Using PM_2.5 and population grid data, the population exposures risk to PM_2.5 in China from 2000 to 2016 were calculated. In addition, the temporal and spatial characteristics of population exposures risk to PM_2.5 during the 17 years were analyzed by using Theil-Sen Median trend analysis, standard deviation and Hurst index. The results showed that:①the population exposures risk to PM_2.5 in the past 17 years had great differences on both sides of Hu Huanyong Line. The risk in the East was high and in the West was low. The average annual risk in the East was 2.787, while that in the west was 0.065. ②There were obvious differences in the range of risk changes on both sides of the Hu Huanyong line during 2000 to 2016. In the west, the overall trend was declining, while the risk has gone up again obviously in 2011 and 2015; From 2001, the risk in the East increased rapidly and remained stable until 2015, then it fell back. ③The stability and sustainability of the population exposures risk to PM_2.5 were significantly different on both sides of Hu Huanyong Line. The main characteristics of the population exposures risk to PM_2.5 were instability and weak anti-sustainability in the East and stability and strong sustainability in the west. ④The total population and population density at dangerous and extremely dangerous levels showed a high spatial distribution in the East and a low spatial distribution in the West.

Satellite remote sensing data (MODIS AOD) and ground meteorological data from 2015 to 2018 were used to retrieve PM_2.5 concentration. The results showed that the retrieval was desirable, with R² between satellite-retrieved and observed PM_2.5 average concentration from 2015 to 2018 reaching 0.94. The retrieved results in dry season was better than that in dry season, results in Pearl River Delta (PRD) was better than that in Non-Pearl River Delta (N-PRD). The possible reasons were that the interpolation errors affected by assumption of aerosol scale height and mass extinction efficiency were larger both in wet seasons with more unstable weather system and in N-PRD with more mountains and straw burning. Also, four different spatial interpolation methods were compared based on in-situ PM_2.5 measurement, using satellite-retrieved PM_2.5 as the true values at those grids without measurement. The interpolation results were similar for these four methods, with the inverse distance weighted (IDW) interpolation method performing slightly better. Uneven site distribution and low site density in some areas might have a significant influence on interpolation performance, so we recommended deploying more ground PM_2.5 observation stations in sparse areas.

In order to evaluate the modeling effects of different air quality models (AERMOD, ADMS and CALPUFF) on dry and wet deposition under complex terrain-weather conditions, using the above models simulated the impacts of dioxins on ambient environment from the medical waste and waste incineration projects which were in a representative mountainous area in southwest China. The deposition effects were verified by analysis of soil sampling data. The results showed that the annual average concentrations in the air modeled by AERMOD, ADMS and CALPUFF were 1.53×10^-8~4.14×10^-6, 5.23×10^-9~3.28×10^-6 and 2.66×10^-9~2.59×10^-7 ngTEQ/m³ respectively; the results of total soil deposition at the monitoring points modeled by AERMOD, ADMS and CALPUFF were 4.41~285.72, 3.07~268.02 and 0.02~1.35ngTEQ/m² respectively. The modeling results of CALPUFF showed great differences in both diffusion & deposition patterns, compared to the other two models. The simulated deposition patterns of AERMOD and ADMS were similar, while the simulated diffusion patterns in the air were not. Through the verification of soil monitoring data, it was found that the correlation coefficients r of AERMOD, ADMS and CALPUFF were 0.66, 0.70 and 0.83 respectively. The modeling results of CALPUFF were superior in spatial distribution and can be used as the guidance model for related projects.

In order to study the process and causes of air pollution in Handan City, we measured the inorganic ion and carbon component to analyze the variation characteristics of PM_2.5 from samples taken at the site of Environmental Monitoring Center of Handan was selected to sample the PM_2.5 concentrations and measure the inorganic ion and carbon component. The air quality model of WRF-CAMx was used to simulate and analyze the PM_2.5 mass concentration contribution of different emission sources in various regions during three heavy pollutions in autumn and winter of 2017~2018. The results showed that water-soluble particles accounted for 62.4% of PM_2.5 mass concentration in Handan during heavy pollution. The secondary ions showed a trend of NO₃^- > SO₄^2- > NH₄⁺. During the three continuous heavy pollution processes in Handan City, the pollution was affected by the ground uniform pressure field, the bottom of high pressure and the zonal circulation of 500hPa at high altitude. The horizontal and vertical transports of pollutant were inhibited. The decrease of boundary layer height further resulted in the increase of PM_2.5 mass concentration. The three heavy pollutions were completely removed with the southward move of Eastern Siberia high pressure and Eurasian Continental high pressure and increase of the boundary layer height. The results of PSAT tracer module showed that the Fuxing District, Congtai District and Yongnian District were the main districts and counties contributing PM_2.5 in Handan City, with the total contribution ranging from 66.8% to 72.2%. The metallurgy, mobile source and residential bulk coal combustion were the three major pollution sources during the heavy pollution period.

The emission inventory of particulate matter of wind erosion from bare soil in the suburbs of Tianjin in 2016 was estimated used PMEI-WES (Particulate Matter Emission Inventory-Wind Erosion System). Monte Carlo simulation was used to analyze the impact of the uncertainty in major meteorological parameters and soil parameters on emissions fluxes, and quantify the uncertainty of emission inventory. The results indicated that the total amount of PM₁₀ emission from wind-blown dust in the suburbs of Tianjin in 2016 was 22025.1731t. Wind speed was the most important parameter affecting emissions. The emission fluxes increased exponentially with wind speed. Soil calcium carbonate was positively correlated with emission fluxes, and soil organic matter was negatively correlated with emission fluxes. The 95% probability range of total emissions was (15237.7581t, 37434.8873t), the uncertainty rate was (-37.48%, 53.60%); the 90% probability range of total emissions was (16111.8606t, 36104.7554t), the uncertainty rate was (-33.89%, 48.14%). The uncertainty of emission amount was most significantly associated with the error of wind speed in each district. The soil parameters had a greater impact on the extreme value of uncertainty.

In order to evaluate the correlations between concentrations of heavy metal species and organic carbon in dustfall, dust samples were collected in Yuncheng city, Shanxi province, and then they were separated into three particle sizes. In this study, the chemical species of As, Pb, Cd, Cr, total organic carbon (TOC) and water-soluble organic carbon (WSOC) were measured, and their correlations were analyzed. In addition, enrichment factors of heavy metals and their bioavailability were determined. Results showed that the total metal concentrations decreased in the following order:As > Cr > Pb > Cd, and the accumulation of all heavy metals increased with increasing particle size, while little difference was found in the chemical species of heavy metals among different particle sizes. The concentrations of WSOC and TOC in dust decreased with the decreases of particle size. The concentrations of TOC and WSOC in dust showed good correlations with some chemical species of Pb, Cd and Cr but a poor correlation with As. The enrichment factor (EF) of heavy metals decreased as follows:Cd > As > Pb > Cr, where Cr and As were relatively stable with little ecological risk, while Pb and Cd exhibited potential health risks. There were significant differences in the behavior of organic compounds and heavy metals, as well as the environmental risks of dust particles in different particle sizes from diverse sources.

