The quest for reliable and adequate power supply in Nigeria has brought about a surge of interest in renewable energy generation, particularly from wind, solar, hydro and biomass resources including municipal solid waste. Waste-derived energy raises unique interest because of the magnitude of benefits to environmental protection and socio-economic advancement. The successful operation of Waste-to Energy (WtE) facilities in Nigeria requires continuous supply of solid waste and enabling environment amongst other factors. This study conducted a state-level assessment of the WtE potential of municipal solid waste (MSW) in Nigeria. Our findings show that the electricity generation potential for the different states in Nigeria varied from 31 to 205 MW, depending on state’s waste generation capacity. The country’s annual electricity generation potential from MSW was estimated to be 26,744 GWh/year, with 89% of the states having sufficient generation capacity at minimum regulatory electricity generation requirement of 50 MW. But, based on current realities such as poor collection efficiencies, Nigeria’s exploitable WtE capacity from MSW was below 3800 GWh/year, with all the states having less than 50 MW capacity. On-site power generation such as dedicated power station for industrial estates and corporate users can be a feasible form of distributing energy generated from WtE facilities. The outcomes of this study are important in informing the siting of WtE facilities in Nigeria and for enabling policy framework

In many developing countries, including South Africa, water scarcity has resulted in poor sanitation practices. The majority of the sanitation infrastructures in those regions fail to meet basic hygienic standards. This along with the lack of proper sewage/wastewater infrastructure creates significant environmental and public health concerns. A self-sustained, waterless "Nano Membrane Toilet" (NMT) design was proposed as a result of the "Reinvent the Toilet Challenge" funded by the Bill and Melinda Gates Foundation. A "cradle-to-grave" life cycle assessment (LCA) approach was adopted to study the use of NMT in comparison with conventional pour flush toilet (PFT) and urine-diverting dry toilet (UDDT). All three scenarios were applied in the context of South Africa. In addition, a Quantitative Microbial Risk Assessment (QMRA) was used to reflect the impact of the pathogen risk on human health. LCA study showed that UDDT had the best environmental performance, followed by NMT and PFT systems for all impact categories investigated including human health, resource and ecosystem. This was mainly due to the environmental credits associated with the use of urine and compost as fertilizers. However, with the incorporation of the pathogen impact into the human health impact category, the NMT had a significant better performance than the PFT and UDDT systems, which exhibited an impact category value 4E + 04 and 4E + 03 times higher, respectively. Sensitivity analysis identified that the use of ash as fertilizer, electricity generation and the reduction of NOx emissions were the key areas that influenced significantly the environmental performance of the NMT system.

• The performance of Stirling engine integrated to a micro-combustor in the NMT system was investigated. • Energy recovery and power generation of 27 Wh/h from combustion of human faeces. • The integrated position of the Stirling engine to the micro-combustor is highly paramount. • Sensitivity of the performance of the Stirling engine to working gas temperature. • Requirements for optimum performance of the Stirling engine for integration with micro-combustor.

Drying is one of the treatment techniques used for the dual purpose of safe disposal and energy recovery of faecal sludge (FS). Limited data are available regarding the FS drying process. In this paper the drying properties of FS were investigated using samples from ventilated improved pit (VIP) latrines and urine diversion dry toilets (UDDT) and an anaerobic baffle reactor (ABR) from a decentralized wastewater treatment systems. Moisture content, total solids content, volatile solids content, water activity, coupled thermogravimetry & differential thermal analysis (TGA-DTA) and calorific value tests were used to characterize FS drying. Drying kinetics and water activity measured at different moisture content during drying (100 °C) were similar for the samples from different on-site sanitation facilities. Experimental heat of drying results revealed that FS requires two to three times that of the latent heat of vaporization of water for drying. Drying temperature was more significant than the sludge source in determining the final volatile solids content of the dried samples. This was reinforced by the dynamic TGA that showed considerable thermal degradation (2-11% dry solid mass) near 200 °C. Below 200 C, the calorific value of the dried samples exhibited no significant difference. The average calorific values of VIP, UDDT and ABR samples at 100 °C were 14.78, 15.70, 17.26 MJ/kg dry solid, respectively. This suggests that the fuel value of FS from the aforementioned sanitation facilities will not be significantly affected by drying temperature below 200 °C. Based on this study, the most suitable temperature for drying of FS for a solid fuel application was found to be 150 °C.

Insufficient available energy has limited the economic growth of Nigeria. The country suffers from frequent power outages, and inconvenient black–outs while residents and industries are forced to depend on self-generated electricity. Life-cycle assessment methodology was used to assess the environmental burdens associated with self-generated electricity (SGE) and proposed embedded power generation in Nigeria. The study shows that SGE from 5 kVA diesel generators contributes to greenhouse gas (GHG) emissions of 1625 kg CO2 eq./MWh, along with other environmental burdens. Based on a point estimate of diesel electric generators in Nigeria, SGE can contribute 389 million tonnes CO2 eq. to climate change every year. This can reposition Nigeria as one of the top 20 emitters of CO2 globally. A mandatory diesel fuel displacement with Jatropha biodiesel can reduce annual GHG emissions from SGE by 76% provided combined cycle power plants are adopted for embedded power generation. The magnitude of these benefits would depend on material inputs, seed yield as well as the environmental status of the reference fuel. Minimal use of fertilizers, chemicals and resources and fossil fuel substitution with renewable options can minimize adverse environmental burdens

• Co-combustion analysis was investigated using a bench-scale combustor test rig. • Raw human faeces (FC) contained 73.9 ± 4.4 wt% moisture as received basis. • Blending with wood dust (WD) in a 50:50 ratio reduced moisture levels by ∼40%. • Minimum acceptable blend for combustion without prior drying is 30:70 WD:FC. • Fuel burn rates are 3.18–4.49 g/min for all the blends at air flow of 12–18 L/min. • Oxygen, potassium and calcium are the most abundant elements in faecal ash.