Research of ozonation process of the biologically pre-purified municipal wastewater
Abstract
The paper considers the problem of post-treatment of municipal wastewater in Odessa using ozone. A significant place is given to the effect of the breakdown of toxic substances and important carcinogens. Based on theoretical studies, it was concluded that biological wastewater treatment does not guarantee a significant effect of the neutralization of many toxicants. The authors hypothesize the significant advantage of ozonation for the disposal and disinfection of wastewater compared to other methods, for example, chlorination. An important place is occupied by the search for optimal ozone treatment parameters. In laboratory conditions, data for mathematical modeling and optimization have been obtained. It has been established that the best treatment effect is achieved for the main wastewater pollutants, especially for synthetic surface-active substances (90 %) and BOD5 (65 %). Moreover, the processing time is 15 minutes at a dose of ozone of 20–25 mg/l. The concentration of total nitrogen decreases the least (20 %). It was found that a significant effect of disinfection by E. coli during ozonation is achieved by treating wastewater for 4 min at a dose of 3 mg/l of ozone. in a mixture of wastewater and natural water, this effect is achieved in 24 hours. The author's hypothesis of the gentle action of ozonation products for the widespread aquatic culture of Chlorella pyrenoidosa is confirmed. A significant effect of destruction under the influence of ozone of carcinogens was observed. It was found that up to 82 % of benzpyrene in wastewater is destroyed within 16 minutes at a dose of 15 mg/l. The authors conclude that ozonation is a universal method for the purification of biologically treated municipal wastewater, which has a significant effect on the destruction of many toxicants and pathogenic microflora, without the presence of ozonation products that inhibit the development of natural aquatic cultures. Further research should focus on finding low cost ozone synthesis methods.
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