Strategies for Reducing the Start-up Operation of Microbial Electrochemical Treatments of Urban Wastewater

Abstract

Abstract:Microbial electrochemical technologies (METs) constitute the core of a number of emerging technologies with a high potential for treating urban wastewater due to a fascinating reaction mechanism-the electron transfer between bacteria and electrodes to transform metabolism into electrical current. In the current work, we focus on the model electroactive microorganism Geobacter sulfurreducens to explore both the design of new start-up procedures and electrochemical operations. Our chemostat-grown plug and play cells, were able to reduce the start-up period by 20-fold while enhancing chemical oxygen demand (COD) removal by more than 6-fold during this period. Moreover, a filter-press based bioreactor was successfully tested for both acetate-supplemented synthetic wastewater and real urban wastewater. This proof-of-concept pre-pilot treatment included a microbial electrolysis cell (MEC) followed in time by a microbial fuel cell (MFC) to finally generate electrical current of ca. 20 A¨m´2 with a power of 10 W¨m´2 while removing 42 g COD day´1¨m´2.The effective removal of acetate suggests a potential use of this modular technology for treating acetogenic wastewater where Geobacter sulfurreducens outcompetes other organisms.

Microbial Electrochemical Technologies for Wastewater Treatment: Principles and Evolution from Microbial Fuel Cells to Bioelectrochemical-Based Constructed Wetlands

“…When the anode potential is controlled in a 3-electrode configuration, the organic matter oxidation is being performed at this working electrode. Some systems have been developed for this purpose, like classical MEC design, based on 2-chambered configuration, separated by an ion exchange membrane [11]. In other cases, the potential is fixed at the cathode, to solve the energy requirements and remove contaminants present in waters by reduction reactions, such as SO4 from groundwater [79], and N from low COD effluents [80].…”

“…It is known that development of electroactive biofilms enables the electron transfer, however a complete understanding of the dynamics related with the transfer between electroactive microorganisms and electron acceptors is still under study [29]. Extracellular electron transfer (EET) of bioelectrochemical microorganism is affected by the potential difference between the final electron carrier and the anode [11,30], and can be executed by two main mechanisms: direct extracellular electron transfer (DEET) and by mediated extracellular electron transfer (MEET).…”

Evolving Microbial Communities in Cellulose-Fed Microbial Fuel Cell

“…For example, Kiely et al [23] reported that a microbial community developed in air-cathode MFCs fed with succinic acid was dominated by Geobacter sulfurreducens, while Geobacter sp. were also reported to dominate consortia where acetate was used as a substrate [24,25]. Geobacter sp.…”

The Planktonic Relationship Between Fluid‐Like Electrodes and Bacteria: Wiring in Motion

“…[35,36] Geobacter speciesh ave been described to be planktonic in groundwater,t heir natural habitat, and moreover, to be more active under this freely suspended lifestylew hen growing with insoluble iron oxidesa ss ole electron acceptors. [37,38] An electrode design able to simulatet he dispersed insoluble iron state could provide an interesting alternative and efficient electron transfer with practical applications. Af reely suspended particles ystem might work as af easible scenario.…”