Organic matter is known to be the precursor of numerous chlorination by-products. Organic matter in the secondary effluent from the Wenchang Wastewater Treatment Plant （Harbin, China） was physically separated into t...Organic matter is known to be the precursor of numerous chlorination by-products. Organic matter in the secondary effluent from the Wenchang Wastewater Treatment Plant （Harbin, China） was physically separated into the following fractions： particulate organic carbon （1.2-0.45 μm）, colloidal organic carbon （0.45-0.1 μm）, fine colloidal organic carbon （0.1-0.025 μm）, and dissolved organic carbon （DOC） （〈 0.025 μm）. Moreover, 〈 0.45 μm fraction was chemically separated into hydrophobic acid （HPO-A）, hydrophobic neutral （HPO-N）, transphilic acid （TPI-A）, transphilic neutral （TPI-N）, and hydrophllic fraction （HPI）. The chlorine reactivity of these organic fractions obtained from both size and XAD fractionations were evaluated. The structural and chemical compositions of the HPO-A, HPO-N, TPI-A, and TPI-N isolates were characterized using elemental analysis （C, H, O, and N）, Fourier transform infrared spectroscopy （FT-IR）, and proton nuclear magnetic resonance spectroscopy （1H-NMR）. Results showed that DOC was dominant in terms of total concentration and trihalomethane formation potential （THMFP）, and there was no statistical difference in both specific THMFP （STHMFP） and specific ultraviolet light absorbance among the 0.45, 0.1, and 0.025 ixm filtrates. HPO-A had the highest STHMFP compared to other chemical fractions. HPO-A, HPO-N, TPI-A, and TPI-N contained 3.02%-3.52% of nitrogen. The molar ratio of H/C increased in the order of HPO-A 〈 HPO-N 〈 TPI-A 〈 TPI-N. The O/C ratio was relatively high for TPI-N as compared to those for the other fractions. ^1H-NMR analysis of the four fractions indicated that the relative content of aromatic protons in HPO-A was significantly higher than those in the others. The ratio of aliphatic to aromatic protons increased in the order of HPO-A 〈 HPO-N 〈 TPI-A 〈 TPI-N. FT-IR analysis of the four fractions showed that HPO-A had greater aromatic C=C content whereas HPO-N, TPI-A, and TPI-N had greater aliphatic C-H content. TPI-N contained more oxygen-containing functional groups than the other fractions.展开更多
Resin adsorption technique with XAD-8 and XAD-4 was used to characterize the raw water from Erlong reservoir in Jilin province of China. The NOM chemical composition sequences of four organic fractions in the raw wate...Resin adsorption technique with XAD-8 and XAD-4 was used to characterize the raw water from Erlong reservoir in Jilin province of China. The NOM chemical composition sequences of four organic fractions in the raw water, from high to low, are fulvic acid （FA） fraction, hydrophilic non-acid （HPINA） fraction, hydrophilic acid （HPIA） fraction, and humic acid （HA） fraction. Experimental results show that FA is the main precursor of THMFP among the four organic fractions. However, HA or hydrophobie acid exhibits the highest chlorination activity in forming THMs. It is also found that the value of FI/DOC or SUVA and the specific THMFP have better positive correlation. It is implied that certain source water has unique nature of NOM and DBPs.展开更多
Characterizing natural organic matter （NOM）, particles and elements in different water treatment processes can give a useful information to optimize water treatment operations. In this article, transformations of pa...Characterizing natural organic matter （NOM）, particles and elements in different water treatment processes can give a useful information to optimize water treatment operations. In this article, transformations of particles, metal elements and NOM in a pilot-scale water treatment plant were investigated by laser light granularity system, particle counter, glass-fiber membrane filtration, inductively coupled plasma-optical emission spectroscopy, ultra filtration and resin absorbents fractionation. The results showed that particles, NOM and trihalomethane formation precursors were removed synergistically by sequential treatment of different processes. Preozonation markedly changed the polarity and molecular weight of NOM, and it could be conducive to the following coagulation process through destabilizing particles and colloids; mid-ozonation enhanced the subsequent granular activated carbon （GAC） filtration process by decreasing molecular weight of organic matters. Coagulation-flotation and GAC were more efficient in removing fixed suspended solids and larger particles; while sand-filtration was more efficient in removing volatile suspended solids and smaller particles. Flotation performed better than sedimentation in terms of particle and NOM removal. The type of coagulant could greatly affect the performance of coagulation-flotation. Pre-hydrolyzed composite coagulant （HPAC） was superior to FeCl3 concerning the removals of hydrophobic dissolved organic carbon and volatile suspended solids. The leakages of flocs from sand-filtration and microorganisms from GAC should be mitigated to ensure the reliability of the whole treatment system.展开更多
