综合法二氧化氯生产系统废水除铬实例

Example of Chromium Removal from Wastewater in a Synthetic Chlorine Dioxide Production System

关键词:  二氧化氯  二氧化硫还原法  含铬废水  六价铬去除率

Key Words:chlorine dioxide  sulfur dioxide reduction method  chromium-containing wastewater  removal rate of hexavalent chromium

摘要:以某浆纸厂含铬废水处理工程实例为研究对象，针对综合利用自产化学药品和现有设备开发的间歇性六价铬（Cr⁶⁺）综合处理系统，探讨了二氧化氯车间Cr⁶⁺废水产生原因及性质，根据不同的反应池pH值、反应温度、反应时间和硫磺投加量对废水中Cr⁶⁺还原效果的影响，确定了二氧化硫还原法去除Cr⁶⁺的最佳反应条件，并结合实际生产数据，展示了Cr⁶⁺还原效果。结果表明，有效去除高浓度含铬废水中Cr⁶⁺的条件为：pH值=2~4、反应温度控制在40~60 ℃、硫磺投加量为理论反应所需投加量的1.4~1.6倍、反应时间40 min。3次二氧化氯车间停修废水出水中Cr⁶⁺含量均低于0.005 mg/L，总铬含量均低于0.06 mg/L，符合《污水综合排放标准》（GB 8978—1996）中的要求，证实了间歇性Cr⁶⁺综合处理系统处理的有效性。

Abstract:In this paper， a new engineering example for the treatment of chromium-containing waste water in pulp and paper mill as the research object， for the intermittent hexavalent chromium（Cr⁶⁺） comprehensive treatment system that developed by the comprehensive use of self-produced chemicals and existing equipment， the reasons for the generation of Cr⁶⁺ wastewater in the chlorine dioxide workshop and the properties of the wastewater were analysized. Based on the effects of different pH value of reaction pool， reaction temperature， reaction time， and sulfur dosage on the reduction effect of Cr⁶⁺ in wastewater， the optimum reaction conditions of the sulfur dioxide reduction process for removing Cr⁶⁺ were determined， and the reduction effect of Cr⁶⁺ was demonstrated in combination with the actual production data. The results showed that the optimum conditions for the effective removal of Cr⁶⁺ from high concentration chromium-containing wastewater were that pH value of 2~4， reaction temperature of 40~60 ℃， sulfur dosage of 1.4~1.6 times of the theoretical dosage required for the reaction， and reaction time of 40 min. The content of Cr⁶⁺ in the effluent of wastewater from the three shutdowns of chlorine dioxide workshop was lower than 0.005 mg/L， and the content of total chromium was lower than 0.06 mg/L， which were in line with the requirements in the GB 8978—1996， confirming the effectiveness of the treatment of the intermittent Cr⁶⁺ comprehensive treatment system.