Abstract

The peculiarities of the Dnieper river water that contains natural organic compounds of allochthonous origin, in the composition of which fulvic acids with a molecular mass of about 1.0 kDa predominate, are investigated. It is established that the use of iron-containing coagulants in the process of purification of such water leads to its enrichment with iron compounds and a corresponding increase in its color intensity. Comparison of the effectiveness of aluminum and iron coagulants showed that both reagents lead to a stable decrease in Dnieper water coloration caused by humic acids. However, the use of iron(II) sulfate does not reduce water coloration caused by fulvic acids because of the formation of stable soluble hydroxofulvate complexes. It is shown that the redox system of Dnieper water is at the transition boundaries between Fe²⁺ and hydroxide Fe(OH)₃ and between Mn²⁺ and oxides MnO₂ and Mn₂O₃. The replacement of the standard chlorine agent with chlorine dioxide results in moving this boundary with the formation of finely dispersed flakes of iron hydroxide and particles of manganese oxides. As a result, the use of chlorine dioxide (ClO₂) in doses of 0.2–1.25 mg/dm³ in the final stage of water purification leads to an increase in water coloration intensity, which can be successfully reduced by filtration. With an increase in the dose of ClO₂, an inverse relationship is established between the dynamics of water colorarion intensity growth and the decrease in the Mn content during filtration. The correlation coefficient between these factors is r = –1, which indicates that the presence of manganese is the main factor for increasing the color intensity upon the treatment of water with chlorine dioxide in the summer season. On the basis of the obtained results, a flexible scheme is proposed for chlorine dioxide supply with the following stages: primary treatment at the entrance to water treatment facilites, secondary treatment after coagulation and settling of water before fast filtration, and final disinfection before supplying drinking water to the city.

中文翻译：

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高含量天然有机物、铁、锰地表水制备饮用水的特点

摘要

研究了第聂伯河水的特性，该河水含有外来来源的天然有机化合物，其中分子质量约为 1.0 kDa 的富里酸占主导地位。已经确定，在这种水的净化过程中使用含铁混凝剂会导致其富含铁化合物并相应地增加其颜色强度。铝和铁混凝剂的有效性比较表明，这两种试剂都可以稳定减少由腐殖酸引起的第聂伯河水着色。然而，硫酸铁 (II) 的使用并不能减少由富里酸引起的水着色，因为会形成稳定的可溶性羟基黄腐酸盐络合物。结果表明，第聂伯河水的氧化还原体系处于 Fe 之间的过渡边界。²⁺和氢氧化物Fe(OH) ₃以及Mn ²⁺和氧化物MnO ₂和Mn ₂ O ₃之间。用二氧化氯代替标准氯剂导致该边界移动，形成精细分散的氢氧化铁薄片和锰氧化物颗粒。因此，在水净化的最后阶段以 0.2-1.25 mg/dm ³的剂量使用二氧化氯 (ClO ₂ )会导致水的着色强度增加，这可以通过过滤成功地降低。随着二氧化氯剂量的_增加，在过滤过程中水着色强度增长的动态与锰含量的降低之间建立了反比关系。这些因素之间的相关系数为r = –1，这表明锰的存在是夏季用二氧化氯处理水时增加颜色强度的主要因素。在此基础上，提出了二氧化氯供应的灵活方案，包括水处理设施入口一级处理、混凝沉降后二级处理、快速过滤前、最终消毒后供应饮用。水到城市。