Kalvani Nima, Mesdaghinia Alireza, Yaghmaeian Kamyar, Abolli Samaneh, Saadi Sommayeh, Rashidi Mehrabadi Abdollah, Alimohammadi Mahmood
Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.
J Environ Health Sci Eng. 2021 May 2;19(1):1005-1013. doi: 10.1007/s40201-021-00665-2. eCollection 2021 Jun.
Groundwater is a viable alternative when access to surface water resources is limited. Iron and manganese are known ions in soil and naturally in groundwater sources. However, human activities also are responsible. To identifying the best module for removing manganese and iron in the water treatment plant (WTP) of Mazandaran, 516 samples were taken from raw and treated water. The concentration of manganese, iron, was measured by atomic absorption spectrophotometry, and turbidity was used with the nephelometry method. The water pollution index (WPI) was applied for categorizing the status of pollution in treated water. The effect of seasonal temperature and backwashing (At flow rates of 3.5, 9.2, and 15.3 m h-1) on the sand filter efficiency was also investigated. The highest concentrations of manganese, iron, and turbidity in raw water were 0.744, 6.70 mg L-1, and 41.8 NTU, and in treated water were 0.67, 1.09 mg L-1, and 5.58 NTU, respectively. The mean concentration of manganese and iron in raw and treated water were 0.24 ± 0.1, 0.93 ± 0.91, 0.105 ± 0.06 and 0.18 ± 0.14 mg L-1 respectively. The WPI statuses in drinking water were excellent for manganese and iron in 95.74 and 53.88 % of the samples and very poor in 1.16 and 12.01 % of the samples, respectively, and its classification for drinking water for manganese and iron was excellent ˃ good ˃ extremely polluted ˃ polluted and the concentration of iron was more than manganese in treated water. The study of temperature's effect on sand filters showed that the removal efficiency in warm seasons was higher than in cold seasons. Also, the turbulence in the backwash with the 9.2 m h rates, is lesser than other speeds, and in this flow, after 270 s, the turbidity decreases to less than 10 NTU. Spearman correlation comparison showed that the parameters amounts after filtration decreased significantly (p ≤ 0.0001) in comparison to raw water. The results showed that module #1 that used open-aeration and chlorine as oxidations, was most effective in removing iron and manganese. In the end, the WTP couldn't diminish the parameters completely and need subsidiary units.
当地表水的获取受限，地下水是一种可行的替代水源。铁和锰是土壤中以及地下水源中的常见离子。然而，人类活动也对此负有责任。为了确定马赞德兰水处理厂（WTP）中去除锰和铁的最佳模块，从原水和处理后的水中采集了516个样本。通过原子吸收分光光度法测量锰、铁的浓度，采用比浊法测量浊度。用水污染指数（WPI）对处理后水的污染状况进行分类。还研究了季节温度和反冲洗（流速分别为3.5、9.2和15.3 m h-1）对砂滤器效率的影响。原水中锰、铁和浊度的最高浓度分别为0.744、6.70 mg L-1和41.8 NTU，处理后水中分别为0.67、1.09 mg L-1和5.58 NTU。原水和处理后水中锰和铁的平均浓度分别为0.24±0.1、0.93±0.91、0.105±0.06和0.18±0.14 mg L-1。饮用水中锰和铁的WPI状况分别在95.74%和53.88%的样本中为优，在1.16%和12.01%的样本中分别为极差，其对饮用水中锰和铁的分类为优＞良＞极污染＞污染，且处理后水中铁的浓度高于锰。温度对砂滤器影响的研究表明，温暖季节的去除效率高于寒冷季节。此外，流速为9.2 m h时反冲洗中的湍流小于其他速度，在此流速下，270 s后浊度降至10 NTU以下。Spearman相关性比较表明，与原水相比，过滤后各参数值显著降低（p≤0.0001）。结果表明，采用曝气和氯氧化的模块1在去除铁和锰方面最有效。最后，该水处理厂无法完全去除这些参数，需要辅助单元。
