About the Project
- Summary
- Objectives
- News
"Testing and modelling of mechanical behavior of biodryed waste as a Waste-to-Energy prerequisite. The proposed project is focused on the experimental investigation and numerical modelling of the biodryed waste. Biodrying is a variation of aerobic process which is used for partial stabilization of municipal waste. After biodrying process the waste is submitted for further processing to extract organically rich fine-grained fraction suitable for disposal on a bioreactor landfill. Once disposed, the waste is once again moisturized in order to energetically reuse produced biogas through generation of thermal and/or electrical energy. There are three operating MBT plants in Republic of Croatia whose final product is suitable for disposal on bioreactor landfill. Those are CIOS-MBO in Varaždin and County centers for waste management Marišćina and Kaštijun. There are no bioreactor landfills built on Croatian territory yet, although the Ordinance on the methods and conditions for the landfill of waste (OG 114/15; R Croatia) recognizes bioreactor landfills. The insufficient experimental data about geotechnical parameters of biodryed waste can be emphasized as one of the reasons. The second reason is the lack of the appropriate numerical model. Due to the mentioned obstacles, the proper design of bioreactor landfill is not feasible. Thus, the main goal of the proposed research is to develop an appropriate constitutive model for general 3-D stress paths as well as its adjustments with respect to the obtained experimental results for the biodryed MBT waste material. By gathering of experimental and computational expertise related to waste mechanics at the Faculty of Geotechnical Engineering University of Zagreb will make it possible to form a distinct niche research area, highly complementary to the existing research experience in Croatia. In particular, the results from the proposed project will allow more rational landfill design procedures and retrofit waste management strategies in different locations not only limited to Croatia. Furthermore, the experimental results will provide a comprehensive set of well controlled, novel generic benchmarks to computationally validate various modelling aspects of the biodryed MBT waste material and contribute towards its improved predictive power for the waste landfill design purposes. The proposal aims to create a distinct longer-term research niche for the Experimental and Computational Laboratory at the University of Zagreb (Faculty of Geotechnical Engineering), through collaboration with centre of excellence in Austria. The cooperation is based on the existing long-standing expertise in computational simulation with constitutive models by Prof Bauer from Graz University of Technology.
" Testing and modelling of mechanical behavior of biodryed waste as a Waste-to-Energy prerequisite.The main goal of the proposed project is primarily oriented to the refined experimental investigation and numerical modelling of stress-strain relationship of biodryed MBT waste material. In order to properly calibrate a more sophisticated model it is necessary to get an estimation about influence of pressure and density on peak state, to clarify whether a critical friction angle and critical density exist or not, to re-formulate the pressure dependent relative density functions of the hypoplastic model and to determine the data for calibration of the moisture dependent solid hardness. Furthermore, it is necessary to get estimation about the influence of the inhomogeneity on the mechanical response by repeating the same test at least two or three times. This question is essential for the calibration of the constitutive equation, i.e. it is of interest which parameters are more or less sensitive to a deviation of the experimental data. For practical application, the complex mechanical behavior of biodryed MBT waste materials should be modeled in appropriate simplified manner to allow an easy calibration of the constitutive constants using data from standard laboratory tests.
1st year
In August 2018, head of project associate professor Igor Petrović visited TU Graz, within bilateral cooperation. You can see a report from the meeting in this link.
On the 1st October 2018 the doctoral student Nikola Kaniski, MEng ENV is temporarily employed on the project.You can find more about Nikola at, „Our Team“ tab. You can see the candidate selection process (in Croatian language only) in the following link.
On 12th October 2018 a triaxial device for testing of mechanical parameters of MBT waste was delivered to the Faculty of Geotechnical Engineering. The purchase of this device is funded by the CSF. The procurement of the device was carried out on the basis of a simple (in Croatian language only) procurement procedure. You can see this device at „Our Laboratory“ tab. The device was put into operation and in January 2019 the first CU test was carried out on a test sample of humus material. You can see the test sample picture at „Experiments in Pics“ tab. Test measurement report is available (in Croatian language only) in this link.
