Re: Heavy metals in activated sludge

[hans schnitzer <schnitzer@glvt.tu-graz.ac.at>]

I have heard that natural Zeoliths - a rather cheap material - could
bind heavy metals in such a way that they are not any more available to
plants and ground water. I don't know who has experience and which types
of zeoliths work.
Does anyone have experience in that fielod?

Hans Schnitzer

Joe Pringle wrote:

> Question from Exnora International in India:
>
> We have taken up composting of vegetable wastes from the Koyambe-
> du  market  in  Madras, Asias's largest  vegetable  market.   The
> Chennai  Metro  Water  Supply and Sewerage Board  has  agreed  to
> compost  the waste by using the activated sludge from the  sewage
> treatment  plant in Koyambedu. But one important issue  would  be
> `How  do  you remove heavy metals in the sludge?'  We  have  been
> writing to several people enquiring about this. Any ideas?
>
> please CC any responses to Exnora International at:
> exnora@giasmd01.vsnl.net.in
> or   exnorain@md2.vsnl.net.in