Estimating microbial electrolysis cell (MEC) investment costs in wastewater treatment plants: Case study

Microbial electrolysis represents a new approach for harnessing the energy contained in the organic matter of wastewater. However, before this approach can be implemented on a practical basis, a cost-effective manufacturing process for microbial electrolysis cells (MECs) must be developed. The objective of this study is to estimate an acceptable purchase cost of an MEC reactor for a domestic wastewater treatment plant. We estimate that for a full-scale MEC operating at a current density of 5 A ma−2 (amperes per square meter of anode) and an energy consumption of 0.9 kWh kg-COD−1 (kilowatt-hour per kg of removed chemical oxygen demand (COD)), a cost of €1220 ma−3 (euro per m3 of anodic chamber) can be established as a target purchase cost at which a break-even point is reached after 7 years.

► Current densities above 5 A m−2 would make domestic wastewater treatment feasible.
► €1220 m−3 can be established as a target purchase costs of MECs.
► Hydrogen prices have a significant impact on MEC feasibility.
► Current density is the parameter that most influences the viability of the MEC.