Ganbaatar Khurelbaatar

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

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.

Table of content

1.             Introduction                                                                 1

1.1.          Statement of problem                                                            1

1.2.          Objectives                                                                              3

2.             Literature review                                                         5
2.1.          Definition and categories                                                       5

2.1.1.      Land treatment                                                                                   5

2.1.2.      Short rotation coppice and short rotation forestry for wastewater treatment        5

2.2.          Historical background                                                            6

2.3.          Removal processes                                                                7

2.3.1.      Organic matter removal                                                                     8

2.3.2.      Nutrient removal                                                                                8

2.3.3.      Pathogen removal                                                                            13

2.3.4.      Metals and other wastewater constitutes                                    14

2.4.          Effects on soil                                                                      15

2.4.1.      Soil pH                                                                                                15

2.4.2.      Soil salinity                                                                                        16

2.4.3.      Soil sodicity (Sodium Adsorption Ratio SAR)                                17

2.4.4.      Soil organic matter (SOM), soil permeability, and clogging                17

2.4.5.      Soil nutrients                                                                                     18

 2.5.          Willow and Poplar wood properties and biomass yield           19

2.6.          Soil‐Willow‐System under cold climate (Influence of cold climate)          20

2.7.          Conclusion on basis of the literature review                           22

3.             Materials and methods                                             25

 3.1.          Introduction                                                                         25

3.2.          Pilot plant in Darkhan, Mongolia                                           25

3.2.1.      The components of the pilot plant                                                 26
3.2.2.      Experimental design                                                                       30

3.2.3.      Sampling and analysis                                                                    31

3.3.          Pilot plant in Langenreichenbach, Germany                           37

3.3.1.      Experimental design                                                                       38

3.3.2.      Sampling and analysis                                                                    40

3.4.          Mass balance approach                                                        43

3.4.1.      Water balance                                                                                 44

3.4.2.      Mass removal rate                                                                          46

3.4.3.      Mass balance analysis                                                                    47
 3.5.          Operation and Maintenance (O&M)                                      52

3.5.1.      Pump calibration                                                                             52

3.5.2.      Tipping bucket calibration                                                             52

3.6.          Possible source of errors                                                        52

3.6.1.      Pilot Plant Darkhan                                                                         53

3.6.2.      Pilot Plant Langenreichenbach (LRB)                                            55

3.6.3.      Biomass analysis                                                                             55

4,          Results and discussion                                                57

4.1.        Pilot plant Darkhan                                                               57

4.1.1.      Water balance                                                                                 57

4.1.2.      Pretreatment                                                                                   59

4.1.3.      Mass removal rate                                                                          60

4.1.4.      Tree growth and biomass yield                                                     65

4.1.5.      Soil                                                                                                    70

4.2.          Pilot plant Langenreichenbach                                              76

4.2.1.      Water balance                                                                                 76

4.2.2.      Pretreatment                                                                                   78

4.2.3.      Mass removal rate                                                                          79

4.2.4.      Biomass yield                                                                                   84

4.2.5.      Soil                                                                                                    86

4.3.        Research Questions                                                               91

4.3.1.      Research Question 1 (RQ‐1): The influence of trees                   91

4.3.2.      Research Question 2 (RQ‐2): The influence of hydraulic loading rate                                  94
 4.3.3.      Research Question 3 (RQ‐3): The influence of seasonal loading pattern           98

4.3.4.      Research Question 4 (RQ‐4): The influence of weekly loading pattern          101

4.3.5.      Research Question 5 (RQ‐5): The influence of daily loading pattern                        103

 4.4.       Design recommendation                                                    106

4.5.        Key findings                                                                       109