Influence of dilute acid, alkali and hydrothermalpretreatments on methane improvement from datepalm waste “Takarboucht” cultivar

This research assesses the impacts of hydrothermal (120 °C for 30 min), dilute acid (2%(w/w) H₂SO4 at 120 °C for 30 min) and alkali (6% (w/w) NaOH at 35 °C for 24 h)pretreatments on the methane yield from date palm waste “Takarboucht” cultivar. The pretreated and untreated date palm waste (DPW) were digested at mesophilic temperature (36 °C) for 20 days. The highest soluble chemical oxygen demand (sCOD) was obtained by DPW hydrolysate from alkali pretreatment. The highest methane yield of 161.86 ml/g VS was obtained from untreated DPW. Among all pretreatments, higher methane yield was obtained from hydrothermally pretreated DPW (153.35 ml/g VS), followed by acid pretreated DPW (141.65 ml/g VS) and alkali pretreated DPW (50.78 ml/g VS). Alkali pretreatment improved the solubilization of DPW, however, it may not necessarily provide an enhancement in the methane yield. The optimization of the conditions of each pretreatment is proposed.