Based on ERA-Interim reanalysis data, air pollution data and meteorological data, the T-mode principal component analysis (PCT) was used to classify the sea level pressure field and the 10m wind field in Chengdu into eight weather types. The air pollution status and the characteristics of pollution meteorological parameters under different weather types were analyzed, and the meteorological characteristics and potential pollution sources under heavy pollution weather types were described from the perspective of pollution meteorology. First, PM_2.5 Pollution in Chengdu area would be aggravated and developed the polluted weather event when the weather type was in high-pressure rear part type, low-front high-back type, saddle-type field and northern high-pressure bottom type. The PM_2.5 pollution was significantly weaker and belonged to the clean type under other four weather types:the west road cold-front front type, the high-pressure edge type, the northwest high pressure bottom type, and the east road cold-front front type. Second, the inversion layer in Chengdu area was stronger and the lower height of the mixed layer was not conducive to the diffusion dilution of PM_2.5 under the polluted weather type. In addition, the southern wind component in the boundary layer was obviously increased, and the northeast wind was weakened. The amount of ventilation was small, thus the wind field had a weak ability to diffuse pollutants. Third, we studied the PM_2.5 pollution transport and potential sources of Chengdu under the polluted weather type. We believed that the southern and southwestern regions of Chengdu had significant effects on the mass concentration of PM_2.5 under various types of polluted weather, and under the saddle weather type, the eastern and northeastern parts of Chengdu were contributing to Chengdu PM_2.5 pollution. Under the northern high-pressure bottom type, the PM_2.5 in the Chengdu area was mainly affected by pollutants in the surrounding areas, and the pollutants imported from other areas were relatively small.

Based on the analysis of the temporal and spatial distribution of the dust storms, the floating dust, the wind fields and the aerosol indices (AI) in winter and summer at 300 weather stations in North Africa over the past 20 years, the long-distance transport pathways of the dust aerosols were discussed. The conclusions were as follows. 1) There were six major sand source areas in North Africa:Algeria, Mauritania, Niger and Central Chad, Eastern Egypt, Northern Sudan and Bodélé depression. The range and intensity of sandstorms were largest in March, and drop to their minimum between August and November. After November, a dust-drifting belt was gradually formed in the Sahel region, with the largest range and intensity in March, and then suppressed and divided into 3~4 minor dust-drifting zones during June and October. 2) Affected by the high surface pressure in winter and spring, the Sahel dust belt originated from the long-range transport of dust aerosols from the sandstorms in the north. Between April and August, the southerly wind from the equator moved northward, and then converged with the northwesterly wind from the Atlantic Ocean at Midwest Sahel, forming a quiet wind zone, which caused the shrink and fracture of the large dust-drifting belts. 3) There were two main dust transport pathways in North Africa, one (I) was from Algeria to the Mediterranean, Egypt and Sudan, then to Sahel, and from east to west to the Atlantic Ocean; the other one (II) was from Algeria to Mauritania and to the Atlantic Ocean from south to west; at the same time, there were four branch paths in main transmission path I.

The objective of this research is to examine the effect of rice husk-derived biochar on nitrous oxide (N₂O) emission in acidic arable soil. The indoor static soil incubation experiment was carried out for 17days after evenly mixing biochar (0% (control), 2%, 5%, and 10% in the mass ratio) with the soil sample to investigate the diurnal variation of N₂O emission rate and the cumulative N₂O emission of the soils. Meanwhile, to unravel the mechanisms that control N₂O emission from the soil amended with biochar, the pH, NH₄⁺-N, NO₃^--N, NO₂^--N, and dissolved organic carbon (DOC) contents of the soils were determined at the end of incubation. The results indicated that the rice husk-derived biochar significantly (P<0.001) inhibited N₂O emission of the acidic arable soil under the condition of facilitating ammonia oxidation, especially for the 5% and 10% treatments. Compared with the control, the cumulative N₂O emission of the 2%, 5%, and 10% treatments decreased by 87.68%, 94.59%, and 96.90%, respectively. The changes of pH, NH₄⁺-N, and NO₃^--N contents of the soil amended with different amounts of biochar before and after incubation showed that the biochar promoted soil nitrification process, especially for the 5% and 10% biochar addition rates. The linear regression analysis indicated that N₂O emission rate was significantly (P<0.01) positively correlated with NO₂^--N content at the end of incubation, and NO₂^--N content could explain 45% variance of N₂O emission rate. The biochar-induced nitrification enhancement that accelerated the conversion of NO₂^- to NO₃^- resulted in N₂O emission decrease by nitrifier denitrification pathway. DOC contents of the 5% and 10% treatments at the end of incubation were significantly higher than the control. However, organic carbon mineralization was not enhanced with biochar addition during the incubation.

The Regional Atmospheric Environment Modeling System (RegAEMS) was used to simulate a severe PM_2.5 pollution event from December 26, 2017 to January 2, 2018 at "2+26 cities" in the Beijing-Tianjin-Hebei region and its surrounding areas. Based on RegAEMS, a module named Air Pollution Source Apportionment (APSA) for pollutant source apportionment was developed to analyse the regional and industrial sources of PM_2.5 in "2+26" cities. This pollution event was characterized by long duration, broad influence and serious pollution, with the hourly maximum PM_2.5 concentration reaching 201~507μg/m³. The results showed that RegAEMS could well simulate the temporal and spatial distributions of PM_2.5 during this period of heavy pollution. The regional source contribution showed that the peripheral areas generally had a greater impact on the border cities, contributing around 15.3% to 57.5%, and had a less impact on the central cities with the contribution lingering around 0.3% to 8.4%. The source contributions of PM_2.5 were greatly affected by near-surface wind field, and showed obvious regional transmission characteristics. Residential, industrial and transportation sources contributed significantly in these 28 cities, with contribution percentages ranging from 26.6% to 45.8%, 16.4% to 37.8% and 13.0% to 35.9%, respectively. This study showed that RegAEMS could be used to perform the analysis of the regional and industrial sources of fine particulate matters in cities and had great application potentials in the scientific management and control of atmospheric pollution.

In this study, the air pollutants emitted from open burning of spent mushroom substrate (SMS) were estimated by using emission factor approach based on the total annual mushroom yields from 2000 to 2017. The spatial-temporal distribution of pollutant emissions was investigated with Mann-Kendall method and cluster analysis. Furthermore, the annual pollutant emission was predicted with regression analysis. The results showed that atmospheric pollutant emissions from SMS open burning had increased significantly from 2000 to 2017, and the accumulative emissions of specific PM_2.5, CO₂, CO, CH₄, NMVOCs, PAHs, NO_x, SO₂ were 1.40×10⁶, 3.48×10⁸, 1.99×10⁷, 8.43×10⁵, 2.08×10⁶, 3.00×10⁴, 6.34×10⁵, 8.29×10⁴t, respectively. The relative high atmospheric pollutant emissions were found from Shandong, Heilongjiang, Zhejiang, Hunan, Jiangsu, Fujian and Henan, while low emissions were found from Guizhou, Ningxia, Tianjin, Beijing, Xinjiang, Chongqing and Gansu. According to regression result, total emission was estimated to increase to 4.25×10⁷t in 2021, which would account for 19.82% of the total pollutant emissions from total biomass burning. These results suggested that pollutant emissions from SMS open burning in China had increased rapidly in recent years, and it is urgent to consider policies to mitigate the emissions.

