Optimal design and operation criteria of constructed wetland-bioelectrochemical systems (CW-BES) for the treatment of wastewater

RESEARCH CONTEXT

Constructed wetlands (CW) are natural wastewater treatment systems that have relatively large surface requirements when compared to intensive technologies and are devoted mainly to the sanitation of small human settlements (rural areas). Bioelectrochemical systems (BES) (such as microbial fuel cells – MFC or microbial electrolysis cells - MEC) generate an electric current by means of electrochemically active microorganisms as catalysts either with the implementation of an external power source (MEC) or without it (MFC). For the past years, research on BES implemented in CWs, and more precisely, on horizontal subsurface flow constructed wetlands (HSSF CW), was focused on energy production rather than other BES applications in CWs or design aspects to optimize the technology. This thesis shall address technical and design aspects on the implementation of BES on CWs for the optimization of wastewater treatment system efficiency and control and the recovery of valuable products (such as micronutrients).

OBJECTIVES

The main objective is to provide optimal design and operation criteria of constructed wetland-bioelectrochemical systems (CW-BES) for the treatment of wastewater”.

This overall objective can be subdivided in the following specific research objectives:

• Specific objective 1; To assess wastewater treatment performance of CWBES in MFC and MEC mode, regarding
  • common pollutants (e.g. organic matter, ammonia) and
  • emerging contaminants

as well as under different conditions in terms of

• • flow (continuous/discontinuous) and
  • organic and hydraulic loading (high/low)

• Specific objective 2; To assess whether it is possible to use MFC current generation as indirect measure of bacterial activity

• Specific objective 3; To assess the effects macrophytes on CWMFC performance

• Specific objective 4; To find out whether CWBES have an effect on micronutrient recovery.

• Specific objective 5; To test the potential of MFCs as biosensors