The study of air pollution in areas with dense economically developed populations was of great significance for ensuring regional environmental security and human settlement health. This article was based on Aura-OMI HCHO data products, it interpreted and analyzed the quantitative distribution, dynamics and influencing factors of formaldehyde column concentration in the Yangtze River Delta region from 2008 to 2017. The results showed that in the past 10years the average value of formaldehyde column was 14.16×10¹⁵ molec/cm², the maximum value was 15.41×10¹⁵ molec/cm², the minimum value was 12.27×10¹⁵ molec/cm², the maximum growth rate was 17.8%, and the average growth rate was 0.17%, the maximum rate of decline was 15.95%. In time, the concentration of formaldehyde has shown a fluctuating upward trend over the past 10years, mainly in the fourth, third and fifth grades, the highest in summer, followed by spring and autumn, and the smallest in winter. The share ratios in spring, summer, autumn and winter were 25.96%, 34.28%, 22.00%, and 17.76%, respectively. In space, the concentration decreases from the central to the both sides, the coastal area was the lowest, and the high value area gradually shifts from northwest to southeast. The main factors affecting the change of formaldehyde column concentration in the Yangtze River Delta were natural factors and human factors. The natural factors were mainly temperature and precipitation,while the human factors were mainly the total energy consumption, the secondary industry, the tertiary industry, the gross production value,the furniture and building decoration materials. There were spatial-temporal evolutions and influencing factors of the Yangtze River Delta and Beijing-Tianjin-Hebei have similarities and differences.

This study aimed to develop an integrated inventory of the atmospheric emissions of total suspended particulate (TSP), inhalable particles (PM₁₀) and fine particles (PM_2.5) from wind erosion at fine resolution in China during the period 1995~2015 and project the trend of emissions from now until 2100. A bottom-up method was utilized to compile this comprehensive inventory with updated historical meteorological data (e.g., wind speed, precipitation and temperature), land use categories and soil contents at provincial level. The national total emissions of TSP, PM₁₀ and PM_2.5 from wind erosion were estimated as 2.27×10⁷t, 6.77×10⁶t and 1.17×10⁶t, respectively. Higher emissions were observed in Northern or Eastern China compared with Southern and Western China. Highest emission intensity was found in Western Inner Mongolia and most of Xinjiang Province. Furthermore, based on the Intergovernmental Panel on Climate Change (IPCC) predictions of future climate change, emission trends of TSP, PM₁₀ and PM_2.5 from wind-erosion process in the future was estimated. Under the combined effects of precipitation and temperature changes, wind erosion dust emissions in 2100 is between -8.5 % ~ 7.7 % compared to 2005. The increase of precipitation will inhibit the emissions of wind-erosion dust while the rapid increase of ambient temperature can make the land surface more prone to produce particles.

The TrajStat software and data from global data assimilation system were used to calculate the 72 hour backward trajectories of air pollutants in Beijing from 2005 to 2016. The cluster analysis method was used to analyze the characteristics of the backward airflow trajectories and their effects on the concentration of particles over Beijing in the whole year and different seasons, combining with the daily concentration data of PM_2.5, during the same period in Beijing. Meanwhile, Potential Source Contribution Factor Analysis (PSCF) and Concentration Weight Trajectory Analysis (CWT) combined with weight factors were utilized to calculate the potential source regions and the contribution of different source regions to Beijing particle concentration in different seasons during the study period. The results showed that, for the whole year, the air flow form northwest with the longest transmission distance, highest transmission height, and fastest transfer speed, occupying 59.97% of the total trajectories. The southeast airflow with the lowest transportation altitude, the shortest distance and the slowest moving speed accounted for 27.64%, and the lowest proportion of the northeast airflow was 12.40%, whose moving speed and transportation distance were between the first two. The main pollution trajectories came from Shandong and Hebei, followed by the northwestern airstreams from Russia, Mongolia, and Inner Mongolia's desert Gobi region. PSCF and CWT analysis found that central inner Mongolia, central Shanxi, southwest Guizhou, northern Henan and Shandong were the main potential areas affecting PM_2.5 in Beijing. However, the differences in the impacts of different seasons and different backward trajectories on PM_2.5 pollutions in Beijing were significant. In the spring, it was mainly affected by the short-distance transmission air flow from the border area of Mongolian and Shanxi. The potential source areas were located in southern Hebei, western Shandong, eastern Henan, and northwestern Anhui. The pollution trajectories in summer come from Shandong and Shanxi, and the potential source areas were northeastern Henan, northern Hebei, and northern Jiangsu. In the autumn, it was mainly affected by short-range air currents from southern Hebei. The potential source areas were northern Shanxi, southern Hebei, northern Henan, and western Shandong. In the winter, it was mainly affected by long-distance air currents from the central and western regions of Mongolia and central inner Mongolia. The potential source areas were mainly in southern Hebei, western Shandong, northern Henan, Shanxi, and western Inner Mongolia.