Mono-aromatic compounds samples from five various emission sources and ambient air of two areas (south area of the city and north area of the city) were collected in Taiyuan. The stable hydrogen isotope(δD) composition characteristics and conversion processes of samples was identified and analyzed. The source apportionment was discussed on the basis of the initial mixed δD value calculated through the hydrogen isotope mass balance equation. The results revealed that the δD values of mono-aromatic in samples of five emission sources were with a range of (-138.7‰~-115.5‰) of diesel volatilization, (-147.0‰~-121.0‰) of solvent evaporation, (-150.8‰~-117.6‰) of gasoline volatilization (97^#), (-131.8‰~-113.8‰) of gasoline volatilization (95^#), (-171.2‰~-120.0‰) of vehicle exhaust (97^#), (-138.9‰~-102.7‰) of vehicle exhaust (95^#), and (-168.3‰~-142.3‰) of domestic coal combustion. The δD value of benzene was significantly lower in vehicle exhaust than in gasoline volatilization. The δD values of mono-aromatic in the north area of the city ranged from -131.7‰ to -115.1‰, while -131.9‰ to -74.9‰ in the south area Taiyuan city. The initial mixed values of δD in the north of city and the south of city were -138.4‰ and -173.9‰, respectively. The results showed that the sources of mono-aromatic compounds in the atmosphere were different in the south area and north area of Taiyuan city.

Aiming at optimizing the Urban Ambient Air Monitoring Network (UAAMN), which borrowed from practices of many countries/cities, the general procedure of assessment management was put forward, the key index matrix of assessment was constructed, and the methodology of air quality monitoring network assessment for distinguishing pollutants was established. Taking 46 stations in Shenyang (including districts and counties) and six surrounding cities as an example, which took cost-benefit into account, this method was used to evaluate the monitoring network of PM_2.5. The results showed that this method can be successfully applied to the optimization of UAAMNA, Shenhe District needed to add a maximum concentration station, Dadong District needed to add a high population density station, Huanggu District needed to add a cross border station. In addition, cross-city sites such as Shenyang-Tieling, Shenyang-Benxi and Shenyang-Liaoyang should be set up. In the future, the further research of urban air quality monitoring network assessment was about to establish regular assessment system of air quality monitoring network, implement classification assessment of monitoring stations and distinguish pollutant types.

Nine weather types (T1 to T9) during 2007 to 2016 in Beijing were first identified with the objective weather classification approach in COST 733. The correlation between these weather types and haze days was then investigated, and the characteristics of air pollution and meteorological parameters under nine weather types were analyzed in combination with the variation of surface PM_2.5 and ozone. The overall occurrence probability of haze days was 21.5% in Beijing during 2007~2016, and haze days were the most frequented in T4 and T9. The variation of haze days in 9 weather types could be divided to two stages. During 2007~2012 (stage 1), haze days were fewer and the interannual change was not significant, while number of haze days increased during 2013~2016 (stage 2). After analyzing the variation of PM_2.5 and ozone concentrations under nine types, it was found that haze days in T1, T3, T4 and T9 mostly occurred in autumn and winter, and the PM_2.5 concentration increased hour by hour. On stage1, there were concentration fluctuations and a daily peak in the morning, which decreased and disappeared on stage2. The PM_2.5 concentrations on stage 2 in haze days were lower than that on stage 1 except for those under T7 and T9 types, which were 23.7% and 3.9% higher. The diurnal variation pattern of ozone had a single-peak in haze days in nine types, with maximum concentrations in afternoon. Daily average ozone concentration of T8 was the highest. In addition, mean ozone concentrations in T3, T5 and T6 were higher on stage 2 than those of stage 1, and the degree of increase in T5 was highest (49.8%). Correlation analysis between haze days and meteorological elements demonstrated that, temperature, wind direction and speed can explain the ozone variation well. While PM_2.5 variation was not only related with the local meteorological elements, but also reflected the emission characteristics and contributions of regional linkage emission reduction to some extent. Thus, a comprehensive consideration of all these factors was a better way to research the PM_2.5 characteristics.

Magnetic covalent triazine-based frameworks (MCTF) were prepared by microwave-assisted synthesis. The morphology and surface groups of MCTF were characterized and analyzed by SEM, TEM and FTIR. The microscopic mesoporous structure and saturation magnetization were measured, which was used to the degradation of sulfamethoxazole (SMX) by activating peroxymonosulfate (PMS). The main significant factors of degradation of SMX in MCTF/PMS system were studied, including dosage of MCTF, PMS concentration, pH, inorganic ions. The results showed that the 100% degradation occurred for 0.05mmol/L SMX after 30min treatment by 0.3g/L MCTF and 1.50mmol/L PMS. The degradation rate of SMX decreased with the increase of pH. SO₄^2- and HCO₃^- had inhibitory effects on SMX degradation, while Cl^- had dual effects on SMX degradation. Cyclic test proved that MCTF had good recycling performance. In the reaction process, the active substances degrading SMX were mainly generated reaction on the catalyst surface by sulfate radical (SO₄^-·) and hydroxyl radical (·OH). The pathways and potential products of SMX was analyzed by UHPLC-MS/MS.

The Fe₃O₄-Cu_xO composite was successfully prepared by a ball milling-calcination method, and the composite was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and magnetic detection. Degradation efficiency of levofloxacin hydrochloride (LVF) was evaluated by Fe₃O₄-Cu_xO composite activated oxone. Effect of calcination temperature and Fe/CuO mass ratio on catalytic performance of the composite was investigated. The degradation efficiencies of LVF over prepared composite were investigated by adjusting the reaction conditions such as the composite dosage, oxone concentration and pH. The results showed that optimum catalytic performance was obtained at calcination temperature of 300℃ and Fe/CuO mass ratio of 1:1. Repeated experiment results showed that Fe₃O₄-Cu_xO composite possessed an excellent catalytic stability. The degradation efficiency of LVF over Fe₃O₄-Cu_xO composite reached to 99.5% after 60min with the composite dosage, oxone concentration and pH of 1.4g/L, 0.6mmol/L and 11, respectively. The quenching experiment and ESR analysis demonstrated that the LVF degradation was determined by the synergistic effect of SO₄^-·and·OH reactive species.

In this paper, the concentration distribution of electrons, ions and free radicals in remote argon plasma was studied by using double suspension probe and electron spin resonance method to predict the optimal surface modification region. Then, PES membranes were placed in this region and modified by remote argon plasma. Water contact angle measurement, X-ray photoelectron spectroscopy and scanning electron microscope were used to characterize the surface structure and properties of PES membranes. Finally, the separation performance and anti-pollution performance of membranes before and after modification were analysed in bovine serum albumin separation experiment. The results showed the electron and ion concentrations in the argon plasma gradually decrease along the axial distance, close to 0 after 30cm, and the free radical concentration at 40cm still remains above 90%, which was the best possible surface modification region. In the remote region, oxygen-containing groups and nitrogen-containing groups were introduced in PES membranes surface, and the (O+N)/C atomic ratio of the membrane was increased from 0.18 to 0.46 to enhance the surface polarity of the membrane. The modified PES membranes in remote region obtained a higher hydrophilicity and the etching by electron and ions on PES membrane surface was prohibited. Under optimal processing conditions, the contact angle decreases from 67° to 18° and the membrane fouling rate after modification reduces from 70.3% to 64.7%.

