Carbon-Negative, Net-Energy-Positive Production of Clean Water, Fuel and Chemicals
Carbon Management Technology Conference
2017
2017 Carbon Management Technology Conference
General Submissions
Confirmed Posters
Recovering and beneficially utilizing waste streams is a key strategic imperative for many plants and industries. A microbial electrolysis cell (MEC, Figure 1) for high strength, wastewater treatment provides a compelling option that beneficially utilizes CO2 and plant wastewater as feeds to produce clean water, hydrogen (H2) and saleable chemicals. Effluent wastewater is used as both an energy source and electrolyte for microbial assisted electrolytic production of H2 and hydroxide ion (OH-). (1) Using microbial oxidation, exoelectrogenic bacteria on the anode oxidize organic matter in the wastewater to produce electrons and protons. The electrons are efficiently transported to the anode using nanowires and other mechanisms (2,3,4) and flow to the cathode where they reduce water to produce H2 and OH-. Metal oxides fed into the acidic anode compartment dissociates liberating a metal ion (M). This is balanced by the OH- produced at the cathode producing metal hydroxide M(OH)2. (5) CO2 fed into the cathode liquid reacts with the M(OH)2 forming carbonates MCO3.
Figure 1: Microbial Electrolysis Cell
The system is carbon-negative, net-energy-positive and profitable without subsidies. CO2, used as a feedstock and buffer, is permanently sequestered as a carbonate solid. This presentation will review the technology, show a system energy balance and describe industrial applications.
1. Lu Lu, Huang Z, Rau GH, Ren Z. Microbial Electrolytic Carbon Capture for Carbon Negative and Energy Positive Wastewater Treatment. Env Sci and Tech 2015;49: 8193-8201
2. Gorby YA, Yanina S, Mclean JS, Rosso KM, Moyles D, Dohnalkova A, et al. Electrically conductive bacterial nanowires produced by Shewanella oneidensis strain MR-1 and other microorganisms. Proc Natl Acad Sci USA 2006;103(30):11358-63
3. Reguera G, McCarthy KD, Mehta T, Nicoll JS, Tuominen MT, Lovely DR. Extracellular electron transfer via microbial nanowires. Nature 2005;435(7075):1098-101.
4. Malvankar NS, Lovley DR. Microbial nanowires: a new paradigm for biological electron transfer and bioelectrics, ChemSusChem 2012;5(6):1039-46.
5. Lu Lu, Yanfen F, Zhe H, Yingping H, Ren Z. Self-sustaining carbon capture and mineralization via electrolytic carbonation of coal fly ash. Chemical Engineering Journal 2016;306: 330–33