A method for controlling heavy metals in river sludge

Abstract

The invention relates to a method for controlling heavy metals in river sludge. The method comprises the following steps: adding adsorbent pellets to the heavy metal-containing sludge, shaking for 2-6 hours, and centrifuging to obtain a treated product. The preparation of the adsorbent pellets comprises: pulverizing and mixing peanut shells and corn stalks, soaking them in river water, sealing and shaking for 30 days; filtering, drying, and grinding to obtain mixed residues; mixing modified mixed residues, modified Clay minerals, modified fly ash and cross-linking agent are mixed and dried to obtain adsorbent pellets. This method avoids the secondary pollution of heavy metals in the river sludge to the environment, and the method has a high removal rate of heavy metals, the material is environmentally friendly, the engineering amount is small, the cost is low, the recycling of solid waste can be realized, and the black and odor of the river can also be suppressed. The water body is generated, and the adsorbent pellets can achieve the purpose of secondary utilization.

Description

technical field [0001] The invention belongs to the field of river pollution control in environmental protection, and relates to a method for treating heavy metals in river sludge. Background technique [0002] At present, with the rapid economic development and population growth year by year, urban river pollution is gradually increasing. Among them, heavy metals are non-biodegradable and easy to bioaccumulate, and eventually affect the top organisms or humans in the "food chain". Therefore, the effective separation of heavy metals in sediment and their fixation or stabilization have become the key issues for the massive reuse of sediment. [0003] Nowadays, most of the heavy metals in the sediment are removed or fixed by cement-fly ash to stabilize and fix the heavy metals in the sediment. This is an important method that is widely used. However, the fixation of cement and other curing agents will cause the sludge to not flow and cannot play a role. Sludge action, and it...

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Problems solved by technology

[0003] Nowadays, most of the heavy metals in the sediment are removed or fixed by cement-fly ash to stabilize and fix the heavy metals in the sediment. This is an important method that is widely used. However, the fixation of cement and other curing agents will cause the sludge to not flow and cannot play a role. Sludge action, and it is not easy to remove; or use dredging and other methods to filter out the sludge, this method requires a large amount of engineering, high cost and easy to damage the river bed; there is also a large amount of chemicals directly sprinkled into the river, but the stabilization time is short and the cost High potential for secondary pollution; or use biological methods to cultivate plants or microorganisms to treat heavy metals in river sludge, but plants or microorganisms have strict requirements on the growth environment, and it is difficult to adjust the growth curve. Sludge heavy metals approach critical