Based on a well-validated three-dimensional hydrodynamic-water quality model, this paper isolated marine and terrestrial organic carbon during summer in the Pearl River Estuary (PRE) to investigate their spatial patterns, relative contributions, and associated fluxes. Results showed a gradually decreasing (increasing) trend of terrestrial (marine) organic carbon from the river outlets to the continental shelf with a mean concentration of 1.45mg/L(0.97mg/L) and 0.87mg/L (1.05mg/L) at the surface and bottom water, respectively. In stratified regions, the concentrations of terrestrial (marine) organic carbon decreased rapidly (increased slowly) with depth, whereas in non-stratified regions the marine and terrestrial organic carbon were both well mixed in the whole water column. The relative contribution of marine organic carbon increased gradually from 4.43% at the inner Lingdingyang Bay to 81.20% at the east of outer Lingdingyang Bay and was lower at the surface than the bottom water with a vertical integrated contribution being 48.26%. The hydrodynamic conditions in the PRE was complicated. Under the effects of river runoff, tides, and monsoon, terrestrial organic carbon was transported offshore with a gradual decrease in its transport fluxes. However, the transport fluxes of marine organic carbon have a large heterogeneity in their spatial patterns. Specifically, marine organic carbon was transported offshore with a gradual increase in its transport fluxes along the pathway at the southwest of the PRE and in contrast was transported onshore with a gradual decrease in fluxes at the northwest. The biochemical reactivity of terrestrial organic carbon was relatively weak, and thus only a small fraction was consumed through the biochemical processes, leading to a dominant role of sedimentation in the migration and transformation of terrestrial organic carbon. Marine organic carbon was mainly controlled by the physical transport near the river outlets and the biochemical consumption at the continental shelf. In addition, the sedimentation effect of marine organic carbon was less profound and the biochemical effect was significantly more important when compared to terrestrial organic carbon.

In the experiment, aluminum sulfate was used as coagulant and Cu²⁺ was added during the coagulation of fulvic acid (FA) to test its influence on turbidity, dissolved organic carbon (DOC) removal efficiency and the chlorination disinfection by-products formation potential (DBPsFP) of it. Three dimensional fluorescence spectroscopy(3DEEM) and ultrafiltration membrane classification were used to characterize the outlet. It was shown that Cu²⁺ could improve the removal of hydrophilic component and aromatic structure by complexation reaction during coagulation. The formation potential of dichloroacetic acid(DCAAFP) and trichloromethane (TCMFP) could be significantly reduced when pH was higher than 7. The results showed that Cu²⁺-coagulation was more likely to affect the molecular weight fraction which was between 10~30kDa in FA, and improved the removal efficiency of DOC and DBPs formation potential.

With the transparent replica fracture model, two typical LNAPL (light non-aqueous phase liquid) pollutants o-xylene and dodecane) were selected to be flushed by water and the SDS (sodium dodecyl sulfonate) solution. The geometry and distribution of the entrapped LNAPL were obtained directly in a series of experiments. The results showed that the removal percentage of the entrapped LNAPL flushed by water and the SDS solution were in the ranges of 8.3%~12.3% and 65.9%~82.1%, respectively. The cumulative removal percentage were increased with increasing Reynolds number of the flushing fluids. Under the water flushing condition, the entrapped blobs were dispersed into smaller droplets, and the droplet numbers were increased by 1.3~2.2times compared with the initial states. SDS surfactant reduced the interfacial tension between LNAPL and water, thus it can effectively remove the larger entrapped blobs in the fracture. After SDS displacement, only small droplets with a single area of about 1mm² remained. Because of the heterogeneity of variable-aperture fractures, water flush was demonstrated to result in the increase of the effective interface area of ‘LNAPL-water’ in the system, which was disadvantageous to the remediation of LNAPL pollutants. Surfactant enhanced displacement could be a more effective method for LNAPL removal.

The feasibility of activated carbon regeneration by sulfate radical (SO₄^-·) activation was explored by studying the effect of SO₄^·- on the adsorption performance of activated carbon on Congo red. The results confirmed that when the concentration of Congo red solution was 100mg/L and the amount of activated carbon was 1.25g/L, the Congo red adsorption efficiency by activated carbon was 62mg/g. The pH value of the solution and KH₂PO₄ and K₂HPO₄ dissolved in the solution have little effect of the adsorption of Congo red by activated carbon. Compared with Congo red removed by activated carbon alone, the removal efficiency of Congo red merely increased by 5% when the persulfate sodium added into systems with the amount of sodium pecould rsulfate was 12 times of Congo red concentration. However, the removal efficiency of persulfate sodium to Congo red could reach 94%~99% at 30~120min at 70℃ under the heating condition in water bath. The removal efficiency of Congo red in the same corresponding time period was 91%~94% when the Congo red removed by the combined action of activated carbon and persulfate sodium under 70℃. However, the removal efficiency of Congo red in the same corresponding time period was 86%~90% when the Congo red removed by the combined action of activated carbon and Ultraviolet rays (UV) under 70℃. It coudl be seen that SO₄^-·have little effect on the adsorption performance of activated carbon. Therefore, it is not feasible to regenerate activated carbon via the advanced oxidation technology of SO₄^·-.

Based on the visual environment of Stella software, we developed a kinetic model of nitrogen cycle in the surface-flow constructed wetland, and complied it in R language. We integrated various algorithms and functions such as programming calculation, data analysis and spatial analysis with the dynamic model, and greatly improved the analysis and prediction performance, the practicability and application ability of the model. We applied our model to study the maximum reduction capacity of ammonia nitrogen pollution load in Dashahe constructed wetland. Our model successfully established the function relationship between the water quality and the water flow. Furthermore, the optimal water inlet water, water quality and the maximum effect of reducing the ammonia pollution load was also determined.

In this study, the Net Anthropogenic Nitrogen Input (NANI) model was first developed combining data for food/feed, nitrogen fertilizer, atmospheric sedimentation and biological nitrogen fixation. Based on the model, we investigated the spatial and temporal distribution, characteristics of the components and their contribution rate, and influencing factors of the net anthropogenic nitrogen inputs in the Three Gorges Reservoir Area from 2006 to 2016 with one-way ANOVA and gray correlation method. The results showed that:(1) Obvious spatial and temporal differences were found in the NANI estimation of the Three Gorges reservoir area. The NANI amount was 10715.2 and 11974.1kg/(km²·a) in 2006 and 2016, respectively, and from 2006 to 2016, the overall inter-annual trend showed a pattern of rising linearly first and then decreasing. Spatially, the NANI amount was high in the head and tail of the reservoir while low in the hinterland of the reservoir, and high in the south while low in the north. (2) Among the components of NANI in the Three Gorges reservoir area, the nitrogen fertilizer application was the main input source, which accounted for 50%~56% of the total NANI, followed by the atmospheric nitrogen deposition, which accounted for 22%~24% of the NANI. In the correlation analysis, the relationship between the application rate of nitrogen fertilizer and NANI was most significant with R²=0.81 (P<0.0001). (3) The correlations between NANI and the population density, grain yield, gross agricultural product and gross regional product were also high, with the value of 0.901, 0.867, 0.794 and 0.689, respectively. The NANI value increased first with the increase of population density, but reached a plateau stage when the population density reached a certain value (500people/km²). NANI value increased with the increase of cultivated land area, while decreased with the increase of forest area.

The purpose of this study was to investigate the adsorption potential/mechanism of biochar obtained from the liquefaction of sewage sludge in ethanol-water co-solvent, which could provide data support and theoretical reference for its application as adsorbent. Methylene blue wastewater was selected as the treatment object. The results showed that the adsorption capacity of biochar firstly increased with the increase of initial pH of MB solution. When the pH of MB solution was higher than 8, the alkaline fading of MB began to appear. The increase of adsorption temperature (30~60℃) had no obvious effects on the adsorption capacity of biochar. The adsorption capacity of biochar overall increased with the increase of adsorption time before 240min. When the adsorption time exceeded 240 min, the adsorption capacity tended to be stable. Too high or too low adsorbent dosage and initial MB concentration were both not beneficial for the adsorption process. Both of them had an optimal critical value of 6mg and 120mg/L, respectively. The adsorption process of MB by biochar matched perfectly with the pseudo-second-order model (R²=0.9994) and the Langmuir model (R²=0.9831), respectively. The adsorption process was spontaneous and endothermic, controlled by both physical and chemical adsorption. The specific adsorption mechanisms include ion exchange, functional group complexation, π-π adsorption, and so on.