PM_2.5 samples were collected at four cities (Xuzhou, Dongshan, Nanjing and Shouxian) from December 13th 2016 to January 5th 2017 to investigate the composition and source of water-soluble ions in this study. Moreover, the time variation of these ionic species coupled with the local meteorological conditions was analysed to shed light on the haze formation and dissipation mechanism in the Yangtze River Delta Region (YRD). The results revealed that: during the observation period, the average mass concentration of PM_2.5 in Xuzhou was 171.5μg/m³, which was much greater than the average mass concentration in the other three sites. The most important ionic components were NO₃^-, SO₄^2-, NH₄⁺, Cl^- and Ca²⁺. The variations of ionic components were due to the combined effects of emissions and weather systems. Under the influence of the same weather system, the pollutant concentration varied consistently in different areas of YRD. Under the static weather condition without obvious regional transport, the ion concentrations were mainly affected by the local sources. Xuzhou was mainly affected by the coal. Nanjing was mainly affected by the chemical industrial source. The major component in both Xuzhou and Nanjing was SO₄^2-. Dongshan is surrounded by the lake on three sides, and Cl^- increased significantly to 6.12μg/m³ under the static weather condition. Shouxian was mainly affected by the ammonia emissions of local agricultural activities, and NH₄⁺ increased significantly to 25.09μg/m³. The concentration of PM_2.5 and water-soluble ions of four sites varied with time consistently. When YRD was controlled by the weak high pressure accompanied with the uniform pressure field, this weather pattern was favorable for pollutant accumulation. The principal component analysis indicated that secondary formation had the largest contribution to PM_2.5 concentration, with the contribution rates of 39.83%, 42.27%, 50.56% and 38.40% at Xuzhou, Nanjing, Dongshan, Shouxian, respectively.

Source markers are very important for apportioning the particulate matter sources. However, some markers like aluminum and silicium could not be measured by online instruments,which might increase the uncertainty of source apportionment results. To figure out this problem, this work proposed a new inverse method to estimate Al and Si concentrations base on PMF (Positive Matrix Factorization) and measured source profiles. Several simulation experiments was designed to estimate the performance of the new method. Three input data, including data without Al and Si, data with reversed Al and Si, data with Al and Si, were setup and run separately by PMF, the calculated source profiles and contributions were compared with the corresponding true values. The results show that running model without Al and Si data increases uncertainties of results, and the new method can improve the model performance, for some cases.

It were chosen for high saline-alkaline soil, S₁[electrical conductivity (EC) 2.60dS/m] and low saline-alkaline soil, S₂[electrical conductivity (EC) 0.74dS/m] in Hetao Irrigation District of Inner Mongolia. The static box method was used in field in-situ observation test for 3year. A 3-yr study was conducted with sunflower crops in intensively managed saline-alkaline soils cropping systems in northeastern China to examine the effects of salt and alkali on N₂O emissions. Results indicated that high saline-alkaline soil significantly increased N₂O emissions with obvious differences as compared with low saline-alkaline soil. The accumulative emissions of N₂O during the 3-year observation period were estimated at 180.6mg/m², 167.6mg/m² and 118.2mg/m² for the low saline-alkaline soil. Compared with low saline-alkaline soil, the high saline-alkaline soil significantly increased the accumulative emissions of N₂O by 19%, 26% and 45% from 2014 to 2016, respectively. Our findings suggest that mitigating N₂O emissions on saline-alkaline soil can be achieved by remediating saline-alkaline soil.

Based on the geochemical cycle of elemental sulfur, the reaction mechanism and product morphology of reductive sulfide produced by biochemical metabolism of Sulfate-Reducing Bacteria (SRB) and sulfite were systematically studied. In biochemical desulfurization of flue gas (biochemical system), the largest sulfur yield (more than 40%) achieved at pH=(4.04±0.10) and ORP=(-134±17mV), but the optimal conditions for sulfur production in SO₂(aq)-S^2-(aq) system were pH=(3.99±0.21), ORP=(-159±40mV) and 1:1 molar ratio of SO₃^2- to S². In addition, the reaction of sulfur production of S₂O₃^2- with S^2- was a side reaction, which was beneficial to the production of sulfur. Sulfur consumption under near-neutral conditions was attributed to the production of polysulfide and polysulfate. The solid products of SO₂(aq)-S^2-(aq) system and biochemical system were characterized as the spherical high-purity orthorhombic sulfur. The sulfur produced in the biochemical system was adhered by the extracellular polymer.

