首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Natural estrogens from humans increasingly attract attention because of their strong endocrine disrupting potency. The discharge of sewage water is considered as the most important source of these endocrine disrupting chemicals (EDCs) in the environment. Therefore, a GC‐MS method was developed for the simultaneous analysis of six natural free estrogens and their sulfate conjugates in municipal wastewater, in which natural free estrogens and sulfate conjugates were successfully separated from an Oasis HLB solid phase extraction (SPE) cartridge with two different eluents, and the sulfate conjugates were then transformed to their corresponding free estrogens by acid solvolysis. Before the analysis with GC‐MS, samples were derivatized by N,O‐bis (trimethylsilyl) trifluoroacetamide (BSTFA) plus 1% trimethylchlorosilane (TMCS) at 80°C for 40 min. Satisfactory recoveries ranging from 64 to 112.3% were obtained by spiking ultra‐purified water, raw, and treated municipal wastewater with the six estrogens at 50, 100, and 50 ng/L, respectively. The method was successfully applied to wastewater samples from one WWTP, which suggested that E1 was the dominant natural estrogens in effluent and E3‐3S was one of the conjugates possibly occurring in the effluent.  相似文献   

2.
Removal of natural free estrogens and estrogen conjugates in a municipal wastewater treatment plant (WWTP) was investigated and analyzed by GC‐MS, in which estrogen conjugates were first transformed to their corresponding free estrogens with an acid solvolysis procedure before their analysis. Natural free estrogens, E1‐3‐sulfate (E1‐3S), and E3‐3‐sulfate (E3‐3S) were detected with high concentrations in both the influent and effluent of the primary settling tank (PS), while no estrogen glucuronides were detected in any of the monitored wastewater samples. Regarding their removal efficiencies, all were almost completely removed, except for E1 with only a minor decrease. The estrogenic/androgenic removal of the same WWTP was also evaluated with estrogen receptor (androgen receptor) (ER (AR))‐binding assays, in which the removal efficiencies for E2 equivalents (EEQ) or testosterone equivalents (TEQ) were 68.5 and 72.2%. In addition, the chemically calculated EEQ from natural estrogens were about 20.6–39.3% that of the ER‐binding assay, in which E3 contributed the biggest proportion in both the influent and PS, while the calculated value of E1 increased from only 6.7% in the influent to as high as 20.6% in the effluent.  相似文献   

3.
The performance of a constructed wetland for wastewater treatment was examined for four months (December 1995 to March 1996). The study area, hereby referred to as the Splash wetland, is approximately 0·5 ha, and is located in the southern part of Nairobi city. Splash wetland continuously receives domestic sewage from two busy restaurants. Treated wastewater is recycled for re‐use for various purposes in the restaurants. Both wet and dry season data were analysed with a view of determining the impact of seasonal variation on the system performance. The physical and chemical properties of water were measured at a common intake and at series of seven other points established along the wetland gradient and at the outlet where the water is collected and pumped for re‐use at the restaurants. The physico‐chemical characteristics of the wastewater changed significantly as the wastewater flowed through the respective wetland cells. A comparison of wastewater influent versus the effluent from the wetland revealed the system's apparent success in water treatment, especially in pH modification, removal of suspended solids, organic load and nutrients mean influent pH = 5·7 ± 0·5, mean effluent pH 7·7 ± 0·3; mean influent BOD5 = 1603·0 ± 397·6 mg/l, mean effluent BOD5 = 15·1 ± 2·5 mg/l; mean influent COD = 3749·8 ± 206·8 mg/l, mean effluent COD = 95·6 ± 7·2 mg/l; mean influent TSS = 195·4 ± 58·7 mg/l, mean effluent TSS = 4·7 ± 1·9 mg/l. As the wastewater flowed through the wetland system dissolved free and saline ammonia, NH4+, decreased from 14·6 ± 4·1 mg/l to undetectable levels at the outlet. Dissolved oxygen increased progressively through the wetland system. Analysis of the data available did not reveal temporal variation in the system's performance. However, significant spatial variation was evident as the wetland removed most of the common pollutants and considerably improved the quality of the water, making it safe for re‐use at the restaurants. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

