(1) Liquid chlorine disinfection
Advantages:
Liquid chlorine has low cost and convenient material source; You don’t need huge equipment; Easy to operate, when the amount of water treated is large, the treatment cost per unit water body is low; After chlorine disinfection, water can keep a certain amount of residual chlorine for a long time, so it has the ability of continuous disinfection, and the disinfection effect is good; Chlorine disinfection has a long history, more experience, is a relatively mature disinfection method.
Disadvantages:
Liquid chlorine is highly toxic and extremely volatile, once the leakage impact surface is large, the harm degree is deep; There is a risk of leakage during transportation, storage and use; The problem of disinfection by-products, after the use of liquid chlorine disinfection, often produce halogenated organic compounds and other disinfection by-products, will be harmful to human body; It has a long history of use, resulting in drug resistance, and the large use of liquid chlorine also brings environmental pollution and the promotion of human diseases; The mechanism of disinfection is single, which can not effectively kill Giardia and Cryptosporidium, and the effect on viruses and fungi is poor. Biological stability of drinking water.
Disinfection method:
Through the purchase of canned liquid chlorine, natural evaporation/evaporator evaporates the gaseous chlorine, through the chlorine system into the water for disinfection.
The disinfection system includes: civil chlorine storage, chlorine adding room, chlorine leakage absorption room, contact pool, etc. The equipment includes chlorine bottles, bus, vacuum regulator, chlorine adding machine, water ejector, residual chlorine meter, chlorine leakage absorption neutralization device, etc.
At present, the disinfection method is mainly used in large water plants.
(2) Sodium hypochlorite disinfection
Advantages:
It has the continuous disinfection effect of residual chlorine, simple operation, safer and more convenient than liquid chlorine; The use cost is higher than liquid chlorine, but lower than bleaching powder; It has better disinfection effect than liquid chlorine.
Disadvantages:
Sodium hypochlorite solution is not easy to be stored for a long time (the effective time is about one year). In addition, a large number of containers are needed to purchase from the factory, which is cumbersome and inconvenient to transport. Moreover, industrial products have some impurities, and the solution concentration is high and more volatile. The equipment is small and the use is restricted; Must consume a large amount of electricity and salt, and liquid chlorine can produce organic chloride and chlorophenol flavor; Sodium hypochlorite is easy to deteriorate, adding sodium hypochlorite has the possibility of increasing inorganic by-products (chlorate, hypochlorite and bromate); High concentration of drug, easy to produce drug resistance; It has little effect on metal ions, residual pesticides, chlorophenol benzene and other chemical organic compounds. It is corrosive to equipment, destructive to the environment and not environmentally friendly.
Disinfection method:
Sodium hypochlorite solution was prepared or purchased on site and put into water by dosing pump for disinfection.
At present, this disinfection method is mainly used in small water treatment stations (1T /h).
(3) chlorine dioxide disinfection
Advantages:
The disinfectant effect is good, the dosage is small, the effect is fast, the disinfection effect lasts for a long time, can keep the remaining disinfection dose; Strong oxidation, can decompose cell structure, and can efficiently destroy protozoa, spores, mold, algae and biofilms; Can simultaneously control the water iron, manganese, color, taste, smell; Affected by temperature and pH, pH range of use is 6-10, not affected by water hardness and salt amount; It does not produce trihalomethanes and haloacetic acid and other by-products, and can oxidize many organic compounds, thus reducing the toxicity and mutagenic properties of water and other characteristics; Chlorine dioxide is used for water disinfection. When its concentration is 0.5-1mg/L, it can kill 99% of bacteria in water within 1 minute. Its sterilization effect is 10 times that of chlorine gas, 2 times that of sodium hypochlorite, and its ability to inhibit viruses is also 3 times higher than chlorine and 1.9 times higher than ozone.
Disadvantages:
Chlorine dioxide disinfection produces inorganic disinfection by-products, chlorite ions (ClO2-) and chlorate ions (ClO3-), and chlorine dioxide itself is also harmful, especially at high concentrations. ClO2- and ClO3- are harmful to red blood cells, can interfere with the absorption and metabolism of iodine, and can raise cholesterol in the blood; In addition, the process of preparing stable chlorine dioxide is particularly strict and waste liquid is discharged. Acidic activator is needed to achieve better disinfection effect when used. There are also some technical problems in preparation and use, such as complex operation of chlorine dioxide, high reagent price and low purity. There are great safety risks in the transportation, storage and production of raw materials needed for chlorine dioxide production. Hydrochloric acid as the raw material of methamphetamine, lax monitoring will bring the risk of meth production.
