Based on the measurement data of PM, aerosol number concentration (10nm~10μm), water-soluble ions (WSIs) and meteorological elements, the characteristics of aerosol size distribution and chemical components during a long-range transport of dust pollution episode in the Yangtze River Delta were analyzed from May 3 to 8, 2017. The results showed that the PM concentration gradually decreased when the dust transmitted from north to south accompanying with the synoptic system, but the duration time of high PM concentrations increased to the contrary. The impact time of the dust was 38h in Hohhot and exceeded 60h in Nanjing. The spectral distribution of number concentration shifted to larger particles on dust days, peaking at 26nm and 33nm on non-dust and dust days, respectively. The aerosol surface area concentration had a trimodal distribution on non-dust days and exhibited four peaks on dust days. The WSI concentrations in PM_2.5 and PM₁₀ on dust days ranked in the order of Ca²⁺ > NH₄⁺ > SO₄^2- > NO₃^- > Mg²⁺ > Na⁺ > Cl^- > NO₂^- > K⁺>F^-, and NH₄⁺ > SO₄^2- > NO₃^- > Mg²⁺ > Ca²⁺ > Cl^- > NO₂^- > K⁺ > Na⁺ > F^- on non-dust days. The mass concentration of Ca²⁺ and Na⁺ in PM_2.5, PM₁₀ on dust days were 9.5, 13.7 and 4.4, 4.6times higher than those on non-dust days, respectively. The proportion of Ca²⁺ to the total WSIs in PM_2.5 and PM₁₀ was 24.7% and 24.9% on dust days, which was 4.9 and 5.7times higher than those on non-dust days. The proportion of NO₃^- in PM₁₀ on dust days (18.7%) was higher than that on non-dust days (13.9%); but was only 7.9% for that in PM_2.5 on dust days, which was lower than that on non-dust days (13.2%). The proportions of F^-, Cl^-, SO₄^2-, NH₄⁺ and K⁺ in PM_2.5 and PM₁₀ on dust days were uniformly lower than those on non-dust days.

The study by using the observation data (from May to September 2016) of Langfang Atmospheric Monitoring Super Station, the pollution characteristics of PM_2.5, extinction characteristics, source analysis and backward trajectory analysis were carried out. During the observation period, the concentrations of PM_2.5 were (43.82±28.68)µg/m³. SO₄^2-, NO₃^-, NH₄⁺, OC and EC accounting for 24.74%, 22.98%, 20.54%, 8.79% and 5.50% of the mass of PM_2.5, respectively. The concentration of components increased with increment of PM_2.5 concentration. Scattering coefficient (Bsp) and absorption coefficient (Bap) of atmospheric extinction were (294.54±257.35), (16.05±9.14)Mm^-1, respectively, The contribution of the coarse particles to the extinction coefficient (11.12%) was the lowest. PM_2.5 played a major role in atmospheric extinction. Among them, Nitrate (32.23%), Sulfate (27.28%) and OM (20.56%) were the most important extinction components. PM_2.5 mainly from industry (14.14%), motor vehicles (15.15%), secondary sources (38.38%), coal combustion (22.22%) and dust and biomass burning(10.10%). The contribution of various pollution sources to the extinction coefficient was 1.32% (industry), 17.25% (motor vehicle), 55.57% (secondary source), 18.56% (coal combustion) and 7.32% (dust and biomass burning). According to the backward analysis, the small-scale, short-distance transmissions from Shandong and Henan provinces as well as the medium and short-distance transmissions from northeastern and central Inner Mongolia were the major sources of the air mass of Langfang City, which were accounted for nearly 80%. The potential distribution areas of pollution sources were mainly in northeastern Shandong, eastern Henan, eastern Shanxi, and southwest Liaoning.

