1.Relative merits of natural clays and geo-synthetics as component in
barriers in landfills.
2.in land fill engineering clay linings are often used as part of a
multi-layer containment system. such linings are often specified as
requring a coefficient of permeability lower than 10 to the power -9
m/s. what is the significance of this figure and how is this
parameter, which is linked to flexibility, likely to change with
moisture content at placement of the clay?
3.inter-relationship between planning law, pollution law and nature
conservation law in the UK.
4. advantage and disadvantage of rapid gravity filters and presure
filter ane what stage in a treatment sequence could rapid gravity
filters be used and why?
5.How and why biological filteration and activated sludge system also
incorporate solids seperation units.
6.with specific examples, how pollutants can enter and move through an
ecosystem and how their toxic effects may be amplified or ameliorated
in the process.

Hi quep,
You might want to reprice your question. Having an environmental
background, I suspect that $2 is a very low price for what is required
to be a very comprehensive answer. Most researchers would not be
prepared to spend a long period of time for such litle gain. I suggest
you look at http://answers.google.com/answers/faq.html#howmuch
and reprice accordingly, or at least declare that you are willing to
tip well for a good answer.