Seasonal characteristics and influencing factors of ammonia (NH₃) volatilization from farmland under traditional irrigation (furrow irrigation) and water-saving irrigation (sprinkler irrigation) in 2016 and 2017 were studied. Effects of soil temperature, volumetric water content, ammonium nitrogen (NH₄⁺-N), nitrate nitrogen(NO₃^--N), temperature and precipitation on ammonia volatilization were analyzed by in-situ ventilation measurements. The results showed that NH₃ volatilization rate increased up to 1~2 weeks after nitrogen application, with the maximum values of 2.67kg/(hm²·d), 11.11kg/(hm²·d) in 2016 and 2.42kg/(hm²·d), 11.73kg/(hm²·d) in 2017, under furrow irrigation and sprinkler irrigation, respectively. The ammonia volatilization showed obvious seasonal pattern in potato growing season, higher in July-August and higher in top-dressing stage than base fertilizer stage. Accumulative volatilization showed sprinkler irrigation produced less NH₃than furrow irrigation, compared with furrow irrigation, sprinkler irrigation with a decrease of 58.15% and 43.55% in 2016 and 2017, respectively. There was a significant positive correlation between NH₃volatilization rate and soil temperature (P<0.05), and significant positive correlations with volumetric water content, NH₄⁺-N and NO₃^--N concentration (P<0.01).

In order to capture the complex and nonlinear relationship between ground-level NO₂ concentrations and predictor variables, random forest (RF) models combined with multiple types of geographic covariates were developed to estimate ground-level NO₂ concentrations. In this process, satellite-based OMI NO₂ tropospheric columns and multi-source geographic covariates (i.e., road network, meteorological factors, land use/cover, DEM and population density) were used as potential predictor variables and ground-level NO₂ concentrations were used as the dependent variable for RF models construction. The reliability of the RF models was validated by comparison with ground-measured NO₂ concentrations and typical linear land use regression (LUR) models. Afterwards, the spatial distribution characteristics of NO₂ concentration mapped by RF models across time scales in mainland China were assessed and analyzed. Results showed that RF modeling outperformed LUR modeling with obvious higher model fitting-based R² and lower RMSE, which were 0.85 and 6.08μg/m³ for monthly RF models compared with 0.53 and 10.48μg/m³ for LUR models. This was confirmed by the cross-validation-based R² and RMSE with values of 0.84 and 6.33μg/m³, while those of LUR models were 0.53 and 10.49μg/m³. The partial dependence of RF models suggested that the actual relationships between ground-level NO₂ concentrations and predictor variables were nonlinear and time-dependent. OMI NO₂ tropospheric columns contributed most strongly to the RF models of NO₂ concentrations, which had largest percentage of IncMSE (ranged from 97.40% to 116.54%). Meanwhile, the importance of different geographic variables could not be disregarded, which had values of IncMSE between 23.34% and 47.53%. Additionally, the NO₂ concentrations simulated by RF models showed that the annual average NO₂ concentrations across mainland China during the study period were 24.67μg/m³, which had significant seasonal variations with value of 31.85, 24.86, 23.24 and 18.75μg/m³ in winter, autumn, spring and summer, respectively. Spatially, higher concentrations of simulated NO₂ concentrations occurred in the North China Plain and decreased to the periphery. Compared with the existing studies focusing on tropospheric NO₂ column density, this study sheds new light on accurate monitoring of spatial-temporal distribution of ground-level NO₂ pollution. Findings from this study will provide new implications for policy making for future national prevention and control of air pollution to reduce the population health burden in China.

The spatio-temporal changes of anthropogenic heat flux (Q_a) in 1980~2015 over China were investigated based on the statistical and gridded population data and the statistics of energy consumption. The surface net solar radiation (R_n) was used to describe the impact of Q_a on land surface energy balance. The results showed that the national average Q_a increased from 0.07W/m² in 1980 to 0.45W/m² in 2015, with an increasing trend of 0.11W/m²/10a(P<0.001). The national average Q_a in 2015 accounted for 27% of the global radiative forcing resulting from anthropogenic CO₂ emissions since the beginning of the industrial revolution. The sites with aQ_a more than 1.00W/m² extended from spotted distribution to continuous areasfrom1990 to 2015, and its area accountedfor 10% of China's total area in 2015. Moreover, the changeof R_n was slightlyfaster than that of Q_a, but not significantly (P=0.381). The mean Q_a in urban areas of the 31provincial capital cities ranged from 1 to 32W/m² and the mean intensity was up to17W/m² in 2015. The ratio of mean Q_a to mean R_n(149W/m²) of the 31capital cities on average was approximately12%. Except for Lhasa, the maximum pixel (0.5min×0.5min) value of Q_a exceeded120W/m² ineach city that implying the local energy balancehas already been changed substantially. We strongly suggested that anthropogenic heat release should be considered in the study of urban climate simulation, regional climate simulation and assessment, and making coping strategy about climate change for better strategy to slow down the warming trend.

In order to study the impact of ATC operations on the aircraft's greenhouse effect quantitatively and visually, firstly, the BP neural network matching model of flight parameters and flight trajectory was established based on the quick access recorder (QAR) data. Secondly, the model was verified based on the QAR data. Then the greenhouse effect characterization parameter calculation model was established. Finally, pollutant emissions and total temperature change potential were estimated based on the test data of flight track on the radar simulator, and the differences in the command of different controllers were compared and analyzed afterward. The results show that the relative error between the estimated fuel flow calculated by the estimation model of fuel consumption and the real value recorded by QAR was less than 2%. The results of evaluating controllers' performance by using fuel consumption and greenhouse effect index were different. The research results can be used to quantitatively analyze the impact of ATC operations on the greenhouse effect.

