Manfred Fehr, Brazil asked:
>Would it not be more to the point of landfill diversion if we
>concentrated on composting of household waste with correct
>opportunity cost accounting methods, and leave the
>vegetable markets alone?

Manfred has raised the issue of whether there is much point in trying to
compost market wastes, when the real burden in swm is the organics in
household wastes.

The commercial makers of compost, such as KCDC and Terra Firma are not
interested in solving the waste disposal problems of the city --they want to
get as pure organics as possible, and so they attempt to get market wastes.

Not all the market wastes are efficiently and informally spirited away to
farms and animal husbandry.  Indeed, the capacity of farmers to obtain these
green wastes seems to be declining.  One factor is that nowadays produce may
be delivered to the markets not by the individual farmer but by commercial
trucks and these truckers are not then returning to farms that want organic
matter.  It is a matter for determination in each city, at each market,
whether there are surplus green wastes that the city solid waste authority
has to collect and dispose of.  So it is difficult to make a general policy
that we should forget about the market wastes.  Still, this discussion does
suggest that each city should take a close look at what is happening to
market wastes, before assuming that there are signficant quantities available
for composting that would contribute to waste diversion.

That said, however, we are left with the problem that the large % of organics
in household/institutional wastes represent potential resources that at
present are a burden upon the sw management system.  This is why source
separation has been urged as the necessary condition for diverting these
organics to composting.

After some years of projects devoted to source separation, the outlook is not
optimistic (in India, at any rate).

That's why I think that the first step should be to capture the market wastes
(if there are surplus wastes).  If these can be composted and marketed
successfully, there may be the basis for more public interest to divert
household organics.

Another option (which has many questionmarks re safety) is to facilitate
farmers optaining decomposed organics from dump sites.  (This is in any case
done in many places in Asia).  The removal of the decomposed matter does not
reduce collection and transportation costs but it saves dump space and so
there are is significant reduction in land costs and perhaps dump management
costs.

Chris