Using the data of the latest-released aerosol optical thickness (AOD) (Collection 6) as derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra spacecraft, the Final Operational Global Analysis data (NCEP FNL) from National Centers for Environmental Prediction, Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP), CERES syn1deg Ed4monthly average data, NCEP/National Center for Atmospheric Research (NCAR) reanalysis data from March 2000 to February 2017, we have investigated the features of variations of graded AOD and their related circulation anomalies. As per the interannual variations of AOD averaged over the eastern part of China, the AOD is divided into 5 different levels, which corresponds to 5pollution grades. The results show that the anomalies of AOD in East China are larger when the surface wind speed is weaker together with the unfavorable aerosol diffusion condition of the anomalous monsoon circulation in the middle and high troposphere. When the aerosol pollution is strongest (weakest), variations of AOD is strongly related to the variations of the solar radiation at the earth surface, surface temperature, wind speed, and precipitation. At other AOD levels, the air pollution is significantly related to the surface solar radiation rather than other variables. When the air pollution is severe, the solar radiation at the earth surface is relatively lower, along with the lower surface temperature. The atmosphere in lower troposphere is cooling, and the wind speed is weakening. Meanwhile, the more precipitation occurs in the southern and less in the northern part of the eastern China. On the other hand, when the air pollution is very light, the solar radiation that reaches the earth surface will increase, and the surface air temperature gets higher. At this time, the surface wind will get stronger, and less precipitation will be received in the southern and more in the northern part of East China.

This paper presents a review of main research progresses on the aerosol dry deposition experiments and theoretical models over the past few decades, started with the definition of dry deposition velocity. Dry deposition of particles from the atmosphere to the earth is not only dependent on the aerosol size, the aerosol density and the air viscosity, but also affected by the aerodynamic resistance, the viscous resistance and the surface collection resistance, which are related to the micro-meteorological factors such as the atmosphere temperature, the wind speed and the relative humidity. The typical methods for the determination of dry deposition velocity include tracking technique, concentration gradient method and eddy correlation method. The instantaneous three velocity components, turbulent kinetic energy, friction velocity, temperature and eddy diffusion coefficient can be measured by the Ultrasonic Anemometer Thermometer. Aerosol size distribution is commonly obtained by the combined measuring devices (Serial multistage sampler, Aerodynamic Particle Sizer and Scanning Mobility Particle Sizer) due to the wide particle size range. In the parameterization of the particle dry deposition, the physical scheme is based on the Stokes' Law which emphasizes the equilibrium of gravitation, buoyancy and drag force, while the semi-empirical formulae introduce the atmospheric turbulence, the molecular motion and the surface collection mechanism which accounts for particle Brownian diffusion, collision, interception, rebound, thermophoresis and diffusiophoresis. However, the discrepancy between model predictions and field measurements is still significant for a certain particle size range. In view of the open problems in the dry deposition, perspectives on the future research directions and techniques are provided.

Satellite remote Sensing data Retrieval based on OMI, the temporal and spatial distribution characteristics of formaldehyde column concentration in the troposphere and its influencing factors in the Pearl River Delta region from 2009 to 2016were studied. The results show that the concentration change of formaldehyde column in the Pearl River Delta was characterized by fluctuations in the past 8years, with an average annual value of 13.11×10¹⁵ molec/cm², the lowest value appeared in 2012 and the highest value appeared in 2016, the maximum reduction rate was 5.8%, the maximum growth rate was 6.3%. The highest in summer and the lowest in winter, the order was summer > autumn > spring > winter, and the monthly variation of formaldehyde in 8a to 96months was larger, showing a single peak structure, with the highest in June every year; The spatial variation was characterized by:The concentration of formaldehyde column decreases from northwest to southeast. Among them, the distribution center of the northeastern part of Zhaoqing, the northern part of Foshan and the western part of Guangzhou constitutes the distribution center of high value area. It consists of the third-level sub-level distribution area in the south-central part of Foshan, the southeastern part of Guangzhou and the northwest half of Jiangmen. In Huizhou, Dongguan, Shenzhen, Zhongshan, Zhuhai and Jiangmen, the coastal areas of the Pearl River Delta are the first-level low-value concentration areas. Meteorological factors such as temperature and pressure affect the formation and distribution of HCHO, and vegetation has a certain contribution to the production of HCHO. There is a positive correlation between the change of formaldehyde column concentration and the factors of economic development, such as automobile ownership, regional GDP, etc, the increase of total energy consumption and total industrial waste gas emission was closely related to the increase of formaldehyde column concentration, and the main reason for the change of formaldehyde column concentration was human factors.

Combined the statistical analysis of Beijing urban haze from the year of 2014 to 2017 with the clustering results obtained by HYSPLIT backward trajectory mode, spatial characteristics and variation of main pollution transport pathways and potential source-zones were identified. The study revealed that the overall air quality in Beijing urban area kept improving during the study period, with the incidence of haze dropped from 50.6% in 2014to 33.7% in 2017and the occurrence of haze days decreased from 165d to 78d. Every year, haze always concentrated appears during coal heating period from October to the next March. The occurrence frequency of the different intensity haze has been decreasing year by year, both the frequency and the intensity of haze pollution happened in autumn and winter seasons declined gradually. There are three main pollution transport pathways in the Beijing-Tianjin-Hebei area, including the southeastern plain area of Hebei, the east foot of the Taihang Mountain and the south foot of the Yan Mountain, which altitudes were all below 1000m of the ground, corresponding to the Beijing average concentration PM_2.5 of 124.1μg/m³ during the study. The frequencies of main transport pathways have reduced gradually, and the contributions to PM_2.5 of Beijing by the same trajectory were also declined. Major potential source-zones of PM_2.5 in Beijing urban area has gradually narrowed to center-south parts of Hebei and northwest Shandong from the north China plain and the Tianjin port, with the decreasing contribution rate of the air pollution from the transport pathways. The favorable weather conditions and the control of human-derived regional emissions were the 2major causes of the air quality improvement in the last 4years.

In order to study the effect of humidity on the aerosol in Nanjing, the influence of the humidity profile on the extinction coefficient was studied and analyzed by using the Raman-Rayleigh-Mie Lidar in Nanjing University of Information Science and Technology; Based on the environmental monitoring data from March 2014 to February 2015, the concentration characteristics of respirable particulate matter were statistically analyzed and compared with the corresponding humidity to contrast monthly and four-season comparative analysis, and then the correlation coefficient between the parameters was calculated with the view of the city layout and planning of Nanjing and to provide more air pollution control reference. It was showed that the extinction coefficient profile was consistent with the trend of relative humidity profile at low altitude. In the range where gravity sedimentation did not occur, the greater the relative humidity, the more favorable the formation of particulate matter, beyond this range, the greater the relative humidity, the lower the concentration of particulate matter. The limit is between 40% and 49% for PM₁₀and between 50% and 59% for PM_2.5 in Nanjing.

