关于硬水的英语论文-What is Hard Water 第2页
GPG
Mg/l 或ppm
硬度分级
小于1
小于17.1
软水
1-3.5
17.1-60
微硬水
3.5-7.0
60-120
较硬水
7.0-10.5
120-180
硬水
10.5以上
180以上
超硬水
Most waters possess hardness minerals in amounts from 3 to 50 gpg (51.3 to 855 mg/l). Unfortunately, where water is extremely hard, the problem is often compounded by the presence of other contaminants such as iron and manganese.
而多数地区的水质硬度在3-50 GPG。不幸的是，硬度过高的地区的水体，其中也伴生铁、锰等污染物问题。
Most people are 论文范文http://www.chuibin.com/ quite aware that a water containing 15 to 30 grains (256.5 to 513 mg/l) of hardness minerals is definitely hard and difficult to use.
硬度达到15-30 GPG(256.5-513 mg/l)的水，因为其硬度过高而难以被利用，这已被很多人所熟知。
On the other hand, many people will tolerate a 5 grain (85.5 mg/l) water that is very objectionable to anyone accustomed to using completely soft water.
另一方面，很多人可能会忍受5 GPG(85.5 mg/l)硬度的水，不过，对于已经习惯了使用软水的人士，则会难以接受。
Why Does Hard Water Constitute a Problem?
为何硬水会带来困扰？
Actually hardness is a source of many problems. One important trouble area is the way hardness minerals react with soaps and detergents.
So important is this aspect of the hardness problem that hardness is sometimes defined as "the effect of certain elements which combine with soap to form an insoluble material known as curd."
其实，水的硬度是很多困扰的根源，其中重要一项便是硬度离子会与皂液或清洁剂反应。这项困扰颇受关注，因而水的硬度有时也被定义为“水中某些离子与皂液混合后生成不溶性凝结物的效果”。
The list of elements that possess this property of hardness include iron, copper and manganese, all present normally in relatively small quantities. More common, of course, are calcium and magnesium, which are usually present in significant amounts. Clothes washed in zero soft water are free of troublesome hard water soap curd. For the homemaker water hardness makes home cleaning operations more difficult.
具有硬度特性的离子，包括铁、铜及锰，通常情形下，这些离子在水中的含量都很低。常见的硬度离子，当然是钙和镁，一般在水中的含量很高。在零硬度的水中洗涤衣物，可避免在硬水中洗涤带来的皂垢困扰。硬水让主妇的家居日常清洁工作更加吃力。