某水厂源水铁锰超标处理试验研究

Experimental Study on Treatment of Excessive Iron and Manganese in Source Water of a Water Plant

通过对某小型农饮水厂源水铁、锰分别超地表水Ⅲ类标准6倍、11倍情况的现场调查及采测分析,得出其铁、锰超标的主要原因是水库会因季节性缺氧及底质中污染物的释放而造成其底层水铁、锰含量升高,同时取水头部是固定式的,离库底仅约1 m,过于接近水库库底。根据对该水库不同取水深度的铁锰含量检测,可以取中上层水,解决该问题。另外通过分别开展烧杯试验验证次氯酸钠及高锰酸钾对该小型农饮水厂源水中铁、锰的去除效果,数据表明,两种氧化剂对铁的去除效果均显著;当有效氯的投加浓度为10.5 mg/L、聚氯化铝浓度为3 mg/L时,1 h、2 h、4 h对锰去除率分别为23.6%、50%、90%,但此时的锰含量仍有0.14mg/L;当源水中滤后锰含量为1.40mg/L、高锰酸钾的投加浓度为2.5mg/L、聚氯化铝浓度为3 mg/L时,反应1 h后,经原子吸收法测处理后锰含量为0.01 mg/L,去除率为99.3%。

Through the on-site investigation and sampling analysis of the situation that the iron and manganese in the source water of a small agricultural and drinking water plant exceed the classⅢstandard of surface water by 6 times and 11 times respectively,it is concluded that the main reason for the iron and manganese exceeding the standard is that the reservoir will increase the iron and manganese content in the bottom water due to seasonal hypoxia and the release of pollutants in the bottom material.At the same time,the water intake head is fixed,only about 1 m from the bottom of the reservoir,too close to the reservoir bottom.According to the detection ofiron and manganese content at different water intake depths of the reservoir,the middle and upper water can be taken to solve this problem.In addition,beaker tests were carried out to verify the removal effects of sodium hypochlorite and potassium permanganate on iron and manganese in the source water of the small agricultural and drinking water plant.The data show that the two oxidants have significant removal effects on iron.When the concentration of available chlorine is 10.5 mg/L and the concentration of polyaluminium chloride is 3 mg/L,the removal rates of manganese in 1 h,2 h and 4 h are 23.6%,50%and 90%respectively,but the manganese content is still 0.14 mg/L.When the manganese content in the filtered source water is 1.40 mg/L,the dosage concentration of potassium permanganate is 2.5 mg/L and the concentration of polyaluminium chloride is 3 mg/L,the manganese content is 0.01 mg/L and the removal rate is 99.3%.