A²O and A²O+BCO process were employed to treat domestic wastewater with low carbon to nitrogen ratio (C/N=3.96) to compare their nutrient removal performance,respectively. The influent loading and operation condition were kept consistent for 134 days, A²O+BCO system achieved a higher nitrogen and phosphorus removal efficiency than A²O system because of the application of denitrifying phosphorus removal technology and two-sludge theory, which could use carbon resource more efficiently and solve the SRT contradiction between nitrifiers and PAOs. PAOs accounts for 22% in the stable A²O+BCO system higher than 7% in the A²O system, which explain the mechanism for the superior nutrient removal performance.

Degradation of triclosan(TCS), a kind of broad-spectrum antimicrobial agent, was studied in water by the UV/chlorine advanced oxidation process. The removal of TCS by single UV, single chlorination and the UV/chlorine process was compared. The effect of different factors on the UV/chlorine process was investigated, including UV intensity, initial residual chlorine, pH value and ammonia concentration. The degradation mechanism and the ecological risk were further discussed. The results indicated that TCS had higher removal by the UV/chlorine process compared with single UV and single chlorination. The reaction fitted pseudo-first-order kinetics. The degradation rate increased with the increase of UV intensity and initial residual chlorine, while decreased with the increase of ammonia concentration. Seventeen intermediates were identified by HRMS Q-TOF, and the possible degradation pathway was also proposed. Both luminescent bacteria experiment and ECOSAR prediction showed that intermediates with high toxicity were produced on TCS degradation by the UV/chlorine process. With the process of reaction, intermediates generated with lower toxicity, and the ecological environment risk was reduced.

Effects of substrate shock on the characteristics of ANAMMOX granules were investigated from the perspective of quorum sensing with the final purpose of providing theoretical guidance and reference for improving the stability and settleability of ANAMMOX granules under substrate shock. The results showed that due to 24h 1500mg/L total nitrogen (TN) shock, the amount of AHLs released by ANAMMOX granules increased significantly from 4.3 to 10.0. At the same time, excessive release of bound extracellular polymeric substances (B-EPS) (increased by 107.3mg/g VSS) was observed, which led to the poor settling performance of granules (density and settling velocity reduced by 53% and 33%, respectively). However, after the TN concentration returned to the level in the stable period, the release amount of AHLs, B-EPS content and granules properties could also return gradually to the level in the stable period. It was inferred that substrate shock resulted in the change of release amount of AHLs, which caused the change of B-EPS production. The results of the batch test also confirmed that the substrate concentration affected the release of AHLs, significantly. Moreover, B-EPS production was closely related to the release amount of AHLs. When the TN concentration was 1000mg/L, the release amount of AHLs was up to 11.7, leading to excessive accumulation of loosely-bound EPS (LB-EPS) (increased by 69mg/g VSS) and poor settleability of granules comparing with 200mg/L TN concentration. In contrast, the tightly-bound EPS (TB-EPS) content was not affected by substrate concentration. Thus, the LB-EPS was considered the key factor for the deterioration of granule settleability. Low concentration inhibitor can effectively inhibit the excessive release of AHLs caused by high substrate concentration, resulting in 36% reduction in LB-EPS content and improvement of the settleability and activity of granules.

Three widely used conditioning methods, including bioleaching (BC), Fenton oxidation (FC), and chemical addition of lime/FeCl₃/PAM (LC), were investigated to determine their effects on sludge dewaterability and physicochemical properties. The results showed that the BC, FC, and LC conditioning methods significantly improved sludge dewatering performance, as exhibiting that specific resistance to filtration (SRF) of already-conditioned sludge by BC, FC and LC only were 0.43%~6.12% of that by conventional PAM addition treatment (CC). Furthermore, compared to chemical treatments (FC and LC), relatively high quantities of plant nutrients (56.9% of organic matter, 4.66% of total nitrogen, 0.47% of water soluble nitrogen, 1.80% of mineralized nitrogen, and 1.60% of total phosphorus) were retained in the dewatered sludge of bioleaching treatment. Meanwhile, after bioleaching treatment, 18.7% of Cr, 50.0% of Mn, 48.7% of Ni and 72.9% of Zn were removed from sludge, respectively. Flow cytometry was further used to examine the variation of sludge cell apoptosis before and after the three conditioning methods. It was found that dosing chemical conditioners (FC and LC) lead to the obvious lysis of the sludge cells and accordingly a large amount of internal water and intracellular substances within the sludge flocs were released, which may be responsible for their increased plant nutrients release and improved sludge dewaterability. The results suggested that bioleaching treatment exhibited excellent performance in improving sludge dewatering and heavy metal removal and maintaining sludge nutrients, therefore it's promising conditioning approach for sludge disposal.