To investigate the seasonal variations and sources of polycyclic aromatic hydrocarbons (PAHs) in fine particles (PM_2.5) in the northern Zhejiang province (NZP), one year-long field PM_2.5 sampling was conducted at four representative sites in both cities of Hangzhou and Ningbo from December 2014 to November 2015 and in total 17 PAHs were analyzed by GC-MS. The results showed that the total annual averaged concentration of all these 17 PAHs ranged from 24.1 to 51.9ng/m³ with an average of (35.5±12.3) ng/m³. Basically, 2~3 rings PAHs were observed in low abundance in particle phases (<1ng/m³), while 4~6rings PAHs accounted for 77.0% of total particulate PAHs. The total concentration of 17 PAHs followed a similar seasonal trend to that of PM_2.5, showing the highest total PAHs concentration in winter while lowest in summer among four seasons. As a tracer for soft wood burning, the concentration of retene was quadruple in winter compared to that in summer, indicating the increased contribution from soft wood burning in NZP. Except at two urban sites during summer, moderate positive correlations were found between OC and PAHs. The PAHs diagnostic ratios implied that aerosols related PAHs in NZP were not significantly contributed by traffic emissions and petrogenic sources, but mainly originated from pyrogenic sources, such as biomass burning and coal combustion.

In order to investigate the characteristics of the airborne bacterial community in Changzhou's PM_2.5samplesduring spring, the 16S rRNA gene of bacterial in PM_2.5 sampleswas studied by high-throughput sequencing. 600150sequences obtained could be divided into 1890~6519 OTUs of each sample at 97% similarity level. The Coverage index of the samples was high and could accurately represent the airborne bacterial community in the samples. Species annotation results indicated that there were 11bacterial phyla, 14bacterial classes, 12bacterial genera with relative abundance greater than 1% in Changzhou's PM_2.5 samples during spring. Proteobacteria, Bacteroidetes and Firmicutes were the top 3dominant phyla, accounting for 80.88% of the total gene abundance. At the genus level, Chroococcidiopsis (6.03%), Rubellimicrobium (5.95%), Microcystis (4.86%) and Sphingomonas (3.16%) were predominant, but the proportion of gene sequences that failed to be classified was up to 81.11%. Based on the source analysis of bacterial community composition in PM_2.5, it was found that the environmental sources of bacteria in Changzhou's PM_2.5 samples during spring were varied, and the main environmental source might be fresh water, followed by soil, plants and anthropogenic sources. The results of redundancy analysis (RDA) for the relationship between environmental factors and bacterial community showed that NH₄⁺, NO₃^-, O₃, SO₄^2-, OC, air pressure and CO were the main environmental factors affecting the bacterial community in Changzhou's PM_2.5 samplesduring spring. At the same time, varied environmental factors had different effects on bacterial groups.

The regional air quality model CMAQ was used to simulate and evaluate the effect of residential coal combustion emission reduction policies on atmospheric BaP pollution in Beijing-Tianjin-Hebei (BTH) region. The simulations included a base scenario (the year of 2014) and two scenarios of emission reductions. The simulation results:the annual average concentration of atmospheric BaP in BTH in the base scenario was 2.54ng/m³, which was more than twice of the national air quality standard (1ng/m³).The levels of monthly average concentration of atmospheric BaP were in the order:January, April, October, July, reflecting the impact of coal for heating in winter on atmospheric BaP concentration. The atmospheric BaP concentration of southern BTH region was higher than that of the northern region over BTH region, the reason was probably the higher BaP emissions in the south of BTH than in the north. The emissions reduction of rediential coal in January has the most significant effect on reducing concentration of atmospheric BaP and depotion.The concentrations of atmospheric BaP in January over Beijing, Baoding and Langfang in low (scenario1) and high (scenario2) were reduced by 30% and 40% respectively compared with the base scenario.The emissions reduction of rediential coal combustion in April, July and October had little effect on the changes of atmospheric BaP concentration and depotion. Taking control measures of residential coal consumption in all BTH region could more effectively reduce the concentration of atmospheric BaP concentration in this area.

Five typical coals with different maturities were selected and burned in the residential stove, and then the individual particles and PM_2.5 samples from these coals burning were collected. A transmission electron microscopy with energy-dispersive X-ray spectrometry (TEM-EDS) was used to analyze physicochemical characteristics of metal-containing individual particles. The concentrations of 14metals (including eight heavy metals) in PM_2.5 were detected by inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometer. The individual particle analysis showed seven different types of metal-containing particles:mineral, K-rich, S[K]-rich, Fe-rich, Zn-rich, and Pb-rich particles, and some carbonaceous particles. Mass concentrations of 14metals and eight heavy metals accounted for 1.29%~15.54% and 0.09%~2.53% in PM_2.5, respectively. Al, Ca and Na were the dominant metals, accounting for 57%~80% of total metals. Zn and Pb were the dominant heavy metals, accounting for 54%~91% of total heavy metals. TEM observations showed that Zn and Pb mainly occurred in Zn-rich and Pb-rich particles with size<1μm, respectively. These heavy metals can be breathed into deep of human lung and pose adverse effects on human health. Therefore, in order to protect human health, we suggest that residents should use clean coal or clean energy to reduce the heavy metals emissions.

An emission inventory of open field straw burning was established on the method of emission factors over the Heilongjiang Province for the year of 2016 in this paper. The temporal and spatial distribution characteristics of emission pollutants were also comprehensive analyzed in this study. Our results showed that the total emissions of CO₂, CO, CH₄, NMVOCs, NH₃, BC, OC, SO₂, NO_x, PM₁₀ and PM_2.5 were 1.314×10⁷, 4.192×10⁵, 3.77×10⁴, 8.35×10⁴, 6.5×10³, 4.4×10³, 3.13×10⁴, 5.0×10³, 3.28×10⁴, 8.81×10⁴ and 1.014×10⁵t, respectively. Further uncertainty analysis for 95% confidence intervals revealed that the uncertainties ranged from a low value of ±86% for NO_x to a high value of ±187% for CO. The reliability analysis also demonstrated that the compiled emission inventory is reasonable. The spatial distribution of higher values for emission pollutants was located in the western and eastern regions of Heilongjiang Province. Temporally, two obviously emission peaks for emitted pollutants from straw burning were presented throughout the year. The decline of open field straw burning would effectively promote the reduction of regional total emission of atmospheric pollutants, and the mode of intensive farming and large-scale management over the reclamation area in Heilongjiang Province can effectively control the regional open field straw burning.

The characteristics of emissions from power plant over Yangtze River Delta were analyzed, and major air pollutants in winter and their impact on air quality were then discussed based on WRF-Chem simulation. The results showed that the annual emissions of major air pollutants from power plant over Yangtze River delta were 826.8Gg, 1475.6Gg and 137.3Gg in 2010 for SO₂, NO_x and PM_2.5, respectively, accounting for 34%, 38% and 14% of total anthropogenic emissions. The high concentrations of major air pollutants (SO₂, NO₂, PM_2.5) were distributed in the city cluster of Nanjing-Shanghai and Hangzhou-Ningbo. The spatial distribution of power plant contribution from SO₂ was consistent with the emissions of SO₂, however, the high contributions of NO₂ and PM_2.5, were mainly distributed on the border of Anhui-Zhejiang-Jiangxi and eastern coast of Zhejiang province. Compared with SO₂ and NO₂, the contributions to PM_2.5 from power plant were relatively low, i.e. normally below 20μg/m³ in most regions (15%). The contributions of power plant emissions to the simulated PM_2.5 and SO₂ during polluted period (6.9%, 34.2%) were higher than clean period (4.9%, 20.7%), while, there were no significant differences for NO₂ between polluted and clean period, with the magnitudes as 10μg/m³. The conditions of low temperature, weak wind speed, and low boundary layer height in winter were not favorable to pollutant diffusion, leading to heavy pollution events.

