Constructed Wetland Coupled Microbial Fuel Cell Technology: Development and Potential Applications

Traditional wastewater treatments require high energy, operation, and maintenance costs and produce a large amount of sludge during treatment. This situation is becoming more complex with increasing population growth and urban areas. Thus, a new paradigm of water-energy nexus is required to meet the new water and energy demands at an affordable cost. The constructed wetlands (CWs) or treatment wetlands are low cost engineered systems that are designed to utilize the natural processes for wastewater treatment. In general, CWs run without any chemical dosing or external energy requirements and are easy to operate and maintain. Thus, CWs need very less cost for operation. The CWs have been established in a large number throughout the world as an alternative to the conventional wastewater treatment systems [1,2]. The foundation of CWs for the wastewater treatment technology was laid by early experiments of Dr. Kӓthe Seidel in the 1960s [3] and by Reinhold Kickuth in the 1970s [4,5]. At the beginning of CW establishment, the CWs were mainly used for the treatment of traditional tertiary and secondary domestic/municipal wastewaters [6]. The early types of CW were often dominated by free water surface CWs in North America and horizontal subsurface flow (HSSF) CWs in Europe and Australia [7,8]. In later years, the application of CWs has also been significantly stretched to purify agricultural effluents [9,10], industrial effluents [11,12]; landfill leachates [13]; agricultural drainage waters [14,15]; acid mine drainage [16]; aquaculture waters [17]; and urban and highway runoff [18,19].