September 9, 1975

Dr. Martin Kaplan

World Health Organization
1211 Geneva 27
Switzerland

Dear Martin,

I did just receive in the mail the publication of the 5th report
on the world health situation and the xeroxed material on research
management and so on. I will be studying this carefully and you magflbe
hearing more from me about that.

I did just want to drop you a note about my own reading of the
literature on composting and fecal waste disposal. It is ironic that
while many developing countries seem to be stalled on problems of
investment in hydrolic disposal, that advanced countries are more and
more looking to composting of sewage sludges as an ultimate method of
disposal!

It does look as if Gotas' 1956 monograph (WHO #31) leaves little to
be improved upon at the present time, but there has been a real burst of
activity in this country in studies supported by EPA and so on on the
dissemination of this idea for minicipal sewage sludge applications.

At the same time I do not see much reference to these traditional
methods in the reports that I had seen so far from WHO on community
water supplies and so forth. Am I just missing the appropriate material
or is somebody else on the wrong boat?

As far as I can tell, the only authenticated mechanism for dis-
infection is the rise in temperature in the compost heap and this does give
me some cause for concern if it is not routinely monitored, especially
with respecta to parts of the dephsit that may be added most recently
and may not reach thé high temperatures of the center. The question of
calculated inoculation of the composts was looked at in a rather superficial
way by Gotas some years ago, and he came to the conclusion that the
requisite microorganisms were always present. He had really no way to
look into webher there were any shortcomings with respect to the optimization
of the process, but he may well be right.

However, these studies have to do with more or less optimally designed
compost heaps that include the necessary amount of straw or similar refuse
to furnish the oxidizable carbohydrate for BRhermogenic bacterial oxidation.
These systems will break down if the compost heaps are not carefully tended
and turned over or if they do not have the approporiate admixture of cellulose
or similar fiber and other organic waste. So, I suspect there is still some
Dr. Martin Kaplan -2- 9/9/75

room for inquiry about recommended procedures in different habitats.

I am also far from convinced that thermogenesis is the whole story
in disinfection since the most prevalent organisms found in the compost
are exactly the ones that we use for antibiotic production. In this resepect,
and in respect to the most rapid oxidation of insoluble carbohydrate there
may well be some room for more calculated manipulation of the flora.

One point that surprised me a little,that Gotas made quite strongly,
is that urine contributes just about as much nitrogen as feces on a daily
basis. There evidently are some sites where separate collection of urine
and feces is then used to get the most efficient recovery of fixed nitrogen
for fertilizer purposes. But again, this is something that there is not
much comment on in any recent literature that I have seen.

At any rate, the somewhat ironic conclusion is that vastly more work
seems to be being done now on the best procedures for the composting of
human wastes in the advanced country context and that not enough use may be
being made of this approach in organizing the sanitation of underdeveloped
countries. So, I would be glad to be brought up to date on WHO's current
activities in this general field and if not enough has been going on, there
would be an obvicus basis to recommend reconvening the appropriate expert
committees. It does seem to me that there could be very large savings in
investment to move away from pipelining waste from one place to another
where they still have to be dealt with and to focus inatead on proper local
disposal.

I have not yet finished my thinking about the other side of the problem
which is to say biological self=purification of water supplies, but I do not
have any particularly good leads on that just yet.

Sincerely yours,

Joshua Lederberg
Professor of Genetics

JL/rr