JDS International Seminar Effects of Nano-Bubble Water on Biogas Production from Anaerobic Digestion of Lignin Student name: Ho Thi Hang Supervisor: Zhang Zhenya Lei Zhongfang Tsukuba, January 2018

Contents Background Objective Methodology Results Conclusions

Environmental pollution from burning lignocellulosic wastes Background Objective Methodology Results Conclusions Environmental pollution from burning lignocellulosic wastes Viet Nam is a country has abundant lignocellulose wastes (about 76 million tons of crop straws per year) Global warming http://keywordsuggest.org/gallery/1315975.html

Anaerobic digestion (AD) technology Background Objective Methodology Results Conclusions Anaerobic digestion (AD) technology https://www.intechopen.com/books/biomass-now-sustainable-growth-and-use/microbial-biomass-in-batch-and-continuous-system

Difficulty in AD of lignocellulosic wastes Background Objective Methodology Results Conclusions Difficulty in AD of lignocellulosic wastes Lignin is one of the major barriers to degradation of lignocellulosic materials (Mussatto et al., 2008)

Methods used for the enhancement of AD of lignocellulosic wastes Background Objective Methodology Results Conclusions Methods used for the enhancement of AD of lignocellulosic wastes Kinds of pretreatment before anaerobic digestion: Physical pretreatment Chemical pretreatment Biological pretreatment

Background Objective Methodology Results Conclusions Nano-bubbles Miniature gas bubbles in liquid with <200 nm in diameter Remain stable in water for a long time Generate highly reactive free radicals Schematic diagram showing macro, micro and nanobubbles (Takahashiet al., 2007b)

Nano-bubbles application Background Objective Methodology Results Conclusions Nano-bubbles application Nano-bubble water can enhance organics degradation (Ashutosh et al., 2011)

Objective of this study Background Objective Methodology Results Conclusions Objective of this study To investigate the effect of nanobubbles in AD of lignin

Background Objective Methodology Results Conclusions Anarobic digester Biogas Anarobic digester Digested sludge Nanobubble water Lignin Acetic acid

Experimental design DW CO2 N2 Background Objective Methodology Results Conclusions Experimental design DW CO2 N2 Inoculum + DW Medium Inoculum + CO2-NBW Medium Inoculum + N2-NBW Medium Inoculum:Digested Sludge; Medium: 90% acetic acid + 10% lignin (based on TOC) DW: deionized water NBW: nanobubble water TOC: total organic carbon

Composition of the medium Nutrients/mineral/buffer Concentration (mg/l) TOC (lignin, acetic acid) 2000 EDTA 789 KH2PO4 220 Na­2HPO4 860 H3BO4 40 ZnCl2 320 CuCl2 6.3 MnCl24H2O 45.5 CoCl26H2O 54.72 NiCl26H2O 11.409 NaCl 300 MgSO47H2O 121.24 CaCl2.H2O 110 NH4Cl L-Cysteine 103.55 Yeast-extract 500 NaHCO3 4000 FeSO47H2O 98.511 Composition of the medium

Cumulative biogas production (ml/g-TOCremoval) Background Objective Methodology Results Conclusions Cumulative biogas production (ml/g-TOCremoval) Nanobubble water addition=> Enhanced biogas production N2-NBW reactor exhibited the highest biogas production

Cumulative methane production Background Objective Methodology Results Conclusions Cumulative methane production NBW added reactors produced much higher amount of methane

Volatile Fatty Acids Concentration Background Objective Methodology Results Conclusions Volatile Fatty Acids Concentration Almost VFAs are converted into biogas Lignin might be degraded to produce VFAs

Total Organic Carbon Removal Background Objective Methodology Results Conclusions Total Organic Carbon Removal TOC removal: 40-50% in all reactors

Background Objective Methodology Results Conclusions Lignin degradation nanobubble water addition => enhanced lignin degradation N2-NBW reactor achieved a little bit higher lignin degradation

Addition of NBW has some positive effects on AD of lignin Background Objective Methodology Results Conclusions Addition of NBW has some positive effects on AD of lignin Enhanced methane production Higher lignin removal Addition of N2-NBW showed a little bit higher biogasification from lignin than CO2-NBW The mechanisms involved need further investigation