代写论文价格-水处理中溶解态NOM与HAA的关系。溶解的NOM对水质对处理的影响以及由于季节变化而引起的水的相应变化做出了重要贡献(Villanueva et al.， 2015)。此外，研究人员还强调了这样一个事实，即冬季低水平地表水或低水平地表水中存在的NOM的数量与春季收集的高地地区地表水存在的数量存在显著差异。许多研究人员已经明确地确定了与处理水中NOM和HAA水平相关的三个不同方面(Ali等人，2014年，Melo等人，2016年)。它们首先包括不同水体之间的水分子组成和变化，其次是在HAA形成过程中水分子反应活性的变化，第三是由于不同的HAA物种在个体水平上的分布而产生的差异。
Another newly standardised process of fractionation, as described by (Yang et al., 2017) has been utilized for the characterization of NOM thereby leading to the separation of NOM into at least 8 different types of fractions. However, the same distribution of NOM factors underwent alteration after chlorination treatment as the nature of NOM is largely hydrophilic. In order to study the impact which arises due to seasonal variations along with the reactivity of NOM fractions and its alterations, the yield of HAA has been expressed in terms of in the form of molar units. The various water samples when collected from different season’s revealed higher levels of HAA in autumn samples compared to those of summer (Yang et al., 2017).
Varied amount of HAA has been reported from the generic fractions of NOM. This separation is based upon hydrophobic, hydrophilic and transphilic criteria when fractions are isolated from water collected in different seasons. This clearly pointed out the role of seasons in NOM distribution and corresponding HAA formation (Villanueva et al., 2015). Amongst all, the hydrophilic neutral factor is reportedly the most reactive one. This was consequently followed by the fractions of hydrophobic acid and hydrophilic acids respectively. Another significant result revealed in a study on HAA formation showed that whenever the bromine occurred to be maximal in treated water, the yield of HAA increased considerably. This phenomenon was more pronounced in autumn and spring seasons where HAA increased significantly. However, the yield of HAA remained more or less at par when samples were collected during summer.
As far as the speciation of HAA is concerned, the distribution of mono or do and tri- HAAs is ubiquitously present in most water bodies where there is a sudden bromide increase in the treated water body. Nevertheless, in waters with lower bromide concentration, such a phenomenon was not observed (Wang et al., 2014). There is conclusive evidence regarding the fact that the distribution of different HAA species varies with regard to concentrations of bromine in the water body without any serious seasonal impact or speciation on the HAA parameters. When the bromide concentration is low, Brominated HAA species have been noted by researchers. However, for water spiked with bromine, there was incorporation of high amount of bromine incorporated species.
Another interesting finding suggested the distribution of NOM fractions of both upland and lowland water similar as far as the hydrophobic content is concerned. However, differences in hydrophilic content have been documented in these water bodies (Agori et al., 2015). Thus, the HAA yield in the fractions of transphilic, hydrophobic and hydrophilic fractions showed alterations. It indicates that hydrophobic content poses importance while studying HAA distribution and its impact and the fraction of hydrophobic acid contributes to maximal generation of HAA respectively.