Enhanced biogas production from anaerobic co-digestion of palm oil mill effluent using solar-assisted bioreactor

• Main Author: Zaied, Khalid
• Format: Thesis
• Language: English
• Published: 2020
• Subjects: T Technology (General); TA Engineering (General). Civil engineering (General)
• Online Access: http://umpir.ump.edu.my/id/eprint/35239/1/Enhanced%20biogas%20production%20from%20anaerobic%20co-digestion%20of%20palm%20oil%20mill.ir.pdf; http://umpir.ump.edu.my/id/eprint/35239/
• Institution: Universiti Malaysia Pahang

Anaerobic co-digestion (ACoD), a sustainable green technology, presents an outstanding opportunity for energy conversion and environmental pollution control. It has become a core method of treating organic wastes on account of its environmental and economic benefits of energy production. Prolonged start-up period, slow reactions, and methanogenesis are highly inhibited in the ACoD process which prevents enhancement in energy production. Instead, oxidization by hydrogen peroxide (OHP) had substantial impacts on biological break down and enhancing biogas production by ACoD methods. Again, lack of nitrogenous substrate and buffering potential has been known as an obstruction for the treatment of POME in the ACoD process. The key objective of this study was to investigate the potential of the ACoD for palm oil mill effluent (POME) treatment with cattle manure (CM) in a solar-assisted bioreactor (SABr) to produce enhanced biogas. Finally, this study developed the artificial neural network (ANN) model which is an appropriate and uncomplicated modeling approach for ACoD applications to predict the outcomes of biogas production using experimental data. Standard American Public Health Association (APHA) methods analyzed the characterization of the samples. The solar panel first converted solar radiation into electricity, which warmed up the POME and CM mixture to maintain the required reactor temperature (35°C). The produced energy was analyzed at 0:100, 25:75, 50:50, 75:25, and 100:0 mixing ratios of POME and CM. The total biogas amount was collected in a gas bag and biogas volume was measured by the water displacement method. The mixture with equal proportions of POME and CM produced the maximum amount of biogas, i.e., 1567.00 mL, while the methane content was 64.13%. The effect of OHP at 1.00% dose with 1 mM FeCl3 addition for Fenton reaction on the POME at 30 min exposure on chemical oxygen demand (COD) and total organic carbon (TOC) removal was 33.80% and 28.31%. The improvement of biodegradable dissolved organic carbon (BDOC) was 59% more for POME at 1.00% OHP doses and thus, BOD/COD was also enhanced up to 0.72 for POME. Biogas and biomethane production can be enhanced up to 46.00% and 64.83% if treated by 1.00% OHP doses. The methane composition is also enhanced up to 72.4% compared to control which was 64.13%. Biogas yield was indicated as the consequence of NH4+ toxicity. To regulate the toxicity impact of the ammonium bicarbonate on the ACoD system, a cycle of dosing from 10 to 40 mg/L was supplemented. The cumulative biogas production of 2034.00 mL was found with the addition of 10 mg/L ammonium bicarbonate and 29.80% more which are higher than that of the control ACoD operation. In ANN, the proposed multi-layered feed-forward neural network model could predict the outcomes of biogas production from the ACoD process with a mean squared error for validation of 0.0562 and an R-value for validation of 0.97733. The approach was found to be effective, flexible and versatile in coping with the non-linear relationships using available information. The economic impact of constructing a biogas plant has been successfully analyzed and predicted as well. The proposed biogas plant seems to be economically feasible because an approximately 3-year payback period, internal rate of return of 23.62% and benefitcost ratio of 1.34 on investment could be achieved if this technology is used on a large scale. So, overall this study may help in minimizing the adverse environmental effects of POME by ACoD treatment in the future and demonstrated that a complete solution to the application of SABr in the integration of different features for enhanced biogas production.