石灰法预处理高浓度甲醛废水工艺的优化研究

Optimization of Lime Pretreatment Process of High Concentration Formaldehyde Wastewater

宁东聚甲醛厂的生产废水中甲醛浓度高达2 000 mg/L,对该废水的处理采用的是石灰预处理+UASB厌氧处理+生物接触氧化法的工艺方法,其中石灰预处理工艺还存在一些不足,本文以宁东聚甲醛装置产生的高浓度甲醛废水为对象,对石灰法预处理高浓度甲醛废水的工艺条件进行了优化,采用正交法考察了pH值、氢氧化钙用量、反应温度等因素对甲醛去除效果的影响。得出较优的实验条件是:反应温度70℃,pH=11,氢氧化钙∶HCHO=0.2∶1,反应时间60 min。

The concentration of formaldehyde in the wastewater from Ningdong polyformaldehyde plant is up to 2 000 mg/L. The treatment process of the wastewater is the combined process of lime pretreatment process method and UASB anaerobic treatment and biological contact oxidation, but there exist some problems in the lime pretreatment process. In this paper, taking the high concentration formaldehyde wastewater from the polyformaldehyde plant as the research object, the process conditions for pretreating high concentration formaldehyde wastewater with lime were optimized. The influences of pH, calcium hydroxide amount and reaction temperature on formaldehyde removal effect were discussed by orthogonal experimental design. The optimum experimental conditions were obtained as follows： reaction temperature 70 ℃, pH=11, calcium hydroxide formaldehyde=02：1, reaction time 60 min.