(best examples and good practices) on household organic waste ...

11
Windrow Composting
Windrow composting is the most common technology used. Windrows system
according to most authors, seems to be very economical <strong>and</strong> easy to use
technology. In the windrow process, the waste is placed in very long piles. The
windrow process needs to be carried out very carefully giving the procedure
details great attention so that the process is completed successfully. The
windrows are usually 1–2,5 m high <strong>and</strong> 2–6 m wide (this is something that
depends on the procedure used). The problems encountered to this procedure,
mainly have to do with the form <strong>and</strong> shape of the windrow, something which
affects several conditions of the process. For example, if the piles are too large,
oxygen cannot reach the center. On the other h<strong>and</strong>, if the piles are too small
they will not reach optimum temperatures. There is no ideal windrow size since
this is something that has to do with weather conditions. The windrow process
could be accelerated if the compost is turned periodically (usually over every
four or five days). Mixing the pile periodically, help’s the material to move from
the inside out, thus allowing air diffusion throughout the pile speeding up the
whole process.
Turning frequency is something that should be based mainly on temperature
conditions, since temperature is among the most crucial factors in regard to the
decomposition process. Temperatures below 38 o C or above 60-64 o C, are
indicators that turning should be made in order to exceed proper
circumstances for Composting process to take place. If the compost is
somewhere between the limits (as they have been determined by a great
number of experiments), turning could still be used in order to accelerate the
decomposition procedure. The complete compost process may require two to
six months depending on the method <strong>and</strong> the materials used for the process.
Picture 1.: Overview of windrow composting operation
(Dubois, González, 2004)