珏儿对《Drinking Water》的笔记(3)

typical quality standards for drinking water parameter unit value ecoli 100/ml 0 colony count ml 100 pesticide ug/l 0.1 bromate ug/l 1 iron mg/l 0.2 manganese mg/l 0.05 ammonia mg/l 0.2 suspended solid fte 1 hardness mmol 1~2.5 sodium mg/l 150 chloride mg/l 150 ph 7.0~9.5 temperature centigrade less than 25

concentration of compounds in water types of compound typical concentration unit sea salt 36 g/l sludge 10(1%) g/kg dissolved material 1,500 mg/l nitrate 50 mg/l toxic(light) 10 ug/l toxic(heavy) 0.1 ug/l endocrine disrupter 1 ng/l

About the water treatment, in Netherland, chlorine was no longer used as a disinfection anymore, because it will cause the formation of trihalomethanes which have negative effects to human health. The hardness is another factor need to be considered. The Netherlands government is the only government supply soft water as drinking water, they lists some benefits of soft water suvh as less metals in water sewage, better soup while showing, saving on washing powder, better taste and appearance, etc. The Dutch water supply companies has get rid of any fluoride in drinking water because they thought the fluoride also may cause some healthy problems.