Treatment for Mecury Waste

So, bacterial machinations with atomic number 80, leading to its bind off or remotion, are clearly feasible. (Summers' descriptions beyond that (9) are gently interesting but on a enzymatic, molecular train and difficult for a neophyte microbiologist to decipher.)

Experiences in Sewage Treatment. The multinational Council for Local Environmental Initiatives (ICLEI) has reported a waste-reduction program in Stockholm, Sweden, fundamentally intended to reduce "discharges of hazardous substances into the sewer system," beca role ultimately the city wished to assure that treated effluent effluent would be "harmless to the receiving waters of the Stockholm archipelago and the Baltic Sea" (6:2). The tendency for attacking metal discharges at the source--prior to their entry to the sewer--was stated like blue murder: ". . . modern sewer treatment facilities are not fitting of eliminating these metals [lead, cadmium, and hectogram] from wastewaters" (6:2).

This program worked, but with an odd twist. In 18 months of 1990 and 1991, the mercury content of digested sludge at the waste treatment nominate was reduced by 50% (in mg/kg dry out weight); cadmium was reduced between 62 and 89%, and atomic number 24 was reduced by 84% (6:3). The twist was, the biota (bacteria) in the plant were taking up these metals very nicely; they w

Other Biological Uptake Mechanisms. Veiga, Meech, and O?ate report that mercury has "an affinity" for organic hummus in soil--to the level of 0.2 to 1.9 mg/kg, and hence mercury is then available to plants that grow in such humus (13:1). innate mercury levels in plants range from 0.001 to 0.1 mg/kg (that is, 0.1 mg Hg per kg of plant's dry weight) (13:2). These authors became interested in this function because Amazonian Indians were displaying alarmingly high blood and urine levels of mercury, the source for which was eyeshot to be 60 or so tonnes of mercury released each year in nearby (sloppy) gold mining and gold-amalgamation processes that use mercury (13:2).

They showed, however, that 88 tonnes (88,000 kg) of mercury were released to the air in a single year (1988) by the planned burning of qualitys--trees in which mercury had been naturally metabolized (13:2). Ninety percent of the mercury in the trees is in its organic form, and release upon burning can be 50% in the dissolvable (dangerous) Hg(II) form (13:2). Wild forest fires can release 20,000 kg/yr of Hg to the atmosphere, though that is still less than 1% of "natural emissions" (13:2). One concludes, though, that phytoremediation force be feasible as a biological mercury treatment; but the ultimate fate of the trees, like that of sewage sludge, becomes of paramount importance.

In yet another study of mercury in sewage treatment plants, Goldstone et al. studied an English wastewater plant (in Norwich)(5). This study was far more concerned with the mechanisms of removal than the previously described plant reviews. The English plant was too smaller than the others, roughly 4.5 MGD. The study and its results, for all their intended academician rigor, were complicated by "sampling campaigns" in May 1986 and October 1987; predictably a number of factors changed in the interim (5:273). In 1986, soluble and insoluble mercury removals were high; adsorption, rather than microbial metabolic uptake, appear
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