Electroactive biofilm-based constructed wetland (EABB-CW): A mesocosm-scale test of an innovative setup for wastewater treatment

A new concept in constructed wetlands: assessment of aerobic electroconductive biofilters

“…50,51 The UF anaerobic EC-biofilter removed 109 g COD m −3 d −1 of the inlet load (120 g COD m −3 d −1 ) and showed a COD removal efficiency of 90% (Table 4). These results are consistent with the data reported by Aguirre-Sierra et al 25 for saturated anaerobic HSSF ECbiofilters (117 g COD m −3 d −1 were removed (90%) from the of the inlet load (131 g COD m −3 d −1 )) at a similar HRT; similar results were also reported by Ramírez-Vargas et al 26 in saturated vertical upflow mesocosm-scale EC-biofilters (90% of COD).…”

“…25 Additional studies based on electric potential values showed how the electron flow profile along the bed is severely affected by using an EC material from METland® instead of inert gravel or sand used in standard CW. 26 This electron flow from the deeper anaerobic bed towards oxygenated upper layers seems to be the driving force to enhance COD removal even under anaerobic conditions. A similar concept has been already described for certain kinds of microorganisms (the so-called cable bacteria) which are capable of forming filaments and capable of transfering electrons from reducing environments in the sediment to upper layers with a more positive redox potential through the cell bodies forming the filament.…”

“…24 In this context, the combination of MET and CW has been successfully implemented in a few previous studies leading to a hybrid technology the so-called METland®. [25][26][27] Other studies have integrated MFC concepts into CW with the purpose of harvesting energy, although the strategy of burying electrodes in the gravel of conventional CW exhibited a minor impact on the wetland performance from the water purification perspective. [28][29][30] In contrast, the METland® concept followed an alternative approach by replacing the classical biofilter material (gravel and sand) with an EC material so bacteria can interchange electrons with the bed.…”

Biosurfactants and Synthetic Surfactants in Bioelectrochemical Systems: A Mini-Review

“…A great effort has been made to utilize BES as a biosensing devices (Cui et al, 2019) and even MFC-driven autonomous, self-powered biosensor (Pasternak et al, 2017), or robots (Ieropoulos et al, 2010) have been reported. BES can be also used for biological remediation (Li and Yu, 2015;Ramírez-Vargas et al, 2019) and, as previously noted, as water desalination devices. In lab scale, several organic compounds were synthesized as final products of bioelectrochemical reactions such as alcohols (Mayr et al, 2019), acetate, or acetoin (Patil et al, 2015;Förster et al, 2017).…”

Wetlands for environmental protection

“…The pilot-scale experiment showed good indication between week 3 and 7, but organics trapped and rapid increase in organic matter concentration compromise the long-term performance for COD assessment, thereby presenting it as a good alarm tool for qualitative water quality assessment rather than a precise COD assessment tool. Furthermore, Ramírez-Vargas et al (2019) studied the efficiency of Electroactive Biofilm based CW (EABB-CW) for the removal of organic matter and nutrients using two electro-conductive materials, PK-A (petroleum coke from crushed electrodes) and PK-LSN (petroleum coke with low sulfur and nitrogen content) in both planted and nonplanted mesocosms operated in continuous upflow mode for 32 weeks with real wastewater. The result showed better removal efficiencies of BOD 5 (88%), COD (90%), NH 4 -N (46%) and PO 4 3− -P (86%) for electro-conductive materials when compared to sand.…”