Thesis and final projects

Master's thesis - Suggested topic

Problem and objective:
The life cycle assessment method is used to evaluate systems, products or services in terms of their environmental impact. In LCA models, a distinction is often made between foreground and background systems. The foreground system contains the explicitly modeled processes (e.g. waste treatment processes in the case of LCA of waste management in a specific region), while upstream and downstream processes (e.g. the provision of energy sources) are modeled in the background system. Ideally, specific data (e.g. primary data from plant balances) is used for the inventory of the foreground system, whereas the background system is usually based on generic data taken from databases. Depending on the case study examined and the impact category evaluated, it is not unusual for data sets from the background system to have a decisive influence on the results of the LCA. It is therefore particularly important to ensure that data sets taken from databases are representative and robust.

A frequently used LCA database in both research and industry is ecoinvent. ecoinvent is used for LCAs in a wide range of applications and contains largely independently verified data sets. Nevertheless, data sets stored in ecoinvent can be outdated or, for example, only represent one of various possible manufacturing processes for a specific product, which does not correspond to the average.

The aim of the advertised master's thesis is to identify relevant background system processes for selected waste management systems as examples and to critically examine the associated process datasets with regard to data quality and representativeness. Based on this, recommendations for the future selection and use of background data sets in LCA modeling will be derived.

Methods:
As part of the advertised Master's thesis, database and literature research is to be carried out and supplemented by LCA evaluations of individual data sets. Previous knowledge of life cycle assessment and the use of life cycle assessment software tools (e.g. openLCA or Brightway2) in combination with the ecoinvent database are advantageous for working on this master's thesis topic.

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Contact:
Dr. Sarah Schmidt
Mail: sarah.schmidt[at]uni-kassel[dot]de
Phone: +49 561 804-3954

Master's thesis - proposed topic

Problem and objective:
According to official statistics, 6,154 kt of plastic waste was generated in Germany in 2017, of which 1224 kt was disposed of as residual and bulky waste (conversio, 2018). Determining the quantities of plastic waste disposed of in residual and bulky waste is highly uncertain, as the use of plastics in various products and composites and the heterogeneous composition of these waste fractions make representative sampling difficult. The plastic waste collected in residual and bulky waste includes, for example, pure plastic products such as plastic packaging or waste collection bags, but also various composite products (e.g. composite packaging, hygiene products, textiles, waste electrical and electronic equipment, furniture, etc.) with varying plastic contents.

As part of the advertised master's thesis, the plastic waste quantities in residual and bulky waste stated in official statistics are to be checked for plausibility using two different estimation methods. The approaches to be used are a waste-side estimation of the proportion of plastics in waste and a product-side estimation of the plastics consumed and generated as waste from various applications. As part of the waste-side estimate, the plastic content in residual and bulky waste is to be extrapolated using sorting analysis results and a determination of the plastic content in various sorting fractions. In the production-related estimation, plastic quantities are to be estimated using production and consumption statistics in combination with
lifetimes for each product group.

The expected result of the master's thesis is reliable statements on plausible value ranges for plastic waste quantities and compositions. This data should serve as a basis for discussing existing recycling potentials and fossil carbon content in the inputs of thermal recycling plants.

Methods:
As part of the Master's thesis, comprehensive literature research is to be carried out and statistics on waste quantities and compositions are to be evaluated. The results are to be summarized and discussed in a material flow analysis. A small amount of experimental work is also planned in order to determine the proportion of plastics in various sorting fractions using waste fractions containing plastics from sorting analyses.

