Long-term effects of composted sewage sludge on brownfield soil remediation and contaminant dynamics in the soil-plant system

Tabea Leonie Kottek

Diplomová práce

Abstract:

The increasing amount of sewage sludge from wastewater treatment presents a major challenge for sustainable waste management. At the same time, large areas of land affected by coal mining activities remain environmentally degraded and require remediation. The reuse of composted sewage sludge as a soil amendment represents a potential strategy that simultaneously addresses sludge disposal and soil remediation. However, the long-term environmental behaviour of composted sewage sludge, particularly regarding metal(loid) mobility and plant uptake, remained insufficiently understood. This thesis re-evaluated the long-term (2021–⁠2025) suitability of composted sewage sludge as an amendment for degraded brownfield soils affected by coal mining. Soil and plant samples were monitored on experimental fields in the Ústí nad Labem region of the Czech Republic to assess the development of soil properties, metal(loid) mobility and nutrient availability. Metal(loid) leaching behaviour was investigated using several standardised leaching procedures simulating different environmental conditions, while plant uptake and translocation were evaluated in the dominant species Tanacetum vulgare. Results demonstrated that composted sewage sludge enhanced soil organic matter and nutrient availability, supporting natural vegetation establishment. Metal(loid) leaching remained largely below or near background levels in 2025, suggesting minimal long-term environmental risk. The leaching tests also indicated that total metal(loid) content remained in the soil-system but less bioavailable over time. Plant uptake was mostly limited to roots but Zn and Cd showed translocation to shoots, while overall metal distribution indicated a predominantly phytostabilising behaviour with limited risk of above-ground contamination. In conclusion, composted sewage sludge can serve as a sustainable soil amendment for post-mining brownfields, improving soil quality without substantially increasing metal(loid) mobility or plant uptake after 4.5 years of amendment application.

Keywords

bioavailability, pollutant accumulation, risk metals, soil reclamation, sustainability

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 21. 3. 2026

Obhajoba závěrečné práce

• Obhajoba proběhla 18. 5. 2026
• Vedoucí: doc. Mgr. Martina Vítková, Ph.D.
• Oponent: Boris Urbánek, Ing., externi

Česká zemědělská univerzita v Praze

Fakulta životního prostředí

Magisterský studijní program:
Environmental Geosciences