4.
Sorptive removal of Ni(II) from electroplating rinse wastewaters by cation exchange resin Dueolite C 20 was investigated at the temperature of 30°C under dynamic conditions in a packed bed. The effects of sorbent bed length 0.1–0.2 m, fixed flow rate 6 dm3 min?1, and the initial rinse water concentration (C0) 53.1 mg L?1 on the sorption characteristics of Dueolite C 20 were investigated at an influent pH of 6.5. More than 94.5% of Ni(II) was removed in the column experiments. The column performance was improved with increasing bed height and decreasing the flow rate. The Thomas, Yoon–Nelson, Clark, and Wolborska models were applied to the experimental data to represent the breakthrough curves and determine the characteristic design parameters of the column. The sorption performance of the Ni(II) ions through columns could be well described by the Thomas, Yoon–Nelson, and Wolborska models at effluent‐to‐influent concentration ratios (C/C0) >0.03 and <0.99. Among the all models, the Clark model showed the least average percentage time deviation. The sorptive capacity of electroplating rinse water using Ni(II) was found to be 45.98 mg g?1.  相似文献   

5.
Bezafibrate (BZF), a widely used lipid regulator, is a potential threat to ecosystems and human health in water, and the recent research showed that advanced oxidation processes (AOPs) are much more effective for BZF degradation. In this study, we investigated the photochemical decomposition of BZF in surface water and effluent from waste water treatment plants (WWTP) by UV/H2O2 process. The results showed that the UV/H2O2 process was a promising method to remove BZF at low concentration, generally at µg L?1 level. When initial concentrations reach 100 µg L?1 in the deionized water, >99.8% of BZF could be removed in 16 min under UV intensity of 61.4 µm cm?2, at the H2O2 concentration of 0.1 mg L?1, and neutral pH condition. Moreover, BZF degradation was inhibited in this process when humic acid (HA) and inorganic solution anions were added to the deionized water solutions, including chloride, nitrate, bicarbonate, and sulfate, significantly. In the surface water and effluent of WWTP, however, the removal efficiency of BZF was lower than that in the deionized water because of the interference of complex constituents in the surface water and effluent. Some main intermediates at the m/z range of 100–400 were observed by high performance LC‐MS (HPLC/MS) and a simple pathway of BZF degradation by UV/H2O2 was proposed.  相似文献   

6.
To remove chromate from a wastewater, a porous permeable reactive barrier system (PRBS), using pyrite and biotite, was adapted. This study included bench‐scale column experiments to evaluate the efficiency of the PRBS and investigate the reaction process. The total chromium concentration of the effluent from the biotite and pyrite columns reached the influent concentration of 0·10 mM after passing through more than 150 pore volumes (PVs) and 27 PVs respectively, and remained constant thereafter. The CrVI concentration in the effluent from the biotite column became constant at about 0·08 mM , accounting for approximately 80% of the influent concentration, after passing through 200 PVs. Moreover, in the pyrite column, the CrVI concentration remained at about 0·01 mM , 10% of the input level, after passing through 116 PVs. This shows that both columns maintained their levels of chromate reduction once the CrVI breakthrough curves (BTCs) had reached the steady state, though the steady‐state output concentration of total chromium had reached the influent level. The variances of the iron concentration closely followed those of the chromium. The observed data for both columns were fitted to the predicted BTCs calculated by CXTFIT, a program for estimating the solute transport parameters from experimental data. The degradation coefficient µ of the total chromium BTCs for both columns was zero, suggesting the mechanisms for the removal of chromate limit the µ of the CrVI BTCs. The CrVI degradation of the pyrite column (6·60) was much greater than that of the biotite column (0·27). In addition, the CrVI retardation coefficient R of the pyrite column (253) was also larger than that of the biotite column (125). The R values for the total chromium BTCs from both columns were smaller than those of the CrVI BTC. Whereas the total chromium BTC for the pyrite column showed little retardation (1·5), the biotite column showed considerable retardation (80). The results for the 900 °C heat‐treated biotite column were analogous to those of the control column (quartz sand). This suggests that the heat‐treated biotite played no role in the retardation and removal of hexavalent chromium. The parameters of the heat‐treated biotite were calculated to an R of 1·2 and µ of 0·01, and these values confirmed quantitatively that the heated biotite had little effect on the transport of CrVI. These solute transport parameters, calculated by CXTFIT from the data obtained from the column tests, can provide quantitative information for the evaluation of bench‐ or field‐scale columns as a removal technology for CrVI in wastewater or contaminated groundwater. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

