Moisture transfer refers to the fact that certain solid waste has an affinity for
moisture. So typically paper as it enters the waste stream is relatively dry. However
as it mingles with other solid waste and is exposed to rain and snow and other
sources of moisture it will absorb that water.
This is important because the downstream uses of the paper (or other absorbent
material) – i.e. recycling or using it for energy are adversely impacted by the
presence of this additional moisture. It – for example – effectively reduces the heat
value of the material since to derive the energy from it – the water has to be first
driven off – which of course – uses energy.