Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Engineering Science

Program

Chemical and Biochemical Engineering

Supervisor

Berruti, Franco

2nd Supervisor

Rehmann, Lars

Co-Supervisor

3rd Supervisor

Moreira Valenzuela, Cesar M

Affiliation

Escuela Superior Politécnica del Litoral (ESPOL)

Co-Supervisor

Abstract

Profitable treatment of low value waste biomass is one of the biggest challenges of the industry. Where most of the current treatment strategies, such as pyrolysis, are efficient in complete breakdown of hard to synthesize, low value waste biomass such as lignocellulosic wastes, it leads to the generation of secondary waste thereby compromising its efficiency. The aim of this research is to utilize the aqueous pyrolysis condensate as a feedstock for anaerobic digestion, previously adapting the microbial consortia to the acidity and other potential organic inhibitors present in the APC, to produce energy in the form of biogas following the path of circular economy. Adaptation was an effective strategy in increasing the tolerance of the consortia to higher APC concentrations. The use of biochar reduced total phenolic content by 80% thereby allowing the consortia to utilise, more efficiently, higher concentrations of the substrate, and improved biogas ratios by 88.8%. Higher biochar:APC ratios created a more favourable environment for the bacterial growth and propagation.

Summary for Lay Audience

With the ever increasing population there comes an issue of continually increasing waste generation. The amount of waste generated is expected to increase by 70% in the coming years. Therefore, it is important to develop effective waste management strategies. Of the several methods available till date, most of the waste utilisation and management result in the generation of more waste, known as secondary waste. One such method is that of thermo-chemical conversion of waste. On the one had this method generates useful products which are environment friendly. However, it also leads to the generation of a complex aqueous waste which is high on acid content. Currently, there are no strict guidelines for the management of this aqueous stream.

Of the various methods available to deal with this aqueous waste stream, most are energy intensive and costly. Also, they, in turn produce more waste streams making it a cycle of never ending waste generation and energy consumption. This makes them an environmental liability.

The current work focuses on the utilisation of this aqueous waste stream to generate a renewable source of energy in the form of biogas. The methods used are energy conserving and environment friendly thereby mitigating the cost involved in the thermos-chemical process. Also, this method promotes the generation of renewable energy without the generation of any waste stream thereby conforming to the standards of circular economy.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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