Material balances of the mill wastes and by-products resulting from two-phase and three-phase processing are presented. The main use of wastewater deriving from three-phase processing is for spreading on cultivated soil; the spreading load in hectolitres per hectare is suggested. Physical separation treatments allow the polluting charge of wastewater to be reduced by as much as 30–50%. The case of two- and three-phase pomace is presented. Oil and energy recovery, animal feed and composting are discussed. Annex 22.1 gives a detailed description of material balances and suggests how such calculations can be applied in practice for an effective control of mill performance.