Proc. Nordic Conf. Nitrogen removal and biological phosphate removal, Oslo, Norway 2.-4. February 1999 The influence of wastewater characteristics on choice of wastewater treatment method Hallvard odegaard Faculty of Civil and Environmental Engineering, Norwegian University of Science and Technology, N-7034 Trondheim -NTNU E-mail: hallvard odegaard@byggntnu.no Introduction In advanced wastewater treatment the effluent standards are currently aiming at removing particles (suspended solids), organic matter(BOD, COD, TOC)and nutrients(nitrogen and phosporous Various treatment methods may be used, physical, chemical and biological as well as combinations of these. Among these main treatment methods, there are many reactor and process alternatives Traditionally the choice of treatment method has mainly been based on the effluent standard set in individual cases as well as practical experience with the various methods. This has resulted in the fact that some methods and processes are more favoured in some places than in others. In UK fo instance, biological treatment has been favoured even in cases where chemical treatment for phosphorous removal (in combination with biological treatment)might have been the right choice from the receiving water point of view. In norway, on the other hand the good experience with chemical treatment for phosphorous removal has lead to the use of chemical treatment even in cases where phosphorous is not the key element from the receiving water point of view After the introduction of biological nitrogen and phosphorous removal this picture has changed it is being realised, however, that in addition to effluent standard and traditional experience, onlesow somewhat but we can still see tendencies towards"preferred"solutions in the Nordic countries solution. In this paper wastewater characteristics will be discussed in this perspective onomiaay has to take account of the characteristics of the wastewater in order to arrive at the most ec Wastewater characteristics There are several ways of characterising wastewater 2. According to the state, such as soluble, colloidal, particulate, gaseous ef nutr 1. According to bulk parameters, such as ded matter, organic matter, nutrients, bacteria etc 3. According to its treat-ability such as biodegradability, ability to separate etc Normally wastewater treatment plant owners restrict themselves to characterising in terms of bulk parameters since this is the way the effluent standards are given, but also because other characterisation methods may be costly and difficult to perform. Bulk parameters do not, however, give sufficient information with respect to optimal selection of treatment method/process and optimisation of operaticProc. Nordic Conf. : Nitrogen removal and biological phosphate removal, Oslo, Norway 2.-4.February 1999 The influence of wastewater characteristics on choice of wastewater treatment method Hallvard Ødegaard Faculty of Civil and Environmental Engineering, Norwegian University of Science and Technology, N-7034 Trondheim - NTNU E-mail : hallvard.odegaard@bygg.ntnu.no Introduction In advanced wastewater treatment the effluent standards are currently aiming at removing particles (suspended solids), organic matter (BOD, COD, TOC) and nutrients (nitrogen and phosporous). Various treatment methods may be used, physical, chemical and biological as well as combinations of these. Among these main treatment methods, there are many reactor and process alternatives. Traditionally the choice of treatment method has mainly been based on the effluent standard set in individual cases as well as practical experience with the various methods. This has resulted in the fact that some methods and processes are more favoured in some places than in others. In UK for instance, biological treatment has been favoured even in cases where chemical treatment for phosphorous removal (in combination with biological treatment) might have been the right choice from the receiving water point of view. In Norway, on the other hand, the good experience with chemical treatment for phosphorous removal has lead to the use of chemical treatment even in cases where phosphorous is not the key element from the receiving water point of view. After the introduction of biological nitrogen and phosphorous removal this picture has changed somewhat but we can still see tendencies towards "preferred" solutions in the Nordic countries. Now it is being realised, however, that in addition to effluent standard and traditional experience, one has to take account of the characteristics of the wastewater in order to arrive at the most economical solution. In this paper wastewater characteristics will be discussed in this perspective. Wastewater characteristics There are several ways of characterising wastewater : 1. According to bulk parameters, such as suspended matter, organic matter, nutrients, bacteria etc 2. According to the state, such as soluble, colloidal, particulate, gaseous etc 3. According to its treat-ability such as biodegradability, ability to separate etc Normally wastewater treatment plant owners restrict themselves to characterising in terms of bulk parameters since this is the way the effluent standards are given, but also because other characterisation methods may be costly and difficult to perform. Bulk parameters do not, however, give sufficient information with respect to optimal selection of treatment method/process and optimisation of operation