Ozone Disinfection Applied in Secondary Water Supply Project
As a kind of strong oxidant, ozone has been widely used in many fields, and it has a long history in water purification process. However, due to the complexity of the ozone disinfection system equipment, large investment and high power consumption, it is only adopted by a few developed countries before. Since the 90s of the 20th century, due to suspecting that chloroform carcinogenic generated by water organic matter and chlorine disinfection, many countries gradually developed interests for ozone disinfection. In our country, ozone disinfection in general is in the initial stage, especially in the water purification process, but in the area of secondary water supply engineering, ozone disinfection has been widely used, and has accumulated some experience.
Ozone disinfection properties
a. Fast sterilization speed and good effects
The results showed that after 2 minutes of 0.45mg/L ozone action, the polio virus was killed, such as chlorine disinfection, the dose of 2mg/L was 3 hours. Ozone can not only kill all pathogenic bacteria, fluorescent bacteria, deformation bacteria, bacteria and other microorganisms, but for some of the common disinfectant resistant microorganisms it also have a very significant bactericidal effect. At the same time, ozone disinfection was almost unaffected by ph.
b. Able to remove organic matter
Ozone can remove a variety of organic matters, especially toxic and harmful micro pollutants, and can make non biological degradation of biological degradation, greatly reducing the cost of treatment.
c. Able to deodorize and decolorize
Ozone can effectively remove odor, argillaceous odour and mouldiness caused by a variety of algae. It is also very effective in decolorization of some colloidal substances and organic matter.
d. Less residue in the water and fewer additional chemical pollutants
There is less residue left in the water after ozone disinfection treatment.It doesn't generate odor such as chlorophenols, also won't produce chloroform and other chlorinated disinfection by-products.
e. Ozone can be generated on site and all it needs is electricity.
Application of ozone disinfection
Mix ozone with water through the water jet and then enter the water tank for full contact with the mixing and reaction. Then transport it to the district network through water pump.
Selection of ozone generator
For secondary water supply, water treatment by ozone generator must use oxygen source ozone generator. If with air source ozone generator, it will produce large amounts of nitrogen oxides. If mixed with water, it will produce carcinogenic substances such as nitrite. It is better use pure oxygen source. However, the cost is too high. Considering the cost of capital and practicability, it is better use O3 Tech ozone oxygen making machine. Built-in oxygen in air as raw material, oxygen purity reaches more than 93%, is almost pure oxygen. No nitrogen oxides.
The germicidal efficacy of ozone mainly depends on the amount of ozone in water, the degree of dispersion of ozone gas in water (i.e., whether the mixture is uniform or not, and the time of ozone and water contact). The higher the concentration of ozone in water, the better the effect of sterilization. But not the more the amount of investment, the better. It can not only caused a waste of more, but also result in a sense of physical discomfort for users. Also the status of water quality should also be considered. For the secondary water supply project, since the raw water quality is good, ozone dosage is generally 0.5 ~ 1.5 mg /L.
Adding time control
Theoretically speaking, it should be casting ozone 24 hours continuouslly, so that it can maintain a continuous disinfection without causing secondary pollution to water quality. However, in the past, the application of ozone disinfection shows that it is not only a waste but not conducive to the health of the human body after inhalation if ozone concentration is too high. As long as enough to ensure adequate contact time, the effect of disinfection will be ideal. Designed to add 6 times a day, an average of 4 h every time, each time 1h.