| The composition of substances in the reclaimed water is complex,and it is easy to produce disinfection by-products?DBPs?during disinfection.At present,the removal of its precursors has received extensive attention.Therefore,the effective removal of DBPs precursors and the reduction of disinfection byproduct formation potential?DBPsFP?are of great significance for improving water quality.This paper explores the related factors?reaction time,oxidant dosage,pH value?based on ultraviolet advanced oxidation technology?UV-AOPs?to remove the precursors of DBPs,as well as the oxidation of UV-AOPs to organic matter and three-dimensional fluorescence?3D-EEM?Analysis,exploring the best UV-based advanced oxidation technology for removing DBPs precursors;studying the effects of water body characteristics on advanced oxidation and the removal of generated DBPs;for bromine-containing wastewater treatment process DBPs precursors The removal effect and bromine ion?Br-?concentration are used to investigate the type change law.The main research results are as follows:?1?The degradation of organic matter by uv/hydrogen peroxide?UV/H2O2?,uv/potassium persulfate?UV/PDS?,uv/Fe?VI??UV/Fe?VI??,uv/percarbonate?UV/SPC?was significantly better than that by single UV and single oxidant,which proved the feasibility based on uv advanced oxidation process.The DBPs production was obviously inhibited in the experiment of removing DBPs precursor UV/PDS compared with UV/H2O2?UV/Fe?VI??UV/SPC.The initial pH value is 5.0,PDS dosage the degradation rate of UV254?COD?TOC was 72.4%?48.9%and 23.5%at 60 min of 0.5 mmol·L-1,reaction,and the removal of HAAs precursor was better than that of THMs,removal rate of 63.8%and 22.2%,respectively.?2?The concentration of organic matter in reclaimed water was simulated by water distribution,purified water was used to dilute reclaimed water and organic matter was changed by changing aeration time.In the reaction with higher concentration of organic matter,the dosage of oxidant is certain,the residual macromolecular organic matter in water increases,and the small molecular organic matter also exists,which makes the reaction efficiency decrease.When the dilution ratio of water in pure water is 4:1,the highest removal rate of UV254?COD?TOC is 70.6%?32.4%and 12.7%,respectively,which also proves the concentration and DBP of organic matters production is positively correlated.when the sludge aeration time was 90 min,the removal rates of UV25454 and DOC were 77.7%and 76.1%,respectively.the organic matter produced by UV/PDS oxidation aeration was significantly lower than that produced by non-oxidation aeration.?3?With the increase of chloride ion,both THMs and HAAs showed an upward trend,but when the chloride ion reached a certain content,the DBPs content gradually decreased,which had no significant effect on the nitrogen-containing disinfection by-product HANs.The presence of nitrate has a certain inhibitory effect on the removal of organic matter.The removal rates of TOC and UV25454 in nitrate-free samples are higher than those in nitrate-containing samples.The removal rates are 18.5%and 7.3%higher,respectively.The increase in bromine ion concentration has promoted the production of hypobromous acid?HBrO?,making the trend of DBPs types change to high bromine and low chlorine.UV/PDS also has a good removal effect on the generated DBPs.After 60 minutes of reaction,the removal rates of THMs,HAAs,HANs,and CH were 90.3%,83.3%,82.4%,and 64.7%,respectively.?4?For the treatment process of bromine-containing sewage with A2/O as the main,the removal effect of organic matter in the sewage is very significant.THMsFP gradually decreases in the treatment along the way,and the HAAsFP and SUVA values increase,that is,HAAs The important precursors are highly aromatic organic substances,and bromine-containing disinfection by-products?Br-DBPs?account for 50%to 65%of the total DBPs;Before and after A2/O treatment,with the increase of Br-concentration,the proportion of bromine binding factor?BIF?in THMs increased from 0.5 to 0.8,and the proportion of BIF in HAAs increased from 0.51 to 0.62.The increasing trend,that is,the increase of bromide ion concentration changes the type of DBPs from chlorine to bromine. |
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