In October 2018, head of project, associate professor Igor Petrović and Ph.D. student Nikola Kaniški, mag.ing.amb. visited TU Graz,within bilateral cooperation, and on that occasion presented the CSF project. You can see a report from the meeting in this link.
In December 2018 and January 2019, calibration of displacement gauge, pressure gauge, muffle furnace and sand bath calibration was performed. You can see the calibration pictures in the "Experiments in Pics" tab. Calibration certificates are available (in Croatian language only) in this link.
In December 2018, sampling of the small fraction of biodried waste was carried out within the MBT plant C.I.O.S. Varaždin. You can see the report (in Croatian language only) in this link.
2nd year
In February 2019 sampling of a small fraction of biodried waste was carried out at WMC Kastijun and WMC Mariscina. You can see the picture attached at „Experiments in Pics“ tab.
In February 2019, Mold assembly for density measuring with vibrating table of mbt waste and pycnometers were delivered to the Faculty of Geotechnical Engineering. The purchase of these devices was financed by the CSF. You can see the device picture attached at "Our Laboratory" tab.
On 27th March 2019, Nikola Hrnčić, MEng GEO, joined the research team of the project. You can find out more about Nikola at "Our Team" tab.
The basic characterization of waste sample from WMC Kaštijun and Marišćina is completed and currently two articles are being prepared for review procedure submission by the end of June 2019. The following parameters were determined: water content, sorting of waste by material type, separation of waste by particle shape (1D, 2D, 3D), particle-size analysis by sieving, density of waste particles, minimum and maximum dry sample void ratio and minimum and maximum dry sample density. You can see the test pictures at "Experiments in Pics" tab.
To follow up recent literature, on project expenses, proceedings were obtained from the following symposiums: International Waste Management and Landfill Symposium - Sardinia (2011,2013,2015 and 2017) International Symposium on Biomass and Waste - Venice (2012, 2014,2016 and 2018). (2012, 2014,2016 i 2018).
On 16th April 2019, Assistant Professor Boris Kavur joined to the research team. Assistant Professor Kavur is geomechanical laboratory specialist. You can find out more about Boris at "Our Team" tab.
From 25 to 26 April 2019, Professor Erich Bauer visited the Faculty of Geotechnical Engineering as part of the bilateral cooperation.
On May 8, 2019, a device for measuring radial displacements in a triaxial cell was delivered to the Faculty of Geotechnical Engineering. The purchase of this device has been partially funded by the CSF. You can see the device image in the "Our Devices" tab.
The following ASTM standards were acquired in May 2019: - 2019 WATER AND ENVIRONMENTAL TECHNOLOGY 11.04 Waste Management - 2019 WATER AND ENVIRONMENTAL TECHNOLOGY 11.05 Environmental Assessment, Risk Management and Corrective Action The procurement of these standards has been partially funded by the CSF.
In May 2019, an additional sampling of a small fraction of bio-dried waste from the WMC Marišćina was conducted. You can see a summary of the February and May 2019 sampling report (in Croatian language only) at this link.
On June 7, 2019, categorization of sampled waste was determined. All physical-chemical parameters were below the maximum allowable concentration except for the DOC parameter, which is expected since this is a waste suitable for disposal to a bioreactor landfill.
From 06 to 14 June 2019, PhD students Nikola Hrnčić, Mag.ing.Aedif. and Nikola Kaniški, Mag.ing.amb. visited TU Graz as part of bilateral cooperation. On that occasion they attended the course "Theory of Materials". The lecturer of the course was Professor Erich Bauer.
On October 23, 2019, due to going abroad for professional development, the project research team instead of dr.sc. Marko Petric joins dr.sc. Ivana Melnjak. Specialty of dr.sc. Ivana Melnjak is managing special categories of waste. You can find out more about Ivana in the "Our Team" tab.
From 23 to 25 November 2019, Professor Erich Bauer visited the Faculty of Geotechnical Engineering as part of the bilateral cooperation.
