Enhanced disinfection of wastewater by combining wetland treatment with bioelectrochemical H2O2 production

Abstract

A highly-loaded constructed wetland (up to 44 ± 21 gCOD m-2 d-1) was connected to a bioelectrochemical system (BES) to produce hydrogen peroxide for disinfection purposes. The anode delivered a current from the wetland effluent up to 3.5 A m-2 (maximum 62% anodic efficiency) but was limited in the supply of organic carbon. Hydrogen peroxide could be produced in situ in wetland effluent. Production rates were tested at various current densities with a maximum rate of 2.7 g m-2 electrode h-1 (4 h at 10 A m-2 , 41% cathodic efficiency). Little difference was observed between production rate in wetland effluent or a 0.3% NaCl solution. The resulting hydrogen peroxide (0.1%) was used to disinfect wetland effluent successfully (<75 CFU ml-1 after 1 h contact time). The combination of wetland water treatment with peroxide production in a BES thus enables generating higher water qualities, including disinfected water, without external input of chemicals.

Urine disinfection and in situ pathogen killing using a Microbial Fuel Cell cascade system

“…Moreover, a linear decrease of ORP was noticed along the CC cascade. These values of CFU LR are in agreement with those observed when the hydrogen peroxide derived from cathodic reactions was used against coliforms [13]. …”

“…The H 2 O 2 synthesis occurs spontaneously at the cathode and was successfully employed to disinfect the effluent of a wetland system. Treating the effluents with H 2 O 2 solution resulted in a significant decrease of total coliforms [13]. Another approach for disinfection with the use of catholyte was described by Jadhav et al [14].…”

Behavior of metal ions in bioelectrochemical systems: A review

“…Fe phthalocyanine (FePc) was applied as cathode catalyst in MFCs and showed a high activity towards ORR than Pt in neutral media [148,154]. A high-performance catalyst derived from aniline and iron was prepared by Tang et al through pyrolyzing ironincorporated polyaniline under an NH 3 atmosphere at 900 C for 30 min, and applied as catalyst for air cathode in an MFC.…”

“…The present of hydrogen peroxide in cathode of BESs can enhance the disinfection of wastewater. In BESs, H 2 O 2 can be produced through reduction of O 2 at the cathode in wetland [154], or Fenton process.…”

A review of incorporation of constructed wetland with other treatment processes

“…But more work should be done to improve the boron removal efficiency of this combined system. Arends et al, [67] succeeded in combining bioelectrochemical systems (BES) with CWs to achieve hydrogen peroxide production with a Ti mesh as the anode (Fig. 4 (b)).…”