Oxidative potential can be used to characterize the impact of atmospheric particulate matter on human health. The DTT assay is a method recently developed to determine the oxidation potential of particulate matter. The extraction and reaction process of the DTT method were improved, and the method was employed to measure the oxidation potential of PM_2.5 (DTT_m & DTT_v) at an urban site in Guangzhou. The DTT_m values of PM_2.5 in Guangzhou in January and April 2018 were found to be (13.47±3.86), (14.66±4.49) pmol/(min·μg), and the DTT_v values were measured to be (4.67±1.06), (4.45±1.02) nmol/(min·m³), respectively. DTT_v showed strongly correlations with mass concentration of PM_2.5, OC, EC and BC, but no correlations were found between DTT_m and carbonaceous particles, implied that carbonaceous particles is not the major contributor to oxidative potential of PM_2.5 in Guangzhou.

The correlation between major atmospheric pollutants PM_2.5 and O₃ under the effect of East Asian monsoons was analyzed by using the environmental monitoring observations from 2013 to 2017 in Xuzhou. Based on meteorological observations, this paper further investigated the seasonal variation of interaction mechanism between PM_2.5 and O₃. The results showed that:PM_2.5 and O₃ were positively related with the correlation coefficient of 0.56 in summer monsoon (SM), while PM_2.5 and O₃ were negatively related with the correlation coefficient of -0.30 in winter monsoon (WM), both passing the confidence test of 99%. This indicated that the interaction of air compound pollutants PM_2.5 and O₃ in Xuzhou presented opposite the seasonal changes. In SM featured by strong solar radiation, high air temperature and strong oxidation, O₃ dominated the atmospheric oxidation, and oxidation effectively promoted secondary particle formation. The promotion of O₃ on PM_2.5 dominated the changes of air compound pollution in SM. In WM, the air temperature was low and the atmospheric oxidation was weak, then the enhanced PM_2.5 levels could suppress atmospheric photochemistry by reducing solar radiation, with the ozone change rate decreasing and peaking time postponing. The inhibitory effect of PM_2.5 on O₃ dominated the changes of air compound pollution in WM in Xuzhou.

Based on the methods of gravity center model, spatial autocorrelation analysis and geographical detector, this paper studied the spatial and temporal distribution of ozone concentration in Eastern China in 2016, revealed the impact of meteorological factors and precursors on the spatial distribution and evolution of ozone concentration. The results showed that:1) Average monthly concentration of ozone went through three phases in Eastern China in 2016, rising gradually from January to March before reaching a fluctuating stage from April to September, it came to a decreasing phrase later from October to December. Ozone pollution was mainly witnessed at the second phase, which contributed 96 percent of the yearly ozone pollution. 2) Mainly affected by meteorological factors, namely lower precipitation, lower relative humidity and longer sunshine duration in the northern part of Eastern China, the annual ozone concentration of northern part was higher than that of southern part in Eastern China in general. Beside, pollution centers in core cities of urban agglomerations generated because of precursors, which was a significant factor of the yearly average ozone concentration distribution. 3) Spatial distribution of ozone concentration went through a higher-in-the-north pattern to the higher-in-the-south pattern in 2016. The monthly gravity center of ozone concentration was moving to the north from January to June, reaching its northernmost point in June. The higher-in-the-north pattern was at its most significant phase at that time, the highest point of pollution level was reached in Bohai Rim region. Then it moved backward to south until December when the southernmost point was reached, during which the distribution pattern was transforming into the higher-in-the-south pattern. During rainy season (from March to September), the spatial distribution of ozone concentration was mainly impacted by precipitation and relative humidity compared with a major impact by temperature in the rest of months. 4) Precursors worked with meteorological factors. A stronger photoreaction, as a result of rising temperature, positively magnified the impact of precursors while the decreasing temperature weakened photoreaction, which, as a result, may promote ozone consumption.