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Contact:
Dr. Sarah Schmidt
Mail: sarah.schmidt[at]uni-kassel[dot]de
Phone: +49 561 804-3954

Bachelor thesis - topic proposal

Problem and objective:

Littering, i.e. the pollution of areas and spaces by carelessly discarded or left waste in the sense of §3 para. 1 KrWG, is an increasing environmental problem. Littering has considerable negative ecological, hygienic, aesthetic and economic consequences. In addition to additional disposal costs[1], which have to be borne by the municipality, littering creates direct and indirect hazards for the environment. Cigarette butts, for example, contain over 7,000 chemicals, some of which are toxic, that can be emitted into the environment. Animals can also be harmed, for example, by swallowing littered waste. Due to the increasing amounts of littered waste and the associated negative consequences, further efforts are needed to reduce the amount of waste introduced into the environment[2].

The aim of the bachelor thesis is to conduct a survey on quantities and fractions of littered waste on selected recreational and green areas in Kassel, over a period of several weeks. Primary data are to be generated through the independent collection of waste on selected areas and the subsequent weighing, sorting and balancing. These will serve as a basis for discussing countermeasures to reduce the amount of littered waste on the type of land under consideration.

[1] INFA (2020): https://www.vku.de/fileadmin/user_upload/Verbandsseite/Presse/Pressemitteilungen/2020/Studie/INFA_Studie_SUP_200818.pdf

[2] Federal Environment Agency (2020): https://www.umweltbundesamt.de/publikationen/status-quo-handlungspotentiale-instrumente

Scope and Content:

• Literature review on littering and on quantifying littered waste in terms of quantity, composition, and follow-up costs.
• Data collection and analysis on selected recreational and green areas in Kassel.
• Quantification of littered waste by type and quantity for the selected recreational and green areas in Kassel.
• Critical discussion of the results and effective measures to reduce the amount of (specific) litter on the considered recreational and green areas

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If you are interested, please contact:  Prof. Dr. David Laner

Master thesis - Proposed topic

Problem and objective:
Grate ash from municipal solid waste incineration (HMVA) represents the largest solid residue from waste incineration in terms of volume. After appropriate processing, the mineral fraction of HMV ash can be used as a building material. As part of the HMV eco-concrete research project(https://www.dbu.de/projekt_36064/01_db_2848.html), processed HMVA is used to partially replace aggregates and binders in concrete. This conserves natural raw materials and reduces CO2 emissions associated with concrete production. However, HMV ash contains salts and heavy metals that, although largely immobilized in concrete during use, could be released after the end of use as part of a potential second life cycle as a replacement building material. Therefore, there is a need to investigate the release of pollutants from HMV ash concrete quarry in order to evaluate possible longer-term environmental hazards and to exclude them by appropriate measures.
The objective of this Master's thesis is to investigate the elution behavior of selected salts and heavy metals by means of column experiments and to draw conclusions on the longer-term pollutant release potential.

Approach and Methods:
The experimental work will be carried out in the pilot plant and laboratory of the Department of Resource Management and Waste Engineering and will also be supervised by the Department of Hydrogeology (Prof. Mellage). The HMVA concrete specimens as well as conventional concrete specimens (as a reference) are provided and are to be crushed to suitable grain sizes in the first step using a jaw crusher. The materials produced are characterized with regard to particle size distribution, selected element contents in the solids and porosity. Subsequently, column tests (at least 2 tests per concrete sample) are to be carried out with the produced materials under water-saturated conditions according to DIN 19528. During the tests, relevant percolate parameters (based on the limit values of the Substitute Building Materials Ordinance) are determined at regular intervals (continuously: pH, electrical conductivity and by external analyses for specific water-solid ratios: Cl, SO4, As, Cu, Cd, etc.). The tests shall be run at least up to a water-solid ratio of 10 L/kg to allow comparison with eluate concentrations (carried out as part of the HMV-Öko-Beton research project) from shaking tests at W/F = 2 L/kg and W/F = 10 L/kg. The experiments are to be evaluated with regard to pollutant release dynamics and discussed against the background of provided data from the HMV-Öko-Beton project as well as relevant literature.

The master thesis is jointly supervised at the Department of Resource Management and Waste Engineering and the Department of Hydrogeology.

PDF document

If you are interested, please contact:  Prof. Dr. David Laner