Sinopec VOCs emission accounting formula and the EPA recommended formula were introduced, and the merits and faults of two methods were compared and analyzed. By the case study of tank emission accounting, the reasons that lead to the different results of the two kinds of method were analyzed, and the result of VOCs emission was determined as 43.43t/a. The method of regression analysis was utilized, and the sensitivity of the main parameters of the Sino-US accounting formula is studied, the R² of each parameter fitting equation is close to 1, based on t test p value at a significance level of 0.05, and the following conclusions were obtained:in the calculation of floating roof tank VOCs emission, the sensitive parameters of Sinopec formula include adhesion coefficient, wind speed, secondary seal coefficient, seal coefficient and wind speed index; and the sensitive parameters of EPA formula were inner surface adhesion coefficient, wind speed, no edge sealing discharge coefficient, wind edge sealing emission coefficient and the floating roof sealing length coefficient, while the wind speed index was non-sensitive parameter.

Dust was monitored hourly based on Himawari 8data. Time series analysis and histogram statistic methods were used for analyzing the brightness temperature of Band15, 13, 11, BT15-BT 13 and BT13-BT 11. The results showed that each object shared the similar value range based on the selected Bands. The Brightness Temperature (BT) of ice cloud was about 220~250K; the BT of dust, water cloud and cold land was about 260~270K; and the BT of low cloud, fog and warm land was about 270~290K. Band13 was sensitive to identify dust because of the low BT value over dust area. The differences of BT in two infrared channels can clearly distinguish dust from other objects. The value of BT15-BT13 was high and the value of BT13-BT11 was low in dust area. The results of correlation analysis showed that BT15-BT13 and BT13-BT11 were significantly related to the ground PM₁₀ concentration at the 0.01level. BT15-BT13, BT13-BT11 and BT13 were used for false color composite for dust monitoring. Combine meteorological data, ground PM₁₀ data, Lidar and satellite remote sensing results, the source, formation process and moving track of dust weather can be monitored hourly from 3dimensions.

A series of Ce-doped Ni-Al-O_x catalysts were prepared by a urea-hydrolysis method, and were applied for CO-NO reaction. The results showed that Ce-doped Ni-Al-O_x exhibited much higher NO conversions than Ni-Al-O_x. Furthermore, the activity increased with the raising of Ce doping ratio. More than 95% NO could be converted at temperature as low as 250℃ over NiAlCe₃₀O and NiAlCe₂₀O. These catalysts also showed excellent resistance to H₂O. Ce-doped Ni-Al-O_x catalysts were characterized by XRD, N₂ physisorption, Raman, XPS, H₂-TPR, NO-TPD, and in situ DRIFTs. XRD and Raman results showed that Ni-Ce-O solid solution was formed in Ni-Al-Ce-O_xcatalyst. Meanwhile, oxygen vacancies increased with the increasing of Ce doping ratio. H₂-TPR results indicated that the redox ability was improved by Ce doping. NO-TPD and in situ DRIFTs results revealed that the increasing number of oxygen vacancies resulted from Ce doping were beneficial to the dissociation of NO to N₂ or N₂O rather than the oxidation of NO to nitrates.

Due to the difficulty of NO₃^--N removal during treatment of high-sulfate (SO₄^2-) actual industrial wastewater (AIW) treatment, we tested the effects of hydraulic retention time (HRT) on treatment performance of simulated wastewater and AIW using CO₂-hydrogen based membrane biofilm reactor (CO₂-MBfR). Results show that the effluent concentrations of NO₃^--N from two kinds of wastewater gradually increased with decreased HRT, and the removal efficiency of NO₃^--N and electron flux distribution ratio (EFDR) in simulated wastewater treatment were better than that of in AIW treatment, but the electron flux distribution pattern was nearly the same:the EFDR of NO₃^--N and SO₄^2- were 90.09%~97.49% and 2.51%~9.91%, respectively. Overall, our results reveal that CO₂-MBfR could high efficiently remove NO₃^--N of AIW. From a practical perspective, HRT higher than 10.4h is suggested for achieving the total nitrogen emission standard of 15mg/L in the actual wastewater treatment.

The stability of partial nitrification at different dissolved oxygen (DO) concentration was studied in SBR at room temperature. Under the low DO concentration of 0.5mg/L, the partial nitrification kept stable for 75cycles with the nitrite accumulation rate (NAR) higher than 80%. Until 105cycles, the NAR gradually decreased and the partial nitrification transformed to the complete nitrification. However, using the same sludge, the partial nitrification kept long-term stable of 180cycles under the DO concentration of 2.5mg/L. Furthermore, NAR was higher than 90%. These results indicated under high DO concentration, the stable operation of partial nitrification can be maintained for a long period of time. The oxygen half saturation constant of AOB and NOB, and qPCR tests indicated that low DO might be benefit to the growth of Nitrospira that resulted in the unstable of the partial nitrification. Moreover, under high DO concentration, AOB had higher affinity for oxygen. Therefore, high oxygen concentration could maintain long-term stability of partial nitrification.

In order to explore the influence of biological sludge return on performance of the mainstream system after chemical phosphate precipitation in the side-stream, phosphorus, nitrogen and organic matter removal, pathway of biological phosphorus removal and sludge sedimentation of the whole system after 85days of side-stream chemical phosphorus recovery with the sludge returned to anoxic tank in the A²/O system were investigated. The results showed that the phosphorus removal of the system could be improved at the beginning of the operation, the concentration of soluble phosphate in effluent was (0.07±0.04) mg/L; After 20 days' operation, the sludge settling performance became worse, and the phosphorus removal performance deteriorated, but the nitrogen and the organic matter removal performance were not significantly affected. The rate of anaerobic phosphorus release and aerobic phosphorus uptake decreased, but the rate of anoxic phosphorus uptake increased. The phosphorus removal ratio of anoxic denitrifying phosphate accumulation to aerobic phosphate accumulation increased from 43.20% to 53.38%, so the denitrifying phosphorus removal was strengthened. The metabolic patterns of PHA and glycogen of microorganism in the sludge were not changed, but the amount of PHA synthesized in anaerobic stage decreased gradually. The maximum recovery amount of phosphorus by side-stream accounted for 24.75% of that in the influent, which achieved considerable phosphorus recovery. When the system collapsed, the side-stream chemical phosphorus recovery was stopped for a short period, the functions of the system were gradually restored, and the continuous operation of the system could be realized in result.

Using polyethylene glycol diacrylate as carrier materials, respectively with N, N, N, ‘N’-tetramethylethylenediamine (TEMED) as promoter and potassium persulfate (KPS) as initiator to immobilize anaerobic ammonium oxidizing bacteria. Orthogonal experiments were used to optimize immobilization conditions of anaerobic ammonium oxidation bacteria:10% PEGDA monomer, 0.25% KPS, 0.5% TEMED, the optimum operation condition was to control the polymerization temperature at 20℃, polymerization time was about 5min, The ratio of bacteria to gum was 1:1. The continuous flow experiment of immobilized pellets showed that after a short period of activity recovery, the nitrogen removal effect was continuously improved,and it had a certain impact resistance to the increase of hydraulic load. The scanning electron microscopy (SEM) showed that the immobilization materials have good biocompatibility and good mass transfer performance. High-throughput sequencing showed that after a period of time of stable operation, the microbial diversity in the pellets decreased slightly. And the Candidatus Kuenenia that belongs to anaerobic ammonium oxidizing bacteria which accounted for 6.58% of the total microbial system was up to 9.8%, the changes in microbial population showed that the performance of anaerobic ammonium oxidation could be improved greatly after immobilization.

