SYSEL, P. Studium chování vybraných kovů v systému půda-kal/biochar-rostlina [online]. Brno: Vysoké učení technické v Brně. Fakulta chemická. 2025.

Posudek vedoucího

Komendová, Renata

The diploma thesis of student Petr Sysel entitled "Study of the behaviour of selected metals in the soil-sludge/biochar-plant system" met the requirements of the assignment. The literature search discusses the current issue of sewage sludge and the risks associated with its application to soil, especially with regard to the content of selected risk elements. The student followed up the theoretical part by proposing the design of experiments in a growbox, where in cooperation with other students, everyone participated in ensuring these time- and space-intensive experiments. An analysis of all input materials was carried out - soils, sludge, biochar and oat grains and subsequently plants grown under set conditions. The analyses were carried out after microwave decomposition on an atomic absorption spectrometer. The obtained results were shown in graphs and commented on. The main finding is that biochar prepared from sewage sludge has the potential to reduce the bioavailability of risk elements when biochar and sewage sludge are applied to soils together. The student was hardworking and independent, both in the preparation of the current literature research and in the field of experiments. During the preparation of the diploma thesis, he used consultations and proposed experimental conditions. The student's overall approach to the preparation of the thesis was excellent, I recommend the thesis and rate it with a grade of A, excellent.

Posudek oponenta

Zlámalová Gargošová, Helena

The thesis focusses on evaluating the effectiveness of biochar obtained from sewage sludge in reducing the bioavailability of risk elements in soil enriched with sewage sludge. For the above-mentioned goals, experiments were conducted with two types of soil matrices (real and artificial) on Avena sativa plants (oats). I consider this topic to be very topical and beneficial in the field of environmental protection. The circular economy supports the meaningful use of transformed waste (which is biochar from sewage sludge). However, it is still necessary to remember the possible risks these matrices (soil sludge and biochar) can pose not only to the soil ecosystem, but also to the quality of the crops grown, if used inadequately. The diploma thesis consists of 67 pages including an Appendix and references (110 most of them are scientific articles from peer-reviewed journals and legislation). The theoretical part of the work deals mainly with the issue of sewage sludge. It describes in readable form their properties, disposal/use, and the benefits and risks that their use on agricultural land can bring. It deals with the mobility, bioavailability, and possible remediation techniques of risk elements (RE) contained in the sludge and presents biochar as a possible solution. It also provides an overview of the legislation that regulates the application of sludge to agricultural land, not only in the Czech Republic, but also in Europe. The experimental part deals with the issue of RE in sewage sludge in various steps. It evaluates their bioavailability (using 0.01 M CaCl2 extraction) from soil matrices enriched with sludge alone or in combination with biochar, and assesses their mobility using a sequential extraction procedure. It also evaluates the transfer of these elements from the soil ecosystem to parts of cultivated plants and ecotoxicological endpoints. Another step was the evaluation of the effect of the presence of biochar on the reduction of the bioavailability of elements for the plant, and thus on the reduction of their content in plant tissue. The results obtained are clearly presented through graphs and discussed and compared with the findings of other authors. Conclusion clearly summarises the obtained results and suggests possible improvements to experiments for the future. I have some remarks to the work: The symbol for percent is used in the work in various ways, with a space, without a space. Multiple citations should be inserted into one square bracket. Decimal points should be used, not commas. The Petri dish should be of capital letter P. References to the literature should no longer appear in the conclusion. This should remain a part of the discussion. Page 24 – legislation: Sb. is a Czech word; in English it is Coll. (Collection). Page 27: The numbers in the chemical formulas should be in the index. I can state that the presented work has a good professional level. It has fulfilled the goals that were set and meets the requirements for this type of work at the Faculty of Chemistry. It brings new knowledge regarding the assessment of bioavailability and bioconcentration of some risk elements in plants in the case of joint application of sewage sludge and biochar. I recommend the thesis for defense and grade it A.

eVSKP id 162139