The influence of prefabricated pipe cement coatings and those made during pipe renovation on drinking water quality

（水泥内衬和水泥修复对水质的影响）

Anna Młyńska and Michał Zielina

Cracow University of Technology, Faculty of Environmental Engineering, Institute of Water Supply and Environmental Protection, ul. Warszawska 24, 31-155 Cracow, Poland

1.2 The risk of water contamination resulting from contact with the cement mortar coating

The risk of the leaching chemical elements from the cement coatings into the water  is determined by the type of cement used. For example, the greatest amount of aluminium is leached from a high-alumina cement coating. In turn, the greatest amount of calcium  is leached from a Portland cement coating [9, 10]. In the case of using blast furnace slag cement for coating, the risk of leaching a greater amount of aluminium and calcium is rather small. Many experiments proved that the greatest impact of cement coating on water quality initially is mainly related to the significant growth of pH [4, 10, 12–15] and aluminium concentration [4, 10, 13–15]. It is also probable that some heavy metals will be leached from the cement coating into the water. Numerous investigations on leaching trace elements from cements into the water were conducted and described in the literature [4,  13–17].

Even a small amount of heavy metal in the human body can contribute to many different health problems. In the Netherlands, in 1996, a great amount of aluminium leaching from a new cement coating was noticed. This leached aluminium contributed to the death of some patients in a haemodialysis centre as a consequence of aluminium poisoning. Aluminium was leached to the water from a newly-installed water system covered inside by a protective cement coating. The concentration of aluminium was forty times higher than the specified limit [18]. Thus, the concentration of aluminium in water making contact with a cement coating in the initial period of time should be controlled.  

Since both pipe cementing techniques and type of used cements significantly influence the dissolution and leaching of chemical components from the cement coating,  a comparison of cement coatings manufactured in factories and prepared on a building site during renovation on water quality was performed in this study. The paper presents the change of chemical elements such as aluminium, chromium, lead and cadmium in water samples coming into contact with two different cement coatings - manufactured in a factory and prepared in a laboratory.  

1.2 与水泥砂浆涂层接触导致水污染的风险

从水泥涂料中浸出化学元素到水中的风险取决于所用水泥的类型。 例如，最大量的铝从高铝水泥涂层中浸出。 反过来，最大量的钙从波特兰水泥涂层中浸出[9,10]。 在使用高炉矿渣水泥进行涂覆的情况下，浸出更多铝和钙的风险相对小一些。 许多实验证明，水泥涂层对水质的影响最初主要与pH [4,10,12-15]和铝浓度[4,10,13-15]的显着增长有关。 一些重金属也可能从水泥涂层中浸出到水中。 从水泥中浸出微量元素到水中的大量研究进行了描述，并在文献[4,13-17]中进行了描述。

即使是人体中的少量重金属也会导致许多不同的健康问题。 在荷兰，1996年，人们注意到从水泥涂层中浸出了大量的铝。 由于铝中毒，这种浸出的铝导致血液透析中心的一些患者死亡。 铝从新安装水泥内衬中浸入水中。 铝的浓度比规定的极限高40倍[18]。 因此，应控制在初始时间内与水泥涂层接触的水中铝的浓度。

由于管道水泥内衬技术和使用过的水泥的类型都会显着影响水泥涂层中化学成分的溶解和浸出，因此本研究对工厂生产的水泥涂料和在水质改造期间在施工工地上水泥涂料修复进行了比较。 本文介绍了水样中铝，铬，铅和镉等化学元素与两种不同水泥涂料接触的变化 - 在工厂生产并在实验室制备。