DEA-HS StEB K

Facts:

Duration: 25 June 2026 – 24 June 2028
Funding reference: 61.56.02.04-2a/2026

Initial situation:

The stricter requirements of the Municipal Wastewater Directive (KARL) call for further optimisation of nitrogen removal at municipal wastewater treatment plants. Recent analyses by the German Association for Water, Wastewater and Waste show that many treatment works face major challenges in meeting future nitrogen requirements. Conventional nitrification/denitrification is energy- and resource-intensive, whereas deammonification offers significant potential for energy savings and CO₂ reduction due to its lower oxygen demand and the absence of external carbon sources. In North Rhine-Westphalia in particular, with its many large sewage treatment works and limited space, main-stream deammonification represents a promising technology for the future. However, due to the characteristics of the microorganisms used – the anammox bacteria – deammonification has so far only been successfully applied in highly contaminated effluent streams. Nevertheless, there is still no proof of long-term stable operation of deammonification under continuous, real-world conditions for its widespread application.

The project:

The DEA-HS StEB K project aims to bridge this gap and lay the foundations for the large-scale implementation of the process. To this end, deammonification is being investigated for the first time in continuous operation at a semi-pilot-scale wastewater treatment plant (HtK) with a reactor volume of 2 m³. The project builds on many years of research carried out by the NOWUM-Energy Institute, as well as Eawag’s successful studies on main-stream deammonification. In the institute’s previous projects, such as LABDEA, Dea-HS and MicronDea, the feasibility, operational limits and potential of targeted micronutrient control were demonstrated in the laboratory. The pilot plant is being operated at the StEB Köln wastewater treatment plant in Cologne-Weiden. In parallel, an Eawag containerised plant based on an SBR (Sequencing Batch Reactor) is being operated, the results of which are closely coordinated with the HtK trials. The results form the basis for the large-scale implementation of main-stream deammonification.

Objectives: 

The aim of the project is to provide proof of stable, continuous operation of main-stream deammonification at the HtK sewage treatment works and to achieve low nitrogen effluent levels. One objective is the continuous operation of the HtK pilot plant, as well as a comparison with established two-stage SBR processes. To this end, the HtK enclosure and an Eawag SBR container enclosure at the Weiden site will be operated in parallel. As part of a structured trial programme, operational data will be continuously recorded and analysed to investigate the influence of various operating parameters on process stability and nitrogen removal. In addition, TU Darmstadt is analysing the microbial development of the deammonification community using 16S rDNA sequencing, with a particular focus on AOB, anammox bacteria, NOB and Comammox. The results are being assessed in terms of process stability, regulatory requirements, scalability to industrial-scale operations and economic viability, and are intended to lay the foundations for the practical implementation of main-stream deammonification.