Investigating the Synergistic Effect of Temperature and pH Dynamics on Biogas Yield from Lignocellulosic Biomass Codigested with Cow dung

Abstract

The study investigated biogas production from control, pre-treated and blended waste samples, while also examining the interaction effects of ambient temperature (AT), slurry temperature (ST), and pH on the biogas volume generated from the waste samples. Experimental research design was adopted for the study. Nine biodigesters of 32L capacity labelled A-I, control (A-C), pre-treated (D-F) and blended (G-I) waste samples were used for the experiment. The digestion was carried out for a period of 35 days using the water displacement method in a laboratory scale bio-digester system. Data analysis was carried out using Excel, SPSS and STATA softwares. The methods used included descriptive statistics, multiple regression and Analysis of Variance (ANOVA). The pH and temperature readings for 35 days ranged from (6.5-8.4), AT (20-290C), ST (23-380C). Based on the study's results, there was a significant difference in the volume of biogas generated among the waste samples (F=6.4, SS=659.379, p=0.002, df=314). Specifically, significant differences were observed between the control and pre-treated samples (p=0.01) and between the control and blended samples (p=0.036). The effects of AT and ST (P=0.03) on the volume of biogas were not significant when analyzed individually; however, an interaction effect between AT and ST on biogas yield was observed. Also, pH, influenced the gas production significantly (F=3.954, p=0.021) likely due to its influence on microbial and enzymatic activity. The interaction effect showed that both temperature and pH had a combined effect on volume of biogas produced (p=0.003). These results underscore the importance of temperature and pH control in optimizing biogas production. Improved understanding of these factors could enhance anaerobic digestion processes, thus reducing greenhouse gas emissions, promoting resource efficiency and supporting circular economy principles.