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 the project head, associate professor Igor Petrovic, visited TU Graz. You can see a report of the meeting on this link.
On 1 October 2018 the doctoral student Nikola Kaniski, MEng EE, was employed. You can find more about Nikola Kaniski on the ‘Our Team’ tab.
On 12th October 2018 a triaxial testing device was delivered to the Faculty of Geotechnical Engineering. The purchase of this device is funded by the CSF. The picture of the purchased triaxial device can be seen in the ‘Our Laboratory’ tab. In January 2019 the first CU test on the humus soil sample was performed. The picture of tested sample can be seen in the “Explore in Pics” tab.
In October 2018, Igor Petrovic and Nikola Kaniski visited TU Graz within the bilateral cooperation. During visit they presented the CSF project to the Austrian partners.
In December 2018 and January 2019, the displacement transducer, pressure transducer, muffle furnace and sand bath were calibrated. You can see the pictures of the calibration process in the "Experiments in Pics" tab. Calibration certificates are available on this link.
In December 2018, a biodried waste samples was taken from the local MBT plant (CIOS-Varazdin).
2nd year
In February 2019, a biodried waste damples were taken from Waste Management Center (WMC) Kastijun and WMC Mariscina. The pictures of sampled waste can be seen on the ‘Experiments in Pics“ tab.
In February 2019, the vibrating table mold assembly for measurement of dry density of MBT waste and two pycnometers for solid particle density measurements was delivered to the Faculty of Geotechnical Engineering. The pictures of the devices can be seen in the "Our Laboratory" tab.
On 27 March 2019, Nikola Hrncic, MEng CE has joined the project research team. You can find out more about Nikola Hrncic on the "Our Team" tab.
In order to follow the recent advances in the waste mechanics field the following symposium proceedings were purchased: International Waste Management and Landfill Symposium - Sardinia (2011,2013,2015, 2017) International Symposium on Biomass and Waste - Venice (2012, 2014,2016, 2018).
The basic geomechanical characterization of the samples takem from the WMC Kastijun and Mariscina has been completed in April 2019. The following parameters were determined: water content, mass percentages of individual waste components, mass percentages of waste particles by it's shape (1D, 2D, 3D), particle size analysis, solid particle density, minimum and maximum void ratio and minimum and maximum dry density. The test images can be seen on the "Experiments in Pics” tab.
On 16 April 2019, Assistant Professor Boris Kavur joined to the project research team. Assistant Professor Boris Kavur is a geomechanical laboratory specialist. You can find out more about Boris Kavur at the "Our Team" tab.
From 25 to 26 April 2019, Professor Erich Bauer (TU Graz) visited the Faculty of Geotechnical Engineering as part of bilateral cooperation.
On 8 May 2019, a device for measuring radial displacements in a triaxial cell (LVDT) was delivered to the Faculty of Geotechnical Engineering. The picture of the delivered LVDT can be seen in the "Our Devices" tab.
In May 2019 the following ASTM standards were purchased : - 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 samples of biodried waste were taken from the WMC Mariscina. The report summary can be found at this link.
On 7 June 2019, the phisical and chemical charactherisation of the sampled biodried waste was determined. All chemical parameters were below the maximum allowable concentrations, with the exception of the DOC parameter.
From 06 to 14 June 2019, PhD students Nikola Hrnčić, MEng CE and Nikola Kaniški, MEng EE visited TU Graz as part of bilateral cooperation. During visit doctoral students attended the course "Theory of Materials". The lecturer of the course was Professor Erich Bauer.
On 23 October 2019, Ivana Melnjak, PhD joined the project research team. Ivana Melnjak PhD is an expert for special categories of waste. You can find out more about Ivana Melnjak in the "Our Team" tab.
From 23 to 25 November 2019, Professor Erich Bauer (TU Graz) visited the Faculty of Geotechnical Engineering as part of the bilateral cooperation.