This study examined the difference of ammonium adsorption by molecular sieve with different silica-alumina ratios that were determined using x-rays fluorescence (XRF) method. Based on the results from scanning electron microscopy (SEM) and X-ray diffraction (XRF), It was investigated the adsorption mechanism of molecular sieve under different silica-alumina ratio conditions from the perspective of molecular sieve framework, surface morphology, and crystal structure. Meanwhile, the ammonium adsorption improvement through the desilicification of molecular sieve framework was revealed, and this would provide technical reference for the molecular sieve based deep denitrification of sewage treatment plant effluent. The results indicated that molecular sieves with different silica-alumina ratio had significant variation in surface morphology, crystal structure, and ammonium adsorption performance. It was found that the increased silica-alumina ratio was associated with decreased crystallization, increased obscuring of crystal grain shape, and decreased adsorption capacity. When the silica-alumina ratio rose from 35 to 237, the equilibrium adsorption capacity of ammonium by molecular sieve decreased from 5.65mg/g to 0.41mg/g, and the monolayer adsorption saturation capacity confirmed by Langmuir adsorption isotherm decreased from 6.5963mg/g to 0.4430mg/g. The adsorption process conformed to the pseudo-second-order kinetic model, which was revealed that the adsorption rate was controlled by the mechanism of ion-exchange chemical adsorption. Both the ion-exchange capacity of molecular sieve and the rate of adsorption decreased with the increase in silica-alumina ratio. It was observed that the ability of ammonium absorption was significantly improved by desilicification process of molecular sieve framework, and the equilibrium ammonium adsorption with a silica-alumina ratio of 35increased by 81.6% after a desilicification process. This would provide an effective technological approach for improving the ammonium adsorption by molecular sieve.

A full-scale A²O-MBR wastewater treatment plant was investigated to analyze the phenomenon and characteristics of foam (quality/quantity and biological feature) in the oxic tank. Furthermore, the possible causes of foaming, as well as the effects of foaming on the pollutants removal and membrane fouling were elucidated. The results showed a significant progression of the foaming phenomenon, whereby the foam quality/quantity parameters (foam quantity-Scum index, SI^* and foam potential/stabilityFoam power, FP) increased considerably with running time. Also, the foam SI^* and FP values were significantly correlated with the concentrations of total EPS and bound EPS. In addition, the abundance of filamentous bacteria and microbial activity in the foam were notably higher than that in the mixed liquor. Analytically, the formation and stability of foam might be caused by EPS and filamentous bacteria (mainly Microthrix parvicella and Eikelboom 0092type). Nonetheless, the efficiencies of pollutants removal (COD、NH₄⁺-N、TN、TP and turbidity) were found to be free from the negative effects of biological foam. In contrast, membrane fouling was influenced by biological foam to some extent.

Hydrothermal liquefaction (HTL) of dehydrated sludge was conducted for bio-oil production in the present study. Results showed that the removal of extracellular polymeric substance caused organic matter to break down into organic polymer compounds at high temperature and promoted the formation of bio-oil. Compared with the non-pretreatment sludge, subcritical water (SCW) pretreatment promoted the deamination reaction and the nitrogen content reduced by 51.74% in the bio-oil. Cetyl trimethyl ammonium bromide (CTAB) pretreatment promoted 19.3wt% of organic matter from the aqueous and gaseous phases to the oil phase and the acid content reduced by 13.49wt%. CTAB-SCW combined pretreatment the bio-oil yield increased by 66.92% and the alcohol content by 28.32%. Transesterification reaction in the combined pretreatment was the main reaction, at the same time, the nucleophilic reaction, the oxidation reaction and the elimination reaction were also remarkably enhanced.

Straw-biochar (SBC) was prepared by rice straw, a cheap agricultural waste, through activation with ammonium hydrogen phosphate ((NH₄)₂HPO₄). SBC was characterized by scanning electron microscopy (SEM), surface area measurements (BET) and Fourier transform infrared spectroscopy (FTIR). The effect of contact time, SBC dosage, initial pH and concentration of anions were investigated. The results indicated that adsorption capacity of SBC reached an equilibrium within 60min with 0.3g/L of SBC and 0.05mmol/L DCF. The removal rate of DCF decreased with pH increasing from 5.00 to 9.00. The addition of Cl^-、SO₄^2- and HCO₃^- had a negligible impact on the adsorption of DCF. The adsorption of diclofenac on SBC could be well fitted by the pseudo-second-order kinetics and Freundlich isotherm model. The maximum adsorption capacity of SBC for DCF was calculated to be 277.78mg/g based on Langmuir isotherm model. Thermodynamic parameters illustrated that the adsorption process was spontaneous and endothermic. Compared with activated carbon (AC) and carbon nanotube (CNT), SAC achieved a better performance on the removal of DCF.

