Method for remediating and modifying heavy metal contaminated soil

Abstract

The invention provides a method for remediating and modifying heavy metal contaminated soil. The method comprises the following steps that (1) modifying agents are added into the heavy metal contaminated soil, and the soil is evenly turned over to be maintained for 10-20 days; (2) mulberries are planted in the modified soil for 1-2 periods, and each period is one year; (3) the mulberries in the step (2) are wholly removed from the soil, activating agents are added, and the soil is activated for 10-20 days; (4) oilseed rapes are planted in the soil activated in the step (3) for 2-3 periods, and each period is one year; (5) heavy metal in the mulberries and the oil seed rapes in the step (2) and the step (3) are recovered; and (6) the step (1) to the step (5) are repeated cyclically until the heavy metal content in the soil meets the standard. By means of the method, the heavy metal content in the soil can meet the soil environmental quality secondary standard after one cycle, and organic matter in the soil is greatly increased.

Description

technical field [0001] The invention relates to the field of contaminated soil treatment, in particular to a method for repairing and improving heavy metal polluted soil. Background technique [0002] Soil heavy metal pollution is toxic and easily accumulates in plants, animals and humans through the food chain, posing a serious threat to human health and the ecological environment. The heavy metals that cause soil pollution mainly include As, Cd, Cr, Cu, Hg, Pb, Zn, etc. The main source of soil heavy metal pollution is the waste discharged by human beings in life and industrial and agricultural production, such as domestic sewage and domestic garbage. The heavy metals contained in the soil go deep into the soil, the abuse of pesticides and fertilizers in agriculture and unreasonable irrigation, and the discharge of waste from mining, smelting and chemical industries in industry, etc., have all aggravated the status quo of soil heavy metal pollution. [0003] After heavy me...

AI Technical Summary

Problems solved by technology

The chemical solidification method can only temporarily fix heavy metals in the soil and reduce heavy metals entering the human body through plants, but it cannot completely remove heavy metals from the soil, and there are hidden dangers; soil leaching method can reduce the availability of heavy metals to plants, but At the same time, a large amount of nutrients will be lost in the soil, and the use of chemical leaching may also lead to acidification or alkalization of the soil; while the cost of electrochemical restoration is relatively high, and the implementation conditions are relatively harsh; and the use of phytoremediation The method is to remove heavy metals from the soil through plant system absorption, accumulation, and volatilization to reduce heavy metal pollution. The cost of this method is relatively low, and it is green and environmentally friendly; Heavy metals are divided into absorbable state, exchange state and refractory state. Heavy metals in a refractory state cannot be absorbed by plants, and different plants have different accumulations of different heavy metals.

In addition, while remediating soil heavy metal pollution, it may destroy soil structure and physical and chemical properties, resulting in soil degradation