To follow up recent literature, on project expenses in December 2019, the following books have been purchased: - Raffaello Cossu, Stegmann R., Solid Waste Landfilling, Concepts, Processes, Technologies, Elsevier 2019 - Sustainable landfilling, Edited by Cossu R., Sloot H. v.d., IWWG International Waste Working Group 2014. - Rao, V.V.S., Sivakumar Babu, G.L., Forensic Geotechnical Engineering, Developments in Geotechnical Engineering, DOI 10.1007/978-81-322-2377-1_26 - Lu, N., Mitchell, J., Geotechnical Fundamentals for Addressing New World Challenges, Springer Series in Geomechanics and Geoengineering, https://doi.org/10.1007/978-3-030-06249-1_9
On December 9, 2019, big oedometer device was upgraded so that a submersible force actuator was purchased. This upgrade makes it possible to measure the friction force along the circumference of the specimen and the oedometer ring. The force actuator will be delivered in February 2020 to the Faculty of Geotechnical Engineering. The purchase of this device is fully funded by CSF.
On December 19, 2019, the tender for the acquisition of Infinite Volume Controler was announced. The device will be shiped in the first half of 2020. The purchase of this device is fully funded by CSF.
In the last quarter of 2019, triaxial experiments were initiated to determine the picnotropy and barotropy at the peak angle of internal friction and to determine whether a critical angle of internal friction exists for MBT waste. Currently, measurements on three waste samples at different cell pressures have been successfully performed. It is expected that the initiated research program will end in 2020 and that the results obtained will be published in 2021. You can see test images in the "Experiments in Image" tab.
Consolidation experiments in the large oeodometer were initiated in the last quarter of 2019. Measurements on two dry specimens have been completed and measurements are being prepared on a wet specimens. It is expected that the initiated research program will end in 2020 and that the results obtained will be published in 2021. You can see test images in the "Experiments in Image" tab.
In 2019, preparations were begun to conduct creep tests in an oeodometer cell. Three measurements are currently being completed. It is expected that the initiated research program will end in 2020 and that the results obtained will be published in 2021.
During 2020, a small experimental program is planned to be implemented on the direct shear device. It is planned that the research will be completed in 2020 and that the results obtained will be published in 2021.
3rd year
In February 2020, a submersible force gauge was delivered to the Faculty of Geotechnical Engineering. The purchase of these device was financed by the CSF. You can see the device picture attached at "Our Laboratory" tab.
In April 2020, 2 rotameters were delivered to the Faculty of Geotechnical Engineering. You can see pictures of this devices attached at „Our Laboratory“ tab.
In May 2020, an infinite volume controller was also delivered. You can also see a picture of this device attached at "Our Laboratory" tab. After a slowdown caused by the COVID-19, this new device is currently being put into operation (September-October).
In May 2020, despite the crisis caused by the COVID-19, a shear strength test of biodried waste in a direct shear device at the Croatian Civil Engineering Institute was conducted. You can see the measurement pictures at „Experiments in Pics“ tab.
In May 2020, the calibration of landfill gas measurement device was performed. You can see a picture of the device at „Our Laboratory“ tab.
In July 2020, sampling of small fraction of biodried waste material was carried out from Waste Management Center Marišćina in order to determine the differences in the composition of waste from the winter and summer period. You can see the pictures of sampling and sampled waste material at „Experiments in Pics“ tab.
A long-term experiment of waste consolidation with allowed biodegradation was initiated in order to determine the amount of settlement caused by waste decomposition. You can see the picture of the experiment at „Experiments in Pics“ tab.
In September 2020, two papers were published at the online symposium Recent Trends in Geotechnical and Geo-Environmental Engineering and Education RTG2EE International Conference. The titles of the articles are Geotechnical properties and bearing capacity of MBT waste and Applicability of the Large pycnometer method for determination of specific gravity of mechanically and biologically treated waste.