In order to study the microscopic percolation of foam, the process and mechanism of removing organic solvents, and the effect of nano-silica particles on the foam properties in the porous media, sandstone micromodel was made and nano-silica particles was modified with sodium stearate. The results showed that the formation, breakdown and migration of foam in porous media were simultaneous. The formation was related to the velocity of injection flow, the breakdown was related to the gas diffusion; A small portion of foam was carried out in the form of a bubble chain while most foam was trapped by pore. The removal of pollutants included emulsification, foam stripping and plugging, and plugging was the main way. Modified nano-silica particles can improve the stability of foam obviously, and there was a positive correlation between concentration and stability. The foam stabled by nano-silica particles still has strong stability when the foam was migrated in the simulation column. With the increase of the foam injection volume, the injection pressure and resistance factor increased, and the blocking effect is enhanced.

How artificial surfactant Tween 80 in groundwater affect ubiquitous tetrachloroethylene (PCE) migration and distribution in coarse porous media was investigated in this work. Batch experiments were first conducted to measure the contact angles and interfacial tensions (IFT) between PCE and quartz surface in water containing different amount of Tween 80. Results showed that the contact angle increased and IFT decreased with the increased concentration of Tween 80, and the effects were more obvious near the CMC value. Three 2-D sandboxexperiments were then conducted.Correspondingly, Tween 80 showed strong effects on the migration and distribution of PCE in the coarse porous media due to its ability to change the medium wettability from water-wet into intermediate/NAPL-wet. The presence of surfactant in the background solution decreased the vertical migration rate of DNAPL, decreased the vertical migration distance, and eventually increased the residual PCE trapped in the migration path. Compared with the situation without surfactant, the Tween 80 in groundwater weakened the tendency of PCE plumes deflect to the direction of water flow. Compared with the water-only case, the distribution area of PCE plumes decreased significantly in the vertical direction, but the amount of DNAPL residues with greater saturation increased.

In order to clarify whether the multi-component mixture of municipal solid waste may have an impact on its methane production performance, effects of inoculum sources on the anaerobic degradation of single and multi-component materials were studied by conducting biochemical methane potential (BMP) experiments on food waste (FW), newspaper (NP) and branch (BR) at mesophilic temperature (37±1)℃. The modified Gompertz model was used to fit and analyze the kinetic characteristics of the methanogenesis process, and a quantitative index method was developed to evaluate the impact on co-degradation performance. The results of experiments and model fitting exercises showed that the inoculum source had no significant effect on the biodegradability of single and multi-component materials, but had significant effect on its degradation rate. In addition, although the mixing of the components promoted the rate of degradation at the initial stage of the test, only the tri-component mixture test group showed a significant synergistic promotion in the final cumulative methane yield, and the methane yield increased by 16% and 14%, respectively, compared with the mono- degradation of materials with two different inocula.

A dynamic leaching experiment was established using CH₃COOH-CH₃COONa solution with a pH of 5.5 and deionized water with a pH of 7.0 as initial leach liquor, aiming at studying the long-term leaching behavior of fly ash solidified body in the domestic waste sanitary landfill site. The difference in pH of the initial leach liquor would affect the structural integrity and the formation of crystal on the surface of fly ash solidified body. When CH₃COOH-CH₃COONa solution was used, the fly ash solidified body would be broken during the experiment. While deionized water was used, CaCO₃ crystals formed on the surface of fly ash solidified body would inhibit the leaching of heavy metals. Both pH value and heavy metal concentration of the two groups' leachate tended to be stable until the experiment lasted about 120 days, and the final pH value of them were close to each other. However, in the group of deionized water, the amount of cumulative leaching of Pb and Cr were significantly higher than that of CH₃COOH-CH₃COONa solution, and the leaching concentration of Pb (0.29mg/L) even once exceeded the landfill entry limit, which should be concerned for the potential risk.

Three shale gas fields in Chongqing were selected. The pollution characteristics of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons in wastewater-based and waste oil-based drilling cuttings from the shale gas mining of five drilling platforms were studied. The concentration of Ba in wastewater-based and waste oil-based drilling cuttings was significantly higher than that of other heavy metals. Zn, Ba, Cr, Ni, Cu and Pb were the main heavy metals in the wastewater-based drilling cuttings. While Ni, Cu, Zn, Pb, Ba, As, Cr were the main heavy metals in the waste oil-based drilling cuttings and among which the concentration of Ni, Cu, Zn and Pb exceeded the corresponding limit. The concentration of PAHs in wastewater-based and waste oil-based drilling cuttings were 1.74~14.8mg/kg and 302~595mg/kg, respectively, which did not exceed the limit of the identification standards for hazardous wastes-identification for toxic substance content. The concentration of the petroleum hydrocarbon in waste oil-based drilling cuttings was 112~213g/kg, which was much higher than the limit of the identification standards for hazardous wastes-identification for toxic substance content. At the same time, the concentration of BaP in the wastewater-based and waste oil-based drilling cuttings was higher than the limit of the soil environmental quality-risk control standard for soil contamination of agricultural land; the concentration of BaP, BbF, BkF and DahA in the waste oil-based drilling cuttings were higher than the screening values of the soil environmental quality-risk control standard for soil contamination of development land and the concentration of the petroleum hydrocarbons in the drilling cuttings were much higher than the intervention values.

