MFC-based biosensor for domestic wastewater COD assessment in constructed wetlands

Abstract

Corbella, C., Hartl, M., Fernandez-gatell, M., Puigagut, J., 2019.MFC-based biosensor for domestic wastewater COD assessment in constructed wetlands. Sci. Total Environ. 660, 218-226. AbstractIn the context of natural-based wastewater treatment technologies (such as constructed wetlands -CW) the use of a low-cost, continuous-like biosensor tool for the assessment of operational conditions is of key importance for plant management optimization. The objective of the present study was to assess the potential use of constructed wetland microbial fuel cells (CW-MFC) as a domestic wastewater COD assessment tool. For the purpose of this work four lab-scale CW-MFCs were set up and fed with pre-settled domestic wastewater at different COD concentrations. Under laboratory conditions two different anodic materials were tested (graphite rods and gravel). Furthermore, a pilot-plant based experiment was also conducted to confirm the findings previously recorded for lab-scale experiments. Results showed that in spite of the low coulombic efficiencies recorded, either gravel or graphite-based anodes were suitable for the purposes of domestic wastewater COD assessment.Significant linear relationships could be established between inlet COD concentrations and CW-MFC Ecell whenever contact time was above 10 hours. Results also showed that the accuracy of the CW-MFC was greatly compromised after several weeks of operation. Pilot experiments showed that CW-MFC presents a good bio-indication response between week 3 and 7 of operation (equivalent to an accumulated organic loading between 100 and 200 g COD/m 2 , respectively). Main conclusion of this work is that of CW-MFC could be used as an "alarm-tool" for qualitative continuous influent water quality assessment rather than a precise COD assessment tool due to a loss of precision after several weeks of operation.

Nutrient Removal Process and Cathodic Microbial Community Composition in Integrated Vertical-Flow Constructed Wetland – Microbial Fuel Cells Filled With Different Substrates

“…Output bioelectrical signals (e.g., voltage) of the CW-MFCs have been reported to correspond to changes in COD concentration ( Xu L. et al, 2017 ; Corbella et al, 2019 ). In this study, it is noteworthy that the voltage output of the CW-MFCs was intermittently fluctuated.…”

Wetlands for environmental protection

“…Corbella, Hartl, Fernandez‐gatell, and Puigagut (2019) studied the potential of using membrane‐less CW‐MFC at laboratory‐scale and follow up experiment using a pilot‐scale setup as suitable domestic wastewater COD biosensor using both gravel and graphite as anodic material. The results showed linear relationships could be established between E cell generated and inlet COD concentration for both gravel and graphite anodic material.…”

Integrated Constructed Wetland‐Microbial Fuel Cell using Biochar as Wetland Matrix: Influence on Power Generation and Textile Wastewater Treatment

“…Constructed Wetland (CW) frameworks are a blend of physiological and biological mechanisms that efficiently treat wastewater from different sources like domestic, agriculture, industrial and mining with advantages as low operating cost and less maintenance requirements [11–14] . Both Microbial Fuel cells (MFC) and CW comprise of two chambers aerobic and anaerobic where reduction and oxidation occur simultaneously [15] .…”

“…This property of CW‐MFC is an appropriate solution for the treatment of the wastewater by eliminating organic compounds and producing electricity [17] . CW‐MFC systems can be built simply by submerging anode within the soil and placing a cathode near the plant root zone at the top of the soil surface [11–13] . The aquatic plant used in a CW‐MFC system typically develops aerenchyma to adapt to the anoxic state of the water‐logged root.…”