Based on aerosol sampling data in 2016 in Hangzhou, the influences of the G20 emission reduction on inorganic water-soluble ions in particulate matter (PM) was investigated. The results proved that the G20 emission reduction had significant impacts on mass concentration, composition and acid-base properties of water-soluble ions in PM. The concentrations of PM and its water-soluble ions were both reduced by the G20 emission reduction. Among them, the concentrations of NO₃^-, SO₄^2-, NH₄⁺ and NO₂^- decreased most obviously, and the concentration decrease of NO₃^- and SO₄^2- made the concentrations of NH₄⁺, Ca²⁺ and Cl^- the top three ions. The size distributions of SO₄^2-, NO₃^-, NH₄⁺ and Ca²⁺ showed mono-modals, and SO₄^2-, NO₃^- and NH₄⁺ were preferably enriched in the fine particles (within range of 0.65~1.10 mm) while Ca²⁺ in the coarse particles (within range of 5.80~9.00mm). The size distributions of Na⁺, Cl^- and K⁺ showed bi-modals with peaks at the particle size of 3.30~4.70mm and 0.65~1.10mm, respectively. the two peaks of Na⁺ were comparable while K⁺ and Cl^- had higher peak values in the size range of 0.65~1.10mm. The main inorganic salts were changed from NH₄NO₃, (NH₄)₂SO₄ and NH₄Cl to NH₄Cl, NaCl and KCl as well as the alkaline enhancement in PM by the G20 emission reduction. The results of this study could provide references for policy formulation and implementation for air quality improvement measures.

To explore the spatial distribution and sources of water-soluble ions in winter PM_2.5 of Northeast Asia, we determined the concentrations of PM_2.5 water-soluble ions in Shenyang during winter of 2017~2018. The concentrations of the total water-soluble ions in winter PM_2.5 of Shenyang was (28.5±11.9) µg/m³, and the concentrations of secondary ions (SO₄^2-、NO₃^-、NH₄⁺) were the highest, accounting for 31.0%, 22.4% and 19.2% of total water-soluble ions in mass fraction. We investigated the sources of winter PM_2.5 water-soluble ions in Shenyang by the ion stoichiometry, correlation analysis of water-soluble ions and primary component analysis. By combining our results with previously reported data in Northeast Asia region (northeast China, South Korea and Japan) in recent 20years, we found a downwind decreasing pattern in concentrations of winter PM_2.5 water-soluble ions from the northeast China, through the South Korea, coastal South Korea and Jeju Island, and the coast of Japan to Japan except some peaks at stations near densely populated areas (e.g., South Korea and Japan). Water-soluble ions showed significant regional differences in percentage of mass fraction in the total water-soluble ions in PM_2.5. In the winter PM_2.5 of South Korea, SO₄^2-, Ca²⁺ and K⁺ were significantly affected by external sources. NO₃^- and NH₄⁺ were mainly from local sources, while Cl^-, Na⁺ and Mg²⁺ were dominantly sourced from local sources or sea salt. In Central Japan, SO₄^2-, NO₃^-, NH₄⁺, Ca²⁺ and K⁺ were originated from local sources, while Cl^-, Na⁺ and Mg²⁺ were dominantly sourced from local sources or sea salt.

By using the numerical model KINAL, the present research simulated the temporal evolution of ozone and bromine species in a typical Arctic ozone depletion event (ODE) under three source fluxes. The organic source intensity was also put to a sensitivity analysis to examine its impact on the ODE. The results have revealed several facts as following:There was a significant negative correlation between the atmospheric ozone and bromine. When there was only inorganic source input, it took 5.4d to completely consume ozone in the boundary layer. After adding organic source emissions of an average intensity to the model, the ozone depleting process was accelerated for about 1.3d. Concentration of bromine in the boundary layer was enhanced, causing the induction stage of the ODE to shorten for 1.2d. The ODE acceleration did not change obviously, whether HOBr or Br₂ made the major species in the organic source emission. The bromine species enhanced the ODE by accelerating the induction stage. A significant positive correlation was found between the organic source intensity and the consumption rate of atmospheric ozone. When the organic source intensity rised, the acceleration effect on the induction stage of the ODE was abated. The induction stage lasted for at least 3days. The temporal evolution of ozone was not greatly impacted by the organic sources.

