Conceptual energy and water recovery system for self-sustained nano membrane toilet

Abstract

HighlightsEnergy and water recovery system from human excreta is modelled in Aspen Plus.The Nano Membrane Toilet is proven to be a self-sustained system.Up to 87% of total amount of water fed to the system can be recovered.Net power output of the entire system is similar to the USB port peak power (2–6 W).The specific net power output varies between 23.1 and 69.2 Wh/kgsettledsolids.

Planning and communicating prototype tests for the Nano Membrane Toilet: A critical review and proposed visual tool

“…This mechanical flush -a rotating bowl and rubber swipe activated by moving the toilet lid -separates the user from a tank underneath the toilet pan (Tierney, 2014;Tierney, 2017). Solids are separated through settling and displacement, transported by an screw conveyor (Mercer et al, 2016) and subsequently dried and combusted (Fidalgo et al, 2019;Onabanjo et al, 2016), while the liquid fraction is extracted through a weir and purified through membrane processes (Kamranvand et al, 2018;Wang et al, 2017), driven by the heat of the combustion, which is transferred via a heat exchanger (Hanak et al, 2016). The toilet pedestal, including the mechanical flush, the screw conveyor, and the liquid weir are considered the NMT's front end.…”

Probabilistic performance assessment of complex energy process systems – The case of a self-sustained sanitation system

“…The thermodynamic performance of the energy and water recovery system of the NMT unit is evaluated using a high fidelity deterministic process model, which is a revised version of the model described earlier by the authors [7] . All the processes both in the original and revised schemes were modelled in Aspen Plus simulation software (AspenTech Ltd., UK) using the thermodynamic equilibrium.…”

“…It integrates a membrane to recover clean water from urine and a compact energy conversion system to treat human faeces thermally. Recent studies confirmed that gasification and combustion are viable thermochemical technologies for the conversion of settled solids from human excreta into chemical or thermal energy [2] , [7] , [8] . Thus, the NMT has the potential to achieve self-sustained operation if energy recovery is optimised.…”

“…Similarly to the development of any novel integrated process, process modelling is essential at the design stage to optimise the NMT system. Previous modelling efforts have focused on using thermodynamic equilibrium models [7] , to simulate the thermochemical conversion of human faecal matter and to explore the thermodynamic viability of the NMT concept. Similar thermodynamic models have been applied widely to examine the conversion of various feedstocks including refinery sludge, sewage sludge and manure [9] , [10] , [11] .…”

Non-isothermal drying kinetics of human feces

“…An example of this approach is the Nano Membrane Toilet (NMT) which is being developed at Cranfield University as a response to the "Reinvent the Toilet Challenge" set by Bill & Melinda Gates Foundation. [5,6] The NMT includes a dryer to reduce the moisture content of HF and a micro-combustor to convert the residual solids into useful energy. The design of both stages is driven by the achievement of a complete conversion of HF into heat and flue gas as the end products and the efficiency of the process.…”