As the most important industrial city in Southwest China, Chongqing produced a large amount of organic solvents. The industries were many, the production points were difference, the components of waste organic solvents were complex and changeable. Based on the summary and analysis of hazardous waste transfer sheet and field investigation, the generation characteristics of waste organic solvents in Chongqing were investigated. The results show that waste organic solvents were produced from11industries in Chongqing. The amount of waste organic solvents in 2011 were about 200,000 tons, which. increased to more than 400,000 tons by 2015. The average annual growth rate was as high as 29%. The amount tended to be stable in 2016 and 2017. The total amount was almost 99% contributed from chemical industry, followed by the electronics industry and the automobile manufacturing industry. The mainly ways to dispose waste organic solvents in Chongqing, which were distillation recovery, incineration and cement kiln co-disposal. Combined with the characteristics of Chongqing's production industry, types and recycling methods, this paper put forward some suggestions on the management of waste organic solvents in Chongqing, such as classified recycling, increasing recovery rate and small exemption.

The surface soil and fir (Abies Mill.) samples were collected in March and December 2017 along the China National Highway 318 in Shergyla Mountain, respectively. The contents of polycyclic aromatic hydrocarbons (PAHs) in the samples were measured. The concentrations of ∑₁₆PAHs ranged from 30.21 to 366.94ng/g (dry weight) in the surface soil and 39.53 to 236.42ng/g (dry weight) in the fir leaves, respectively, and the lower rings (2- or 3-ring) constituents were dominants. The results of diagnostic ratios and principal component analysis suggested that the PAHs mainly originated from the combustion of fossil fuel and biomass, and also affected by oil leaks and atmospheric transmission. The atmospheric transmission pollution of PAHs could mainly result from the Indian subcontinent based on the backward air mass trajectories. The incremental lifetime cancer risks of PAHs in the soils along the highway in Shergyla Mountain were lower than 1×10⁶, indicating a lower carcinogenic risk to the local residents.

A two-year field experiment was conducted to study the effects of organic fertilizer and lime on remediation of Cd-contaminated paddy soil. The application strategies of the soil amendments including continuous application and application only in the first year were compared. The results showed that the individual or combined application of organic fertilizer and lime both increased significantly pH and available Cd contents in the soil as well as Cd contents in different parts of the planted rice. The Cd contents of brown rice in the first year were reduced significantly by 35.9%, 69.2%, and 65.4% compared with the control, respectively. Under the continuous application strategy, the soil pH significantly increased by 0.27, 0.57 and 1.05 units respectively, the contents of available Cd in the soils decreased by 26.6%, 29.7% and 59.4% respectively and the rice Cd concentrations decreased significantly by 63.1%, 79.5% and 83.6%, respectively. Especially under continuous application of both organic fertilizer and lime, the rice Cd contents was 0.20mg/kg which had reached the National Standard of Pollutant in Food of China (GB 2762~2017). Under the strategy of application only in the first year, the Cd contents in the brown rice reduced significantly by 49.2%, 69.7% and 75.4%, respectively. The two-way ANOVA suggested no significant difference between the two strategies of continuous application and application only in the first year. The results indicated that the application of organic fertilizer and lime can effectively reduce the contents of available Cd in soil and Cd in rice, and the remediation effects can lasts two years without significant reduction after the first application.

Selective removal of organic matter or iron oxide from three typical dry-period soils were explored to investigate its direct effect on P fractions and adsorption-desorption behavior in the water-level-fluctuating zone (WLFZ) of the Three Gorges Reservoir (TGR). The data showed that kinds of P fractions in three dry-period soils were not significant decreased with removal of readily oxidizable organic matter. However, kinds of P fractions were significantly decreased with removal of free iron oxides in the three soils. Notably, different P fractions were both in the order as follows: Ca-P > OP > Fe/Al-P, before and after removal of organic matter or free iron oxides in the three soils. Moreover, after removal of organic matter, the adsorption capacity of yellow soil (FJ), purple alluvial soil (KX), grey brown purple soil (FL) for P was only decreased by 0.5%, 2.3%, 6.5%(P=0.017<0.05, significant difference), respectively, which indicated that P adsorbed on the three soils were little influenced by organic matter. In addition, after removal of free iron oxides, the adsorption capacity of FJ, KX, FL soil for P was significantly decreased by 45.6%, 51.7%, 43.9%(P=0.004<0.05, significant difference), respectively, which revealed that P adsorbed on the three soils were dominated by free iron oxides. More importantly, the desorption capacity of three soils for P was increased after removal of free iron oxides, which presented that free iron oxides were also the predominant factor to control desorption behavior of freshly sorbed P. Then, the desorption capacity of FL for P was little decreased after removal of organic mater, and there were no distinction for it before and after removal of organic matter in KX and FJ soils, which showed that the desorption capacity of three soils for P were influenced by organic matter related to soil category.