In order to follow the recent advances in waste mechanics field the following books have been purchased in December 2019: - 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 9 December 2019, the upgrade procedure of the large oedometer device with submersible load cell is initiated. This upgrade allows measurement of friction force between waste specimen and oedometer ring. The submerible load cell will be delivered to the Faculty of Geotechnical Engineering in February 2020. 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 delivered in the first half of 2020. The purchase of this device is fully funded by CSF.
In the last quarter of 2019, triaxial CU experiments were started. It is expected that the initiated research program will end in 2020 and that the results obtained will be published in 2021. The test images can be seen in the "Experiments in Image" tab.
Consolidation tests in the large oeodometer device were initiated in the last quarter of 2019. It is expected that the initiated research program will end in 2020 and that the obtained results will be published in 2021. The test images can be seen in the "Experiments in Image" tab.
In 2019, the procedure for conducting a set of oedometer creep tests is initiated. It is expected that the initiated research program will end in 2020 and that the results obtained will be published in 2021.
During 2020 measurement of biodried waste shear strength using direct shear device is anticipated. It is planned that measurements will be completed in 2020 and that the obtained results will be published in 2021.
3rd year
In February 2020, a submersible load cell was delivered to the Faculty of Geotechnical Engineering. The picture of the submersible load cell can be seen at "Our Laboratory" tab.
In April 2020, two rotameters were delivered to the Faculty of Geotechnical Engineering. The picture of rotameters can be seen on the ‘Our Laboratory’ tab.
In May 2020, an Infinite Volume Controller was delivered. The picture of this device can be seen at "Our Laboratory" tab.
In May 2020 a direct shear strength tests on a biodried waste samples was conducted. The used shear strength apparatus is owned by the Croatian Civil Engineering Institute. The measurement pictures can be found on the „Experiments in Pictures“ tab.
In May 2020, the calibration of the GA 5000 landfill gas analyser was performed. The picture of the GA 5000 device can be found in the ‘Our Laboratory’ tab.
In July 2020, additional samples of biodried waste material was taken from the WMC Marišćina. The pictures of sampled waste material can be found on the ‘Experiments in Pictures’ tab.
A long-term consolidation experiment with allowed degradation process was initiated in order to determine the amount of settlement caused by the decomposition of organic waste. 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. The pictures of his presentation can be found here and here.
Two articles are currently being prepared for the Waste Management Symposium, Zagreb 2021. In addition, two papers are planned for publication in journals with high impact factor under the working titles "Determination of particle density of biodried MBT waste" and "Collapsible behavior of biodried MBT waste."
In November 2020, the employment of a new PhD student is anticipated. The student will work on the CSF project „Career Development Project for Young Researchers – Training of New Doctors of Science; DOK-2020-1“.
On 2 November 2020 the doctoral student Dino Bosilj, MEng EE was employed. You can find more about Dino Bosilj at the „Our Team“ tab.
In November 2020, the Testo portable gas analyzer was delivered to the Faculty. The device picture can be seen at "Our Laboratory" tab.
4th year
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 PhD degree within the doctoral study with the topic title: "Influence of humidity change on compressibility parameters of methanogenic fraction of biodried waste".
On May 18 2021, 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 shredder were purchased. The devices will be used to prepare samples used to simulate the biodrying process. You can find pictures of these devices in the "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 cell; measurement of sample temperature and settlement; measurement and controll of air flow using air compresspor and rotameter; measurement of CO2 at the exit of the cell; air conditioning (dehumidification and increase of air temperature at the inlet of the bioreactor cell); measurement of mass sample change. So far, seven trial experiments 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 within the scope of this project. You can see their presentations here: Special features of biodried waste testing in a triaxial cell" and Development of a bioreactor cell to simulate the biodrying process.
