Readers, dear readers, almost a year has passed since the issue of DST 70 preceding it. This is much longer than we used our readers in recent years. It is also not in line with the editorial team’s stated objective to search for a publication frequency of 3 issues per year. Several reasons explain this delay. First, in parallel with the preparation of this issue 71, we worked on a special edition of the journal, which will publish a selection of extensive articles from the International Scientific Colloquium “Water, Dechet” (E3D 2016) organised by the University of Lomé, Togo, from 7 to 11 March 2016. This special issue should cover 6 articles and will appear in just one month. We will therefore finally see the publication of two issues in 2016, but at a very close interval to the other. On the other hand, despite our efforts, the procedure for examining manuscripts by two expert readers is relatively lengthy, as it often requires several returns between authors and readers in order to reach, when the manuscript is accepted, the final version that can be published. However, this procedure is essential in order to guarantee the originality of the articles and the level of quality that allows our readers to find an interest in reading them and quoting them in their own publications.To see the glass half full rather than half empty, the positive point of the long delay without publication of DST that has just passed is that it undoubtedly created an even stronger thirst for our readers to reproduce in our articles what makes the DST magazine rich and specific: The intersection of the approaches and views taken by research teams in the north and south on the shared theme of environmental science and engineering, which makes such a strong contribution to shaping the future of our communal planet, so good reading!