Drinking water is completely different from industrial water:

(1) different water production process;Different water quality;Different USES

A. different water production processes

(a) common water preparation processes for drinking purified water:

Large equipment: tap water → quartz sand filter → activated carbon filter → security filter → reverse osmosis → water

Household water purifier: tap water →PP cotton filter → particulate activated carbon filter → carbon rod filter → reverse osmosis → post activated carbon filter → water

(b) the industrial pure water for electronic water level water Ⅰ level (for example) water making process:

Tap water to quartz sand filter, activated carbon filter to soften cation exchange (< 5 m3 / h) or adding scale inhibitors (5 m3 / h or higher) - > security filtering - ultrafiltration - level 1 reverse osmosis to adjust pH value adding NaOH solution, level 2 reverse osmosis - Yang bed - vacuum degassing tower to Yin bed to early mixed bed, EDI, deaerator (palladium catalytic resin, through hydrogen) - 254 UV (sterilization) - 0.2 mu m filter - 185 UV (removal of TOC) to extract mixed bed, 0.2 mu m filter to terminal polishing mixed bed, water

It can be seen from the above that although both drinking water and industrial water are made from tap water purification, there are many more processes to make industrial water, the process is much more complex, and the equipment is much more expensive.The author has long been in the production of large-scale integrated circuit (commonly known as "chip") factory ultra-pure water workshop work, the detection of water quality, so know.

B. different water quality

(a) national standard of the People's Republic of China: electronic-grade water (GB/T 11446.1-2013). Technical indicators of water quality are shown in table 1.We can see from table 1, and even the most demanding industrial pure water EW - Ⅰ, the water still contains a variety of minerals.In fact, we in the factory every day to test the industrial water in a variety of negative, cationic namely mineral content.There is no such thing as "pure water" without minerals.

Table 1 technical indicators of electronic grade water quality

(b) the quality of potable and industrial pure water is very different. We have listed the same items in the relevant water quality standards for comparison, as shown in table 2.

As can be seen from table 2, the mineral, various anions and cations contained in drinking pure water are much more than that of industrial pure water.

Table 2. Water quality index comparison table of drinking water and industrial pure water

Note 1, * : according to annex 4C of document no. 161 [2001] of the ministry of health, health law supervision, ministry of health [2001], health safety and function evaluation standard for domestic drinking water quality processors -- reverse osmosis treatment device, 6.4, except for the indexes listed in table 7, other items shall not exceed the limits specified in GB5749, and lead, fluoride, nitrate, etc. shall reach the corresponding removal rate.

Note 2: according to GB5749 and CJ94, nitrate (N) ≤10mg/L, nitrate (NO3) ≤44300 g/L.

(c) electrical conductivity or its reciprocal resistivity is an important indicator of the content of ionic impurities (i.e. minerals) in water.The lower the conductivity, the higher the resistivity, and the lower the content of ionic impurities (i.e. minerals) in the water.

From table 3 we can see the execution standard, TDS value, conductivity and resistivity of various water.

Table 3 execution standard, TDS value, conductivity and resistivity of all kinds of water

Note 1 the conductivity of water (m 2 /cm) is calculated as the total dissolved solids (mg/L) x2.If press CJ94, drinking water purification of the total solid solubility index for 500 mg/L, convert electrical conductivity is 1000 mu s/cm, then convert the resistivity (conductivity) from bottom, 0.001 M Ω/cm

C. different USES

(a) the pure drinking water made by reverse osmosis has a relatively high mineral content, is hygienic, safe, healthy and clean, and is suitable for people to drink.