Abstract:

There exists the problem of inhibition of nitrification system caused by thiourea in electroplating wastewater. Taking an electroplating wastewater plant in Guangdong province as an example，through the inhibition principle of thiourea on nitrification，the inhibition and recovery characteristics test of copper ion and thiourea on nitrification，and the analysis of long-term project operation data of electroplating wastewater biochemical treatment system were carried out. It was concluded that the addition of sodium hypochlorite and the interaction between copper ion concentration and thiourea resulted in the inhibition and recovery of nitrification in the operation of electroplating wastewater biochemical treatment system. After the copper ion and thiourea formed the complex，they no longer inhibited the ammonia-oxidizing bacteria. However，sodium hypochlorite could remove the coordination state of thiourea and copper ion and make thiourea regain inhibition to the ammonia-oxidizing bacteria. An experience showed that 0.2，0.5 and 1.0 mg/L thiourea could inhibit the nitrification of ammonia-oxidizing bacteria by 59.5%，82.5%，and 100.6%，respectively. Through the inhibition and recovery tests of Cu（Ⅱ） and thiourea，it was concluded that the nitrification rate recovery rates of Ammonia-oxidizing bacteria with 0.5，2，and 5 mg/L Cu（Ⅱ） under the inhibition of 1.0 mg/L thiourea were 13.1%，42.6%，and 104.4%，respectively. The experimental conclusion can be used for reference for biological nitrification treatment of electroplating wastewater containing thiourea and solve the problem of biological denitrification stability.

Key words: thiourea, electroplating wastewater, nitrification inhibition, biological nitrogen removal

摘要：

针对电镀废水中因含有硫脲类物质而造成生物处理系统硝化受抑制的问题，以广东省某电镀废水厂为例，通过硫脲对硝化的抑制原理、铜离子与硫脲对硝化抑制与恢复特性试验及电镀废水生物处理系统长期项目运行数据分析，得出电镀废水生物处理系统运行中次氯酸钠投加、铜离子浓度与硫脲相互作用是导致硝化抑制与恢复的原因。铜离子与硫脲形成配合物后不再对氨氧化菌产生抑制，而次氯酸钠可解除硫脲与铜离子的配合态，使硫脲对氨氧化菌重新获得抑制性。小试研究发现0.2、0.5、1.0 mg/L的硫脲对氨氧化菌分别造成59.5%、82.5%、100.6%的硝化抑制率，并通过Cu（Ⅱ）与硫脲的抑制恢复试验得出0.5、2.0、5.0 mg/L Cu（Ⅱ）在1.0 mg/L硫脲抑制条件下氨氧化菌的硝化速率恢复率分别为13.1%、42.6%、104.4%。试验结论对含有硫脲类电镀废水的生物硝化处理提供借鉴和解决了生物脱氮稳定性的难题。

关键词: 硫脲, 电镀废水, 硝化抑制, 生物脱氮

CLC Number: 

• X703