In October 2021, Assoc. Professor Igor Petrović and doctoral student Nikola Kaniški participated in the conference Sardinia 2021. Two papers were presented during conference: 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". During conference, three papers were presented. Abstracts of the presented 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 long-term consolidation experiment with allowed degradation process was conducted. During experiment settlements, CO2 and CH4 gases were continously monitored. The obtained results will be presented at the conference CORFU 2022.
Consolidated undrained experiments conducted in triaxial cell 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.
5th year
On February 28, 2022, a paper was published in the Bioresource Technology Reports journal. The article title is "„Correlations between field capacity, porosity, solid particle density and dry density of a mechanically and biologically (biodried) treated reject waste stream“.
In May 2022, research group members Nikola Kaniški, Nikola Hrnčić and Dino Bosilj visited the leading international fair for environmental protection - IFAT München.
From June 14, 2022, Prof. Igor Petrovic participated in the 9th International Conference on Sustainable Municipal Waste Management in Greece. He presented the findings and conclusions of the article "„Short-and long-term settlement properties of MBT waste“.
On June 16, 2022, a paper was published in the journal Applied Sciences entitled "„Variability in the Solid Particle Density and Its Influence on the Corresponding Void Ratio and Dry Density: A Case Study Conducted on the MBT Reject Waste Stream from the MBT Plant in Marišćina,“.
From June 22, 2022, Assoc. Prof. participated in the 5th Symposium of the Macedonian Geotechnical Society in Ohrid, Macedonia. He presented the findings and conclusions of the article "Determination of the apparent specific gravity of a biodried municipal solid waste by “gas pycnometry”".
On July 11, 2022, doctoral student Dino Bosilj successfully defended the topic proposal of his doctoral dissertation at the Faculty of Geotechnical Engineering. You can see the picture from the defense here i here.
On July 22, 2022, the large oedometer was upgraded. The existing computer-controlled hydraulic loading actuator of the large oedometer was replaced with more advanced force actuator. The pictures of the upgraded oedometer can be seen here i here.
On October 5, 2022, a new project prooposal was submitted to the Croatian Science Foundation IP-2022-10 project call. The international research group is consisted from: prof. Erich Bauer (Graz University of Technology, Graz, Austria), prof. Sandro Lemos Machado (Federal University of Bahia, Brazil), assistant professor Mehran Karimpour-Fard (Iran University of Science and Technology, Iran), prof. Dragoslav Rakić and assistant professor Irena Basarić Ikodinović (University of Belgrade, Serbia) and Ph.D. Richard Beaven (University of Southampton, United Kingdom).
From December 12 to 14, 2022, associate professor, Ph.D. Igor Petrović, and doctoral students Nikola Hrnčić and Dino Bosilj participated in the XVI International Symposium on Waste Management in Zagreb. On that occasion, the articles "Analiza biološki i mehanički obrađenog miješanog komunalnog otpada metodom izluživanja". and "Sastav i osnovni geotehnički parametri bioosušenog komunalnog čvrstog otpada". were presented.
On January 17, 2023, at the 4th regular session of the Senate of the University of Zagreb, doctoral student Dino Bosilj was approved to start the process of obtaining a doctorate in science within the framework of the doctoral study on the topic of Relationship between environmental and geotechnical parameters of waste biodrying.
On February 11, 2023, a paper was published in the journal Waste and Biomass Valorization entitled "Creep and Collapse Behaviour of Mechanically and Biologically Pretreated Solid Waste in Oedometer Tests".
On May 22, 2023, doctoral student Nikola Kaniški successfully defended his doctoral dissertation entitled Influence of humidity change on compressibility parameters of methanogenic fraction of biodried waste.You can see pictures from the defense here i here.
From June 21, 2023, Prof. Igor Petrovic participated in the 10th International Conference on Sustainable Municipal Waste Management in Greece. He presented the findings and conclusions of the article "„Duration of the biodrying process as a function of the initial moisture content of municipal solid waste“.
The raw results of all measurements are freely available to download from the Dabar Geotechnical Faculty repository.
The project has officially ended on June 30, 2023.