Taking the air quality and meteorological data of 2017 in Ganzhou as the research object, the optimal feature subset was extracted by the maximal relevance minimal redundancy algorithm (MRMR) and used as the input data of the prediction model. At the same time, the hybrid kernel (HK) was constructed to improve the traditional support vector machine model (SVM) and finally the MRMR-HK-SVM model was established. The experimental results show that the MRMR-HK-SVM model has a lower mean absolute error (MAE), mean absolute percentage error (MAPE) and root mean square error (RMSE), compared with the traditional SVM model, the mean absolute error of the prediction results decreased by 26.9%, and and it can track the sudden change of PM_2.5 concentration more accurately. It can be seen that MRMR-HK-SVM model has better generalization ability and can more accurately predict PM_2.5 concentration.

To accurately characterize the effect of complex urban building structures on pollutant transport and diffusion processes, a one-way coupled WRF-Fluent model was constructed and applied to simulate the pollutant dispersion from an elevated source in Yuzhong county. The performance of WRF model was validated systematically using data obtained from the Urban Meteorological and Tracer Experiment, and it is found that WRF can provide accurate and time-varying meteorological driving field for Fluent. The spatial and temporal evolution of the flow field and pollution plume in Yuzhong County was simulated explicitly using WRF-Fluent model with embedded three-dimensional geometric model of Yuzhong County and the results were compared to the measured tracer concentration data. The WRF-Fluent model can well reproduce the complex flow patterns and the evolution of the polluted plume. The simulated maximum ground level and urban canopy top concentrations are within a factor of three of the observations. The constructed WRF-Fluent model has good performance for urban dispersion, and is an effective tool for urban planning, urban air quality management and environmental risk assessment.

In order to reduce ammonia emissions from the source during pig breeding and reduce the ammonia concentration in piggery, this paper proposed a combination prediction method based on ARIMA-BP neural network for the concentration of ammonia in piggery, and compared with the combined prediction method based on ARIMA-BP neural network, from the perspective of optimal weight and residual optimization. The proposed prediction method was applied to the prediction of ammonia concentration in a piggery in Yixing, Jiangsu province. The results of the prediction experiments showed that the prediction accuracy of the combination prediction method based on ARIMA-BP neural network residual optimization was the highest. Compared with the BP neural network, ARIMA prediction method and the optimal weight combination prediction method based on the ARIMA-BP neural network, the evaluation indexes MAE, MAPE and RMSE were 0.0319, 0.1580% and 0.0365respectively.The ammonia prediction method proposed in this paper can be used as a scientific basis for the precise control and management of piggery environment in order to reduce the ecological environmental pollution caused by ammonia emission from piggery.

The NEDC、FTP75and WLTC cycle fuel consumption test were carried out in a stabilized gasoline car with three different driving ways including smooth, rough and normal driving by the same driver. Based on the evaluation of energy rating (ER), distance rating (DR), energy economy rating (EER), absolute speed change rating (ASCR), root mean squared speed error (RMSSE) and inertia work rate (IWR), the rationality of the boundary conditions of fuel consumption test were obtained through the analysis and calculation of the above evaluation index and the change of fuel consumption of each test. Smooth and rough driving both resulted in the regular change of evaluation index in FTP75 and WLTC test. However, the different driving way had little effect on fuel consumption in NEDC test. The boundary conditions of fuel consumption test were obtained as below. When ER was in the range of (0.25±0.47)%, ASCR was in the range of (1.20±0.97)%, RMSSE was in the range of (0.85+0.15)km/h, IWR was in the range of (2.15±1.27)%,the driving ways of the WLTC cycle fuel consumption test were reasonable. For the cycle of FTP75, the reasonable driving ways of fuel consumption test ought to make sure that EER, ASCR, RMSSE and IWR ranged among (-0.09±0.69)%, (-0.59±0.42)%, (0.88+0.34)km/h and (-0.69±1.66)% respectively.

