Study On The Efficacy Of Ozone-Tea Polyphenols Combined Disinfection And Microbial Characteristics Of Pipeline Network

In traditional drinking water disinfection methods,chlorine disinfection is easy to produce disinfection by-products,ozone and ultraviolet disinfection have no sustainability.In the face of the country's major needs in strengthening the safety and security of drinking water and improving the quality of water,it is urgent to study green and efficient drinking water disinfection treatment technology.Tea polyphenols,as a natural tea extract,have the functions of inhibiting and killing bacteria and viruses,and also have health effects.This paper studied the disinfection effect of ozone-tea polyphenols combined disinfection,determined the disinfection durability of combined disinfection,and observed the concentration changes of tea polyphenols in the disinfection process.At the same time,the microbial characteristics of the pipeline network were studied by simulating the pipeline network system,which provided a theoretical basis for determining the feasibility of the application of ozone-tea polyphenols disinfection process.In the study of ozone-tea polyphenols combined disinfection effect,it was found that when tea polyphenols were used to disinfect drinking water alone,if the dosage of tea polyphenols was low,the disinfection effect could not meet the requirements of the total number of bacteria in the Sanitary Standards for Drinking Water(GB5749-2006);if the dosage of tea polyphenols was increased,the chroma of the effluent could not reach the standard.When combined ozonetea polyphenols disinfection,ozone disinfection will produce a certain concentration of oxidative free radicals in water.For tea polyphenols,when the concentration of oxidative free radicals in water is low,tea polyphenols exhibit oxidative activity,release hydroxyl radicals,and increase the concentration of hydroxyl radicals in water;when the concentration of oxidative free radicals in water is high,tea polyphenols exhibit antioxidant activity.In the process of ozone-tea polyphenols combined disinfection,the concentration of oxidative free radicals in water is related to the dosage of ozone and the contact time of ozone before adding tea polyphenols,so the dosage of ozone,the contact time of ozone and the dosage of tea polyphenols should be taken into account when determining the optimum conditions of ozonetea polyphenols combined disinfection.Interaction between them.Through the response surface methodology design principle design experiment,the optimum experimental conditions of ozone-tea polyphenols combined disinfection obtained by optimization model equation are: ozone dosage 2.5 mg/L,ozone contact time 25 min,tea polyphenols dosage 20 mg/L.The results of simulating the operation of PPR pipeline network show that the biological safety of water quality is better,whether ozone-tea polyphenols or ozone-sodium hypochlorite can meet the microbial safety requirements;in contrast,stainless steel pipeline network has the risk of microbial exceeding the standard in the way of ozone-sodium hypochlorite combined disinfection.Scanning electron microscopy was used to observe the microbial morphology of the inner wall of the pipe network.During ozone disinfection alone,microorganisms gathered quickly and formed obvious spatial structure on the inner wall of the pipe network.Ozonesodium hypochlorite combined disinfection made the microbial structure of the pipe wall appear larger porous erosion,and the microbial community structure loose and easy to fall off.Ozone-tea polyphenol combined disinfection resulted in the formation of microbial community structure in the pipe network.Slow,and due to the adsorption of tea polyphenols on the inner wall of the pipe network,the microbial community on the pipe wall is thin and can not form a layered spatial structure.By comparing the community structure of microorganisms in water and inner wall of pipe network under different pipe materials and different disinfection methods,the microbial community structure was analyzed at five levels: phylum,class,order,family and genus.From the subordinate level,compared with ozone disinfection alone,ozone-tea polyphenols combined disinfection had stronger inhibitory effect on Bacillus and Hydrophage,and at the same time,it had stronger inhibitory effect on Bacillus and Hydrophage.Ozone-sodium hypochlorite combined disinfection methods such as Cystis,Pseudomonas and Porphyromonas could not control microbial populations,and ozone-tea polyphenols combined disinfection had better control effect.In order to ensure the safety of water supply network in operation,ozonetea polyphenols combined with ozone-sodium hypochlorite combined with two disinfection methods can ensure the safety of microbial quantity in water supply network when the pipe material is PPR.For some chlorine-resistant bacteria,tea polyphenols have better killing effect.