An anaerobic baffled reactor (ABR) was employed to investigate the operational performance and the distribution of syntrophic methanogens during the treatment of sugar refinery wastewater. The distribution of syntrophic methanogens was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). COD removal was 61.5% and volatile fatty acids (VFAs) in effluent were 1808mg/L at sludge acclimation stage. After the regulation operation of two stages, the VFAs were dramatically reduced and methane content was increased to above 55%. The COD removal was achieved 94.8% at the stable state. The granular sludge with good settling performance was formed in the last 3compartments. PCR-DGGE explored that the dominant hydrogen-producing acetogens were related to the genera Syntrophobacter and Pelotomaculum, which were distributed in the third and fourth compartments of ABR. The acid-tolerant hydrogenotrophic methanogens (Methanoregula and Methanosphaerula) were mainly distributed in the first and second compartments, while acetotrophic methanogens (Methanosaeta and Methanothrix) mainly existed in the third and fourth compartments. The present study found the diversity of methanogens was higher than that of hydrogen-producing acetogens, indicating hydrogen-producing acetogenesis is more likely to be a rate-limiting step when the system is shocked.

Aerobic sludge granulation was investigated in a horizontal mechanical stirred and aerated SBR with lower ratio of height to diameter (H/D) of 1.2. The average shear rate that granules suffered was calculated and the effect of horizontal agitation on the granulation process was discussed. The results show, the aerobic sludge was granulated in the reactor with a mean diameter of 1.12mm and settling velocity of 21.41m/h finally. The average shear rate of granules was calculated out as 27.25s^-1, and the shear force 3.38×10^-2N/m². The average shear rate acted on the surface of the granules positively related to mechanical agitation speed and superficial gas upflow velocity, of which the mechanical agitation speed contributed more to the shear rate, about 37.48times of that the superficial gas upflow velocity did. It was considered that the eddy secondary flow pattern with appropriate shear force caused by transverse rotation of stirrer was essential to aerobic sludge granulation in the reactor with lower ratio of height to diameter.

The heavy metal flocculant, named mercaptoacetyl hydroxg-polyacrylamide (MAMPAM), was prepared by mixing polyacrylamide, formaldehyde, sodium hydroxide and mercaptoacetic acid as raw materials, and its removal performance of Cu²⁺ and humic acid (HA) from water samples was investigated. MAMPAM had a certain effect on the removal of Cu²⁺ or HA from the single system contained Cu²⁺ or HA, respectively. The Cu²⁺ removal efficiency increased with the increase of the initial pH value. The highest removal rate of Cu²⁺ and HA reached 95.92% and 66.98% at pH 6.0, respectively, in the single Cu²⁺ or HA system. Moreover, synergistic promotion of Cu²⁺ and HA was observed in the mixture system contained Cu²⁺ and HA. The coexisting HA could promote the Cu²⁺ removal from water samples and the removal efficiency of Cu²⁺ increased with increasing HA concentration or pH value in the mixture system. Similarly, the HA removal by MAMPAM was enhanced due to the coexisting Cu²⁺ and its removal efficiency was also improved when HA concentration increased in the mixture system.

The backwashing residuals from iron and manganese removal biological filter of underground waters was made into granular adsorbent (GA) and magnetic powder adsorbent (MPA) to solve the problem that it is difficult to separate the exhausted backwashing sludge powder adsorbent (BSPA) and treated water. The arsenic removal capability of BSPA、GA and MPA were compared. And their structure and surface feature were compared by SEM, TED, XRD, BET and FTIR to find the cause of difference in arsenic removal capability among these three adsorbents. Results showed that the maximum As (V) adsorption capacity of BSPA, GA and MPA were 40.980, 5.048 and 8.694mg/g respectively. As it suggested, the As (V) adsorption capacity of GA and MPA decreased compared to BSPA. BSPA was a mixture with amorphous structure, lepidocrocite was the main ingredient, goethite and poor crystallized ferrihydrite also mixed in it. The XRD spectrum of GA appeared crystal diffraction peaks of quartz crystal and a small amount of hematite, while the main component of MPA was maghemite with high crystallinity. There are hydroxyl functional groups that are conducive to adsorption in all three materials. The specific surface areas of BSPA, MPA and GA were 253.150, 238.660 and 43.803m²/g respectively. Phase changes and increase of crystallinity, reduction of surface hydroxyl group and decrease of specific surface area may be the main factors lower the adsorption capacity of GA and MPA compared with BSPA.

The MSL was constructed to treat rural domestic wastewater. Biofilm colonization, effects of hydraulic loading rate (HLR) on the treatment of domestic wastewater by the MSL, and biofilm characteristics during the working process of the MSL were investigated. The biofilm colonization was success after 28d of influent by "continuous manner", and at this moment, removal efficiencies of COD, ammonia, TN and TP reached 84.5%, 74.7%, 66.7%, and 76.4%, respectively. During the treatment process of the domestic wastewater, the MSL exhibited a strong adaptability on the variation of HLR. The average removal efficiencies of COD, ammonia, TN, TP reached 93.4%, 94.9%, 80.4%, and 94.7%, respectively, which meet to the 1A discharge standard of the Discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002), when the HLR was adjusted to 400L/(m²·d). Pathways of the removal of COD, ammonia, TN and TP by the MSL showed that the biological decomposition and biotransformation processes of microorganisms were the most important pathway for the removal of COD, ammonia, and TN, while TP was mainly removed by the chemical reaction with iron irons. q-PCR showed that the nitrifying bacteria in the biofilm were about 35.5% of the total flora.

The microcosm experiment were conducted to investigate the remediation effect of uranium contaminated groundwater by β-glycerophosphate. The variations of pH and nitrate, sulfate, phosphate, and uranium concentrations were monitored during the incubation, and the uranium species and the proportion of U(IV) in sediments were analysed. It was found that, after 25d incubation, the concentrations of uranium in liquids in the β-glycerophosphate and glycerol amended groups decreased from 2.96 and 2.99mg/L to 0.030 and 0.044mg/L, respectively, which were lower than the limits of contaminants stipulated in the regulations on radiation and environment protection in uranium mining and milling in China. β-glycerophosphate worked as the carbon and phosphate sources and reduced the proportion of the uranium species in exchangeable and carbonate fractions in sediments and increased the proportion of the uranium species in Fe(Mn) oxides, organic matter and residual fractions in sediments. The proportion of U(IV) in the sediment of β-glycerophosphate amended group amounted to 91.79%, which was 28.82% higher than that of the glycerol amended group. After 45d anaerobic incubation, the proportion of U(IV) in the sediment of β-glycerophosphate amended group almost remained unchanged, while that in glycerol amended group decreased by 7.98%. Therefore, β-glycerophosphate could work as carbon and phosphate sources and could immobilize uranium in-situ through bioreduction and biomineralization.