7.
The present work investigated the biosorption of nickel from synthetic and electroplating industrial effluents using a green marine algae Ulva reticulata. Preliminary batch results imply that pH 4.5 was optimum for nickel uptake and the isotherm experiments conducted at this pH condition indicated that U. reticulata can biosorb 62.3 mg g–1 nickel ions from synthetic solutions, according to the Langmuir model. Desorption was effective and practical using 0.1 M CaCl2 (pH 2.5, HCl) and the biomass was regenerated and reused for three cycles. Continuous biosorption experiments were performed in an upflow packed column (2 cm I.D and 35 cm height). Among the two electroplating effluents used, effluent‐1 is characterized by excess co‐ions and high nickel ion content. This influenced the column nickel uptake with U. reticulata exhibiting 52.1 mg g–1 in the case of effluent‐1 compared to 56.5 mg g–1 in the case of synthetic solution. On the other hand U. reticulata performed well in effluent‐2 with uptakes of 53.3 and 54.3 mg g–1 for effluent‐2 and synthetic solution, respectively. Mathematical modeling of column experimental data was performed using nonlinear forms of the Thomas‐ and modified dose‐response models, with the latter able to simulate breakthrough curves with high correlation coefficients.  相似文献   

8.
A reversed‐phase fractionation method with subsequent biological and chemical analysis has been developed to estimate the contributions of the most potent estrogens to observed estrogenic effect potentials. Surface water samples were taken in the German Baltic Sea (Inner Wismar Bay and Darss Peninsula, sampling campaign July 2003) and were separated into seven individual fractions. Three fractions showed significant estrogenic activities and clear dose‐dependant responses were obtained in the yeast estrogen screen (YES). In the 2nd fractions liquid chromatographic‐electrospray‐tandem mass spectrometric (LC‐ESI‐MS‐MS) analyses showed the presence of bisphenol A (Inner Wismar Bay: 4.8 ng L–1 and 6 ng L–1; Darss Peninsula: 0.91 ng L–1 and 1.7 ng L–1) and ethinylestradiol (Inner Wismar Bay: 2.0 ng L–1 and 6.0 ng L–1; Darss Peninsula: < MDL and 1.7 ng L–1), whereas estrogenic activities in the YES were only around 10% of the positive control E2. Although not identified prior in the total extract the natural hormones estradiol (Inner Wismar Bay: 0.13 ng L–1 and 0.19 ng L–1; Darss Peninsula: 0.12 ng L–1 and 0.16 ng L–1) and estriol (Inner Wismar Bay: < MDL and 0.33 ng L–1; Darss Peninsula: < MDL) could be detected in the 3rd fractions, where high estrogenic potentials could be observed. The 4th fractions showed high responses as well and estrone were herein quantified with concentrations of 0.16 ng L–1 and 0.18 ng L–1 (Darss Peninsula) up to 0.37 ng L–1 (Inner Wismar Bay). Measured and calculated estradiol equivalents for individual fractions correlated very well (R2 = 0.78), when disregarding results of the 2nd fraction, where high deviations occurred.  相似文献   

9.
Experiments were conducted to study the airborne microbial contamination generated by a wastewater treatment plant (WWTP). Aerosol samples were collected simultaneously, by sedimentation and impact methods, from the area and the surroundings of the WWTP. Total colony forming units (CFUs) of heterotrophic bacteria (HPC), as well as members of the Enterobacteriaceae, staphylococci, enterococci, actinomycetes, and microscopic fungi were determined. Bacterial (HPC) concentrations ranged between 101 and 104 CFU/m3, fungi 0 and 104 CFU/m3. Higher numbers of HPC bacteria in air samples were observed in summer, fungi in autumn. The main emission of microorganisms to atmospheric air was from the mechanical sewage treatment devices of the WWTP. The facilities of the biological sewage treatment of the plant did not generate large amounts of bioaerosols. In the air obtained from the premises of the WWTP, 25 species of the Enterobacteriaceae were isolated (Salmonella spp., Klebsiella pneumoniae, Escherichia coli). At the fence and in the surroundings only Pantoea spp. were identified. This suggests that the sewage bacteria were mainly discharged in the area of the WWTP. The presence of enteric bacteria, especially Enterobacteriaceae reflects the level of air pollution with bioaerosols from sewage and is an important factor during monitoring the quality of the air around WWTPs.  相似文献   