In order to explore the community structure of zooplankton and the environmental factors at Aha Reservoir in Guizhou Province, the community composition and spatio-temporal distribution characteristics of zooplankton were analyzed combined with the comprehensive nutritional status index, biodiversity index and redundancy analysis (RDA). The water samples were collected among November 2017 (dry period), April 2018 (level period) and July 2018 (flood period). Total of thirty-eight metazooplankton species were identified which consisted of 25species of rotifers, 9species of cladocerans and 4species of copepod. The dominant species included Keratella cochlearis, Keratella valga, Keratella quadrata, etc. The abundance of zooplankton was among 105.47ind./L during the dry period, 120.65ind./L during the level period, 524.64ind./L during the flood period. Zooplankton biomass was 1.40mg/L (dry period), 0.37mg/L (level period) and 1.61mg/L (flood period) respectively. Additionally, the maximum values of zooplankton biomass appeared in the flood period. The spatial and temporal distribution of diversity index was significantly different and the mean values of shannon-wiener index (H') and Margalef index (D) were 2.52 and 1.63. The results of redundancy analysis and principal component analysis showed that water temperature and nutrient salt which affect the change of zooplankton community were the main environmental factors. The reservoir was in light eutrophication and moderate pollution based on the results from the dominant species of metazooplankton, biodiversity index and trophic state index.

The combined EEMs-PARAFAC model and hydrogen and oxygen stable isotopes were applied to characterize the fluorescence characteristics and sources of DOM, the distribution of hydrogen and oxygen stable isotopes, and deuterium surplus. Four fluorescence components were identified in DOM, and the tyrosine-like component 1 dominated the DOM pool. The DOM was affected by autochthonous, exogenous and atmospheric precipitation at the same time, but mainly by autochthonous input. The proportion of atmospheric precipitation recharge was larger than that of Dawen River. The dissolved organic carbon input in atmospheric precipitation might have an important effect on the DOM in Dongping Lake, which need further systematic study. Hydrogen and oxygen stable isotopes were found to be significant correlated to dissolved organic carbon and humic-like fluorescence, which could indicate the changing trend of DOM to a certain extent.

In total, 64 aquatic plant species were found in the investigation of 87 lake wetlands within the watershed of Lake Taihu in 2018, which belonged to 51genera and 33families. In general, the species richness, abundance and coverage of aquatic plants all decreased in research area compared to the historical data. This paper studied the taxonomic diversity and functional diversity of aquatic plants in four different (eastern, western, southern and northern) geographical regions. Results showed that the diversity index α was respectively 4.33, 5.58, 5.01 and 3.46 and the diversity index β was 3.46, 4.23, 1.63 and 7.02, respectively. Significant differences in taxonomic diversity α of aquatic plants were found between northern and western, northern and southern, eastern and western, eastern and southern, western and southern parts of the watershed. Meanwhile, taxonomic diversity β of aquatic plants was also significantly different between northern and eastern, northern and western, northern and southern, western and southern parts of the watershed. With respect to the functional diversity, the diversity index β of aquatic plants among four regions was respectively 0.18, 0.14, 0.09 and 0.30, which were significantly different in pairwise comparison. CCA results showed that the degree of explanation to the composition of aquatic plants in the lake wetlands with the environment variables was 21.21%, and the eutrophication might be one of the major issues leading the decline of aquatic plants.

This study focused on the optimal concentration of yeast mixed with acetic bacteria to promote sludge hydrolysis and acidification. The concentrations of orthophosphate, ammonia nitrogen and soluble COD released from sludge were investigated. The changes of protein and polysaccharide in extracellular polymeric substances (EPS) at different layers were also studied. At yeast and acetic acid bacteria dosage of 10 and 20g/L, the highest short chain fatty acids (SCFAs) production of 719mgCOD/gVSS was achieved on the fifth day of fermentation, in which the acetic acid was 328.78mgCOD/gVSS, accounting for 45.72% of the total SCFAs. Adding exogenous bacteria significantly promoted the hydrolysis of excess sludge to produce SCFAs with acetic acid as the main component. The addition of exogenous bacteria promoted the release of ammonia nitrogen and orthophosphate during hydrolysis acidification. The maximum release of ammonia nitrogen and orthophosphate was 80.66mg/gVSS and 22.38mg/gVSS under the optimal conditions, respectively, which was conducive to the recovery of nitrogen and phosphorus from excess sludge. The release of proteins and polysaccharides from the inner layer to the outer layer of EPS was improved, providing substrates for acid production. Exogenous addition of yeast and acetic acid bacteria was an effective means to promote hydrolysis and acidification of excess sludge.

The changes in the characteristics of nitrosation biofilm were compared in two long-running moving-bed biofilm reactors (MBBR) with two different aeration modes, i.e. continuous aeration and intermittent aeration regimes. The results showed that both continuous aeration and intermittent aeration could achieve the stable growth of the nitrosation biofilm(K_d>0). When with the intermittent aeration regime, continuous biofilm detachment had no effects on the total biomass, and the biofilm growth was more stable. The biofilm under intermittent aeration could obtain a higher total biomass (1.42g/m²) when the MBBR reactor operation was stable. While with the continuous aeration regime, the biofilm could obtain higher PN/PS (1.8~2.0) and PN/VS (0.145), and lower HS/VS (0.05) and the percentage of dead cell (13.66%). This indicated that the biofilm under continuous aeration had a higher proportion of active biomass and living cells, a lower inert biomass, so the biofilm activity was higher and microbial metabolism was more active. The q-PCR results further confirmed that the amount of ammonia-oxidizing bacteria (AOB) was much higher in the biofilm with the intermittent aeration regime than that with the continuous aeration regime. It seemed that the continuous aeration was more beneficial to the AOB growth than that of the intermittent aeration regime in the MBBR (2.36copies×10⁸/g > 0.25copies×10⁸/g).

In order to recover water resources from domestic sewage and reduce the reactor volume for subsequent treatment, aquaporin biomimetic forward osmosis membrane was used to concentrate domestic sewage. The effect of different draw solution on domestic sewage concentration and membrane fouling was explored. In the process of concentration, the volume of sewage was reduced to about 1/10 of the initial volume; while the concentrations of nitrogen and phosphorus were about 1~3 times of their initial concentrations, the concentration of organic matter and metal ions were about 4~7 times of their initial concentrations. The ratio COD/TN of sewage increased from 2.9 to 10.9, which increased the potential for biological nitrogen removal. Due to the reverse salt diffusion of the draw solution and the increase of the pollutant concentration in the feed solution, the high ionic strength affected the rejection of pollutants. Using draw solution with high concentration can cause severe scaling and fouling of the membrane surface. MgCl₂ as the draw solution can effectively alleviate the accumulation of salinity during the concentration process, and Mg²⁺ can promote microbial activity, but it could also lead to the decomposition of aquaporin.

The effects on the reduction efficiency and microbial community in simultaneous removal of Cr(Ⅵ) and NO₃^- from water by hydrogen autotrophic reducing bacteria (HARB) using sequential batch experiments was investigated under different Cr (Ⅵ) concentration, NO₃^- concentration, pH value and H₂ content conditions. Results showed that Cr(Ⅵ) can be reduced by active HARB. When the influent concentration of Cr(Ⅵ) was less than 2000μg/L, the reduction rates of Cr(Ⅵ) and NO₃^-, and the activity of HARB was not affected by the initial concentration. As a preferred electron acceptor, NO₃^- competed with Cr(Ⅵ), causing a decrease in the reduction rate of Cr(Ⅵ). The optimum pH value for simultaneous reduction of Cr(Ⅵ) and NO₃^- by HARB was about 7.0. Both acidic and alkaline environments can inhibit the reduction of Cr(Ⅵ). NO₂^- accumulated gradually with the increase of pH value. H₂ as an electron donor was a necessary factor for the reduction of Cr(Ⅵ) and NO₃^-, while excess H₂ did not increase the reduction rate of Cr(Ⅵ) and NO₃^-.

