Development of a xurographically fabricated miniaturized low-cost, high-performance microbial fuel cell and its application for sensing biological oxygen demand

The rapid quantification of biological oxygen demand (BOD) plays an important role in monitoring water quality as well as its management in municipal wastewater treatment. Conventional methods based on consumption of dissolved oxygen over 5 days are slow, labor-intensive and usually require skilled personnel and a well-equipped laboratory. Microbial fuel cells (MFCs) have the ability to convert energy from the chemical form to electrical form and could be used directly measure BOD in an automated way. Nevertheless, these transducers are large, expensive and have a relatively long response time which limits their application as BOD sensors. Here, we use xurographic fabrication technology to rapidly fabricate a low cost micro-MFC and demonstrate its suitability to measure BOD. The miniaturized sensor was fabricated in 10 min, with small reaction volume of only 1.8 µL resulting in a faster response time of only 1.1 min and a larger detection range of 18492 mg/L BOD. These findings demonstrate that the use of xurographic methods to fabricate MFCs can enable low cost measurement of BOD in a rapid manner. These sensors have potential for application in wastewater treatment plants for both monitoring as well as control.