Mn/TiO₂ (MT), Ce/TiO₂ (CT) and Ce-Mn/TiO₂ (CMT) sorbents for mercury removal were prepared by the impregnation method. Mercury adsorption experiments were conducted on a fixed-bed reactor. The mercury removal performance of the three sorbents gradually increased with the increase of temperature in the range of 100~200℃. The maximum mercury capture efficiency of 91%, 58% and 95% were observed at 200℃ for MT, CT and CMT, respectively. The mercury removal efficiency decreased when the temperature was higher than 200℃. When MT and CT sorbents were exposed in the flue gas with N₂+6%O₂+1000×10^-6SO₂, the decrease of mercury removal efficiency to 50% within 30min was observed, indicating the weak SO₂resistance of MT and CT. However, mercury removal efficiency of more than 80% was maintained by CMT within 2h. It revealed that Ce doping in MT not only improved the mercury removal performance, but also enhanced the SO₂resistance. Physicochemical characteristics of the sorbents were analyzed by N₂adsorption/desorption, X-ray diffraction (XRD), H₂-temperature programmed reduction (H₂-TPR) and X-ray photoelectron spectroscopy (XPS). The spent sorbents were analyzed by thermogravimetric analysis (TG) and temperature programmed desorption (TPD) experiments. Based on the experimental and characterization results, the mechanism of SO₂resistance of the CMT for mercury removal was interpreted. The doping of Ce improved the dispersion of active components on the sorbent surface and the ratio of Mn⁴⁺, which was favorable for mercury removal; Compared with MnO₂, CeO₂preferentially react with SO₂, which inhibited the toxic effect on Mn⁴⁺, thus improving the SO₂resistance.

The in-situ generation method was proposed to prepare the catalytic functional polyphenylene sulfide (PPS) filter material. PPS would be activated with C₂₁H₄₀NNaO₄S, and then treated in the metallic cations solution to adsorb Mn²⁺, Fe²⁺, Co²⁺, Ce³⁺ rapidly. After positive reaction with KMnO₄, reactive metal oxides were produced in the PPS materials. The (0.9) Mn-Ce-Fe-Co-O_x/PPS composite filter materials were characterized by SEM, EDX and TPD. Catalytic performance in the low -temperature catalytic conversion of NO and Hg⁰ were then explored. The influences of reaction temperature, O₂, NO, ammonia-nitrogen ratio and SO₂ on the catalytic performance of catalytic PPS were investigated systematically. The results showed that MnO_x, CeO_x, CoO_x, Fe₂O₃ were uniformly distributed on the PPS filter material in a flocculent structure; The catalytic PPS materials performed a synergistically NO and Hg⁰ removal efficiency of more than 80% in the conditions of T=170℃,O₂≥5%, NO≤ 500×10^-6, NSR=1.0, SO₂≤100×10^-6; The results of Hg-TPD desorption indicated that the mechanism of Hg⁰ oxidation promotion of SO₂ was that the heterogeneous reaction between SO₃ and Hg⁰ was faster than sulfation reaction of SO₂, and the NO-TPD results also showed that NO mainly acted in the form of nitrite on the surface of PPS, and followed by the form of adsorbed NO₂.

A recovery reregulation was adopted for a completely autotrophic nitrogen removal over nitrite (CANON) system, for which the shortcut nitrification process deteriorated. The evolution of the microbial construct was evaluated by 16S rDNA sequencing technology during the recovery regulation period, paying special attention to nitrifiers and anammox bacteria. The high concentration of NH₄⁺-N (over 300mg/L) and extending the ratio of aeration/non-aeration to 1:3could effectively inhibit nitrite-oxidizing bacteria (NOB). In the later period of the stable phases, the nitrite-oxidizing rate (NOR) and ΔNO₃^--N/ΔNH₄⁺-N decreased to 2.30g N/(m³·h) and 0.13respectively; while, the total nitrogen removal rate (TNRR) gradually increased to 0.35kg N/(m³·d). Then, extending the non-aeration time to 90min reduced NOR to nearly zero. The results of 16S rDNA gene high-throughput sequencing indicated that the relative abundance of Nitrospira, the major bacteria of NOB, decreased from 3.96% to 0.64%, and the relative abundance of Candidatus_Jettenia, the major bacteria of anaerobic ammonia-oxidizing bacteria (AnAOB), increased to 49.98% from 46.68%. Our findings elucidated that increasing the influent concentration of ammonia nitrogen can inhibit and eliminate NOB effectively, making AnAOB get enrichment and favoring CANON system recovery.

