Nafisa Fari
School of Mechanical, Aerospace and Civil Engineering
Grantham Scholar
- Profile
-
Optimisation of a Micro-aerated Two-Stage Anaerobic Digestion System for Off-Grid Energy Access in Nigeria
The project:
My research focuses on optimising a micro-aerated two-stage anaerobic digestion (AD) system to support decentralised, off-grid energy generation in Nigeria, particularly in rural and peri-urban communities where electricity access remains limited. Nigeria generates large quantities of agricultural residues and agro-industrial wastes that are currently underutilised, while energy access challenges continue to constrain socio-economic development. Anaerobic digestion offers a promising pathway to convert these locally available resources into dispatchable renewable energy in the form of biogas, alongside nutrient-rich digestate for agricultural use.
The work investigates how controlled micro-aeration in the hydrolytic/acidogenic stage can enhance the breakdown of lignocellulosic biomass, increase soluble organic matter release, and promote volatile fatty acid production without compromising methane yield. Batch biochemical methane potential (BMP) tests are used to define COD-normalised, pulse-timed oxygen dosing strategies, which are then translated into continuous operation in a two-stage system comprising a micro-aerated continuously stirred tank reactor (CSTR) coupled to a methanogenic anaerobic fluidised bed reactor (AFBR). Particular emphasis is placed on preventing oxygen carryover into the methanogenic stage through operational timing and degassing strategies.
In addition to process optimization, the research integrates microbial community analysis to link microbial dynamics with reactor performance and identify practical biomarkers for stable operation. The study is further supported by a Nigeria-specific life-cycle assessment (LCA), techno-economic analysis (TEA), and regulatory review, providing insight into environmental impacts, economic feasibility, and deployment pathways. Overall, the research aims to deliver practical operating guidelines and decision-grade evidence to support the scalable deployment of micro-aerated two-stage AD systems for sustainable off-grid energy generation in Nigeria.
Social media: