Arsenic removal method through combination of oxychlorination, ferric salt flocculation and microfiltration

Abstract

The invention discloses an arsenic removal method through combination of oxychlorination, ferric salt flocculation and microfiltration, which is used for removing arsenic in drinking water and comprises the following steps: adding ferric oxychloride and ferric salt into a flocculation reactor, providing certain flocculation action in an aeration or mechanical stirring manner, and oxidizing arsenic (III) into arsenic (V) by means of the oxychlorination agent; and meanwhile, enabling the hydrolysate of the ferric salt and arsenic (V) in raw water to form floccules, and separating by using a hollow fiber membrane to achieve the purpose of removing the arsenic. The arsenic removal method has the following benefits: a right amount of oxychlorination agent and ferric salt are added into an arsenic-containing water source, so that the residual arsenic and ferric content in the treated water can meet the requirements of sanitary standards for drinking water, thus being of great importance in reducing the incidence rate of drinking water type arsenic poisoning in China. A hollow fiber microfiltration membrane assembly can be designed into a fixed type or a mobile type as required, and the design scale can be flexibly selected so as to be applicable to emergent water supply for rural and remote regions and field water supply or emergency.

Description

technical field [0001] The invention belongs to water treatment technology, and in particular relates to using groundwater or surface water as a water source to remove arsenic in drinking water production. Background of the invention [0002] Arsenic, including elemental substances and most compounds, is highly toxic, carcinogenic, mutagenic, and teratogenic to animals. Drinking water high in arsenic for a long time can cause various cancers and inflammations, and it has been identified as a first-class carcinogen by the US Center for Disease Control and the International Agency for Research on Cancer. my country's high-arsenic water areas involve about 30 counties (banners) in 10 provinces (regions) including Taiwan, Xinjiang, Inner Mongolia, and Tibet, and the exposed population is as high as 15 million. Drinking water-type arsenic poisoning has become a major endemic disease in my country. my country's current "Drinking Water Hygienic Standards" (GB 5749-2006) stipulates...

AI Technical Summary

Problems solved by technology

The coagulation-sedimentation method requires a long hydraulic retention time and occupies a large area. For source water with a high concentration of arsenic, it is difficult to meet the current drinking water hygiene standards after treatment.

The arsenic removal efficiency of the adsorption method is low, and the adsorbent needs to be frequently regenerated, the operation is complicated, and a large amount of cleaning waste liquid is discharged

The ion exchange method has a high efficiency of arsenic removal, but the investment cost is high, and pretreatment is required when the raw water has a high salt content, and the regeneration operation of the ion exchange resin is complicated, and a large amount of regeneration waste liquid is discharged

Membrane separation methods, such as reverse osmosis, electrodialysis, etc., have high arsenic removal efficiency, but the investment cost is also high, which is not conducive to popularization

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