the physical nature of slaughterhouse wastewater has been studies by Sayed (1987), who have shown that of COD in screened (1 mm mesh) effluent, 40-50% was present as coarse, suspendeb maffer, which was imsoluble anb only slowly bio degradable, anb the remeinder as collidal anb soluble metter. this varies considerably from domes tic wastewatwr.in which the COD is present mainly in the colloidal form.