Poor operational stability and effluent manganese (Mn) concentration exceeding limitation were found during the same layer of purification process with the low-temperature (5~6℃) groundwater containing high ammonia nitrogen(NH₃-N), iron (Fe) and Mn contents (TFe:9~15mg/L, Fe²⁺:6~12mg/L, NH₃-N:1.4~2.0mg/L, Mn²⁺:1.4~2.0mg/L). In order to achieve efficient purification, the start-up of "two-stage aeration combined with two-stage filtration" purification process was investigated in water plant purification workshop, and the two-stage bio-purification was started separately by using the differential filtration rate and the same filtration rate. Results showed that two startup methods were started successfully after 59 days and 106 days. The start-up with the same filter speed shortened the startup time effectively, and the efficiency of Fe、NH₃-N and Mn were 110.69g/(m²·h), 18.80g/(m²·h) and 19.54g/(m²·h) respectively. Fe was removed to trace level at 60cm of the primary filter column; NH₃-N was evenly removed by 85.08% in the primary filter column, with the remaining 14.92% removed from the secondary filter column; the efficiency and the oxidation-removal active sites of Mn were obviously affected by the filtration rate as well as the influent NH₃-N concentration. Mn was removed by 33.72% and 66.28% in the primary filtration columnand and the secondary filtration column, respctively. Mn removal remains a decisive factor in filter maturity.

The activity changes of anaerobic ammonia-oxidizing bacteria during the enrichment process was studied based on the membrane bioreactor (MBR). Completely autotrophic nitrogen removal over nitrite (CANON) process was started up by constant aeration rate. Simultaneous denitrification of ammonia oxidizing bacteria (AerAOB) and anaerobic ammonia oxidizing bacteria (AnAOB) by optimizing the intermittent aeration and effectively inhibiting the activity of nitrite oxidizing bacteria (NOB), then the simultaneous nitrification, anammox and denitrification (SNAD) process was started up successfully by adding the the carbon source (sodium acetate). The results showed that enhanced the activity of anaerobic ammonia-oxidizing bacteria during the enrichment process of anaerobic ammonia-oxidizing bacteria by continuously shortening the hydraulic retention time (HRT) and increasing influent nitrogen loading. The average activity of the anaerobic ammonia-oxidizing bacteria increased from 0.603mgN/(h·gVSS) to 8.1mgN/(h·gVSS). When the constant aeration rate was 50mL/min and the intermittent aeration (non-aeration time:aeration time, mim/min) was 4:10, the removal of ammonium by AerAOB and AnAOB accounted for 58.8% and 41.2% of the total ammonium removal respectively, and the amount of nitrite nitrogen oxidized by NOB accounted for 15.3% of the total nitrate nitrogen production, successfully inhibiting the activity of NOB. When the C/N ratio was 0.5 and the intermittent aeration was adjusted to 4:15, the nitrogen removal rate in the denitrification process accounted for 20.9% of the total nitrogen removal rate, and the nitrogen removal rate in the anaerobic ammonia oxidation process accounted for 79.1% of the total nitrogen removal rate. The purpose of synergistic denitrification of AerAOB, AnAOB and denitrifying bacteria (DNB) was achieved finally.

