Exploring technological strategies for valorization of solid sisal waste: A research review
Keywords:
sisal waste, anaerobic digestion, mushrooms, valorisationAbstract
The sisal industry in Tanzania generates large amounts of waste which is an un-tapped bioresource. Research was undertaken to establish appropriate technologies for its valorisation to mushrooms, biogas and biogas manure (BGM).Physical and biological pre-treatments achieved methane yield increments of 23-30% whereas co-digestion with fish waste achieved methane yield increments of 59-94%. Sisal fibre waste was demonstrated to be a novel biofilm-carrier for treating sisal pulp leachate. With a loading rate of 9.0 kgVS/m3/day, the packed-bed bioreactor was operated without process stress. Sisal decortication waste (SLDW) and sisal boles (SBW) were found to be suitable for oyster mushroom cultivation. With water-pretreated SBW and saline-SLDW, biological efficiencies of 26-86% were obtained. SBW was utilized for commercial-scale mushroom cultivation and yielded 250kg/ton of wet substrate. Residues of mushroom cultivation (SMS) were anaerobically co-digested with cow dung manure and yielded 230-300L CH4/kg VSadded which indicated the potential of SMS for AD.Co-digestion of SLDW with cow dung manure in a 10m3 continuous stirred tank reactor gave about 400 litres CH4/ m3/day, and 260 L/day of BGM which was superior to NPK fertilizer. In conclusion, sisal waste has potential for valorisation, and integrating mushroom and biogas production for better economics is feasible.
The sisal industry in Tanzania generates large amounts of waste which is an un-tapped bioresource. Research was undertaken to establish appropriate technologies for its valorisation to mushrooms, biogas and biogas manure (BGM).Physical and biological pre-treatments achieved methane yield increments of 23-30% whereas co-digestion with fish waste achieved methane yield increments of 59-94%. Sisal fibre waste was demonstrated to be a novel biofilm-carrier for treating sisal pulp leachate. With a loading rate of 9.0 kgVS/m3/day, the packed-bed bioreactor was operated without process stress. Sisal decortication waste (SLDW) and sisal boles (SBW) were found to be suitable for oyster mushroom cultivation. With water-pretreated SBW and saline-SLDW, biological efficiencies of 26-86% were obtained. SBW was utilized for commercial-scale mushroom cultivation and yielded 250kg/ton of wet substrate. Residues of mushroom cultivation (SMS) were anaerobically co-digested with cow dung manure and yielded 230-300L CH4/kg VSadded which indicated the potential of SMS for AD.Co-digestion of SLDW with cow dung manure in a 10m3 continuous stirred tank reactor gave about 400 litres CH4/ m3/day, and 260 L/day of BGM which was superior to NPK fertilizer. In conclusion, sisal waste has potential for valorisation, and integrating mushroom and biogas production for better economics is feasible.
Key words: sisal waste, anaerobic digestion, mushrooms, valorisation
