Evolution The violent spirit to forge a civilization vol 1

environment. If you can get rid of some of the nuisance metals that currently

limit the amount of these biosolids we can use in fields and forests, and at

the same time recover valuable metals and other elements, that's a win-win,"

says Ph.D. Kathleen Smith (^) [ 71 ]. In treatment plants, wastewater goes

through a series of physical, biological and chemical processes. The end

products are treated water and biosolids. Smith, who works at the US

Geological Survey (USGS), says that more than 7 million tonnes of biosolids

leave US wastewater facilities each year. About half of that is used as

fertilizer in fields and forests, while the other half is incinerated or sent to

landfills.

Smith and his team are on a mission to find out exactly what's in our

waste. ─We have a two-pronged approach─, she says. ─In one part of the

study, we're looking to remove some regulated metals from biosolids that

limit their use for land applications. In the other part of the project, we are

interested in collecting valuable metals that could be sold, including some of

the most technologically important metals, such as vanadium and copper

found in mobile phones, computers and alloys─. To do this, they are

experimenting with some of the same chemicals, called leachates (^) [ 72 ], that

this industry uses to extract metals from rock. While some of these leachates

have a bad reputation for damaging ecosystems when they leach or spill into

the environment, Smith says that in a controlled environment, they could be

used safely to recover metals in treated solid waste. In the treated waste,

Smith's group has already begun to discover metals such as platinum, silver

and gold. She says they have observed microscopic-sized metal particles in

biosolids using a scanning electron microscope. ─The gold we found was at

the level of a minimum mineral deposit─ she says, meaning that if that

amount were in rock, it could be commercially viable to mine it. Smith adds

that ─the economic and technical feasibility of recovering metals from

biosolids must be assessed on a case-by-case basis.

«But how is it that the alchemical machine of the human body can

process gold?» Let us look at the following examples based on

chrysotherapy: Chrysotherapy is the use of gold or its salts in palliative or

curative treatments in living beings. The term comes from the Greek khrysós