Characterisation and assessment of water treatment technologies for reuse

A key element in the Aquarec project is the development of a water treatment matrix in which wastewater treatment process schemes are categorized as a function of the raw wastewater quality and the reuse application. Starting point is the definition of reuse applications; municipal wastewater can be reused for an industrial, a domestic, a natural, and an agricultural purpose. Next step in building the treatment matrix is the construction of treatment trains. With existing primary, secondary and tertiary unit process operations numerous different treatment trains can be constructed. The EU directives discharge limits should be the starting point for further treatment of municipal wastewater for reuse. Therefore effluent will be the main primary source for wastewater reclamation in the short term. Based on this conclusion a set of typical or standard schemes was developed. The typical or standard schemes are illustrated by case studies. In the long term, schemes alternative to the traditional chain can become feasible options. One of the innovations is direct membrane filtration of raw wastewater. Other innovating technologies are advanced oxidation processes. The latter become more and more important since substances such as pesticides, endocrine disrupters, etc. are given priority.

Any existing wastewater reclamation scheme can be described with one of the typical or standard schemes possibly with some modifications on minor elements. The standard schemes are described with case studies from all over the world. Because of the existing levels of wastewater treatment in Europe secondary effluent will be the main primary source for wastewater reuse in the short term. The treatment of this effluent should be accomplished by more advanced or tertiary techniques. The construction of one standard reuse matrix is not possible. The reuse matrix depends greatly on the existing wastewater treatment infrastructure and the possible applications. So it is a very specific instrument that can vary from case to case. On the long term schemes alternative to the traditional chain can become feasible options. One of the promising alternatives is direct membrane filtration of raw or pre-settled wastewater. Effluent discharge limits will become more and more stringent which makes it necessary to remove also components such as pesticides, pharmaceuticals, endocrine disrupters, etc. and necessitating for innovations in treatment processes. Processes expected to be able to remove the “new” components are amongst other advanced oxidation processes.