Even though there is rapid growth in the number of facilities being
sited, there remains very little published data indicating the
potential environmental impacts from yard waste composting
facilities. One purpose of this study is to add to the existing data
base of information regarding compounds present in yard waste compost
leachate and to evaluate whether these compounds are causing ground
water quality impacts beneath and adjacent to these facilities. This
aspect of the study is much needed as most composting studies to date
have focused on analysis of leachate and surface waters to evaluate
the potential for ground water impacts without ever actually sampling
ground water quality near the site.

The other purpose of this study is to evaluate the appropriateness of
yard waste composting facility regulations in the state of Wisconsin.
A recent study (Varsa, 1994) found that regulations pertaining to
yard waste composting sites vary considerably from state to state.
There does not appear to be any sort of national consensus regarding
the most appropriate requirements for siting or operating compost

                           Site Descriptions

To protect the identity of the study sites, each facility will be
labeled, respectively, "Site A", "Site B", "Site C", and "Site D".
Ground water monitoring wells were installed at Sites A and B, while
sites C and D were used solely for the collection of supplemental
leachate quality data.

Site A

Site A is a large, county operated yard waste composting facility
that has approximately 15,000 yds3 of material on site at any given
time. The site is located in southern Wisconsin (Figure 1) and
serves as a composting site for several nearby municipalities. The
site is unlined with no surface water run-off collection. The site
slopes gradually to the north and drains into a large wetland
complex. The subsurface geology consists of a thick silty sand
glacial outwash deposit overlain by a silty clay loess deposit that
averages about 6 feet thick. All of the wells at the site were
completed in the sand outwash deposit.    The water table ranged from 3
feet below the surface near the wetlands to 15 feet below the surface
in the upgradient well near the road.

The yard waste is arranged into a series of large (10 to 15 feet
high) piles.   Waste accepted at the site is neither screened nor
shredded prior to placement in a pile and it appears that the
majority of the waste is composed of grass clippings.    Once a pile is
established, it is rarely disturbed and is usually left for a period
of one to two years before being distributed to the public.
Decomposition is primarily by anaerobic decomposition and large pools
of black liquid can typically be found at the base of the piles.