Decolorization of Black Liquor Wastewater Generated from Bioethanol Process by Using Oil Palm Empty Fruit Bunches

Abstract

Abstract Bioethanol from oil palm empty fruit bunches as a second-generation bioethanol (bioethanol G2) has been developed. It produces high amounts of black liquor wastewater which also contains alkaline solution (NaOH). Black liquor wastewater is harmful to aquatic ecosystems if discharge directly into waters. This study aimed to determine decolorization of black liquor wastewater by using chemical and biological methods. Coagulation-flocculation method by using Poly Aluminium Chloride (PAC) and alumwith different ratio was also investigated. This study also identified the ability of white-rot fungi to decolorize black liquor wastewater on agar and liquid medium.The results showed that black liquor wastewater with initial concentration 30,000 ppm can be decolorized by using two methods, coagulation-flocculation and decolorization by white-rot fungi.The optimum condition to obtain 96% decolorization was using concentration coagulant 1% combination alum-PAC 3:1 with total retention time 33 minutes.Out of the three fungi studied, Trametes versicolor U97 showed the most degraded fungus onagar medium containing black liquor. In liquid medium, the percentage of decolorization ranged from 70% to 89% at 30 days depending on the fungal strain.