Method for treating arsenic-containing waste water

Abstract

The invention relates to a method for treating arsenic-containing waste water. The method comprises the following steps: (1) firstly adding FeSO4, wherein the dosage of the FeSO4 is four times more than the arsenic content of raw water; (2) then adding sodium hydroxide to regulate the pH value of the waste water to 8.8, and coprecipitating by utilizing the characteristic that generated colloid Fe(OH)3 can absorb ferric arsenate and ferric arsenite; and (3) finally adding negative ions of 2.5 ppm, stirring for 16 minutes, precipitating for 16 minutes, filtering, and measuring the arsenic content of filtered water. The method disclosed by the invention has the advantages that the pH of the waste water is regulated to 8.5-9.5 by firstly adding the FeSO4 and then adding the sodium hydroxide, the colloid Fe(OH)3 generated in reaction can adsorb the ferric arsenate and the ferric arsenite to realize coprecipitation, and finally the negative ions are added, sufficiently stirred, precipitated, filtered and detected. The method disclosed by the invention has the advantages of low cost, small dosage, easiness for operation, no secondary pollution, no toxic gas generation and high arsenic removal rate of 99.6%.

Description

technical field

[0001] The invention relates to wastewater treatment technology, in particular to a treatment method for arsenic-containing wastewater. Background technique

[0002] Water is a very finite natural resource and in many cases the quality of the water is not up to domestic or drinking standards. Many pollutants detected in water are harmful to human health and the environment, among which arsenic is considered as a priority pollutant; arsenic is found in rocks, soil, water, plants and animals, volcanic activity, rock erosion and forest Fires are all sources of arsenic, and human activities are also the main source of arsenic released into the environment, such as preservatives, paints, drugs, dyes, metals, and semiconductors. Burning of fossil dyes, mining, refining, and other industrial activities also contribute to the introduction of arsenic into the environment.

[0003] With the development of metallurgy, chemical industry, petroleum and other industries ...