10.
This study was carried out to evaluate the occurrence of the fluoroquinolone antimicrobial agent ciprofloxacin (CIP) in the effluent of the Hospital of the Federal University of Santa Maria (HUSM). Measured environmental concentrations (MECs) of CIP in the hospital wastewater, both before (P1) and after (P2) cesspit/filter system treatment (CFTS), were determined by means of solid phase extraction and reversed‐phase liquid chromatography with fluorescence detection (LC‐FLD) and reversed‐phase liquid chromatography with mass spectrometric detection (LC‐MS/MS). The MECs (n = 7 daily composed samples) were 19 to 155 μg L–1 (average: 54 ± 21 μg L–1) and 32 to 99 μg L–1 (average: 65 ± 45 μg L–1) in P1 and P2, respectively. No relevant removal was observed from P1 to P2. In a worst case scenario, the final effluent was regarded as MECs of surface water. These MECs were generally 5 to 20,000‐fold higher than what was previously known. If the present data is drawn on to form a model of the situation in developing countries, the picture provides a first rough indication that the environmental risk associated with the use and emission of pharmaceuticals into the environment in developing countries might be higher than in developed countries.  相似文献   

11.
In this study the occurrence of diclofenac and sub‐products in effluent emerging from the University Hospital at the Federal University of Santa Maria was investigated. One metabolite was identified and, in aqueous solution, three degradation products. The quantification was conducted by means of HPLC‐DAD, and the determination of metabolite and degradation products by LC–ESI–MS/MS–QTrap. For the HPLC‐DAD method, a 70:30 mixture of methanol/sodium phosphate was used in isocratic mode. For the LC–ESI–MS/MS–QTrap determinations, a mobile phase, where phase A was an ammonium acetate solution 5 × 10?3 mol L?1, and phase B was methanol (5 × 10?3 mol L?1)/ammonium acetate (9:1, v/v), on gradient mode. The LDs for the HPLC and LC–MS/MS methods, respectively, were 2.5 and 0.02 µg L?1, the LQs, 8.3 and 0.05 µg L?1, and the linear range from 10 up to 2000 µg L?1 and 0.05 up to 10 µg L?1. As expected, the LC–ESI–MS/MS–QTrap method was more sensitive and less laborious. The metabolite 4′‐hydroxy‐diclofenac was identified. Photolysis was used for the degradation studies and three products of diclofenac were identified (m/z of 214, 286 and 303) in aqueous solution. These results notwithstanding, no degradation products of diclofenac were found in the hospital effluent.  相似文献   

12.
Breeding ornamental fish in wastewater was a successful solution not only to decrease sanitary risks but also to encourage fish growth. In fact, the secondary treated effluent was used to grow a walking catfish (Clarias batrachus), a western mosquitofish (Gambusia affinis; Poeciliidae), and a leopard pleco (Glyptoperichthys gibbiceps). The growth rate of fish reared in final treated wastewater was significantly higher than of treated effluent (25 and 50%) and the relative growth rate during 2 months reached 2, 4, and 2.5, respectively. Bacterial loads were important in the gills compared to other fish organs (intestine, skin, and edible muscles). However, the total aerobic germs ranged between 2 × 103 and 3.4 × 103 cfu/g in the edible fish species cultured in secondary treated effluent. The pathogenic bacteria Aeromonas hydrophila was absent in all examined fish muscles. However, the presence of tested fishes did not prevent the reduction of the treatment biological parameter (BOD and COD) at half, in the three treated wastewater proportions (25, 50, and 100%) and thereafter, they clearly participated to the tertiary biological treatment of used water. Further bacteriological and physico‐chemical analyses indicated that the use of treated wastewater in aquaculture is safe and risks to human health are reduced.  相似文献   