This paper focused on the removal and transformation of the dissolved organic matter （DOM） in secondary effluent during the granular activated carbon （GAC） treatment. Using XAD-8/XAD-4 resins, DOM was fractionated...This paper focused on the removal and transformation of the dissolved organic matter （DOM） in secondary effluent during the granular activated carbon （GAC） treatment. Using XAD-8/XAD-4 resins, DOM was fractionated into five classes： hydrophobic acid （HPO-A）, hydrophobic neutral （HPO-N）, transphilic acid （TPI-A）, transphilic neutral （TPI-N） and hydrophilic fraction （HPI）. Subsequently, the water quality parameters of dissolved organic carbon （DOC）, absorbance of ultraviolet light at 254 nm （UV-254）, specific ultraviolet light absorbance （SUVA） and trihalomethane formation potential （THMFP） were analyzed for the unfractionated and fractionated water samples. The results showed that the order of the DOC removal with respect to DOM fractions was observed to be HPI〉HPO-A〉HPO-N〉TPI-A〉TPI-N. During the GAC treatment, the THMFP of the unfractionated water samples decreased from 397.4 μg/L to 176.5 μg/L, resulting in a removal efficiency of 55.6%. The removal order of the trilaalomethanes （THMs） precursor was as follows： HPO-A〉TPI-A〉TPI-N〉HPO-N〉HPI. By the GAC treatment, the specific THMFP of HPO-A, TPI-A, TPI-N and the original unfractionated water samples had a noticeable decrease, while that of HPO-N and HPI showed a converse trend. The Fourier transform infrared （FTIR） results showed that the hydroxide groups, carboxylic acids, aliphatic C-H were significantly reduced by GAC treatment.展开更多
This study investigated the removal and transformation of organic matter through laboratory-scale soil-aquifer treatment (SAT) soil columns over a 110-day period. Reductions in total organic carbon (TOC), dissolved or...This study investigated the removal and transformation of organic matter through laboratory-scale soil-aquifer treatment (SAT) soil columns over a 110-day period. Reductions in total organic carbon (TOC), dissolved organic carbon (DOC), biodegradable dissolved organic carbon (BDOC), nonbiodegradable dissolved organic carbon (NBDOC) and absorbance of ul-traviolet light at 254 nm (UV-254) averaged 71.46%, 68.05%, 99.31%, 33.27% and 38.96% across the soil columns, respectively. DOC/TOC ratios increased slightly with depth while BDOC/DOC ratios showed a converse trend. DOC exiting the soil-column system contained only a very small biodegradable fraction. SAT decreased the concentration of DOC present in feed water but increased its aromaticity, as indicated by specific ultraviolet light absorbance (SUVA), which increased by 50%～115% across the soil columns, indicating preferential removal of non-aromatic DOC during SAT. Overall, laboratory-scale SAT reduced triha-lomethane formation potential (THMFP), although specific THMFP increased. THMFP reduction was dominated by removal in chloroform. All samples exhibited a common general relationship with respect to weight: chloroform>dichlorobromomethane >dibromochloromethane>bromoform.展开更多
文摘Organic matter is known to be the precursor of numerous chlorination by-products. Organic matter in the secondary effluent from the Wenchang Wastewater Treatment Plant （Harbin, China） was physically separated into the following fractions： particulate organic carbon （1.2-0.45 μm）, colloidal organic carbon （0.45-0.1 μm）, fine colloidal organic carbon （0.1-0.025 μm）, and dissolved organic carbon （DOC） （〈 0.025 μm）. Moreover, 〈 0.45 μm fraction was chemically separated into hydrophobic acid （HPO-A）, hydrophobic neutral （HPO-N）, transphilic acid （TPI-A）, transphilic neutral （TPI-N）, and hydrophllic fraction （HPI）. The chlorine reactivity of these organic fractions obtained from both size and XAD fractionations were evaluated. The structural and chemical compositions of the HPO-A, HPO-N, TPI-A, and TPI-N isolates were characterized using elemental analysis （C, H, O, and N）, Fourier transform infrared spectroscopy （FT-IR）, and proton nuclear magnetic resonance spectroscopy （1H-NMR）. Results showed that DOC was dominant in terms of total concentration and trihalomethane formation potential （THMFP）, and there was no statistical difference in both specific THMFP （STHMFP） and specific ultraviolet light absorbance among the 0.45, 0.1, and 0.025 ixm filtrates. HPO-A had the highest STHMFP compared to other chemical fractions. HPO-A, HPO-N, TPI-A, and TPI-N contained 3.02%-3.52% of nitrogen. The molar ratio of H/C increased in the order of HPO-A 〈 HPO-N 〈 TPI-A 〈 TPI-N. The O/C ratio was relatively high for TPI-N as compared to those for the other fractions. ^1H-NMR analysis of the four fractions indicated that the relative content of aromatic protons in HPO-A was significantly higher than those in the others. The ratio of aliphatic to aromatic protons increased in the order of HPO-A 〈 HPO-N 〈 TPI-A 〈 TPI-N. FT-IR analysis of the four fractions showed that HPO-A had greater aromatic C=C content whereas HPO-N, TPI-A, and TPI-N had greater aliphatic C-H content. TPI-N contained more oxygen-containing functional groups than the other fractions.
