Upgrading fluidized bed bioelectrochemical reactors for treating brewery wastewater by using a fluid-like electrode

Anaerobic digestion has historically shown critical operational limitations for treating industrial wastewater. Our work aims to evaluate the resilience capacity of a novel concept so-called microbial electrochemical fluidized bed reactor (ME-FBR) for treating real brewery wastewater under continuous operation mode over one year period. All assays were run in parallel using a conventional anaerobic fluidized bed reactor (AFBR). The resilience tests were designed attending to the most typical operational problems showed by the AFBR technology in real brewery wastewater treatment plants. Four different stress situations were tested: i) pollutants overloading (as high as 51.2 kgCOD/m³ d), ii) presence of an active biocide in the fed stream (5% V_biocide/V_reactor), iii) operation of the reactors after long starvation periods (16 days) and iv) operation at low temperature (<25 °C). Our pre-pilot scale ME-FBR outperformed traditional AFBR for wastewater treatment capacity under all stress test regarding COD removal rate, total nitrogen (TN) removal rate and bioenergy recovery (bioelectrochemical-assisted hydrogen generation). Among all stress test, low temperatures and long starvation periods deeply decrease the robustness of both technologies.