EPoNa – Water Reuse in Northern Namibia

The aim of this project is to improve the efficiency of wastewater ponds. Here, the focus will be on technical measures targeted towards water reuse for irrigation purposes. The sustainable operation of water treatment and irrigation will be facilitated by training sessions and management structures. Furthermore transfer potentials will be pointed out.

Research approach

A wastewater pond in Outapi, central-northern Namibia, will serve to analyze different methods of water treatment, irrigation and plant cultivation. The project team consists of members from research institutions, practice partners as well as from the municipality. EPoNa pursues an integrated systems approach which comprises wastewater collection, treatment and reuse. It is ISOE’s task to investigate aspects of governance as well as adapted management structures and to develop methods of finance controlling. The research team will also conduct a social-ecological impact assessment and an analysis of transfer potentials. In order to secure the plants’ long-term operation, a handbook will be compiled that can be used for training operators and decision makers at existing and future locations.


Sustainable reuse of water resources is one of the UN Sustainable Development Goals (SDG). The joint project EPoNa contributes to the SDGs by improving already existing solutions for water treatment by adding approaches with regard to water reuse for dry, arid regions. In the project area of northern Namibia, livestock farming is of high economic and socio-cultural significance. This is the starting point for the research project which aims to provide sufficient amounts of irrigation water for the production of animal feed throughout the year. Furthermore, adequate water treatment and reuse can minimize contaminations in case of flooding and thus reduce health risks for the population. Additionally, methane emissions caused by insufficient water treatment are decreased with the help of the proposed approaches. Hence, EPoNa’s concept of water reuse is directly connected with agricultural production, health, and climate protection.

Research and project partners

  • Technical University of Darmstadt, Institute IWAR, Department of Wastewater Technology
  • Institute of Environmental Engineering and Management at the University of Witten/Herdecke
  • University of Geisenheim, Institute for soil science, plant nutrition and vegetable gardening
  • CNP – Technology Water and Biosolids GmbH
  • H. P. Gauff Ingenieure GmbH & Co. KG – JBG

Practice partners

  • Outapi Town Council (OTC)
  • Ministry of Urban and Rural Development (MURD)
  • Ministry of Agriculture, Water and Forestry (MAWF)
  • University of Namibia (UNAM)
  • Namibia University of Science and Technology (NUST)
  • Olushandja Sub Basin Management Committee (OLBMC)


EPoNa is funded by the BMBF funding measure “Future-Proof Technologies and Concepts to Increase Water Availability and Desalination” (WavE).


Frick-Trzebitzky, Fanny/Thomas Kluge/Stefan Stegemann/Martin Zimmermann (2022): Capacity development for water reuse in in-formal partnerships in northern Namibia. Front Water 4, 906407

Zimmermann, Martin/Felix Neu (2022): Social-Ecological Impact Assessment and Success Factors of a Water Reuse System for Irrigation Purposes in Central Northern Namibia. Water 14(15), 2381

Zimmermann, Martin/Birte Boysen/Ehsan Ebrahimi/Michaela Fischer/Elmar Henzen/Johannes Hilsdorf/Jürgen Kleber/Susanne Lackner/Aydin Parsa/Karl-Ulrich Rudolph/Sebastian Schöller/Faruq Shalizi/Jochen Sinn/Jana Zinkernagel (2021): Replication Guideline for Water Reuse in Agricultural Irrigation. Upgrading wastewater pond systems to generate irrigation water for animal fodder production using the example of Outapi, Namibia. ISOE-Materialien Soziale Ökologie, 63. Frankfurt am Main: ISOE - Institut für sozial-ökologische Forschung

Mohr, Marius/Thomas Dockhorn/Jörg E. Drewes/Sybille Karwat/Susanne Lackner/Bryan Lotz/Andreas Nahrstedt/Andreas Nocker/Engelbert Schramm/Martin Zimmermann (2020): Assuring water quality along multi-barrier treatment systems for agricultural water reuse. Journal of Water Reuse and Desalination 10 (4), 332-346

Frick-Trzebitzky, Fanny/Martin Zimmermann/Thomas Kluge (2019): Capacity Development for Wastewater Management and Water Reuse in Informal Partnerships in Northern Namibia. Book of Abstracts. 12th IWA International Conference on Water Reclamation and Reuse, Berlin, 16-20 June 2019, 756-762


2016/09 – 2020/08