Toxicity reduction treatment

Evaluate toxicity as treatment progresses. Is the toxicity severe enough to warrant dose reduction or pharmacologic treatment Record graded toxicities according to the NCI CTC V3.0 criteria. 

The toxicity (before and after treatment) of solutions subjected to a chemical or electrochemical oxidation/reduction treatment should always be tested. 

Wastes that fail a toxicity characteristic test are considered hazardous under the RCRA. There is less incentive for a refinery to attempt to reduce the toxicity of such waste below the toxicity characteristic levels because even though such toxicity reductions may render the waste nonhazardous, it may still have to comply with new land disposal treatment standards under Subtitle C of the RCRA before disposal. Similarly, there is little positive incentive to reduce the toxicity of listed refinery hazardous wastes because, once listed, the waste is subject to Subtitle C regulations without regard to how much the toxicity levels are reduced. 

Butterworth, S.L. Granular activated carbon as a toxicity reduction technology for wastewater treatment. Proc. Am. Chem. Soc. Spring Natl. Meet. Fuel Chem. Div. 1996, 41 ), 466. 

Baud-Gasset, F., Safferman, S. I., Baud-Gasset, S. Lamar, R. T. (1994). Demonstration of soil bioremediation and toxicity reduction by fungal treatment. In Bioremediation of Chlorinated and Polycyclic Aromatic Hydrocarbon Compounds, ed. R. E. Hinchee et al., pp. 496-500. Boca Raton, FL CRC Press. 

Mercury may be present in air in different chemical states such as the elemental form (as a vapour or adsorbed on particular matter) or in the form of volatile mercury compounds (mercury chloride, methyl-mercuric chloride, and dimethyl mercury). Although elemental mercury is only one of the mercury forms which is not as toxic as its organic or ionic forms, analytical determination of elemental mercury is of special importance. Such analysis is used not only for determination of elemental mercury in environment, but also as a method for determination of other forms of mercury after reductive treatment. 

Toxicity reduction assessment of new treatment technology for specific industrial sectors... 

U.S. EPA 1999. Toxicity Reduction Evaluation Guidance for Municipal Wastewater Treatment Plants. EPA/833B-99/002. 

After completion of the WaterTox program, the test battery continued to be applied by laboratories from Argentina, Chile and Colombia to assess different types of environmental matrices. These initiatives facilitated the development or application of new or existing ranking systems that enabled evaluation of the effectiveness of biological treatment for the toxicity reduction of wastes and combined effluents. These studies are described herein. 

Figure 2. Effect of biological treatment on toxicity reduction of cosmetic industry effluents as indicated by PEEP index values.

Toxicity reduction requirements dictate in the development of new technologies for the treatment of these toxic pollutants in a safe and cost-effective manner. Foremost among these technologies are electrochemical processes. 

United States Environmental Protection Agency (USEPA) (1989a) Toxicity Reduction Evaluation Protocol for Municipal Wastewater Treatment Plants, Botts, J.A., Braswell, J.W., Zyman, J., Goodfellow, W.L. and Moore, S.B. (eds), USEPA 600/2-88/062. Reduction Engineering Laboratory, Cincinnati, OH. 

UKWIR (2000) UK Direct Toxicity Assessment (DTA) Demonstration Programme Review of Toxicity Reduction Evaluations at Sewage Treatment Works. Report 00/TX/02/05... 

Real-time toxicity testing will enable a toxicity reduction evaluation to be made speedily when unacceptable levels of toxicity are detected by monitoring of industrial waste streams, and thus result in rapid corrective action. Hence decisions can be made before such toxic insults cause interference with processes in a downstream wastewater treatment plant, or cause environmental damage. 

Asano, T., ed. 1998. Wastewater Reclamation and Reuse. Lancaster, PA Technomic Publications. Experts from around the world contributed to this useful and unique text that analyzes and reviews aspects of wastewater reclamation, recycling, and reuse in countries around the world. This is volume 10 of an 11-volume series, the Water Quality Management Library, which thoroughly addresses issues in wastewater treatment, sludge, nonpoint pollution, toxicity reduction, and groundwater remediation. 

Techniques for produced water treatment for toxicity reduction are still under development. Novel treatment technologies may yet be applied, but good water management of existing facilities will certainly contribute to the overall control of toxicity. Water treatment chemicals, which reduce the dispersed oil content in the effluent water, can also contribute to the toxicity of such effluent. Other chemicals used to control scale, bio-fouling, and corrosion can also contribute to effluent water toxicity, but are commonly required to reduce equipment maintenance costs. As a result, optimization of the chemicals application program can help control effluent toxicity as well as reduce the overall chemical usage costs. 

Toxic or malodorous pollutants can be removed from industrial gas streams by reaction with hydrogen peroxide (174,175). Many Hquid-phase methods have been patented for the removal of NO gases (138,142,174,176—178), sulfur dioxide, reduced sulfur compounds, amines (154,171,172), and phenols (169). Other effluent treatments include the reduction of biological oxygen demand (BOD) and COD, color, odor (142,179,180), and chlorine concentration. 

In removing excess free chlorine from municipal or industrial water and from wastewater, sodium sulfite competes with bisulfite or sulfur dioxide. Other commercial appHcations of sodium sulfite in wastewater treatment include the reduction of hexavalent chromium to the less toxic Cr " salts as well as the precipitation of silver and mercury. 

Vitamin D withdrawal is an obvious treatment for D toxicity (219). However, because of the 5—7 d half-life of plasma vitamin D and 20—30 d half-life of 25-hydroxy vitamin D, it may not be immediately successful. A prompt reduction in dietary calcium is also indicated to reduce hypercalcemia. Sodium phytate can aid in reducing intestinal calcium transport. Calcitonin glucagon and glucocorticoid therapy have also been reported to reduce semm calcium resulting from D intoxication (210). 

---