Study of inorganic and organic sulphur-based compounds on the quality of water

人们普遍认为，饮用水应该没有引起疾病的有机体、令人讨厌的气味、浑浊和由溶解物质产生的任何颜色。一些主要的饮用水来源，即地表水和地下水，含有引起难闻气味的物质。其中一些气味通常与水中低氧化态硫化合物的存在有关。硫化物和多硫化物就是这种低氧化态硫化合物的例子。有机硫化合物，如三甲基硫化物，被认为是造成水中恶臭的重要因素。这些低氧化态的硫是在各种生物和非生物过程中产生的，包括硫化氢和硫化物矿物的氧化，硫酸盐还原和有机硫化合物的转化。我的短期目标包括在饮用水源中对这些化合物进行表征。特别是，拟议研究的一部分将旨在检查是否有任何硫的低氧化态离子化合物负责形成在水中发现的有机硫化物。我的长期目标之一是进行一项机械方法研究，旨在了解这些还原硫化合物是如何形成的。我的另一个长期目标是为从有这些问题的水源中去除难闻气味提供必要的实用步骤。目前，这部分是通过氯化处理来实现的，氯化处理主要是为了去除饮用水中的有害微生物。氯化的缺点是，任何残留的氯都有可能与一些溶解的有机物质反应，产生三卤甲烷，这是致癌的嫌疑人。我将调查其他氧化剂是否适合去除饮用水中的难闻气味。这项研究预计将大大有助于了解在水中产生难闻气味的过程，并有助于开发处理这些气味的有效和环境友好的方法。

It is widely recognized that drinking water ought to be free from disease-causing organisms, objectionable odours, turbidity, and any colours resulting from the dissolved substances.  Some of the major sources of drinking water, namely surface water and groundwater, contain substances that cause offensive odours. Some of these odours have been commonly associated with the presence of low-oxidation state sulphur compounds in water. Sulphides and polysulphides are examples of such low-oxidation state sulphur compounds. Organic sulphur compounds such as trimethylsulphide are known as significant contributors to the offensive odours in water. These sulphur species with low oxidation states are produced during a variety of biotic and abiotic processes including the oxidation of hydrogen sulphide and sulphide minerals, sulfate reduction, and the transformation of organic sulphur compounds.My short term-goals include the characterization of these compounds in drinking-water sources. In particular, part of the proposed study will be aimed at examining whether any of the low-oxidation state ionic compounds of sulphur are responsible for the formation of the organic sulphides found in water. One of my long-term goals is to perform a mechanistic-approach study aimed at an understanding of how these reduced sulphur compounds form. My other long-term goal is geared towards providing useful practical steps necessary in the removal of offensive odours from water sources having such problems. Currently this is in part carried out through chlorination, which is primarily intended for removal of harmful microbes from our drinking water. The down side of chlorination is that any residual chlorine has the potential of reacting with some dissolved organic matter to produce trihalomethanes which are carcinogen-suspects.  I will investigate whether other oxidizing agents are suitable for removing the objectionable odours from our drinking waters. This study is expected to significantly contribute towards the understanding of the processes that cause offensive odours in water and to the development of effective and environmentally-friendly means of dealing with these odours.