Development of Soil-Willow-System for wastewater treatment and wood production under the extreme climate conditions of Mongolia

Ganbaatar Khurelbaatar Development of Soil-Willow-System for wastewater treatment and wood production under the extreme climate conditions of Mongolia Band 35 der Schriftenreihe des Bauhaus-Instituts für zukunftsweisende Infrastruktursysteme (b.is). 17. Jahrgang 2016. 2016. Format B5. Hardcover. 154 Seiten. Zahlreiche Tabellen und Abbildungen, 25 davon farbig. ISBN 978-3-944101-61-3. Preis 38,00 Euro. RHOMBOS-VERLAG, Berlin 2016 This research work was funded by the German Ministry of Education (BMBF) within the frame of the MoMo-II project (033L003A). Gutachter: Universitäts-Professor Dr.-Ing. Jörg Londong (Weimar) Bauhaus-Universität Weimar, Professur Siedlungswasserwirtschaft http://www.uni-weimar.de/Bauing/siwawi/home/_home.htm Professor Dr. Dietrich Borchardt (Dresden) https://www.ufz.de/index.php?de=39119 Professor Amgalan Jamsaran (Darkhan) Herausgeber der Schriftenreihe: Bauhaus-Institut für zukunftsweisende Infrastruktursysteme (b.is) http://www.uni-weimar.de/de/bauingenieurwesen/institute/bis/ Das Bauhaus-Institut für zukunftsweisende Infrastruktursysteme (b.is) verfolgt das Ziel, die Kooperation der beteiligten Professuren Siedlungswasserwirtschaft, Biotechnologie in der Ressourcenwirtschaft und Urban Energie Systems zu intensivieren, um Lehr-, Forschungs- und Beratungssaufgaben auszubauen. So sind beispielsweise die Weiterentwicklung von Studiengängen, gemeinsame Doktorandenkolloquien oder gemeinsame Forschungs- und Entwicklungsaufgaben angedacht. Das b.is will sich deutlich sichtbar im Bereich der Infrastrukturforschung aufstellen. Die Forschung und Lehre in diesem Bereich orientiert sich am medienübergreifenden Modell der nachhaltigen Gestaltung von Stoff- und Energieflüssen, die verbindendes Konzept der Kernprofessuren des Instituts sind. Dem b.is gehören an: Professur Biotechnologie in der Ressourcenwirtschaft (Prof. Dr.-Ing. Eckhard Kraft) http://www.uni-weimar.de/de/bauingenieurwesen/professuren/biotechnologie-in-der-ressourcenwirtschaft/ Professur Siedlungswasserwirtschaft (Prof. Dr.-Ing. Jörg Londong) http://www.uni-weimar.de/de/bauingenieurwesen/professuren/siedlungswasserwirtschaft/ Junior-Professur Urban Energy Systems http://www.uni-weimar.de/Bauing/energy/index.html Professur Technologien urbaner Stoffstromnutzungen (Kommissarischer Leiter: Prof. Dr.-Ing. Jörg Londong) http://www.uni-weimar.de/de/bauingenieurwesen/professuren/technologien-urbaner-stoffstromnutzung/ Professur Verkehrssystemplanung (Prof. Dr.-Ing. Uwe Plank-Wiedenbeck) http://www.uni-weimar.de/de/bauingenieurwesen/professuren/verkehrssystemplanung/ Honorarprofessor Dr.-Ing. U. Arnold http://www.ahpkg.de/index.php?id=93 Summary and conclusion The existing and already altering wastewater treatment plants in Mongolia face a number of challenges due to a combination of environmental, technical, and financial factors. The long cold winters in Mongolia limit the treatment performance of the conventional wastewater treatment plants, unless those are protected from the cold through housing and/ or additional heating, which are often associated with high investment and maintenance cost. Additionally, the existing treatment plants are already in very critical condition, requiring renovation or replacement. Therefore, a reliable, low cost treatment technology with low operation and maintenance requirement is needed, which is also compatible with the climatic conditions. A combination of land application of primary treated wastewater and short rotation coppice system (Soil-Willow-System) might be an attractive technology for Mongolian conditions. While land treatment systems are known for its robust and reliable treatment (Paranychianakis et al., 2006), the investment and O&M costs associated with the short rotation willow coppice for wastewater treatment are often lower compared to conventional technologies (Dimitrou and Aronsson, 2011; Rosenqvist et al., 1997). These systems are typically operated for the treatment of secondary effluents in some regions of the world, including the cold temperate regions of North America (US-EPA, 1987) and the subarctic climate conditions of Sweden (Aronsson et al., 2010). However, very few studies have investigated the use of primary treated wastewater. Furthermore, no experiments have been conducted focusing on primary treated wastewater under Mongolian climatic conditions, which consists of long cold winters and short, hot summer. In order to obtain the understandings of the mechanism involved in the removal of wastewater pollutants in the Soil-Willow-System, investigations were carried out on two pilot plants. A pilot plant, consisting of primary settling tank and four treatment beds was established at the Mongolian University of Science and Technology in Darkhan. Additionally, two pilot scale beds were established at the eco‑technology research site in Langenreichenbach, Germany. Water quality, biomass, and soil experiments were carried out at both pilot plants. The data obtained from two years of operation at the pilot plant in Mongolia and for two years of operation at the pilot plant in Germany was analyzed using a water and mass balance approach. The results of the investigation demonstrated the beneficial effect of the application of primary treated wastewater on the survival and growth of domestic willow and poplar trees. Furthermore, the trees influenced the treatment performance by enhancing the mass removal rates for the pollutants associated with applied wastewater. No negative changes in soil characteristics have been observed over the study period. The results also presented that the Soil-Willow-System can be operated successfully, under different operational variations, such as hydraulic load and loading patterns. Depending on the amount of wastewater, land availability, financial condition, and environmental goals the Soil-Willow-System can be implemented under the regional conditions of Mongolia. In General, the implementation of Willow‑Soil‑System could contribute to alleviate three main problems being faced in the region: a poor sanitary situation, water scarcity, and shortage of fire fuel. The high mass removal efficiencies that the Soil-Willow-Systems are able to reach might be a key to improve the existing sanitary situation in Mongolia. Wastewater application can be considered as a water reuse practice (irrigation) for the production of wood. This in turn contributes to reduce the water scarcity and shortage of firewood issues. The results of this study also demonstrated that different design options can be selected depending on site specific factors such as land availability, financial conditions, groundwater vulnerability, and the community’s interest. However, further experiments and research are to be carried out in order to scale‑up the systems for implementation in real conditions.