Wastewater treatment trace contaminants

Weston RF, Chairman PE, Morrell RA. 1977. Treatment of water and waste water for removal of heavy metals. Viruses and trace contaminants in water and wastewater. Ann Arbor, Ml Ann Arbor Science Publishers, Inc., 167-181. 

The eflBciency of solids/liquid separation processes for reduction of trace contaminants (such as heavy metals) and toxic organic compounds associated with the particulate fraction could be estimated if the chemical composition of the particulates as a function of size were known. However, such data are scarce and of questionable accuracy. As a first approximation, the distribution of an adsorbed constituent between various size classes in the particulate fraction can be estimated from a knowledge of the power-law coeflBcient. This combined with performance models of solids/liquid separation processes should provide an improved basis for process selection to meet increasingly stringent standards for water and wastewater treatment. 

The presence of PFCs at a base level of contamination due to pollution from diffuse sources and global/continental distribution may occur nowadays. The background level in many European rivers has been known for some years. The source of PFCs in the environment can usually be traced to a discharging factory, accidental spUl or wastewater treatment plant. 

Weston, R. F. and Morrell, R. A. (1977), Treatment of Water and Wastewater for Removal of Heavy Metals, in Viruses and Trace Contaminants in Water and Waste Water (ed. J. A. Borchardt, J. K. Cleland, W. J. Redman, and G. Oliver), Ann Arbor Science, Ann Arbor, Michigan, pp. 167-82. 

The principal health hazards is instead associated with the chemical constituents of the initial wastewaters which can therefore produce contamination of crops or groundwaters. Cu, Cr, Zn and Se are essential trace elements however, they are PTEs, and above certain concentrations may interfere with or inhibit the actions of cellular enzymes. After the treatment, even if toxic materials are not present in the sludge in concentrations likely to affect humans, they might well be at phytotoxic levels, which would limit their agricultural use (Table 11.5). Furthermore, Hillman (1988) has drawn attention to the particular concern attached to the cumulative poisons, principally PTEs, and carcinogens, mainly organic chemicals. World Health... 

New York City, which drew some of its water supply from a point three and a half miles to the south, installed seven shallow test wells near Liberty Aircraft in 1945 and initially found no contamination. When the war ended, further investigations began, with dozens of new monitoring wells installed. In 1948, chromium was detected in three of the city test wells near Liberty, and a plume of contamination was traced for a mile from the plant. At Grumman, chromium had been found in public supply wells more than 100 feet deep. By 1949, all of Long Island s aircraft plants had installed treatment systems to remove chromium from their wastewater.31... 

Input pathways of the detected compounds were traced back by sampling various input sources of organic matter like discharge of wastewater and Lippe river tributaries. The major proportion of contaminants were ubiquitous in Lippe river water and also occurred in effluent from a municipial sewage treatment plant and in samples from the tributaries characterizing a dominant contribution of typical sewage derived pollutants. 

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