Job description
Annotation
In Central Europe, fishpond management is associated with the long-term accumulation of organic matter, nutrients, suspended solids, and various contaminants originating from fish production, agricultural runoff, and surrounding catchments. Regular sediment removal is necessary to maintain pond functionality, water quality, and ecological stability. However, dredged pond sediments are frequently classified as waste materials, creating economic and environmental burdens related to their disposal and management. At the same time, these sediments contain substantial amounts of organic carbon, nitrogen, phosphorus, and micronutrients, indicating significant potential for reuse within circular bioeconomy systems (Drozdz et al., 2020).
Increasing environmental pressure, stricter European legislation, and the need to reduce dependency on mineral fertilizers highlight the urgent necessity to develop safe and sustainable strategies for sediment valorization. Current knowledge concerning the environmental risks, treatment efficiency, and long-term impacts of sediment application on soil and aquatic ecosystems remains fragmented and insufficiently standardized. Furthermore, there is limited understanding of how treatment technologies such as composting, anaerobic digestion, pyrolysis, hydrothermal carbonization, or biochar stabilization influence contaminant mobility, nutrient availability, and the overall environmental footprint of sediment utilization (Drozdz et al., 2020; Marval et al. 2020)).
Within this framework, pond sediments could become an important source of bio-based fertilizers, soil amendments, substrates for ecological restoration, or raw materials for industrial applications (Drozdz et al., 2020). However, successful implementation requires comprehensive evaluation of sediment quality, environmental safety, treatment technologies, economic feasibility, and stakeholder acceptance.
The main hypothesis
- Appropriately treated pond sediments can serve as a safe and effective secondary resource for nutrient recovery and agricultural applications within circular bioeconomy systems.
- Advanced sediment treatment technologies (e.g., composting, pyrolysis, hydrothermal carbonization, or biochar stabilization) significantly reduce the environmental risks associated with pond sediments, including contaminant mobility.
· The valorization of pond sediments through circular bioeconomy approaches provides measurable environmental and economic benefits compared to conventional sediment disposal, including reduced waste generation, improved nutrient recycling efficiency, and lower environmental footprint.
Aim(s) of the Ph.D. thesis
- To characterize the physicochemical, microbiological, and contaminant profile of pond sediments originating from different aquaculture management systems, with emphasis on nutrient content, heavy metals, and micropollutants.
- To evaluate and optimize sustainable treatment and valorization technologies for pond sediments, including biological, thermochemical, and stabilization approaches, in order to improve nutrient availability and reduce environmental and health risks.
- To assess the environmental, agronomic, and economic potential of treated pond sediments within circular bioeconomy applications using integrated sustainability indicators, including nutrient recovery efficiency, ecotoxicological safety, and life cycle assessment (LCA).
Possible approaches to reach the aims / to verify the hypotheses
- Collection of sediment samples from different aquaculture systems followed by physicochemical, microbiological, and contaminant analyses, including nutrients, organic matter, heavy metals, micropollutants.
- Testing of treatment and stabilization technologies: Evaluation and optimization of sustainable sediment treatment methods such as composting, vermicomposting, anaerobic digestion, pyrolysis, hydrothermalcarbonization, and biochar-based stabilization to reduce environmental risks and improve nutrient recovery.
- Assessment of agronomic and environmental safety: Performance of germination, phytotoxicity, and plant growth experiments to evaluate nutrient availability, soil improvement potential, contaminant mobility, and possible ecological risks associated with sediment application.
- Sustainability and circular bioeconomy evaluation: Application of life cycle assessment (LCA), nutrient flow analysis, and economic assessment to compare conventional sediment disposal with circular valorization pathways and identify sustainable utilization strategies.
References
- Drozd, D., Malinska, K., Mazurkiewicz, J., Kacprzak, M., Mrowiec, M., Szczypiór, A., Postawa, P. and Stachowiak, T., 2020. Fish pond sediment from aquaculture production-Current practices and the potential for nutrient recovery: a Review. International Agrophysics, 34(1).
- Marval, Š., Hejduk, T. and Zajíček, A., 2020. An analysis of sediment quality from the perspective of land use in the catchment and pond management. Soil and Sediment Contamination: An International Journal, 29(4), pp.397-420.
Funding
NAZV PFAS3AKVA (Gebauer PI), Interreg Aquacycle (Malinovskyi PI, Gebauer responsible for Laboratory of Nutrition)
CENAKVA Research program
RP3 Sustainable aquaculture with a responsible water and nutrient management
Areas of Research
- Environmental Science
- Fisheries & Aquaculture
- Soil Science
