It is useful to bear in mind that the selected technologies are of special interest under the current Dutch conditions for the treatment of municipal wastewater. Conditions that include 'soft' socio-cultural factors, such as acceptance, as well as 'hard', conventional factors, such as effluent standards and the economic situation, will certainly influence the perception of innovative and feasible technological choices. It is unfortunately beyond the scope of this report to evaluate the selected technologies in a worldwide context except for the countries the study has been focusing on.
Regarding the actuality of the information provided we tend to review the selected technologies and give a snapshot of promising future wastewater treament methods. As with all group pictures, there will be always someone left out who should have been included.
Advanced treatment techniques are taken for granted, especially the developing complexity of the engineering and the constraining limits of budget and time were the reasons that some techniques were not included. It is therefore acknowledged that a number of other technologies exist, though unknown to us, and have therefore not been included in this study.
It is hoped that this selection can serve as a reference guideline for engineers, authorities, and interested institutions in other countries. It might also give nspiration to look more often across borders to avoid the ever present pitfall of inventing and developing technologies already available elsewhere.
The report has been written in English to avoid inaccessibility due to language barriers and to make the content available to a wide audience. A glossary of the technical terms has not been included due to the scope and focus of the project. The interested reader is therefore referred to cross-language dictionaries such as Elseviers Dictionary of Hydrology and Water Quality Management (English-French-Spanish-Dutch-German) for a reliable translation of the technical terms into the language that is requested.
Information from literature review has been used as accurately as possible. Where appropriate the wording and structure of the available information was not changed as to ensure that the information is being given correctly.
Sources are acknowledged and listed in every fact sheet under the heading Literature references. However, in order to provide a consistent style and layout throughout the considerable number of different fact sheets the available information has partly been restructured and reworded. In this case too, sources are acknowledged, but might be referenced directly in the paragraph or part of the text. For obvious reasons it neither was nor is intended to claim authorship or copyright for information and knowledge that was obtained from sources other than the authors had at their own disposal.
Patent descriptions are public and can be a valuable source of technical detail about a particular process design. It was attempted to provide patent numbers where possible as to provide the interested reader with easy access to information too detailed to be included in the fact sheets. However, not in all cases it has been possible to find the corresponding patents of the technologies in question and with some technologies there might not even be useful patent information as such.
In using patent information it is advised to accept the limited actuality of patent information. Patents may have been registered a number of years or even decennia ago and the implemented technologies based on said patents may have been subject to major technological changes in answering the needs of practical applicability. The patent databases of the European Patent Office are accessible via the internet at http://ec.espacenet.com