An indoor incubation experiment was conducted to reveal the effect of atmospheric nitrogen deposition on soil respiration of water level fluctuating zone in the Three Gorges Reservoir area. The results showed that the response of soil respiration rate to nitrogen addition was a short term effect. Under the present atmospheric nitrogen deposition flux, soil cumulative CO₂ release was not changed by inorganic nitrogen addition, while, it was inhibited by organic nitrogen addition. Except soil cumulative CO₂ release was depressed by ammonium addition of double present atmospheric nitrogen deposition flux, it was promoted by all the simulated atmospheric nitrogen deposition composition under both double and triple present atmospheric nitrogen deposition flux. Compared with ammonium, nitrate was more conducive for promoting cumulative CO₂ release under double and triple present atmospheric nitrogen deposition flux.

The spent mushroom substrate (SS) and Microbacterium.sp.Q2 bacteria were used to remediate petroleum-contaminated soil and four different treatments which contained spent mushroom substrate immobilized microorganisms (SIM), spent mushroom substrate-free bacteria (SMSB), spent mushroom substrate alone (SMS) and no treatment (CK) were designed in this paper. The aim of this study is to investigate soil microbial number, enzyme activities and the degradation rate of total petroleum hydrocarbon (TPH), exploring an ideal reparative treatment. The results indicated that soil respiration intensity, microbial number and enzyme activities of SIM group were obviously higher than others and the removal rate of TPH was highest which was increased by 11.84%, 22.15% and 54.09% compared with other treatments. Furthermore it is showed that the dehydrogenase activity and microbial activity were significantly correlated with the degradation rate of TPH and immobilized microorganism had the synergistic mechanism of bioaugmentation and biostimulation for remediation of petroleum contaminated soil.

In order to understand the time-varying characteristics and control mechanisms of complex resistivity in soils with different contamination degree, the experiment of sand column and water column was designed to measure the phase in 10⁰~10³Hz by taking NaCl, MnCl₂ and artificial seawater as contaminants. The results showed that the phase decreased with the pollutant concentration and increased with the frequency. The phase in sand column was more sensitive than that in water column with the change of pollutant concentration. Under the background of soil and water, when contaminated by 1g/L NaCl, the phase of soil decreased by about 42%, while the change in water column was almost invisible at 1Hz. The results of repeated measurements for fixed frequencies showed that the phase in water column was stable while it took on obvious time-varying property in sand column (>16Hz). This property also decreased with pollutant content in solution. At 10²Hz, the background value of phase measurement in sand column was between -4.05~-11.67mrad, the variance reached 4.8 while it was only 0.09 in water column. Complex resistivity method has better performance in detection and monitoring of cations contaminated sites, the change of its parameters is mainly related to the content of cations in pore water. However, due to the interface properties and the complexity of the pore structure, migration and polarization of charge carrier in the medium are chaotic by the alternating current, and finally cause phase fluctuation.

A self-designed biomass combustion system was used to measure the emission factors of grassland burning based on the MODIS image data of Inner Mongolia zone and the temporal and spatial patterns of pollutants emitted from burning of grassland from 2000 to 2017 were analyzed. The results showed that the average emission factors of CO₂, CO, NO_x, C_xH_y, PM_2.5, TC, OC and EC from the burning of Phragmites communis, Setaria viridis, Pennisetum alopecuroides and Calamagrostis epigeiosare were 1402.6~1550.1, 140.3~253.8, 0.67~1.55, 21.5~93.7, 3.74~6.89, 1.66~3.06, 1.42~2.71, 0.23~0.44g/kg, respectively. Inner Mongolia grassland biomass density had uneven spatial and temporal distribution and the distribution of biomass density had gradually decreasing from northeast to southwest. The total biomass burnt was 8061.46kt, and the total amounts of the emitted CO₂, CO, NO_x, C_xH_y, PM_2.5, TC, OC and EC were 11296.13 kt, 1609.79 kt, 10.80 kt, 408.96 kt, 44.50 kt, 20.06 kt, 17.23 kt and 2.83 kt, respectively. A total of 49,374 grassland fires had occurred, with the fire points and fire areas were unbalanced in time and space. The monthly variation exhibited a bi-modal distribution, the main-peak fire point (March) was significantly higher than the secondary-peak fire point (September), and the distribution of fire density and fire area had a gradually decreasing trend from northeast to southwest.

Based on the sub-watershed unit, landscape pattern and soil conservation service was quantitatively characterized via landscape pattern index and InVEST model, and the relationship between the two issues was also discussed from the perspectives of spatial statistics. The results showed that the sub-watersheds with higher soil conservation services in 2014 had the characteristics of single landscape types composition, non-uniform distribution among different landscape types, existence of dominant patches, and low landscape separation degree. In 2014, the significant spatial correlations between soil conservation services and landscape pattern was mainly in 14 sub-watersheds,which accounted for 37.84% of the total number of sub-watersheds. In the model selection, spatial lag model (SLM) was superior to the non-spatial linear model (OLS), which indicated that soil conservation was spatially dependent. Diversity and evenness of landscape types were considered as important indicators affecting soil conservation in the Bailongjiang watershed in Gansu Province.