Ecological water conservancy restoration system and method for heavy metal polluted farmland soil

Abstract

The invention provides an ecological water conservancy restoration system and method for heavy metal polluted farmland soil. The ecological water conservancy restoration method comprises elution and purification of soil heavy metals in a planting intermission period and water and fertilizer combined prevention and control of soil residual heavy metals in a planting period; in a rice planting intermission period, circular treatment of environmental-protection elution, field water recession and forced drainage and receded water ecological purification is carried out on heavy metal polluted soil sequentially, so that overproof heavy metals in rice soil can be gradually transferred into a water body to be treated, and thus the rice field is cleaned; in a rice planting period, field water and fertilizer combined prevention and control is carried out on the residual heavy metals after the rice soil is eluted, so as to prevent and control the heavy metals from entering the rice; a series of treatment measures to the soil heavy metals in the rice planting intermission period and the planting period can ensure the treatment on symptoms and root causes of the heavy metal polluted rice soil and further can ensure the safe planting of rice.

Description

technical field [0001] The invention relates to the fields of farmland resource protection and polluted soil treatment, in particular to an ecological water conservancy restoration system and method for farmland soil polluted by heavy metals. Background technique [0002] According to the latest statistics from the Ministry of Land and Resources, more than 12% of the country's 1.826 billion mu of arable land is polluted by heavy metals such as cadmium, lead, arsenic, and mercury. The incident of cadmium rice in Hunan Province in 2013 was even more shocking at home and abroad. In addition to Hunan, there are rice cadmium exceeding the standard in Guangdong, Guangxi, Fujian, Zhejiang and other places in southern China, and the exceeding rate is about 5% to 15%. Long-term consumption of food with excessive heavy metals will seriously damage the human liver, kidneys and nervous system, threatening the lives and health of the people. 60% of my country's population takes rice as ...

AI Technical Summary

Problems solved by technology

The engineering measures include plowing, alien soil and soil replacement. The engineering volume is relatively large, and a large amount of clean soil is required. It is suitable for site restoration, but it is difficult to deal with the regional treatment of large-scale polluted rice fields.

Soil improvement measures rely on amendments to stabilize heavy metals, which cannot reduce the content of heavy metals in the soil and remove the risk of heavy metal pollution, and there are problems of amendments causing secondary pollution to the soil and destroying the ecological balance of the soil itself

Soil chemical leaching technology is suitable for the remediation of contaminated sites, with short implementation period, high efficiency, and thorough removal of heavy metals. However, the use of chemical agents is likely to cause secondary soil pollution. It is urgent to find environmentally friendly farmland soil leaching agents

Agricultural measures inhibit the absorption of heavy metals by crops through fertilization and field water regulation, which cannot reduce the content of heavy metals in the soil. The requirements for fine regulation are high, and the risk of heavy metal pollution is difficult to eliminate

The cost of phytoremediation is low and does not damage the site structure, but the cycle is long and the effect is slow. On the one hand, the rice fields cannot be planted for a long time, affecting rice production; and the reprocessing of plants after absorbing and enriching heavy metals is also a problem, so there are no large-scale plants in China. The case of remediation of heavy metal polluted paddy field soil

[0004] In summary, the existing treatment technologies are limited to the in-situ or ex-situ treatment of heavy metals in polluted soil media, which is costly and interferes with normal farming, making it difficult to apply them on a large scale.

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