Constructed wetland, pilot systems


The Future of Nature-Based Wastewater Treatment Solutions?

Hybrid Microbial Electrochemical Technology Constructed Wetlands



Hybrid Microbial Electrochemical Technology Constructed Wetlands (CW) are a novel approach for the development of CW technology based on microbial fuel cell (MFC) principles. MFCs are bioelectrochemical systems which use microorganism to oxidize organic and inorganic matter and convert their chemical energy into electric energy. In these systems, so-called electroactive microorganisms establish a direct redox interaction with electrically conductive materials. Electrons produced by the metabolism of electroactive bacteria can be transferred to an electrode, which acts as a terminal electron acceptor as any other natural acceptor like oxygen, nitrate, etc. The use of electroconductive wetland material (instead of sand/gravel) results in what can be referred to as “hybrid microbial electrochemical constructed wetlands (HyMETland)”. Based on reported studies, microbial electrochemical-constructed wetlands represent a powerful hybrid technology that can outperform conventional CWs. However, several questions remain regarding pollutant removal processes (e.g., nitrogen removal pathways, etc.), greenhouse gases emissions, and media characteristics that most promote exoelectrogenic bacteria activity.

Project objectives

  • to assess the effect of material properties (beyond electroconductivity) on microbial community composition and activity in HyMETlands opening pathways for material and systems optimization.
  • to identify microbial-driven processes involved in organic matter oxidation and N cycling in bioelectrochemical systems.
  • to measure and estimate the greenhouse gas emission potential of HyMETlands.
  • to elucidate and report, for the first time, the effect of Artic conditions (e.g. low temperatures, snow and ice cover) on pollutant removal processes in HyMETlands.

Implementation and timetable

The project will run for 4 years (2021- 2024). Researcher tasks have been allocated to 2 different work Packages (WPs)

  • WP1 – Systems performance and material suitability
  • WP2 – HyMETland vs constructed wetland: systems functioning and process understanding

Project founder, coordinator, and collaborators

The project has been funded by Maa- ja Vesitekniikantuki ry and is supported by the University of Oulu. Dr, Elisangela Heiderscheidt from the Water, Energy and Environmental Engineering research unit, University of Oulu, is the project coordinator. Project collaborators include: Dr. Carlos Alberto Arias and Dr. Carlos A. Ramírez-Vargas, Centre for Water Technology (WATEC), Arhus University, Arhus, DK. Christopher Carstens, CEO of Carbon Culture, Helsinki, FI. M Sc (Tech), Hannu Roikola, Director and CEO of Lakeuden Keskuspuhdistamo Oy, Kempele, FI. Academy Research Fellow, Dr. Katharina Kujala, Water, Energy and Environmental Engineering research unit, University of Oulu, FI.


Elisangela Heiderscheidt
Post-Doctoral researcher, University of Oulu
P.O.BOX 4300
90014 University of Oulu

Last updated: 3.6.2021