PIGGERY WASTE TREATMENT BY ANAEROBIC-DIGESTION AND NUTRIENT REMOVAL BY IONIC EXCHANGE

Piggery wastes must be treated before their disposal. The high solids content and high chemical oxygen demand of piggery wastes indicated th at anaerobic biological treatment could be successfully applied as pri mary treatment, For that reason, a comparison between upflow anaerobic sludge bed reactor (UASB) and anaerobic fixed bed reactor (AFBR) at a similar organic volumetric loading rate of 5 kg DQO/m(3) day was carr ied out. 60% of the piggery waste COD was removed with the AFBR compar ed to 40% with the UASB, thus showing a better performance of the AFBR . After l-h sedimentation secondary process, both anaerobic effluents were treated by ionic exchange with natural zeolite due to their high values of ammoniacal nitrogen (NH4+ plus free NH3). The high removal o f nutrients reported (90%) shows zeolite to be a good choice as tertia ry treatment.