The experiment of remediating PCE with surfactant (Tween 80) was carried out in two-dimensional sandbox filled with quartz sand, and the removal processes of NAPL phase under different source zone architectures (SZA) were monitored via image analysis technology. Considering the lack of experimental data on dissolved phase NAPL concentration, numerical simulation using UTCHEM software was further performed to understand the mass transfer process between NAPL phase and aqueous phase, and the effects of surfactant concentration and injection rate on the DNAPL remediation efficiency were investigated. Results from Sandbox experiments and numerical simulations confirmed that:subsurface heterogeneity largely governs the DNAPL SZA, resulting discrepancies in ganglia-to-pool (GTP) ratio. Due to the larger contact area of discrete ganglia with surfactant, DNAPL ganglia is preferentially removed. The higher the initial GTP ratio, the higher the remediation rate and the remediate efficiency of DNAPL; Though the DNAPL remediation rate could be increased by increasing the surfactant concentration or the injection rate, the surfactant remediate efficiency was reduced significantly by 93% over the course of the test. The linear driving force dissolution model can effectively simulate the process of surfactant remediation for DNAPL. Numerical simulation is an important quantitative tool for the assessment of SEAR in the field DNAPL-contaminated sites.

Different reactors (SBBR, Fe(0)-SBBR, Fe(Ⅱ)-SBBR, Fe(Ⅲ)-SBBR) were employed in this paper to investigate the treating processes of acrylic fiber wastewater by different valence forms of iron as well as the variation of microbial communities during these processes. The results showed that acrylic fiber wastewater was well treated by Fe(0)/Fe(Ⅱ)/Fe(Ⅲ)-SBBR, especially the removal rate of NH₄⁺-N was above 90%. And, the Fe(0)-SBBR worked best throughout the entire operating cycle. Illumina MiSeq high throughput sequencing was also utilized to analyze the structure of microbial communities during the processes. It was found that the dominant bacteria were significantly different at the genus level between Fe(0)/Fe(Ⅱ)/Fe(Ⅲ)-SBBR systems. Gemmata、Planctomyces、Aridibacter、Fluviicola were the dominant genera in Fe(0)-SBBR. Thermomonas、Aridibacter、Bacillus、Paracoccus were the dominant genera in Fe(Ⅱ)-SBBR. Planctomyces、Bacillus、Nostocoida、Aridibacter were the dominant genera in Fe(Ⅲ)-SBBR. Compared with control group SBBR, Fe (0)-SBBR could strongly stimulate the growth of bacteria which were at a relative disadvantage. Moreover, the change of microbial community by Fe (0) and Fe (Ⅲ) were greater than that by Fe (Ⅱ).

To definite the adsorption characteristics of chlorohydrocarbon and aromatic hydrocarbon combined pollutants in groundwater aquifer, adsorption tests were carried out with toluene, benzene, 1,2-dichloropropane, 1,2,3-chemical propane (TCP) as typical pollutants. The results showed that the adsorption process could be described by linear model of Henry with distribution coefficient (K_p) of 0.38, 0.41, 0.73 and 1.00kg/L, respectively, which indicated that the order of adsorption strength of the pollutants is toluene > benzene > 1, 2-dichloropropane > TCP. Furthermore, it was observed that benzene obviously increased the adsorption of toluene in fine sand and toluene decreased the adsorption of benzene conversely; 1, 2-dichloropropane restrained the adsorption of TCP, however, the effect of TCP on the adsorption of 1, 2-dichloropropane was not significant. As for different type of pollutants, the adsorption capacity of TCP in aquifer medium increased with the concentration of toluene; When the initial concentration of toluene was lower than 2mg/L, the TCP acted as a stimulus for the adsorption of toluene, on the contrary, TCP acted as an inhibitor for the adsorption of toluene in aquifer medium.

Hydraulic capture technique is one of the most widely applied technologies to purify or constrain contaminants from further contaminated groundwater. Thus, how to determine the optimal pumpage is the key issue.The optimal pumpage calculated by commonly used deterministic methods were usually unreasonable. Therefore, the Monte Carlo method based on the stochastic theory, in consideration of the stochastic property of hydrologic-geologic parameters, was applied to investigate the effect of the spatial variation of hydraulic conductivity on the fate of hydraulic capture zone and a new method to estimate the optimal pumpage was suggested. It had been proved that when the 110m³/d determined by means of deterministic methods was adopted as optimal pumpage, the contaminated area lay exactly within the capture zone of the well, Then, stochastic method was used to investigate the effect of spatial variation of hydraulic conductivity on hydraulic capture zone and the results indicated that the capture zone did not always cover the entire contaminated area when the optimal pumpage adopted the same value (110m³/d) according to traditional deterministic methods, facing a convergent mean risk criterion as high as 24%. This study showed that the optimal pumpage concluded from the Monte Carlo method was more reliable than commonly used deterministic method, because it could takes such spatial variation of hydraulic conductivity into account to study how the spatial variability effected the hydraulic capture zone, that provided a stochastic method to estimate the optimal pumpage from the perspective of acceptable convergent mean risk criterion.

In this study, gallic acid (GA), tannic acid (TA) and sodium dodecyl benzene sulfonate (SDBS) were chosen as surrogates of natural organic matter (NOM) to investigate the effects of chemical structures on carbon nanotubes (CNTs) suspension. The critical micelle concentration (CMC) of TA (CMC_TA) was 1.12mmol/L and the CMC_SDBS was 0.24mmol/L. But GA could not form micelles in the range of tested concentration. Comparing the adsorption process of NOM on CNTs and the dispersion process of CNTs, it was showed that steric hindrance and micellar encapsulation were the two main mechanisms for promoting CNTs dispersion. The transmission electron microscopy (TEM) and average hydrodynamic diameter (DLS) of suspended CNTs were measured. Less adsorption (S_e ≈ 0.01mmol/g) for the rigid structure of TA can lead to higher CNT suspension than SDBS with the flexible structure which was hardly dispersed due to the entanglement of alkane chain on CNTs surface. The suspension of CNT was the worst in the plane structure GA (S_e > 0.2mmol/g) due to the poor steric hindrance. The semi-micelles and micelles of SDBS (S_e > 0.13mmol/g) can be formed over CMC. The suspension of CNT can be increased by the micellar wrapping. This study highlighted that the steric hindrance and micellar wrapping were the main dispersion mechanisms of CNTs, depending on different the NOM structures.

The concentrations of thiotungstates formed under various experimental conditions simulating natural aquatic environments were quantitatively determined by an ultraviolet/visible spectrophotometer, with their effects on the formation and species transformation of thiotungstates being evaluated. The results demonstrate that weakly acidic to neutral pH values were necessary for the substantial formation of mono-, di-, tri-, and tetra-thiotungstates, especially tri-and tetra-thiotungstates, and the thiolation of tungstate to the highest degree occurred at pH=5. Under acidic conditions, thiotungstates were prone to be the major species of tungsten even at relatively low molar ratios of sulfide to tungsten (e.g. S(Ⅱ)/W ratio=10:1).With an increase of S(Ⅱ)/W ratio to 20:1, complete thiolation of tungstate was observed, and the dominant species of tungsten became mono-thiotungstate WO₃S^2-. At S(Ⅱ)/W ratios of 30:1and 40:1, di-and tri-thiotungstates WOS₃^2- predominated in the solutions, respectively. Moreover, for the acidic solutions, the increase of ionic strength obviously inhibited the thiotungstate-forming reactions. In contrast, the variation of solution ionic strength had little effect on the tungsten speciation under neutral conditions.