Batch tests were conducted to study the effects of various organic substances on ferric ion-dependent phosphorus removal, and to reveal their mechanism. The results showed that the influencing strength of chosen organic substances was in the order of citric acid, fulvic acid, polysorbate-80, bovine serum albumin, glucose and starch. The influence of citric acid was 5 times to 20 times higher than that of the other five organic substance. Compared with organic substances containing hydroxyl, organic substances containing carboxyl had more negative effects on the removal of ferric ion-dependent phosphorus. Tests showed that the HFO was the main intermediate product to react with phosphate when ferric iron was used to remove phosphate. Organic substances with carboxyl, such as citric acid, competed with phosphate to bind to the HFO, which resulted in less combination of phosphate to HFO and decrease of phosphate removal. Among all tests, the biggest decrease of phosphorus removal caused by citric acid reached 90.70%.

A heterotrophic nitrification-aerobic denitrification bacterium named HY3-2 was isolated from the high-salt aerobic granular sludge system. The morphological observation and 16S rDNA sequence analysis showed that HY3-2 was Klebsiella quasipneumoniae subsp.quasipneumoniae. The removal characteristics of ammonia nitrogen, nitrate and nitrite by HY3-2 were studied. The results showed that the strain had good heterotrophic nitrification and aerobic denitrification performance, and the removal rates of ammonia nitrogen, nitrate and nitrite were 63.57%, 88.11% and 98.38% respectively. The study on the nitrogen removal performance of the strain showed that:HY3-2 used glycerol as carbon source. Under the condition (C/N 25, temperature 20℃ or 30℃, rotation speed 150r/min, initial pH 7~10, salinity less than 50g/L), the effect on NH₄⁺-N removal with the concentration of 100mg/L was good, and the removal rate was 90.7%. When the sodium citrate was used as carbon source (C/N 25, temperature 30℃, rotation speed 150r/min, initial pH 5~9), the aerobic denitrification can be performed when the salinity was less than 15g/L, the NO₃^--N removal rate was over 99%.

The release and distribution characteristics of polycyclic aromatic hydrocarbons (PAHs), chlorobenzene and benzene series in the flue gas of rural solid waste (RSW) incineration were studied under the different temperatures and moisture content conditions. The results showed that when the incineration temperature was less than and more than 550℃, the total release of PAHs and chlorobenzene in flue gas showed a trend of increase and decrease, respectively with increasing of the incineration. The release amount reached the maximum when the temperature rose to 550℃. High temperature incineration of RSW could not only reduce the release concentration of PAHs and the generation of PAHs with large molecular weight in flue gas, but also reduce the release amount of chlorobenzene and chlorine algebra. Thus, the toxicity of RSW incineration flue gas was effectively reduced. With the increase of temperature, the benzene series changed from pyrolysis to high-temperature synthesis, and the release amount also increased. Moisture content had a greater influence on the release of PAHs and chlorobenzene in the flue gas than the release of benzene series. When the incineration temperature was at 400℃ and 850℃, the moisture content promoted and inhibited the release of PAHs on the whole, respectively. The moisture content of RSW showed inhibitory effect on chlorobenzene, and could reduce chlorobenzene compound chlorine algebra.

A cement solidification experiment was conducted by substituting waste incineration fly ash or compound silicate cement and garbage leachate concentrate for water to co-dispose fly ash and leachate concentrate. The solidification effect and the leaching behavior of heavy metals (Zn、Pb、Cd、Cr、As、Ba) were investigated under different fly ash dosages (40%, 50% and 60%). The results showed that the compressive strength of solidified body was decreased with the increasing dosage of fly ash, but there was no significant effects associating with the substitute of leachate concentrate for water. Differential effects of fly ash dosages on the leaching behavior of heavy metals were found in the experiment. The increase of fly ash dosage reduced the leaching of Zn, but increased the leaching of Pb and Cd in the solidified blocks. At the 36th day, the accumulated leaching concentration of Zn, Pb, Cr and As reached a stable status, while the concentration of Ba increased continuously. However, the leaching amount of heavy metals (Pb, Zn, Cd, Cr, and As) in the solidified blocks did not exceed the standard limits set in pollution control standard with the use of leachate concentrate, and thus, the process met the requirement of solidification treatment for leaching toxicity.

The pyrolysis experiments with or without phosphoric acid pretreatment of Sedum spectabile were conducted at different temperatures in a tube furnace to study the migration characteristics and speciation distributions of As and Pb. The results showed that the recovery rate of As fluctuated and the recovery rate of Pb was increased firstly and then decreased with the increase of temperature. The recovery rate of As and Pb both reached maximum at 500℃ with 66.2% and 73.08% respectively. The recovery of As and Pb was increased after adding 8% phosphoric acid in a certain temperature range and reached maximum at 300℃ with 83.75% and 92.78% respectively. When the pyrolysis temperature was increased from 300℃ to 600℃, the stable form (F4 + F5) of As in biochars was increased from less than 20% to about 70%, and the most stable form (F5) of Pb was increased from 3% to 32%. After the pyrolysis with 8% phosphoric acid pretreatment, the stability of As in biochar was increased slightly with F5 increasing by 20% and 5% respectively at 500℃ and 600℃; and the stability of Pb was increased remarkably with (F4 + F5) reaching more than 90%. The dosage of phosphoric acid had no significant effect on the distribution of heavy metals. These results indicated that phosphoric acid pretreatment could be used for pyrolysis of phytoremediation plants to increase the recovery and stability of heavy metals in the biochars. In the meantime,the potential ecological risk index was also reduced.

A field experiment was conducted to investigate the influence of different passivating agents (i.e., lime-biochar and lime-humic acid) and their dosages on the Cd content in rice, rice yield and the rice quality. And a comprehensive assessment was also carried out by considering the cost of each treatment. The results showed that the Cd content in rice and the available Cd in soil were significantly decreased by 17.39%~45.96% and 18.29%~29.88%, respectively, with the addition of two passivating agents into soil. When the addition amounts of biochar and humic acid were 5000 and 6000kg/hm², respectively, the effect of this passivating agent on reducing Cd concentrations in rice was optimum. In the treatment of lime-biochar remediation, the soil pH and soil available Cd content (P<0.05) were the main factors for reducing Cd content in rice, while in lime-humic acid remediation treatment, the soil organic matter content and soil available Cd content (P<0.05) were the main factors. Through soil remediation, the rice yield could reach 6637.49~7890.92kg/hm² and the amylose content was in the range of 19.47%~27.26%. When the dosage of humic acid was 7500kg/hm², the rice yield increased by 10.90%. However, the lime-biochar treatment had no significant effect on the rice yield. The analytic hierarchy process (AHP) results showed that the weighting coefficients of the four indicators including the Cd content, rice yield, rice quality and remediation cost in the comprehensive assessment were respectively 0.608, 0.150, 0.102 and 0.140. It was concluded that the optimal in-situ passivation treatment of Cd-contaminated paddy soil was to simultaneously apply 1200kg/hm² lime and 6000kg/hm² humic acid to the contaminated soil.

