Publications Repository - Gdańsk University of Technology

Every year huge amounts of bottom sediments are extracted worldwide, which need to be dis-posed. The recycling of bottom sediments for soil fertilization is in line with the long-promoted circular economy policy and enables the use of micro and macronutrients accumulated in sedi-ments for soil fertilization. When considering potential agricultural reuse of the dredge sediments, the first necessary step should be to analyze whether the heavy metal content meets the obligatory criteria. Then, the contents of valuable elements required for plant growth and their ratios should be assessed. In this study, the content of nitrogen, organic carbon, phosphorus and potassium was tested and iron, sulfur, calcium and magnesium were also analysed along vertical profiles of sed-iments extracted from 4 urban retention tanks in Gdańsk (Poland). The sediments were indicated to have a low content of nutrients (Ntot 0.01-0.52%, Corg 0.1-8.4%, P₂O₅ 0.00-0.65%, K 0.0-1.0%) while being quite rich in Fe and S (0.2-3.3%, 0.0-2.5% respectively). The C/N ratio changed in the range of 17.4-28.4, which proved good nitrogen availability for plants. The mean values of the Fe/P ratio were above 2.0, which confirms that phosphorus in the sediments would be available to the plants in the form of iron phosphate. To sum up, the bottom sediments from municipal reten-tion reservoirs are not a perfect material for soil fertilization, but they are a free waste material which, when enriched with little cost, can become a good fertilizer. Future research should focus on cultivation experiments with the use of sediments enriched with N, P, Corg.

Authors

• dr inż. Karolina Matej-Łukowicz link open in new tab ,
• prof. dr hab. inż. Ewa Wojciechowska link open in new tab ,
• Joanna Strycharz link open in new tab ,
• Marta Szubska,
• dr hab. Karol Kuliński,
• dr Jacek Bełdowski,
• Aleksandra Winogradow link open in new tab