Anammox, an abbreviation for ANaerobic AMMonium OXidation, is a microbial process of the nitrogen cycle. It takes place in many natural environments. There is a huge interest in application of the anammox-process in wastewater treatment. Practical implementation is currently limited to side-treatment (e.g. warm reject water after dewatering of digested sludge). The proposed concept of this TKI project could be applied for main-stream nitrogen removal via anammox in wastewater treatment, including potential application at lower temperatures.
It is the aim to test the anammox-process for nitrogen removal from municipal and industrial wastewater in main-stream mode into a small and modular membrane bioreactor (MBR) by application of fine sieving, online monitoring and remote control.
It is the intention to treat municipal and industrial wastewater with the anammox-process in a small and modular MBR. The first step is to flocculate suspended solids in a reactor, thus binding many particles and organic matter, after which a sufficient amount of suspended matter is removed with a fine screen and cake filtration before the wastewater stream enters the anammox reactor. By inter alia the use of selective removal, the desired anammox bacteria may be separated from the unwanted micro-organisms to subsequently remove the latter from the system. This can be achieved by the use of the differences in biomass properties such as sedimentation rate or size (this TKI project). The autotrophic anammox bacteria are growing very slow, but are forming granulates. The anammox granulates will be separated and returned into the anammox reactor by fines sieving the biological excess sludge. The depleted biological excess sludge with unwanted micro-organisms will be transferred into the sludge treatment unit. State-of-the-art monitoring and remote control will help to understand and influence the anammox process. This project is an important step to practical application of anammox in the main-stream wastewater treatment by developing and testing of innovative water technology.
The anammox process is already used to treat, for example, reject water on wastewater treatment plants, but at higher temperatures (around 30°C). Application in the main-stream at lower temperatures (10-20°C) is another major challenge. The desired biological response is more than 50% conversion of ammonium through ammonium oxidizing bacteria (AOB) to nitrite and then conversion of the remaining ammonium with the formed nitrite by anammox bacteria. However, there is competition for nitrite between anammox bacteria and nitrite oxidizing bacteria (NOB). The retention of active anammox bacteria in a reactor is a challenge, because they grow very slowly at low temperatures.
The first step for main-stream wastewater treatment with the anammox process is to flocculate suspended solids in a reactor, thus binding many particles and organic matter, after which a sufficient amount of suspended matter is removed with a fine screen and cake filtration before the wastewater stream enters the anammox reactor. The anammox granulates will be separated and returned into the anammox reactor by fines sieving the biological excess sludge. The granulate enriched sieve goods will be returned; the depleted biological excess sludge will be transferred into the sludge treatment unit.
Activities include the development, design and construction of a fine screen anammox MBR pilot installation for main-stream nitrogen removal. Online sensors and remote control will be implemented to make it also possible to monitor the improvements of the process and to achieve remote control for a decentralized, small and modular treatment facility. Testing, optimization and evaluation of the system will take place at two locations:
a) at the pilot manufacturing site in Germany (municipal wastewater).
b) at an industrial wastewater treatment plant in the Netherlands.
This TKI project will result in a tested small and modular anammox MBR pilot installation. State-of-the-art sensors and remote control will be installed, which helps to understand and influence the anammox process. Besides the optimized pilot installation, deliverables of the TKI project will be a monitoring plan, a public TKI-report and probably several presentations at (inter)national conferences and articles. A technical workshop to present the outcomes of the project is intended.
Next persons are involved in the research project:
- Prof. dr. ir. M. van Loosdrecht, TU Delft en KWR
- Mr. Klegraf, Suptratec Membrane Gmbh
- Mr. Joep Appels, microLAN / Aqualabo
- Dr. ing. K. Roest, KWR
- Ir. J. Muñoz PDEng, KWR
- Mr. D. Smet, HydroBusiness