| Water resources is an indispensable living resource for human survival,and it is an important factor to ensure social harmony and stability and production development.Water pollution is becoming increasingly serious and a serious shortage of water resources,accelerating people’s exploration and research on wastewater reuse resources.Urban sewage treatment plant secondary effluent quality and stability,large amount of resources,is a good choice for the second source of water.In view of the existing processing technology to remove the efficiency,large footprint,high cost and other issues,this study has developed a high-level oxidation process.And the operation effect,process parameters and so on of the combined process were investigated.The results of denitrification treatment showed that NO3-and NO2-were 0.03 mg/L,0.001 mg/L,and the removal rate was 99%and 99.7%respectively after 45 d treatment with secondary water.NH4+-N decreased from 14 mg/L to 2 mg/L(<A standard 3 mg/L),and the influent load was 0.5 kg/(m3·d),Time gradually stabilized,stable after the removal rate was 85.7%;Organic nitrogen decreased from 0.85 mg/L to 0.17 mg/L,and the removal rate was 80%after stable;TN decreased from 18 mg/L to 6.5 mg/L(<A standard 10 mg/L),the influent load is 0.65 kg/(m3·d),and the fluctuation curve of TN is obviously larger than that of other indexes.This is because the organic nitrogen,nitric acid-nitrite,ammonium Root ion and other changes will affect the value of TN,stable after the removal rate of 64%.Turbidity decreased from 4.4 NTU to 0.4 NTU,indicating that the combined process of almost no suspended particulate matter;TP content before and after treatment were 1.07 mg/L,0.30 mg/L(= A standard 0.30 mg/L),the removal rate was about 72%.The results show that the two-layer denitrification tank has the functions of denitrifying and removing phosphorus,and the treatment effect is good.The results of organic pollutants treatment showed that the COD of effluent from 50 mg/L to 12 mg/L(<A standard 30 mg/L)The load is 1.8 kg/(m3 d),the final removal rate is 76%;TOC is reduced from 8.1 mg/L to 2.0 mg/L,the inlet load is 0.29 kg/(m3·d),to achieve a stable removal rate of 75%.The EEM scan secondary water contains tryptophan protein and aromatic protein.The proportion of PⅠ + Ⅱ+Ⅳ in the total fluorescence intensity is more than 80%,and the proportion of P Ⅰ + Ⅱ + Ⅳ in the total fluorescence intensity is less than 20%after the combined process.The results showed that the combined process significantly degraded the metabolites and protein substances of the cells,and significantly improved the effluent quality.A double-layer denitrification filter+MBR+ozone process was developed for upgrading and reconstruction of wastewater treatment plant in Tianjin.The hybrid process was used to treat secondary effluent from wastewater treatment plant in Tianjin.The results showed that ammonia nitrogen(NH4+-N)concentration was 2 mg/L,total nitrogen(TN)concentration was 6.5 mg/L,total phosphorus(TP)concentration was 0.3 mg/L,and chemical oxygen demand(COD)concentration was 12 mg/Lin the effluent of hybrid process.The hybrid process can significantly reduce the pollutants in the secondary effluent of the municipal wastewater treatment plant,and is suitable for long-term engineering application. |
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