13.
The aim of this study is to evaluate the feasibility of sludge digester effluent as feeding solution to enrich anaerobic ammonium oxidation (anammox) bacteria. The performance of the two parallel pilot scale‐upflow packed bed anammox reactors (UPBAn1 and UPBAn2) are examined in terms of the enrichment of anammox bacteria. The control experiment is set up conducting synthetic wastewater as feeding solution in the UPBAn1 reactor whereas, the sludge digester effluent is fed to the nitritation reactor and then the partially nitrated digester effluent to the UPBAn2 reactor. Anammox activities are evaluated by mass balances based on ammonium (NH4+), nitrite (NO2?), and nitrate (NO3?) analysis and NRR. Microbial community of anammox bacteria is analyzed using real‐time polymerase chain reaction (PCR). The results demonstrate that UPBAn 1 and UPBAn2 reactors are successfully enriched on days 64 and 40 with NRRs of 19.54 and 19.43 g N m?3 per day, respectively. This study reveals that both synthetic wastewater and digester effluent are suitable for the enrichment of anammox bacteria; however, digester effluent as feeding solution for enrichment of anammox bacteria based on the ease of process control and process stability is more advisable.  相似文献   

14.
Competitive sorption of estriol (E3) and 17α‐ethinylestradiol (EE2) was studied on activated charcoal. Better sorption of E3 (88.9%) and EE2 (69.5%) was observed with single‐solute sorption system than with bi‐solute sorption system. Single‐solute sorption kinetics of E3 and EE2 were evaluated with two (Langmuir and Freundlich) and three (dual mode and Song) parameter models. Freundlich model (R2, 0.9915 (E3); 0.9875 (EE2)) showed good prediction compared to other models for single‐solute sorption. Adsorption capacity documented reduced efficacy (86.4% (E3); 65.9% (EE2)) due to induced competitive behavior between the estrogens in aqueous phase. Bi‐solute adsorption kinetics of E3 and EE2 were described by IAST with two and three parameter models. Among these models, IAST‐Freundlich model (R2, 0.9765 (E3); 0.9985 (EE2)) was best in predicting bi‐solute sorption of E3 and EE2 by activated charcoal. All these models showed favorable representation of both single‐ and bi‐solute sorption behaviors.  相似文献   

15.
To evaluate the performance of Spirodela polyrrhiza grown in swine wastewater for protein and starch production under field conditions, a pilot‐scale duckweed culture pond was installed at Barham Farm, Zebulon, North Carolina and operated from May to November 2010. The anaerobically treated swine wastewater was fed to the duckweed pond intermittently to provide nutrients for the growth of duckweed, and the duckweed biomass was harvested regularly from the pond and prepared as a protein‐ or starch‐rich feedstock for the production of animal feed or fuel ethanol. Over the experimental period, the duckweed pond produced protein and starch at rates of 2.68 and 1.88 g m?2 day?1, respectively. During the same time, NH4–N and o‐PO4–P in the wastewater were, respectively, removed at rates of 92.9 and 2.90 mmol m?2 day?1.  相似文献   

16.
A vertical flow constructed wetland (VFCW) filled with natural zeolite had higher ammonium removal (82.4–94.0%) than another VFCW filled with volcanic rock (51.3–69.4%) treating piggery wastewater under any of three recirculation ratios. To reveal the underling reasons, physicochemical characteristics and ammonium‐oxidizing prokaryotes (AOPs) of two substrates were determined. The calculated maximum ammonium adsorption of zeolite (11.6 mg g?1) was remarkably higher than that of volcanic rock (0.21 mg g?1), mainly because the former contains two cationic binding crystalline species, and montmorillonite. Quantitative analyses indicated that ammonium‐oxidizing archaea (AOA) are the dominant AOP of zeolite and ammonium‐oxidizing bacteria (AOB) are the dominant AOP of volcanic rock respectively. Diversity and phylogenetic analysis further showed that both AOB and AOA communities were significantly different between two substrates. Nitrosospira‐like AOB (92.6%) and sediment/soil clade AOA (71.4%) were the main components of AOB and AOA in natural zeolite, whereas Nitrosomonas‐like AOB (76.1%) and water/sediment clade AOA (77.1%) dominated the AOB and AOA in volcanic rock. These results suggest that the substrates show high selectivity to AOP community. Thus, in addition to physicochemical characteristics, the AOP of substrates is very likely to affect ammonium removal in VFCWs.  相似文献   