Disinfection method:
Chlorine dioxide/chlorine mixed gas is produced by a field generator and put into water by a water ejector for disinfection.
The disinfection system includes: the civil construction has raw material storage, equipment room, contact pool, etc., equipment has raw material storage tank, chlorine dioxide generator, water ejector, etc.
At present, the disinfection method is mainly used in small and medium-sized water plants. Due to technical reasons, the equipment scale can not meet the disinfection requirements of large water plants.
(4) Ozone disinfection
Advantages:
Good sterilization effect, less dosage (0.1% can be), fast action, help coagulation; Can simultaneously control the water iron, manganese, color, taste, smell. No water quality change; No halogenated disinfection by-products; It is less affected by pH, water temperature and ammonia content; Than the traditional chlorine disinfectant disinfection effect is better; No energy consumption, simple operation
Disadvantages:
Ozone molecules are unstable and easy to decompose by themselves, and the retention time in water is very short, less than 30 minutes. Ozone disinfection produces bromate, bromate, aldehydes, ketones and carboxylic acid by-products, among which bromate and bromate are stipulated in the water quality standards, aldehydes, ketones and carboxylic acid by-products are some compounds harmful to health, so ozone disinfection is limited in use; Production complexity, high cost; For large and medium pipe network system, chlorine must be relied on to maintain the continuous disinfection effect in pipe network when using ozone disinfection; Disinfection has certain selectivity, such as penicillin, chloramphenicol has certain resistance to ozone, need a long time to kill it; Because its oxidation potential is 2.07, it can only treat 60-70% of phycotoxin, and has limited effect on many refractory chemical organic compounds. It has certain corrosion effect on natural rubber or natural rubber products or copper products (in the presence of water and gas). When the ozone generator is working, the flammable gas exceeding the explosion limit should not be introduced. Ozone penetration is weak, and the ability to kill bacteria deep in the object is low
Disinfection method:
Ozone is produced by field generator and put into water by cloth air cap or water injector for sterilization and disinfection.
The disinfection system includes: civil ozone generation room, contact pool, etc., equipment has air source, ozone generator, ozone injection device, exhaust gas destruction device, monitoring instrument and electric control system, etc.
At present, the disinfection method is mainly used in pure water plant, and it is also often used in deep purification of tap water and sewage in developed areas in China.
(5) Chloramine disinfection
Advantages:
Disinfection by-products are much less than liquid chlorine, among which haloacetic acid production is reduced by 90%, trihalomethanes production is reduced by 70%; It can last for a long time in the pipe network and effectively control the propagation of bacteria in the pipe network.
Disadvantages:
Long reaction time, slow action; The killing effect of Giardia and Cryptosporidium is not good; It may have a toxic reaction to the inherited gene.
(6) Disinfection with potassium monopersulfate compound salt
Advantages:
The non-combustible and non-explosive powder dosage form disinfectant overcomes the leakage, overturning, explosion and corrosion of other disinfectants in many aspects such as production, transportation, storage and use. Store at room temperature for up to two years; The first one in China does not contain chlorine and uses a variety of reactive oxygen species as bactericidal components, which fundamentally eliminates the generation of chlorinated by-products and greatly reduces the serious impact of traditional disinfectant by-products on human health (including carcinogenesis and reproductive toxicity). The unique and perfect chain cycle reaction enables the product to continuously produce a large number of active ingredients after entering the water, ensuring that the surplus of active ingredients in the water body of the disinfectant is not attenuated; The coexistence of a variety of active ingredients not only strengthens the bactericidal ability, but also expands the antibacterial spectrum, ensuring the disinfection and killing effect of various pathogenic microorganisms other than bacteria. It is little affected by temperature, pH value and other factors; Has a very strong ability to continue sterilization; Strong oxidation of equipment pipe wall passivation, prolong the service life of equipment; Easy to add and maintain, low comprehensive cost;
Disadvantages:
It is corrosive to a certain extent and does not mix with alkaline substances.
Post time: Sep-19-2022