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Optimising the Hydraulic Retention Time in a Pilot-Scale Microbial Electrolysis Cell to Achieve High Volumetric
Daniel D Leicester1, Jaime M Amezaga1, Andrew Moore2
1School of Engineering, Newcastle University, Newcastle-upon-Tyne NE1 7RU, UK.
Molecules (Basel, Switzerland)
|July 2, 2020
Summary
Pilot-scale microbial electrolysis cells (MECs) show promise for energy-neutral wastewater treatment. Optimizing hydraulic retention time with high-organic wastewater achieved the highest volumetric treatment rates for MECs, suggesting industrial viability.
Area of Science:
- Environmental Engineering
- Electrochemistry
- Microbiology
Background:
- Bioelectrochemical systems (BES) offer energy-neutral wastewater treatment.
- Pilot studies show efficacy at low temperatures with real wastewater.
- Low volumetric treatment rates (VTRs) hinder competitiveness with activated sludge (AS).
Purpose of the Study:
- To evaluate a pilot-scale microbial electrolysis cell (MEC) for continuous flow wastewater treatment.
- To optimize MEC performance using return sludge liquor and hydraulic retention time (HRT).
- To assess the industrial viability of MECs as a pre-treatment for activated sludge systems.
Main Methods:
- A pilot-scale microbial electrolysis cell (MEC) was operated continuously for 6 months.
- The reactor was fed return sludge liquor, a high chemical oxygen demand (COD) wastewater.
- Hydraulic retention time (HRT) was optimized to maximize VTR.
Main Results:
- The highest VTR for a pilot-scale MEC treating real wastewater was achieved.
- An average VTR of 3.82 kgCOD/m³∙day was recorded at a peak HRT of 0.5 days.
- A 55% COD removal efficiency was obtained.
Conclusions:
- Optimized HRT and high-organic wastewater significantly increased MEC VTR.
- MECs show potential as an industrially viable pre-treatment for return sludge liquor.
- Reduced loading on activated sludge systems could lead to significant cost savings.
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