Pee power urinal – microbial fuel cell technology field trials in the context of sanitation
Summary (2 min read)
- Power performance was monitored with a multi-channel Agilent 34972A, LXI Data Acquisition Unit (Farnell, UK) and were then processed using the Microsoft Excel and GraphPad Prism software packages.
- Parameters such as pH and conductivity were measured with a Hanna 8424 pH meter (Hanna, UK) and 470 Jenway conductivity meter (Camlab, UK) respectively.
- COD was analysed using the potassium dichromate oxidation method (COD HR test vials, Camlab, UK) with an MD 200 photometer (Lovibond, UK) where 0.2 mL samples were taken before and during MFC treatment and filter-sterilised prior to analysis.
- Total Nitrogen (TN) was measured using MD 500 colorimeter (Lovibond, UK) and Vario Tube Test (0.5-25 mg/L) on diluted samples.
- The concentration of anions in the anolyte (inlet, outlet) and catholyte samples was determined by ion chromatography using a 930 Compact IC Flex (Metrohm, UK).
Results and Discussion
- Initial MFC module testing A single box assembled with 36 MFCs was initially tested under laboratory conditions.
- Inset graph is a magnification of the marked area, where the load was changed to 2.3Ω for approximately 24 hours.
- 1 activated sludge and urine mix, MFC modules were installed in the urinal and fed with neat fresh urine, also known as After inoculation with 1.
- The highest total nitrogen reduction was >50% for the anolyte and the lowest was <20%, which was the same for the synthesised catholyte (Fig. 5d ).
- The data presented in Figure 6a shows the stack power performance over the period of 8 days.
- The long decrease in capacitor voltage between the 27th-28th June is when the lights were intentionally left ON for 24 hours.
- Power output is significantly higher than the power levels recorded for the campus Pee Power Oxfam trial, which might be due to the increased number of modules (from 8 to 12), very high flow rate at the festival and elevated temperature due to the direct sunlight exposure.
- The very high flow rate and reduced HRT, did however affect the COD reduction capability of the system as a whole, recording a maximum of ca. 70%, a minimum of 15% and mean for the majority of the time of 25%.
- MFC electrochemical treatment is actively changing the chemistry of the treated substrate favouring pH and ion separation (see Supporting information), which leads to the recovery of slow-release fertiliser and electricity from urine (Zang et al., 2012) .
- The provision of safe water, adequate sanitation and hygiene, is critically important for promoting individual and community-level health in the Developing World.
- MFC based technologies prove to be a sustainable solution even in remote locations, improving sanitation and hygiene, and opening the way to elemental recycling.
- The Authors would like to thank Dr Andy Bastable from Oxfam for the useful discussions and financial support, as well as Dunster House Ltd for donating both the urinal structures and further supporting the trials -in particular Mr Carl Dolby.
- The Authors would like to thank Mrs Clare Backman for organising the field trials and Dr Benjamin Taylor for assisting in the Glastonbury trial.
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Cites methods from "Pee power urinal – microbial fuel c..."
...The use of ceramic membranes has allowed for MFCs to be used in field trials, with one example being by Ieropoulos et al (2016) ....
Cites background or methods from "Pee power urinal – microbial fuel c..."
...A special urinal was fabricated, and the collective urine was fed in a stack of MFCs connected in parallel, as shown in Figure 8 ....
...For a period of 5 weeks, an average power of 75 mW was achieved each day, and a maximum COD reduction of 98% was observed during the trial ....
...(a) Pee power field trial in Glastonbury Music Festival, June 2015; (b) urinal assembly and a microbial fuel cell stack arranged in 12 modules ....
...8 mW/m(2), and the total COD reduction was 78% after an operation of 190 h ....