Two background profiles (B1, B2) and three potentially polluted profiles (S1, S2, S3) around a uranium tailings pond in South China were selected. The characteristics and behaviors of exogenous heavy metal pollution in the soil of uranium tailings pond were discussed by comparing the distributions of heavy metal elements in each profile. Results showed that:(1) Compared with the background profile, the main and minor components in the soil adjacent to the uranium tailings reservoir were significantly input. (2) The tailings pond was the direct source of soil heavy metal pollution in the area, and the heavy metals such as As, Pb, Sb, Cd and U were transported to the peripheral soil, as shown in PCA. (3) The metal elements in potential polluted soil were closely related to LOI (loss on ignition), K and P, and have secondary correlation with Na, CA, Mn, pH and Fe. Heavy metals were significantly enriched in potential polluted profile (S1 and S2) according to the leaching and migration degree of heavy metals. From the tailings pond to its surrounding soil, the lateral migration characteristics of the heavy metals were different. (4) The potential risks of the tailings pond should be controlled because from tailings pond to its surrounding soil 30m, As, Pb, Sb, Cd and U were significantly polluted, and their contents exceed much larger than the agricultural land soil pollution risk control standards and the background value of the soil elements specified in the provincial level.

The effects of groundwater table fluctuation (GTF) on the remediation of a petrochemically polluted riverside in northwestern China by soil vapor extraction (SVE) were investigated. The migration and transformation of benzene, toluene, ethylbenzene, and o-xylene (BTEX) in cases of natural attenuation and SVE with GTF were simulated using TMVOC model. The remediation rates of BTEX were analyzed by remediation effect, transformation among phases, and saturation variation under different conditions. The results showed that the optimized extraction well pressure and influencing radius of the target site were 9.1×10⁴Pa and 8m, respectively. The removal rates of BTEX in cases of natural attenuation, SVE without GTF, and SVE with GTF were 17%, 85%, and 96%, respectively. The NAPL saturation can reach as high as 0.066 and 0.044 in case of SVE without GTF, and SVE with GTF, respectively. In case of SVE without GTF, the remediation rate of BTEX in gas, aqueous, and NAPL phase decreased gradually. In case of SVE with GTF, more NAPL phase contaminant was transported to gas phase contaminant, and extracted by SVE during the stage of falling groundwater tables.

The effects of different species of bacterial-feeding nematodes on soil microbial activity and diversity in oil-contaminated soil were studied in an effort to provide a preliminary theoretical basis and a new research perspective for the bioremediation of oil-contaminated soil. Five treatments were set up in our experiment:nematode-free soil (NFS), oil-contaminated soil (SP), oil-contaminated soil + Caenorhabditis elegans (SPN1); oil contaminated soil + Cephalobus persegnis (SPN2); oil contaminated soil + Rhabditis marina (SPN3). After 168d of the experiment, the findings were as follows:the soil basal respiration and microbial biomass carbon of SP increased due to oil pollution, while the activities of urease and sucrase decreased, and the richness, diversity index and evenness index of microorganisms decreased too. Compared with SP, the basal respiration of SPN1, SPN2 and SPN3 inoculated with nematodes increased, while the microbial biomass carbon decreased by 34.59% to 72.48%, and the sucrase activity increased by 15.66% to 22.89%. Relative to 0d, the microbial richness (S) of SP, SPN1, SPN2 and SPN3 decreased by 5, 7.25, 2.5 and 9.75, respectively, and the shannon-wiener index (H') decreased by 0.18, 0.15, 0.15 and 0.23. The results demonstrated that different species of bacterial-feeding nematodes helped to improve the microbial activity in oil-polluted soil and enhance the oil degradation through predation.

Based on the land use/cover data in Qihe River basin from 2000 to 2015, we first amended ecosystem service value of different terrestrial ecosystems in China using the equivalent factor method. We also combined bivariate correlation analysis with Ecosystem Services Trade-off Degree Model to analyze trade-offs and synergies of ecosystem services, and introduced human activity intensity index assessment model to analyze the spatial characteristics of human activity influences. Last, we used the spatial autocorrelation model and LISA cluster analysis to investigate the spatial relevance between human activity impact and ecosystem service value. The results indicated that:First, the value of ecosystem services in Qihe River basin was declining from 2000 to 2015. In 2010, the ecosystem service value was the lowest (1.929billion yuan), the average value of waste treatment was the highest (368million yuan), and the average value of entertainment culture was the lowest (81million yuan). Second, from the perspective of trade-off and synergy ecosystem, the two types of correlation analysis showed that the ecosystem services in the study area were dominated by synergistic relationship. Supply services, regulation services and support services were mutually beneficial synergies. However, cultural services and support services, supply services and regulation services were trade-off relationships. Ecosystem services trade-off degree showed that the synergy degree of soil conservation and raw materials, soil conservation and biodiversity were the highest (4.4), and the trade-off degree of water conservation and raw materials, water conservation and biodiversity were the highest (-5.2). Third, there were great spatial differences in human activity intensity in Qihe River basin, and the impact intensity of human activity in the downstream was significantly higher than that in the upper stream. The spatial correlation between human activity and ecosystem service value switched from positive to negative during the our research period (2000~2015).

In order to explore the exchange range and capacity of the "WDYT" project on the Taihu Lake water body, this study coupled the convection diffusion and water body exchange model, and conducted numerical simulation studies under 10 different working conditions according to different flow rates and conventional wind fields. The results showed that:(1) Flow rate was the main factor affecting the exchange rate of water body. The semi-exchange period of Gongwan Bay with 200m³/s flow rate was steady at about 8~9 days, which was not strongly related to the conventional wind field. (2) Conventional wind field had significant impacts on the spatial distribution of the local exchange area. Under the conditions of north wind and northwest wind, the exchange area of ??the Taihu Lake was mainly occurred in the Donghu area. Under the conditions of the east wind and southeast wind, the exchange area was mainly occurred in the Northwest area. (3) In order to mitigate the unfavorable impacts of the Yangtze River water on the lake water quality, the water diversion time/plan of the "WDYT" project should consider the Taihu Lake area weather forecast, and it was better to conduct the water diversion work under the conditions of the East or Southeast wind.

In order to get a better understanding of the annual structural changes and succession rules of phytoplankton community and the interspecific association of the dominant species in lakes at arid-cold regions, the phytoplankton community in Nanhai Lake at Baotou, Inner Mongolia from Dec. 2017 to Nov. 2018 was investigated and analyzed. A total of 151 species of 66 genera of 7 phyla were identified, among which 15 species of 15 genera of 4 phyla were dominant phytoplankton species although those species and their abundance varied with seasons. The improved Levins formula and Petraitis were applied to determine the niche metrics of the phytoplankton dominant species. The results showed that the niche breadth and niche overlap of each dominant species varied seasonally, and the adaptability of each dominant species to the environmental factors also presented a great difference. Under various habitat conditions in the different seasons during the year, the niche of Merismopedia tenuissima had the most significant variation. It could be used as an indicator species of water body pollution status in Nanhai Lake based on a reliable basis of ecology. The niche overlap results showed that ΔSO_ij could represent the trend of species development, which would indicate immediately whether the lake water quality was affected by external factors or not. The test results of the community species correlation and interspecific association showed dominant species pairs showed a significant association, indicating that the interspecific association in the phytoplankton community was positive correlated in general. However, only 10 out of the 128 dominant species pairs showed a significant association, indicating that the phytoplankton community in Nanhai Lake was still in the early and intermediate stages of succession with a loose interspecific association and unstable community structure.

