste stream by immobilized bacteria. Appl Environ Microbiol 56 2967-2973. 

Aqueous waste solutions should be disposed of properly, and in particular solutions carrying heavy metals need to be treated. Untreated solutions, if released, can contaminate the geological environment. 

Using an evaporator for raffinate concentration and production of strip solutions, a closed wet cycle is obtained and no aqueous waste pollutes the environment. 

Water-based solvent systems originally developed for the separation and purification of proteins and other biomaterials (Walter et al., 1985) have been suggested for the treatment of contaminated aqueous waste-streams. Certain pairs of water-soluble polymers are incompatible in solution together, and this can lead to phase separation in which two phases are formed. Both phases are predominantly water, and each contains only one of the two polymers. Similar phase behavior results with some polymers and high concentrations of organic salts. The properties of the two phases ensure that the environment-afforded targeted species is different in the two phases. 

Cooper, W.J., Nickelsen, E., Meacham, D.E., Cadavid, M.G., Kurucz, C.N., and Waite, T., High-energy electron beam irradiation an innovative process for the treatment of aqueous based organic hazardous wastes, /. Environ. Sci. Health, A27(l), 219-244, 1992c. 

For the bulk production of CPs, the chemical method is used. It is essentially a scaleup of the procedures used in the laboratory. In the case of PANi, benzidine is a byproduct formed during oxidation of aniline and is a carcinogen. Consequently, it must be removed by extraction or copolymerization during oxidation. In addition, the aqueous waste must be either treated before release into the environment or recycled. 

In aqueous waste-removal operations, the solute is often an undesirable species to be removed from wastewater. After solute recovery, the rich streams, with solute in low concentrations, are disposed of, returned to the environment, recycled, or reused. Clearly, when returned to the environment, these streams must meet the latest federal, state, or local regida-tions. When recycled or reused, solute concentrations must be sufficiently low to meet the requirements of sinks elsewhere in the process. 

Eary, L.E., and D. Rai. 1988. Chromate removal from aqueous wastes by reduction with ferrous ion. Environ. Sci. Technol. 22 972-977. 

The codisposal of trace metals (e.g. Co), synthetic chelates (e.g. ethylenediaminetetraacetic acid, H(4) EDTA) and water-miscible organic solvents has occurred at some contamination sites. The reactions of Co(II)-EDTA with a redox reactive naturally occurring solid, goethite, in aqueous and semiaqueous (methanol-water, acetone-water) suspensions was studied. UV-visible spectroscopy indicated that goethite catalysed oxidation of Co(II)-EDTA to Co(III)-EDTA by dissolved O2. These reactions have important implications on the fate of the redox-sensitive metal in complex, mixed waste environments. 

Combustion in an incinerator is the only practical way to deal with many waste streams.This is particularly true of solid and concentrated wastes and toxic wastes such as those containing halogenated hydrocarbons, pesticides, herbicides, etc. Many of the toxic substances encountered resist biological degradation and persist in the natural environment for a long period of time. Unless they are in dilute aqueous solution, the most effective treatment is usually incineration. 

Sewer Disposal. Photoprocessing and printing wastes tend to be aqueous solutions that ate combined with other plant effluents and sent to the local sewer plant for treatment. The parameters of concern include silver, pH, and biological oxygen demand (BOD). BOD is a measure of how well a waste material degrades in the environment. Lower values ate preferred. Silver-bearing waste streams ate typically treated on-site, and the treated effluent is released to the drain. The printer usually receives a small cash credit for silver recovered. 

Delayed-action cytotoxin that inhibits protein synthesis (ribosomal inactivating protein) that is obtained from castor beans (Ricinus communis). Waste from production of castor oil contains about 5% ricin by weight. It is a white powder that is soluble in water and relatively heat stable. Aqueous solutions are resistant to chlorine at 10 ppm. It is persistent in the environment. 

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