Disinfection byproduct(DBP)precursors in wastewater during the reversed anaerobic–anoxic–oxic(A~2/O)process,as well as their molecular weight(MW)and polarity-based fractions,were characterized with UV scanning,fluorescence excitation emission matrix,Fourier transform infrared and nuclear magnetic resonance spectroscopy.Their DBP formation potentials(DBPFPs)after chlorination were further tested.Results indicated that the reversed A~2/O process could not only effectively remove the dissolved organic carbon(DOC)and dissolved total nitrogen in the wastewater,but also affect the MW distribution and hydrophilic–hydrophobic properties of dissolved organic matter(DOM).The accumulation of low MW and hydrophobic(HPO)DOM was possibly due to the formation of soluble microbial product-like(SMP-like)matters in the reversed A~2/O treatment,especially in the anoxic and aerobic processes.Moreover,DOM in the wastewater displayed a high carbonaceous disinfection byproduct formation potential(C-DBPFP)in the fractions of MW100 k Da and MW5 k Da,and revealed an increasing tendency of nitrogenous disinfection byproduct formation potential(N-DBPFP)with decrease of MW.For polarity-based fractions,the HPO fraction of wastewater showed significantly higher C-DBPFP and N-DBPFP than hydrophilic and transphilic fractions.Therefore,although the reversed A~2/O process could remove most DBP precursors by DOC reduction,it led to the enhancement of DBPFP with the formation and accumulation of low MW and HPO DOM.In addition,strong correlations between C-DBPFPs and SUVA,and between N-DBPFPs and DON/DOC,were observed in the wastewater,which might be helpful for DBPFP prediction in wastewater and reclaimed water chlorination. 相似文献
In this study, a full-scale internal circulation(IC) reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste(MSW)incineration plant, in which anaerobic sludge granulation was intensively investigated. Results showed that the IC reactor achieved excellent treatment performance under high organic loading rates(OLR) of 21.06–25.16 kg chemical oxygen demand(COD)/(m3? day). The COD removal efficiency and biogas yield respectively reached 89.4%–93.4% and 0.42–0.50 m3/kg COD.The formation of extracellular polymeric substances(EPS) was closely associated with sludge granulation. Protein was the dominant component in sludge EPS, and its content was remarkably increased from 21.6 to 99.7 mg/g Volatile Suspended Solid(VSS) during the reactor operation. The sludge Zeta potential and hydrophobicity positively correlated with the protein/polysaccharide ratio in EPS, and they were respectively increased from-26.2 m V and 30.35% to-10.6 m V and 78.67%, which was beneficial to microbial aggregation. Three-dimensional fluorescence spectroscopy(3 D-EEM) and Fourier transform infrared spectroscopy(FT-IR)analysis further indicated the importance of protein-like EPS substances in the sludge granulation. Moreover, it was also found that the secondary structures of EPS proteins varied during the reactor operation. 相似文献
A novel technology of two-step fast microwave-assisted pyrolysis(f MAP) of corn stover for bio-oil production was investigated in the presence of microwave absorbent(Si C) and HZSM-5catalyst. Effects of f MAP temperature and catalyst-to-biomass ratio on bio-oil yield and chemical components were examined. The results showed that this technology, employing microwave, microwave absorbent and HZSM-5 catalyst, was effective and promising for biomass fast pyrolysis. The f MAP temperature of 500°C was considered the optimum condition for maximum yield and best quality of bio-oil. Besides, the bio-oil yield decreased linearly and the chemical components in bio-oil were improved sequentially with the increase of catalyst-to-biomass ratio from 1:100 to 1:20. The elemental compositions of bio-char were also determined. Additionally, compared to one-step f MAP process, two-step f MAP could promote the bio-oil quality with a smaller catalyst-to-biomass ratio. 相似文献
Journal of Material Cycles and Waste Management - The use of industrial byproducts as replacement of natural aggregates has been extensively investigated to design eco-friendly roads. One of the... 相似文献
Previous studies demonstrated that short-term exposure to gaseous pollutants (nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3)) had a greater adverse effect on cardiovascular disease. However, little evidence exists regarding the synergy between gaseous pollutants and cardiovascular disease (CVD). Therefore, we aimed to estimate the effect of individual gaseous pollutants on hospital admissions for CVD and to explore the possible synergistic effects between gaseous pollutants. Daily hospitalization counts for CVD were collected from January 1, 2014, to December 31, 2015. We also collected daily time series on gaseous pollutants from the Environment of the People’s Republic of China, including NO2, SO2, and O3. We used distributed lag nonlinear models (DLNMs) to assess the association of individual gaseous pollutants on CVD hospitalization, after controlling for seasonality, day of the week, public holidays, and weather variables. Then, we explored the variability across age and sex groups. In addition, we analyzed the synergistic effects between gaseous pollutants on CVD. Extremely low NO2 and SO2 increase the risk of CVD in all subgroup at lag 7 days. The greatest effect of high concentration of SO2 was observed in male and the elderly (≥ 65 years) at lag 3 days. Greater effects of high concentration of O3 were more pronounced in the young (< 65 years) and female at lag 3 days, while the effect of low concentration of O3 was greater in male and the young (< 65 years) at lag 0 day. We found a synergistic effect between NO2 and SO2 for CVD, as well as between SO2 and O3. The synergistic effects of NO2 and SO2 on CVD were stronger in the elderly (≥ 65) and female. The female was sensitive to synergistic effects of SO2-O3 and NO2-O3. Interestingly, we found that there was a risk of CVD in the susceptible population even for gaseous pollutant concentrations below the National Environmental Quality Standard. The synergy between NO2 and SO2 was significantly associated with cardiovascular disease hospitalization in the elderly (≥ 65). This study provides evidence for the synergistic effect of gaseous pollutants on hospital admissions for cardiovascular disease.