Modern technologies for remediation of bottom sediments contaminated with heavy metals

Relevance. The need for timely control of the state of water basins and prevention of their catastrophic pollution due to the processes of handling bottom sediments. Aim. To generalize normative and published data devoted to the problem of assessment of bottom sediments pollution and application of modern technologies of remediation of sediments contaminated with heavy metals. Results and conclusions. The article shows that the most significant transformations in the composition and properties of bottom sediments naturally occur in the conditions of the highest load, typical for historically industrialized and urbanized regions. The authors have carried out a review of regulatory support for the assessment and remediation of contaminated bottom sediments. The paper highlights the gaps in the existing regulatory framework applied in Russia related to the lack of requirements for safe concentrations of toxic metals in bottom sediments. Systematization and analysis of applied technologies for bottom sediments remediation are carried out. The main directions of such works include application of physical, physico-chemical, chemical and biological methods of bottom sediments remediation and purification. These methods can be implemented either in situ or ex situ. The advantage of the first option is the lower cost of the works, while the remediation of sediments outside the water body allows achieving a higher degree of purification from heavy metals. The review shown the prospect of using hybrid remediation technologies with the selection of a set of methods that meet the requirements for treatment efficiency and economic feasibility, as well as the possibility of using contaminated sludge for the production of marketable products.