Deammonification – Energy saving nitrogen removal
The Giessen-Friedberg University of Applied Science is working with EMW filtertechnik GmbH on a project to further develop a sewage purification process. Prof. Dr. Markus Röhricht and Prof. Dr. Harald Platen, both of the Faculty of Hospital and Medical Technology, Environment and Biotechnology of the Applied Science University in Giessen are heading up the scientific side. The three year project is being sponsored by the Federal Ministry of Education and Research (BMBF).
High nitrogen depositions in our bodies of water can create big problems. They lead to over-fertilisation and vigorous algae growth. In addition, some nitrogen compounds are poisonous to fish. All of the larger sewage plants in Germany need to remove nitrogen for these reasons. This is done by a combined method (nitrification and denitrification). Because of the high requirement for oxygen and the related high air intake into the water, approximately 3.6 kilowatt hours are needed for every kilogramme of nitrogen. An alternative process, deammonification, enables the energy consumption to be reduced to less than 1.5 kilowatt hours. However, the use has failed up to now been because of, among other things, the very slow growth of the microorganisms (planctomycetes) responsible for this process. They have a doubling time of over ten days, while normal sewage plant bacteria double in as little as twenty minutes.
The planctomycetes are supposed to be retained in a test plant using a specially developed carrier material from EMW, the project partner from Diez. The company has developed and patented a special process for this. The immobilisation of the planctomycetes carried out beforehand and the optimum properties of the carrier material PORET®aqua are designed to retain the valuable cultures permanently. The advantage of the process is that the very slow growing organisms are not washed away, which would be the case in conventional sewage plants.
This system is to be analysed and further developed by two users who are participating in the project. In the first instance a field study will be set up at “Lecher Privatbrauerei“, a private brewery which is a partner in the project, to remove nitrogen from oxygen free pre-treated sewage. The second cooperation partner, the “Mittelhessische Abwasserbetriebe“, is a group of sewage plants. A pilot plant in their sewage treatment plant is to be fed with highly nitrogenous sludge liquor. Such cooperation is part of the sponsorship objectives of the “FHprofUnt“. In this way the BMBF supports cooperation between applied science universities and businesses in research and development.