Method for removing heavy metal Cd from river sediment

Abstract

Relating to a municipal solid waste disposal technology, the invention provides a method for removing heavy metal Cd from river sediment by microbial leaching, and the method of the invention aims to provide a solution to the problems of severe heavy metal Cd pollution in urban river sediment and utilization restriction of dredged sediment in agriculture and forestry. The method is realized by: adding a proper amount of cultured and acclimated inoculation liquid into a reaction system, and keeping a substrate at a concentration of 30g / L, the inoculation liquid in a volume ratio of 5%, the dissolved oxygen at a concentration of 7.5-9.0mg / L and the temperature in a range of 25-32DEG C, and regularly supplementing the moisture evaporated in a reactor. The method of the invention employs microbial leaching so as to make the removal rate of heavy metal Cd reach 16%-18%.

Description

technical field [0001] The invention relates to a method for treating heavy metals in river bottom mud, in particular to a technical method for removing heavy metal Cd in dredged bottom mud by biological leaching. Background technique [0002] River sediment (sediment) pollution is an important environmental problem in the world. Pollutants enter the water body through atmospheric deposition, wastewater discharge, rainwater leaching and scouring, and finally deposit in the bottom mud and gradually enrich, the bottom mud is gradually polluted, and finally the bottom mud becomes a pool of pollutants. After effectively controlling the external pollution sources of the river, when the water environment changes, the nitrogen and phosphorus nutrients, heavy metals and refractory organic matter deposited in the sediment will be re-released into the water body, affecting the water quality of the overlying water body. Form "secondary pollution". In addition, bottom mud is the main ...

AI Technical Summary

Problems solved by technology

The disadvantage of this technology is that soil organic matter and structural water are easily destroyed, and it takes a lot of energy to drive away soil moisture

This method has a certain effect, solidifying heavy metals in situ, greatly reducing the cost, but it also has certain limitations: it only changes the existing form of heavy metals in the soil, and it is not well understood about the long-term stability of the soil and its impact on the ecosystem. research in this area

[0005] Due to long-term sedimentation, the river sediment contains a small amount of heavy metal cadmium (Cd). Although the cadmium content is relatively small, when the untreated dredged sediment enters the terrestrial ecosystem, the heavy metal cadmium will enter the food chain with the ecological cycle and accumulate. To the upper organisms in the food chain, and ultimately endanger human health, it is easy to cause itai disease, rickets and other diseases

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