锰砂滤池处理高浓度铁锰及氨氮地下水pH影响研究

发布时间：2018-05-03 07:08

  本文选题：pH + 除铁锰　； 参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：地下水除铁除锰是水工业中一个历史悠久的研究课题，国内外已对此展开了大量的研究。地下水除铁除锰理论及技术先后经历了自然氧化法、接触氧化法和生物法三个发展阶段。但是，我国的地理环境多样化，地下水的特征差异大，同时影响除铁除锰的因素众多，对于不同的地下水及处理工艺，铁锰去除机理难以确定。本文以影响铁锰去除的敏感因素pH值作为重点考察对象，以哈尔滨某区含高浓度铁(平均15mg/l)、锰(平均1.0mg/l)和氨氮(平均2.2mg/l)的地下水为水源，研究pH分别为7.5,7.0和6.5的条件下，滤料的成熟时间及其铁、锰和氨氮去除效果，以加深对滤料除铁除锰机理的认识。 进水pH值对砂滤池水处理效果的影响研究结果表明：进水pH越高，砂滤池挂膜时间越短，出水水质越好。在pH为7.5,7.0和6.5时，滤池分别在40、60和150天表现除氨氮能力，90、140和210天后，不同pH下滤池除氨氮效果趋于一致，维持在0.4-0.5mg/l；pH值越高越有利于锰的去除，pH7.5的滤池分别运行150天（锰砂）和170天（石英砂），出水锰0.05mg/l达标，pH7.0的砂滤池有一定的除锰能力，锰砂出水锰浓度为0.3mg/l，石英砂为0.6mg/l，pH6.5的滤池运行220天，没有除锰效果；pH对滤池除铁没有影响，运行150天后，出水铁均为0.2mg/l以下，除铁主要是依靠接触氧化作用；进水pH越高越有利于砂滤池对浊度的稳定高效去除。锰砂和石英砂在不同pH下对铁和氨氮的去除效果没有显著区别，对于锰的去除，在pH7.5和7.0的条件下锰砂对锰的去除效果要优于石英砂，pH6.5时两者一致没有除锰效果。在pH为7.5的条件下，两级除铁除锰的成熟速度要明显快于单级除铁除锰，但是在pH为7.0和6.5的条件下，两种除铁除锰工艺的水质处理效果没有明显的区别，这表明在一定范围内，pH对滤料成熟速度的影响远大于反洗频率对其的影响。 pH对砂滤池除锰影响的机理探讨研究表明：随着pH的降低，铁在滤池中的去除深度会增加，压缩除锰带，滤池的主要除锰带向下移动；随着pH值的降低，滤料表面铁含量逐渐升高，锰含量逐渐降低，，三价铁氢氧化物会覆盖滤料表面，阻碍“锰质活性滤膜”的生成，从而干扰锰的去除。 锰砂吸附及再生除锰效能研究结果表明：锰砂吸附锰的过程符合二级动力学方程，说明锰砂吸附锰是化学吸附过程，吸附质与吸附剂之间有离子交换的过程发生；在锰砂吸附锰的过程中，前6h的吸附速率由内扩散控制，6h-12h吸附速率由膜扩散控制，12h以后为吸附平衡阶段。用不同pH溶液洗脱吸附饱和的锰砂时，在pH为1，2和3下，吸附饱和的锰砂会有大量的锰被洗脱，但是只有在pH为1时，锰砂达到121%的再生率；pH为2-8时的再生情况相差不大，再生率为55-65%；在pH≥9时再生率有提高的迹象。
[Abstract]:Removal of iron and manganese from groundwater is a long-standing research topic in water industry, which has been studied extensively at home and abroad. The theory and technology of removing iron and manganese from groundwater have experienced three stages: natural oxidation method, contact oxidation method and biological method. However, the geographical environment of our country is diversified, the characteristics of groundwater are different, and there are many factors that affect the removal of iron and manganese, so it is difficult to determine the removal mechanism of iron and manganese for different groundwater and treatment process. In this paper, the pH value of the sensitive factor affecting iron and manganese removal was taken as the main object of investigation. The groundwater containing high concentrations of iron (15 mg / L), manganese (1.0 mg / l) and ammonia nitrogen (2.2 mg / l) in Harbin was used as the water source, and the pH values were 7.5% 7.0 and 6.5 respectively. The maturation time of filter media and the removal effect of iron, manganese and ammonia nitrogen were studied in order to better understand the mechanism of iron removal and manganese removal. The effect of influent pH value on the water treatment effect of sand filter is studied. The results show that the higher the influent pH is, the shorter the time of suspended membrane is, and the better the effluent quality is. When the pH was 7.5 ~ 7.0 and 6.5, the ammonia nitrogen removal capacity of the filter was 90140 and 210 days after 40 ~ 60 and 150 days, respectively, and the effect of ammonia nitrogen removal in the filter was similar at different pH values. The higher pH value of 0.4-0.5 mg / L ~ (-1) O _ (2 +) is beneficial to the removal of manganese from the filter with pH 7.5 and 150 days (manganese sand) and 170 days (quartz sand), respectively. The sand filter with effluent manganese 0.05mg/l up to pH 7.0 can remove manganese to a certain extent. Manganese concentration in effluent is 0.3 mg / l and quartz sand is 0.6 mg / L pH 6.5 for 220 days. There is no effect of manganese removal and pH has no effect on iron removal in filter. After 150 days of operation, the iron in effluent is below 0.2mg/l, and iron removal mainly depends on contact oxidation. The higher the influent pH is, the more stable and efficient removal of turbidity is in the sand filter. There is no significant difference between manganese sand and quartz sand in the removal of iron and ammonia nitrogen at different pH. For manganese removal, manganese sand under pH7.5 and 7.0 is better than quartz sand in removing manganese at pH 6.5. Under the condition of pH 7.5, the ripening rate of two-stage iron and manganese removal is faster than that of single-stage iron and manganese removal, but under the conditions of pH 7.0 and 6.5, there is no obvious difference in the water quality treatment effect between the two kinds of iron and manganese removal processes. It shows that the influence of pH on the maturation rate of filter media is much greater than that of backwash frequency in a certain range. The study on the effect of pH on the removal of Manganese in Sand filter shows that with the decrease of pH, the removal depth of iron in the filter will increase, and the main strip of removing manganese in the filter will move down with the decrease of pH, and the removal depth of iron in the filter will increase with the decrease of pH value. The iron content on the surface of the filter media increases gradually, and the manganese content decreases gradually. The trivalent iron hydroxide will cover the surface of the filter material, thus hindering the formation of the "manganese active filter membrane", thus interfering with the removal of manganese. The results show that the process of manganese adsorption by manganese sand accords with the second order kinetic equation, which indicates that the adsorption of manganese by manganese sand is a chemical adsorption process, and the ion exchange process occurs between adsorbent and adsorbent. In the process of manganese adsorption by manganese sand, the adsorption rate of the first 6 h is controlled by internal diffusion and the adsorption rate is controlled by membrane diffusion for 12 h. When the adsorbed saturated manganese sand is eluted with different pH solutions, a large amount of manganese can be eluted at pH 1 ~ 2 and 3, but only when pH is 1, the regeneration rate of mn sand reaches 121% and the regeneration rate of mn sand reaches pH 2 ~ 8. The regeneration rate was 55-65, and the regeneration rate increased at pH 鈮

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