Treatment of poultry slaughterhouse wastewater in hybrid upflow anaerobic sludge blanket reactor packed with pleated poly vinyl chloride rings

► The maximum achieved OLR was 19 kg COD/m3 d. ► The maximum CH4 yield was 0.32 m3/kg CODremoved at an OLR of 9.27 kg COD/m3 d. ► Black matured granules varying between 2.5 and 5 mm size were observed. ► RTD study showed mixed flow behavior at the end of study. ► Methanosarcina, Coci and rods were predominant at the end of performance study.