In this study, an innovative integrated two-stage (ITS) anaerobic bioreactor was designed and constructed in pilot scale. The integrated reactor used the dual-cylinder configuration to separate the acidogenic stage in inner cylinder with the methanogenic stage in outer cylinder. The reactor was operated for 184days treating food waste with elevated organic loading rates (OLR). The ITS reactor showed high efficiency and stability. In the stable operation phases, the organic load was 3.0kgVS/(m³·d), volumetric gas production rate reached an average of 1.69m³/(m³·d), and highest value is up to 2.72m³/(m³·d); the gas production rate was 0.57m³/(kgVS·d), and the organic solids removal rate was 77.2%. Due to phase separation effect, pH value of outer cylinder was about 0.3~0.4unit higher than that of inner cylinder, the average volatile fatty acids (VFAs) and soluble chemical oxygen demand (sCOD) concentration of outer cylinder was 25% and 23% lower than that of inner cylinder, respectively. The integrated two-stage (ITS) anaerobic reactor realized the separation of acidogenic and methanogenic phases in one reactor. The inner acidogenic phase performed the hydrolysis and acidogenic steps and reduces the impact of acid accumulation on the outer methanogenic phase, which played a key role in the stable operation of the reactor.

Forty-four alluvial samples were collected at 22locations in the Pearl River Delta to study the distribution and sources of 8heavy metals with factor analysis, enrichment factor and lead isotopic tracing methods. The study showed that the concentrations of all heavy metals were enriched relative to the background value of soil of China and Guangdong Province. The concentrations of Cr and Ni were similar in top and deep soils, while the concentration of As, Cu, Zn, Cd, Pb in top soils were slightly elevated to deep soils, while the concentration of Hg was significantly enriched in the top soils. Factor analysis indicated that the concentration of Cu, Cr, Ni was mainly controlled by the natural conditions, and the anomalies of As, Pb, Hg were caused by anthropogenic contamination. In some cases, the high concentrations of Cd and Zn were controlled by both geological background and anthropogenic contamination. The results of enrichment factor analysis indicated that the pollution levels of 8heavy metals were Hg > As > Cd > Cu > Pb > Zn > Cr > Ni. The enrichment factor values would be low if the elements were enriched in deep soils. The scatter plot showed there was significantly negative correlation between Pb concentration and ²⁰⁶Pb/²⁰⁷Pb ratio. A binary comprehensive model show that at least 30% Pb in the top soils were derived from anthropogenic contamination. In conclusion, the study found that enhanced levels of Hg, Cd, As, Pb were due to contamination.

Taking the Huang-Huai-Hai Plain (HHHP) and middle reaches of the Yangtze River and Jianghuai Region (MYJR) as the study area, the data of heavy metals in the cultivated soil were collected from published literatures. The single factor index method and Nemerow synthesis index method were used to evaluate the pollution degree of heavy metals. Combined with the soil survey data in the 1980s, the spatial and temporal variation characteristics during the period of the 1980s and 2000s was analyzed. Results showed that:(1) The heavy metals in cultivated soils in the study area were at a safe level, and more than 80% of the HHHP and more than 60% of the MYJR were at the clean level. (2) Heavy metal pollution in the MYJR was more serious than that of the HHHP. The single factor index evaluation results showed that the exceedance percentages of soil heavy metals pollution was 35.02% in MYJR, which is twice that of 15.97% in the HHHP. The Nemerow synthesis index method found that there were 20.29% and 13.17% in the pollution levels, where the proportion of light and serious pollution in the MYJR was larger than that in the HHHP and the proportion of serious pollution in the MYJR was three times that in the HHHP. (3) The order of proportions of pollution at the different location was as follows:the farmland soils near the industrial and mining area, the farmland soils in the sewage irrigation area, the farmland soils in the main agricultural production area, and the suburban farmland soils. (4) The heavy metal pollution proportion increased during the 1980s and 2000s. The increased exceedance percentages of Cd, Zn, Hg, and As in the HHHP were 6.34%, 1.98%, 12.78%, and 0.91%, respectively. And those of Cd, Ni, Zn, Cu, Hg, and As in the MYJR were 14.02%, 11.36%, 7.28%, 5.49%, 1.93%, and 0.72%, respectively. Area of worsening pollution were mainly located in Tianjin, Cangzhou in Hebei, Ji'nan in Shandong and Yueyang in Hunan. In the process of urbanization, industrialization and agricultural development, the cultivated soils are threatened by the heavy metal pollution in the study area, which calls for the effective measures to prevent and remedy heavy metals pollution.

To reveal effects of the elevated CO₂ concentration on soil microbial biomass and enzyme activity, typical paddy soil was selected from a subtropical area with a long history of rice cultivation. We studied the contents of soil microbial biomass carbon and nitrogen, and enzymes activity related to soil organic matter degradation (including β-glucoside, xylanase and chitinase) under different rice growth period. The results showed that:the plant biomass and soil microbial biomass were increased by the elevated CO₂ concentration (800×10^-6) comparing to the normal CO₂(400×10^-6). The soil microbial biomass carbon and nitrogen contents were significantly affected by rice growth stages (P<0.05), which reached to the peak at the rice booting stage. The enzyme activities of β-glucoside, xylanase and chitinase were increased by the elevated CO₂ concentration (800×10^-6) comparing to the normal CO₂(400×10^-6). All the enzyme activities measured in this study increased in the rice booting stage, and then decreased in the mature stage. The enzyme activity followed the sequence as β-Glu > Xyl > N-Ac under the same sampling time and CO₂ concentration. The multivariate analysis of variance showed that the CO₂ concentration and rice growth period significantly influenced the rice plant biomass, soil microbial biomass carbon and nitrogen and the enzyme activity measured in this study. Moreover, the interaction of the CO₂ concentration and rice growth period had a significant effect on soil microbial biomass carbon and enzyme activity. Furthermore, the correlation analysis showed that there was a significant positive correlation between soil microbial biomass carbon and soil β-glucosidase, chitinase and xylanase activities. In conclusions, the elevated CO₂ can promote the rice growth, soil microbial biomass and soil enzyme activity. Especially, soil microbial biomass has close relationship with soil enzyme activity. These changes were varying with the rice growth, and all of them reached to the maximum at the rice most productive period (booting stage).

Among inland water bodies, lakes and reservoirs are potential N₂O sources and play important roles in nitrogen cycle. Based on the N₂O flux data of 479 lakes and 83 reservoirs collected from published literatures, the influences of the latitude, area, depth and trophic status of the lakes and reservoirs were analyzed, and the global mean total N₂O flux from lakes and reservoirs was estimated. The results indicated that most lakes and reservoirs acted as N₂O sources. The mean N₂O flux from lakes[(3.21±5.71)μmol/(m²·d)] was lower than that from reservoirs[(20.82±113.94)μmol/(m²·d)]. At the annual temporal scale, N₂O flux from lakes and reservoirs decreased with increasing latitude. The N₂O flux from lakes increased with increasing area, but opposite for reservoirs. The N₂O flux over deep lakes were larger than those over shallow lakes. The N₂O flux over eutrophic lakes and reservoirs were higher with comparison to oligotrophic lakes and reservoirs. The annual mean total N₂O flux from lakes and reservoirs were 0.12 and 0.06Tg N/a, respectively, and accounted for 12% and 7% of the total N₂O emission from inland waters.