基金Sponsored by the Key Project of Jilin Provincial Science &Technology Program (Grant No.20070409)
文摘Resin adsorption technique with XAD-8 and XAD-4 was used to characterize the raw water from Erlong reservoir in Jilin province of China. The NOM chemical composition sequences of four organic fractions in the raw water, from high to low, are fulvic acid （FA） fraction, hydrophilic non-acid （HPINA） fraction, hydrophilic acid （HPIA） fraction, and humic acid （HA） fraction. Experimental results show that FA is the main precursor of THMFP among the four organic fractions. However, HA or hydrophobie acid exhibits the highest chlorination activity in forming THMs. It is also found that the value of FI/DOC or SUVA and the specific THMFP have better positive correlation. It is implied that certain source water has unique nature of NOM and DBPs.
基金Project supported by the Hi-Tech Research and Development Program(863) of China (No. 2002AA00601140)the National Natural Science Foundation of China(No. 50578155, 20477054)
文摘Characterizing natural organic matter （NOM）, particles and elements in different water treatment processes can give a useful information to optimize water treatment operations. In this article, transformations of particles, metal elements and NOM in a pilot-scale water treatment plant were investigated by laser light granularity system, particle counter, glass-fiber membrane filtration, inductively coupled plasma-optical emission spectroscopy, ultra filtration and resin absorbents fractionation. The results showed that particles, NOM and trihalomethane formation precursors were removed synergistically by sequential treatment of different processes. Preozonation markedly changed the polarity and molecular weight of NOM, and it could be conducive to the following coagulation process through destabilizing particles and colloids; mid-ozonation enhanced the subsequent granular activated carbon （GAC） filtration process by decreasing molecular weight of organic matters. Coagulation-flotation and GAC were more efficient in removing fixed suspended solids and larger particles; while sand-filtration was more efficient in removing volatile suspended solids and smaller particles. Flotation performed better than sedimentation in terms of particle and NOM removal. The type of coagulant could greatly affect the performance of coagulation-flotation. Pre-hydrolyzed composite coagulant （HPAC） was superior to FeCl3 concerning the removals of hydrophobic dissolved organic carbon and volatile suspended solids. The leakages of flocs from sand-filtration and microorganisms from GAC should be mitigated to ensure the reliability of the whole treatment system.
基金Project (No. 2004CB418505) supported by the National Basic Research Program (973) of China
文摘This paper focused on the removal and transformation of the dissolved organic matter （DOM） in secondary effluent during the granular activated carbon （GAC） treatment. Using XAD-8/XAD-4 resins, DOM was fractionated into five classes： hydrophobic acid （HPO-A）, hydrophobic neutral （HPO-N）, transphilic acid （TPI-A）, transphilic neutral （TPI-N） and hydrophilic fraction （HPI）. Subsequently, the water quality parameters of dissolved organic carbon （DOC）, absorbance of ultraviolet light at 254 nm （UV-254）, specific ultraviolet light absorbance （SUVA） and trihalomethane formation potential （THMFP） were analyzed for the unfractionated and fractionated water samples. The results showed that the order of the DOC removal with respect to DOM fractions was observed to be HPI〉HPO-A〉HPO-N〉TPI-A〉TPI-N. During the GAC treatment, the THMFP of the unfractionated water samples decreased from 397.4 μg/L to 176.5 μg/L, resulting in a removal efficiency of 55.6%. The removal order of the trilaalomethanes （THMs） precursor was as follows： HPO-A〉TPI-A〉TPI-N〉HPO-N〉HPI. By the GAC treatment, the specific THMFP of HPO-A, TPI-A, TPI-N and the original unfractionated water samples had a noticeable decrease, while that of HPO-N and HPI showed a converse trend. The Fourier transform infrared （FTIR） results showed that the hydroxide groups, carboxylic acids, aliphatic C-H were significantly reduced by GAC treatment.
基金Project (No. 2004CB418505) supported by the National Basic Research Program (973) of China
文摘This study investigated the removal and transformation of organic matter through laboratory-scale soil-aquifer treatment (SAT) soil columns over a 110-day period. Reductions in total organic carbon (TOC), dissolved organic carbon (DOC), biodegradable dissolved organic carbon (BDOC), nonbiodegradable dissolved organic carbon (NBDOC) and absorbance of ul-traviolet light at 254 nm (UV-254) averaged 71.46%, 68.05%, 99.31%, 33.27% and 38.96% across the soil columns, respectively. DOC/TOC ratios increased slightly with depth while BDOC/DOC ratios showed a converse trend. DOC exiting the soil-column system contained only a very small biodegradable fraction. SAT decreased the concentration of DOC present in feed water but increased its aromaticity, as indicated by specific ultraviolet light absorbance (SUVA), which increased by 50%～115% across the soil columns, indicating preferential removal of non-aromatic DOC during SAT. Overall, laboratory-scale SAT reduced triha-lomethane formation potential (THMFP), although specific THMFP increased. THMFP reduction was dominated by removal in chloroform. All samples exhibited a common general relationship with respect to weight: chloroform>dichlorobromomethane >dibromochloromethane>bromoform.