17.
Wastewater production in a hospital laundry and the treatment of the most critical wastewater stream, are assessed. Hospital laundry wastewaters are hazardous to the environment due to their high pollutant concentrations and the chemicals added during the clothes washing process. Heterogeneous photocatalysis with UV, O3 and TiO2 and their possible combinations were used for disinfection purposes. A ramp‐type reactor was used for TiO2 (P25 Degussa) fixation and for photochemical diffusion of the ozonized air. After assessing 5‐day biological oxygen demand, chemical oxygen demand, pH, turbidity, and surfactant content, and checking for the presence of thermotolerant coliforms and Escherichia coli, it was concluded that UV/O3/TiO2 was the best process/combination, yielding a 100% disinfection rate and a microbiological inactivation of 0.5070 min–1 for E. coli and of 0.5505 min–1 for thermotolerant coliforms.  相似文献   

18.
A method for the determination of nickel in water was developed. The procedure involves preconcentration of nickel by using dispersive liquid–liquid microextraction. The Ni(II) ions were extracted in chloroform in the form of complex with the reagent 2‐(2′‐benzothiazolylazo)‐p‐cresol. Ethanol was used as the disperser solvent. After injection of the extracting mixture in a solution of nickel, a cloudy mixture was observed. A quick centrifugation induces phase separation and thus the settling of rich phase. The nickel content in the rich phase is measured by flame atomic absorption spectrometry. Under optimal conditions, the limit of detection and quantification obtained were 1.4 and 4.7 µg L?1, respectively. Some parameters used to characterize preconcentration systems, such as enrichment factor and consumption index were calculated and resulted in 29 and 0.34 mL, respectively. After optimization of variables and determination of analytical characteristics, the method was used for the analysis of certified reference materials (BCR‐713: wastewater, effluent and BCR‐414: plankton) and real water samples.  相似文献   

19.
Disposal of wastewater treatment plant (WWTP) effluent into sea, a typical anthropogenic disturbance, may influence many environmental factors and change the coastal microbial community structure. In this study, by setting up coastal sediment microcosms perturbed by WWTP effluent, the changes of microbial community structure under different degree of disturbances were investigated. Quantitative PCR (qPCR) and terminal restriction fragment length polymorphism (T-RFLP) were used to analyzed the biomass and biodiversity. High throughput sequencing analysis was used to identify the classification of the microorganisms. Our study suggested that low ratio of WWTP effluent may stimulate dominant species, which increase the biomass but decrease the biodiversity; while high ratio of WWTP effluent may depress all species, which decrease the biomass but increase the biodiversity. In other words, the impact was dose-dependent. The changes of microbial community structure may provide a metric for water environmental assessment and pollution control.  相似文献   

20.
The occurrence and fate of six phthalate esters were investigated in the River Seine and two tributaries in the Paris area, at six sites from upstream to downstream, throughout different seasons, with special attention given to a flood episode. At all sites, except the River Marne, whatever the period, diethylhexyl phthalate (DEHP) displayed the highest concentration (0·323–0·779 µg l?1 as mean values), followed by di‐n‐butyl phthalate (DnBP; 0·211–0·526 µg l?1 as mean values), which is consistent with the production pattern. High phthalate concentrations appeared to be related to population density and industrial distribution. The strongest values were located downstream from wastewater treatment plant effluent inputs. Seasonal variations were closely related to river flow and air and water temperature. The annual evolution of phthalates was linked to the hydrological conditions. During the flood episode at Paris, the DEHP concentration displayed a sharp increase (260 to 1123 ng l?1) occurring 9 days before the flood peak. The simultaneous fluctuations of NH4, typical of domestic origin, and of DEHP suggests a similar origin from combined sewer overflows for both compounds. Other elevated values corresponded to the highest precipitation amounts, and demonstrated the contribution of non‐point‐source runoff and wastewater overflow to DEHP inputs. The DEHP concentration relationship with river flow displayed a clockwise hysteresis loop, corresponding to a ‘first‐flush’ effect in which the finite supplies are swept along in the early stage of the flood. Annual fluxes for 2004 at Paris were 2257 kg of DEHP and 1613 kg of DnBP. The flood period seemed to have a minor impact on annual phthalate transport (29·5% and 41% of the total for DEHP and for DnBP, respectively), which is contrary to annual suspended solids transport (69%). Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号