Occurrence of cyanobacterial blooms can induce considerable patchiness in the quantity and quality of dissolved organic matter (DOM). The present study investigated the changes of dissolved organic carbon (DOC), chromophoric DOM (CDOM) and fluorescent DOM (FDOM) in an inoculated 32-day laboratory incubation. The biodegradation of individual FDOM components was further studied using parallel factor analysis (PARAFAC) and two dimension correlation spectroscopy (2D-COS). The results showed that the DOC concentration decreased significantly initially, followed by a slow biodegradation. Fitting by G model successfully separated the DOC into labile (40%), semi-labile (37%) and refractory (23%) pools, suggesting that 77% of the DOC can be metabolized quickly after its production. The values of SUVA₂₅₄, spectral slope ratio, and HIX indicated that the aromaticity, molecular weight, and humic degree of DOM increased with biodegradation. The bioavailability of 4PARAFAC components followed the order of:tyrosine-> tryptophan-> fulvic acid-> humic acid-like component. Tyrosine-and tryptophan-like component accounted for a large proportion of the labile and semi-labile DOM, while the refractory DOM was mainly composed of fulvic-acid-and humic acid-like component. Synchronous fluorescence spectra combined with 2D-COS revealed that the fluorescent compounds with lower excitation wavelengths were preferentially biodegraded.

Sediment core from the Yap Trench located in the west Pacific Ocean was collected by manned deep-sea research submersible Jiaolong. Geochemical parameter analyses (e.g. total organic carbon (TOC), δ¹³C, grain size composition and specific surface area (SSA)), combined with an end-member mixing model, a degradation model and principal component analysis (PCA) were conducted in order to 1) study the vertical distribution of the organic carbon (OC) and corresponding affecting factors, 2) assess the degradation and accumulation rate and the flux of the sedimentary OC in the Yap Trench. The mean TOC content of the Yap Trench was (0.31%±0.10%) and was comparable with those of the neritic sediments. Probably due to enrichment of the allochthonous organic matter in the large grain-sized particles (e.g. silt) and intense decomposition of OC by microorganisms, the TOC content was positively related with silt% and negatively related with SSA and clay%. The microorganism-derived OC was the dominant proportion of the sedimentary TOC (52%±21%), followed by the marine (37%±19%) and terrestrial (11%±4%) OC. The OC contents of those three sources all decreased downward. Based on PCA, decoupling between the microorganism-derived and the allochthonous OC indicated that the OC delivered by the submarine groundwater was probably an important nutritional supply for the microorganisms in the trench. The degradation rate of the refractory OC which dominated the vertical profile of TOC was around 0.0012a^-1, slightly higher than that of the normal deep ocean but lower than the neritic environment. The accumulation rate and settling flux of TOC in the Yap Trench were around 1.8×10^-5gC/(cm²·a) and 2.2×10⁹gC/a.

On-board incubation experiments were conducted at three sampling stations from May to June 2016 in the South China Sea (SCS) to explore the impact of dust and haze addition on phytoplankton biomass and community structure. By providing the nutrients such as N and P, the addition of dust and haze in general promoted the growth of phytoplankton, and the promotion magnitude is tightly related to the amount of dust and haze addition. By calculation of nutrient index and chlorophyll a cumulative concentration, it was found that the accumulated chlorophyll a during the incubation experiment showed statistically significant positive correlation with the amount of added dust (R²=0.87, P<0.01); In terms of the dust, similar promotion mechanism was found when the haze concentration was low (R²=0.91, P<0.01). However, when the haze concentration continued to increase, the accumulation of chlorophyll a was hindered to some extent, likely an effect of the high content of toxic substances in haze. Size-fraction chlorophyll a showed that the addition of dust and low concentration of haze facilitated that the transition of dominant phytoplankton species from pico-sized phytoplankton to micro-and nano-sized phytoplankton, while the synthetic effect of nutrients and toxic substance, resulting from the addition of high haze concentration, yielded no obvious effect on the size structure of phytoplankton. The pico-sized phytoplankton abundance tests showed that the dust addition promoted the development of all three species including Synechococcus, Prochlorococcus and picoeukaryotes, whereas the addition of high concentration haze addition may inhibit the growth of Synechococcus and picoeukaryotes.

Based on the data of nutrients, chlorophyll a and hydrological environment parameters collected in Bohai Bay during the early summer of 2016, we studied the distributions of nutrients and analyzed their possible limitation on the phytoplankton growth by analyzing both the minimum threshold and N:P:Si atomic ratios of nutrient required by phytoplankton cells. The results showed that concentrations and spatial distributions of nutrients were influenced by terrigenous input, cold water from central of Bohai Sea and phytoplankton uptake. Both dissolved inorganic nitrogen (DIN) and silicate (SiO₃^2--Si) concentrations decreased from nearshore to the offshore bay mouth, and the mean concentration of DIN was (7.67±6.48) μmol/L and SiO₃^2--Si was (5.44±3.01) μmol/L. In the surface of bay mouth, the concentration of DIN was (2.21±2.94) μmol/L in average, and 50% of samples was below the threshold, especially, 58.3% of them showed DIN limitation for phytoplankton growth. Comparatively, concentrations of activated phosphate (PO₄^3--P) were high in the nearshore and the bay mouth due to riverine input, and a zone with low concentration appeared in the middle probably caused by the phytoplankton uptake. The mean concentration of PO₄^3--P was (0.07±0.07) μmol/L in the whole study area. The concentrations of PO₄^3--P in the surface water were below the threshold of 0.03μmol/L at about 74.3% stations in the middle zone of study area, showing an obvious P limitation for phytoplankton cells. With the increasing disparity of riverine input between nitrogen and phosphorus, the P limitation for phytoplankton would be more serious in our study area.

Based on multi-temporal remote-sensing images (1990, 2002, 2010) in the Huayang Lakes area, a typical lakes area in Yangtze river basin, we built the Ecosystem Services Value (ESV) assessment model using the equivalent factor method and developed the ecosystem service flow gain-and-loss matrix. Meanwhile, a human activity intensity index (HAI) was introduced and correlated with ESV by bivariate spatial autocorrelation method. The results indicated that:The ESV decreased continuously for 20years mainly resulted from the conversions of water area, tidal-flat area into cultivated land and construction land. From 1990to 2010, the lakeside area showed a massive reduction in ESV. The high ESV areas were distributed mainly in the central and northeastern lake areas because of the returning from farmland to forest in hilly areas. The southern lake areas decreased substantially with the decreased area expanded because of the agricultural bases and new cities construction. The supply and support services functions had been strengthened, conversely, the regulation and cultural services had been weakened. Spatially, human activities intensity was dominated by low-intensity, medium-intensity and medium-high intensity. The low-intensity human activities were mainly distributed around lake areas, with medium-intensity and medium-high intensity interlaced in the northern region and high-intensity in the southern and southwestern regions. According to the bivariate spatial autocorrelation analysis, HAI was discovered to have the significant negative correlation with ESV. Spatial correlation was significant and the degree of spatial agglomeration was relatively high in the study area. The bivariate LISA figures between HAI with ESV showed the high-low clusters located near the south shore of lakes and the low-high groups mainly gathered in the center water area. It is vital to establish the regional differentiated utilization management policies under the principle of ecological and economy coordinated development in this region and even in the whole Yangtze River basin.