On September 8, PhD student Nikola Kaniški successfully presented and defended the proposed topic of his PhD thesis at the Faculty of Geotechnical Engineering, and the proposed PhD thesis was sent to further procedure. You can see the picture from the presentation here and here.
There are currently two articles being prepared for the symposium Waste Management – Zagreb 2021 and two papers are planned for publication in journals with high IF under the working titles Determination of particle density of biodried MBT waste and Collapsible behavior of biodried MBT waste.
In November 2020, it is planned to employ new PhD student to work at CSF project „Career Development Project for Young Researchers – Training of New Doctors of Science; DOK-2020-1“.
On the 2st November 2020 the doctoral student Dino Bosilj, MEng ENV is temporarily employed on the project.You can find more about Dino at, „Our Team“ tab.
In November 2020, the Testo portable gas analyzer was delivered. You can also see a picture of this device attached at "Our Laboratory" tab.
4rd year
On May 18, 2021, members of the research group Nikola Kaniški and Nikola Hrnčić participated in the online conference "Waste to Resources". More detailed information about this conference can be found at this link. The titles of the articles are Settlement characteristic of saturated Mechanical Biological treated waste from Croatia and Maximum and minimum void ratio characteristic of MBT waste.
In 2021, a jaw crusher and a chopper were purchased. The devices will be used to prepare samples to simulate the biodrying process. You can find pictures of these devices in th "Our devices" tab.
In March 2021, a bioreactor cell was built with the following characteristic: measurement of humidity, temperature and atmospheric pressure at the inlet and outlet of the cells; temperature measurement in the sample; sample settlement measurement; measuring and controlling air flow with a rotameter; measuring CO2 at the exit of the cell; air conditioning (dehumidification and temperature increase) at the inlet to the bioreactor; compressor operation management; measuring the change in mass of the sample. So far, seven trial trials have been conducted.
On June 18, 2021, the first doctoral conference on the Faculty of Geotechnical Engineering entitled "Research in Environmental Engineering" was held. At the conference, members of the research group Nikola Kaniški and Dino Bosilj presented the results of the research obtained in the scope of this project. You can see their presentations here: Peculiarities of biodried waste testing in a three - stage device" and Development of a bioreactor cell to simulate the biodrying process.
In October 2021, Assoc. Professor Igor Petrović and a member of the research team Nikola Kaniški participated in the conference Sardinia 2021. On that occasion, two papers were presented: Shear strength of biodried municipal solid waste and Basic geotechnical parameters of biodried waste from winter and summer period.
From 2-3 December 2021, members of the research group Nikola Kaniški, Nikola Hrnčić and Dino Bosilj participated in the conference "Waste Management and Recycling". On that occasion, three papers were presented. Summaries of these papers can be found here: Application of sensors based on the Arduino system in the process of bio-drying of municipal solid waste, Stability analysis of a bioreactor landfill and Influence of wetting procedure on the compressibility of the bioreactor landfill.
In December 2021, members of the research group Nikola Kaniški, Nikola Hrnčić and Dino Bosilj participated in the IRB Scientific School entitled "A comprehensive approach to the study of anthropogenic pressures on the environment". More information about the science school program can be found at the following link.
From 18 January 2021 to 18 January 2022, a lengthy consolidation experiment was conducted on a waste sample. The aim of this experiment was to determine the amount of subsidence sampled by waste decomposition. In addition to subsidence, CO2 and CH4 gases were measured continuously. The results of these measurements will be presented at the conference CORFU 2022.
CU triaxial cell experiments were completed. It was determined that a critical state line can be determined for the tested waste. Normally consolidated and overconsolidated (OCR=4) samples were tested. The experiments did not reveal significant differences in behaviour between normally consolidated and preconsolidated samples.
At the 5th Session of the Senate of the Univeristy of Zagreb held on January 26, 2021, a member of the research group Nikola Kaniški was approved to initate the procedure for obtaining a doctorate of science within the doctoral study entitled: "Influence of humidity change on compressibility parameters of methanogenic fraction of biodried waste".