In order to explore the complex relationship between vegetation productivity and diurnal warming in Xinjiang, this study quantitatively analyzed the variation trend of diurnal warming and the temporal lagging in responses of vegetation, via Normalized Difference Vegetation Index, to asymmetric diurnal warming in the northern of Xinjiang, southern of Xinjiang and Yili valley. The results indicated that:The trend of the diurnal warming in all the three regions were asymmetric with a significant spatial heterogeneity. The nighttime warming was approximately 1.67 times that of daytime in northern Xinjiang during growing seasons, 1.59 times in southern Xinjiang, and 2.67 times in Yili valley. The diurnal temperature difference reduced significantly in Yili region. There was a significant difference in the response of vegetation to the asymmetric diurnal accumulated temperature. The average temporal lags of vegetation response to cumulative T_max and T_min in Xinjiang were approximately (0.97±0.93) months and (0.91±0.95) months. Overall, the daytime warming had significantly positive effects on the coniferous forests, broad-leaved forests and meadow grassland vegetation in all three regions; and the nighttime warming had significantly positive effects on the desert grassland and typical grassland.

Based on MODIS Gross Primary Production (GPP)/Net Primary Production (NPP) data, the carbon utilization efficiency (CUE) of vegetation in Three-River Headwaters region was calculated. Combined with the meteorological data and elevation data, the spatiotemporal distribution characteristics of vegetation CUE were investigated from 2001 to 2017 with the linear regression method. The response of vegetation CUE to air temperature, precipitation and evapotranspiration in the study area were further analyzed by using the methods of correlation analysis. The results showed that:(1) the vegetation CUE in the Three-River Headwaters region was first increasing and then decreasing with the peak in June during the active period between March and October each year from 2001 to 2017. (2) The annual vegetation CUE in the Three-River Headwaters region was ranging between 0.73 and 1.00, with an average of 0.85. Spatially, the vegetation CUE was higher in the north and west, but lower in the south and east in the study area. (3) The vegetation CUE was found to be positively correlated with air temperature, but negatively correlated with precipitation and evapotranspiration between April and October. On an annual basis, the CUE was more sensitive to precipitation than air temperature, but least sensitive to evapotranspiration.

Under the laboratory and simulated conditions, the tolerance of Shewanella oneidensis MR-1 and Shewanella putrefaciens to V(V) was tested with anaerobic incubation. The effects of different V(V) concentration, inoculated quantity, pH value and anthraquinone-2,6-disulfonate (AQDS) concentration on V(V) reduction were investigated. The mechanisms of V(V) microbial reduction were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that V(V) at the concentration within 10mg/L slightly affected the growth of S. oneidensis MR-1 and S. putrefronens, while cells growth and V(V) reduction were inhibited when the concentration of V(V) was over 20mg/L. With the increasing quantity of microbial inoculation, the reduction ability of the two bacteria to V(V) was gradually enhanced. The optimum pH for the growth of two bacteria was about 7.0, and the reduction rate of V(V) in weak alkaline growth environment was higher than that in the weak acid environment. The addition of 1mmol/L AQDS could enhance the reduction of V(V). The SEM analysis were carried out for the bacteria after 3days incubation, which found that S. oneidensis MR-1 and S. putrefaciens reduced V(V), accompanied with a small amount of adsorption. The XPS energy spectrum analysis indicated that V(V) were reduced to V(IV) by S. oneidensis MR-1 and S. putrefaciens.

Uranium contamination is getting more and more attention due to its potential harm to environment and human health. Physical and chemical techniques are widely used in remediation, whereas generally expensive and challenging. Microbial mediated uranium bioreduction is an environmental-friendly technology, showing great potential in uranium remediation. Over the past twenty years, a diverse range of soil bacteria have been identified with the ability in reducing U(VI) to U(IV), including but not limited to Fe(III)-and sulphate-reducing bacteria. The recent progress in molecular mechanisms of bacterial U(VI) reduction was reviewed, especially the various pathways of extracellular electron transfer, including the metal-reducing pathway of Shewanella oneidensis MR-1, the porin-cytochrome-mediated pathway and nanowire pathway of Geobacter sulfurreducens PCA. Competitive electron acceptors and coexisting ions played important roles in bacterial U(VI) reduction. The molecular mechanisms by which bacteria transfer electrons across the outer membrane and then exchange electrons with extracellular minerals remain unclear. It also remains unclear how Geobacter spp. nanowires interact with the porin-cytochrome to transfer extracellular electron. In the future, studies could be focused on the mechanisms of bacterial U(VI) reduction and how to improve the efficiency and stability of uranium bioremediation.

In order to investigate the characteristics of the nirS-type denitrification bacteria structure of eutrophic urban lakes in Inner Mongolia Plateau, a specific functional gene nirS was measured to determine the denitrifying bacterial diversity in the surface sediments of Nanhai Lake, Baotou. Based on the physicochemical indexes analysis of the sediments at each sampling point, the nirS-type denitrifying bacteria community and diversity were studied. Results showed that the Shannon Index ranged from 3.07 to 3.41. Comparing with other studies, biodiversity of denitrifying bacteria was relatively low and the dominant bacteria involved in the denitrification remained the same as most of the lakes with genera Pseudomonas and Rhodobacter being the majorities. The redundant analysis (RDA) indicated that various types of pollutants in the urban lake exerted significantly promotive effects on the denitrifying bacteria. Rhodobacter was positively correlated with nitrate nitrogen (NO₃^--N) and nitrite nitrogen (NO₂^--N), and Pseudomonas presented a strong positive correlation with total phosphorus (TP) in addition to nitrate nitrogen (NO₃^--N) and nitrite nitrogen (NO₂^--N). The main bacteria among the nirS-type denitrifying bacteria in Nanhai Lake promoted the denitrification thus accelerated the removal of nitrogen.

This paper constructed a benchmark model of China's waste paper recycling decision system in 2017, focusing on the impact of nonstandard waste paper recycling on the economic and environmental benefits of China's domestic waste paper recycling system. This model construction was followed by sensitivity analysis of the relevant parameters affecting the efficiency of the waste paper recycling system. Finally,the system's economic benefits and GHG emissions were forecast in the context of integrating nonstandard recycling vendors. The results showed that the economic benefit of China's waste paper recycling in 2017 was approximately 458.3 yuan/t and that the GHG emissions were 901.1kgCO₂eq. The standard recovery rate and nonstandard recovery acceptance rate would both have a significant impact on the system's economic benefits and improved the GHG emissions structure. In the context of integrating nonstandard recycling enterprises and individual recycling vendors, the economic benefits would rise to 3312.5 yuan/t in 2030, while GHG emissions would rise to 942.9kg CO₂eq. And through scenario prediction, it was found that the integration of nonstandard recycling could improve the standard recovery rate, which could effectively regulate China's waste paper recycling market.

Based on panel data on 273 prefecture-level cities in China from 2010 to 2016, the propensity score matching-difference in difference method (PSM-DID) was wsed to investigate the effect of carbon emission trading policy on urban carbon emission intensity and its mechanism. The study found that such policies significantly and continuously lead to the reduction of carbon intensity in pilot cities, and the effect became more significant in recent years. Consequently, through the mediation effect analysis, this paper found that adjustment on the industrial structure and energy saving methods effectively reduced the carbon intensity while the impact of scientific research remained unclear. Based on the finding, this paper suggested further nationwide promotion on carbon emission trading policy, optimization of industrial structure, increase in tertiary industry proportion, promotion on enterprise energy saving, and establishment of a green low-carbon consumption concept.