The mechanisms of mobility and retention of titanium dioxide nanoparticles (nTiO₂) in well-defined porous media composed of clean quartz sand in the presence of fulvic acid (FA) and humic acid (HA) were studied under acidic conditions. nTiO₂ were immobile in the porous media in the absence of FA and HA at pH 4.0. FA and HA could be adsorbed onto the surface of nTiO₂, change the electrokinetic properties of nTiO₂, and facilitate the transport of nTiO₂. The elution of nTiO₂ increased from 0.01 and 0.88 to 0.91 and 0.94 with the increase of FA and HA from 1mg/L to 10mg/L respectively. Compared to FA, more HA was adsorbed onto nTiO₂, and thus the facilitated effect of HA on transport of nTiO₂ was stronger. Ions inhibited the mobility of nTiO₂, and the effect of CaCl₂ was greater than that of NaCl in same concentration. The mobility of nTiO₂ was better in the presence of HA than FA. In addition, 7%~56% nTiO₂ was deposited in the secondary energy minimum well in the presence of HA, higher than 4%~17% in the presence of FA, which could be easily released when the environmental conditions changed. High energy barriers between nTiO₂ and quartz promoted the mobility of nTiO₂, while a combination of the secondary minimum energy, straining, diffusion and gravitational deposition were involved in the retention of nTiO₂.

In order to explore the differences in bacterial community structure and its driving factors in the sediment of Nanfei River, the key physiochemical parameters including pH, CEC, TOC, DOC, and various forms of nitrogen were determined in the surface sediment samples along Nanfei River with different land uses such as urban, suburb, industrial park and rural areas. Specially, sediment bacterial community structure characteristics were analyzed by using MiSeq high-throughput sequencing technology. The relationships between sediment bacterial community structure and aforementioned physiochemical parameters were examined by redundancy analysis (RDA). The results showed that the major bacterial phylum is Proteobacteria in the surface sediments, followed by Chloroflexi, Bacteroidetes, Firmicutes. At the level of class, the major bacterial class are Anaerolineae, Gammaproteobacteria, Clostridia, Deltaproteobacteria besides the unclassified. Epsilonproteobacteria were detected mainly in sediment samples from downstream of the Nanfei River, suggesting that they were not ubiquitous in the sediment ecosystem of the Nanfei River. Most of the genus is unclassified, with Longilinea and Bellilinea being predominant species. Different types of land uses along the Nanfei River led to different pollution sources and discharging load will result in different physicochemical properties of surface sediment, which in turn reshape the bacterial community structure of the sediment. The bacterial diversity in the sediments from urban and industrial areas of the middle reaches is generally higher than that in the upper and lower reaches. RDA analysis indicated that the sediment CEC, TOC, DOC, TP, nitrogen in weak acid extractable form (WAEF-N) and nitrogen in ion exchangeable form (IEF-N) were the key factors driving the differences in the structural characteristics of bacterial communities in the sediment of Nanfei River. The influence of TP was significant on Proteobacteria, Bacteroidetes and Firmicutes, and WAEF-N had a greater influence on Chloroflexi.

This review discussed the cultivation-independent approaches which have been developed to identify functional-yet-uncultivated soil microbes in situ and revealed their functions in PAHs degradation. PAHs-degrading microbes, degradation mechanisms and functional genes were summarized. The principles, characteristics and applications of cultivation-independent methods, including Fluorescence in situ hybridization (FISH), Stable-isotope probing (SIP), Metagenomics, Transcriptomics, Single-cell technology and Magnetic nanoparticle-Mediated Isolation technology (MMI) were also discussed. Examples were given on the application of these cultivation-independent approaches in identifying PAHs-degrading microbes. SIP technology is the most stable and widely used in the study of PAHs degradation mechanism. As a novel cultivation-independent approach, MMI technology provides a deep insight into exploring functional-yet-uncultivated PAHs-degrading microbes, which stands out for its ability to separate active functional microbes.

Based on Pigou Theory, environmental tax is an external regulation to solve environmental pollution. In order to test whether the environmental tax and fee policies could produce a double dividend, namely reducing pollution and encouraging green technology innovation, we constructed the dynamic panel models and the panel threshold models of environmental tax and fee policies in this paper. The results showed that the high population density in the region hadn`t become the constraint of environmental dividend, and the industrial structure and the energy structure need to be further optimized to promote double dividend effect. The panel threshold model estimation results of the environment taxes showed that there was a nonlinear time-varying characteristics between the environmental tax and environmental pollution, and green technology innovation. The double dividend effect can only be achieved well by selecting the appropriate environmental tax interval. And the higher the level of economic development, the more obvious of the double dividend. Therefore, it should be the key to win the battle of environmental protection to make the comprehensive environmental tax system based on the heterogeneous characteristics of regional economic development in 2018.

In this paper, a novel ecological efficiency evaluation system was proposed which considered both the indicator of ecological resources and the indicator of economic waste caused by environmental pollution. Firstly, an optimized super efficiency SBM model was used to calculate the ecological efficiency of China by introducing the non-expected output in the model. Then, Malmquist index method was used to examine the dynamic changes between Total Factor Productivity (TFP) and ecological efficiency. Finally, Tobit regression model was applied to explore the directions, intensities and dynamic trends of the main factors affecting the ecological efficiency. The new ecological efficiency evaluation system could help us to capture the overall situation of circular economy development in China. By analyzing the annual panel data of 30provinces in China, the empirical results showed that, there existed a gradual convergence pattern in the ecological efficiency from east to west and from the coast to the inland. There also existed a significant step-by-step regional imbalance in the development of circular economy between the eastern coastal areas and the central and western inland areas. The cluster effect of ecological efficiency was obvious, while the radiation effect was not so evident. The development of circular economy was also uneven in either different regions or different provinces of the same region. The deficit in the ecosystem triggered by economic development was gradually reduced, but the contradiction between economy and ecology still existed in the near future, especially in the northwest region. The proportion of tertiary industries, technological progress and market opening level had a significant positive effect on the promotion of ecological efficiency and the impacts were strengthening more and more. Government regulation and population density had a significant positive effect on the improvement of ecological efficiency but the impacts were weakening gradually. The proportion of secondary industries and the structure of energy had a significant negative impact on the improvement of ecological efficiency and the impacts were strengthening more and more.

This paper calculated and compared the before-and-after results of efficiency of town sewage treatment by using three-stage DEA Model to eliminate the effects of environmental factors and random error. The results show that such environmental factors as economy, society and water resources endowment could influence greatly the investment efficiency of town sewage treatment and overestimate the comprehensive technical efficiency of sewage treatment. At present, the comprehensive technical efficiency level of town sewage treatment in China was rather low, only at 0.797. And among the east, middle and west regions, the comprehensive technical efficiency of east region and middle region was higher than that of the west region. From the perspective of pure technical efficiency and scale efficiency, most provinces in China were at the stage of low-high type, indicating the phenomena of backward management technology, redundant scale and low treatment rate of sewage which yield to the investment efficiency of sewage treatment. Therefore, it was necessary to increase the amount of sewage treatment and improved the construction of sewage treatment scale, as well as to enhance the management technology of sewage treatment.