Eight Different Processes for Pure Water Treatment

Pure water refers to purified water, typically sourced from municipal tap water. Through multi-layer filtration, harmful substances such as microorganisms are removed, but essential minerals like fluoride, potassium, calcium, and magnesium are also lost.

I. Ozone Sterilization for Ultrapure Water Treatment

The disinfection principle of ozone (O3) is as follows: Ozone's molecular structure is unstable at room temperature and pressure, quickly decomposing into oxygen (O2) and single oxygen atoms (O). The latter is highly reactive and has a strong oxidizing effect on bacteria, killing them. Excess oxygen atoms recombine to form ordinary oxygen atoms (O2), leaving no toxic residue. Therefore, it is called a pollution-free disinfectant. It not only has a strong killing ability against various bacteria (including hepatitis viruses, E. coli, Pseudomonas aeruginosa, and other bacteria), but is also effective against toxins.

1. The sterilization mechanism and process of ozone is a biochemical process, oxidizing and decomposing the glucose oxidase necessary for the oxidation of glucose within bacteria.

2. It directly interacts with bacteria and viruses, damaging their organelles and ribonucleic acid, and decomposing DNA, RNA, proteins, lipids, and polysaccharides, thus disrupting bacterial metabolism and reproduction.

3. It penetrates cell membrane tissues, invading the cell membrane and acting on the outer membrane lipoproteins and internal lipopolysaccharides, causing permeability distortion and leading to cell lysis and death. It also dissolves, denatures, and destroys genetic material, parasitic bacteria, parasitic virus particles, bacteriophages, mycoplasmas, and pyrogens (bacterial and viral metabolic products, endotoxins) within the dead bacteria.

II. Activated Carbon Adsorption Pure Water Treatment Process

Activated carbon primarily removes organic impurities such as discoloration, odor, residual chlorine, and residual disinfectants from water through adsorption and filtration.

III. Membrane Microfiltration (MF) Pure Water Treatment Process

Membrane microfiltration includes three forms: depth filtration, screen filtration, and surface filtration.

Depth filtration uses a matrix made of woven fibers or compressed materials to retain particles through inertial adsorption or trapping, such as commonly used multi-media filtration or sand filtration. Depth filtration is a relatively economical method, removing over 98% of suspended solids while protecting downstream purification units from clogging; therefore, it is often used as pretreatment.

Surface filtration has a multi-layered structure. When a solution passes through the filter membrane, particles larger than the internal pores are retained and mainly accumulate on the membrane surface, such as commonly used PP fiber filters. Surface filtration can remove over 99.9% of suspended solids, so it can also be used for pretreatment or clarification.

Sieve membranes have a generally uniform structure, like a sieve, retaining particles larger than the pore size on the surface (the pore size of these membranes is very precise), such as the point-of-use security filters used in ultrapure water systems. Microfiltration is generally placed at the final point of use in the purification system to remove residual trace resin flakes, carbon deposits, colloids, and microorganisms.

IV. Ion Exchange (IX) Pure Water Treatment Process

The principle of ion exchange is to purify water by exchanging inorganic salts and cations in the water, such as calcium ions (Ca2+), magnesium ions (Mg2+), sulfate (SO42-), and nitrate (NO3-), with ion exchange resin.

V. Reverse Osmosis (RO) Pure Water Treatment Process

This process uses pressure as the driving force and the selective permeability of the reverse osmosis membrane (allowing only water to pass through but not solutes) to extract pure water from water containing various inorganic substances, organic matter, and microorganisms. The pore size of the reverse osmosis membrane is less than 10 angstroms (1 angstrom equals 10⁻¹⁰ meters), possessing extremely strong sieving ability. Its desalination rate is as high as 99%, and its sterilization rate is greater than 99.5%. It can remove impurities such as inorganic salts, sugars, amino acids, bacteria, and viruses from water. Based on the quality of raw and finished water, and with proper design, RO (Reverse Osmosis) is the most economical and effective method for purifying tap water, and also the best pretreatment method for ultrapure water systems.

VI. Ultrafiltration (UF) Pure Water Treatment Process

While microporous membranes remove particles based on their pore size, ultrafiltration (UF) membranes act like molecular sieves, allowing the solution to pass through extremely fine pores based on size, thus separating molecules of different sizes in the solution.

Ultrafiltration membranes are strong, thin, and selectively permeable membranes, typically considered to have a pore size of approximately 0.01 μm. They can retain molecules larger than a certain size, including colloids, microorganisms, and pyrogens. Smaller molecules, such as water and ions, can pass through the membrane.

VII. Ultraviolet (UV) and Ozone Sterilization Ultrapure Water Treatment Process

Using 254nm/185nm ultraviolet light emitted by ultraviolet lamps can effectively kill bacteria and degrade organic matter.

VIII. EDI Pure Water Treatment Process

A new method for deionized water treatment. Also known as continuous electro-desalination technology, the EDI device uses ion exchange resin sandwiched between anion/cation exchange membranes to form an EDI unit. This method eliminates the need for resin regeneration with acids or alkalis, making it environmentally friendly.