This article reported the start-up process of sludge digestion supernatants treatments by CANON process based on MBBR reactor. The pilot system with a volume of 8.55m³ was used and filled with SPR-Ⅲ filler, which had a filling rate of 44%. The CANON process was successfully started after 70d with dynamic inflow of CANON sludge, and the inoculation ratio was below 1%. After 200d, the TN removal volumetric loading was stable at 0.9kgN/(m³·d), the mean value of the concentration of effluent ammonia nitrogen was 63.9mg/L, and the removal rate of ammonia nitrogen and total nitrogen were 91% and 85% respectively. The N-removal pathway ofdenitrificationand anaerobic ammonium oxidation occurred simultaneously due to small amount of organic matter presence in the influent, which accounted for 5% to 7%and 93% to 95% of total nitrogen removal, respectively. By controlling of pH and aeration intensity, the scaling of suspended carriers was prevented and the relationship among DO, aeration intensity and biofilm thickness was balanced. As a result, the biofilm always maintained suitable thickness, which stabilized the treatment effect of the system. The high flux sequencing indicated that AOB and AnAOB were dominant species on the suspended carriers, and their abundance reached 17% and 14% during steady operation. There was no NOB in the system, indicating that the short-nitrification effect was good. The denitrifying bacteria abundance was 2%~3% and relatively stable, indicating that the small amount of organic matter in the influent did not affect the increase of anammox bacteria.

To increase the efficiencies of sewage sludge degradation and hexavalent chromium reduction, the effect of CaO₂ dosage on simultaneous treatment of sewage sludge and hexavalent chromium wastewater in microbial fuel cell (MFC) was studied. Specifically, the effect of different CaO₂ dosage on the degradation of sewage sludge in the anodic chamber, reduction of hexavalent chromium in the cathodic chamber, and promotion of electricity generation in the MFC were also investigated. Results showed that when the CaO₂ dosage were 0, 0.1, 0.2, 0.4, 0.6, 0.8gCaO₂/gVSS, respectively, the hexavalent chromium reduction efficiencies were 73.38%, 78.91%, 99.47%, 97.70%, 97.04%, 96.37% after operating for 120h, and TCOD degradation efficiencies of sludge in anodic chamber were 72.4%, 76.9%, 81.0%, 78.2%, 75.7% and 74.2% after operating for 30days, demonstrating the enhanced effectiveness through CaO₂ dosage. The optimal dosage was 0.2gCaO₂/gVSS with voltage output of 1.15V. The reduction efficiency of hexavalent chromium was increased by 36.08% and the degradation efficiency of TCOD by 11.88%. In addition, the electrochemical activity of the MFC increased after the addition of CaO₂, indicating that it can also enhance the efficiencies of sewage sludge degradation and hexavalent chromium reduction as well as accelerate the electron transfer process of the MFC.

The polyvinylidene fluoride (PVDF) microfiltration membrane was modified by vacuum filtration method with graphene oxide (GO), titanium dioxide (TiO₂) and graphene oxide-titanium dioxide (GO-TiO₂) as modifiers. The structure and hydrophilicity of the composite membranes were investigated by contact angle measurement, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). At the same time, humic acid (HA) was selected as the representative of micro-pollutants in water to examine the anti-pollution performance of the composite membrane. The removal efficiencies of ammonia nitrogen by composite membrane under dark and ultraviolet light conditions were studied by using the lake water samples from Gehu Lake branch in Changzhou as raw water. The results showed that GO, TiO₂ and GO-TiO₂ (GT) composite membranes had better hydrophilicity and anti-pollution performance than PVDF membranes. Under dark condition, GO composite membrane with GO concentration of 1mg/ml had the highest ammonia nitrogen removal rate (26.4%) under dark condition, while that of GT composite membrane with GO-TiO₂ concentration of 1mg/mL and GO/TiO₂=3:1could reach the best (58.2%), for there was synergistic effect between GO and titanium dioxide under ultraviolet light.

A novel macromolecule flocculant polyethyleneimine-sodium xanthogenate (PEX) was prepared by chemical reaction to graft dithiocarboxylic groups onto polyethyleneimine (PEI). The removal performance of turbidity by PEX and ferrous/ferric salts from water samples containing low turbidity was studied by using flocculation experiments. The initial turbidity and pH value had a certain effect on the removal properties of turbidity by only using PEX. The removal efficiency of turbidity decreased with the decrease of the initial turbidity of water samples, and increased at first and then decreased with the increase of pH value. When the initial pH value of the water samples approached the isoelectric point of PEX, the removal rate of turbidity was highest, and reached 88.46%, 91.17% and 92.73% at the original turbidity of 10.0, 15.0 and 30.0NTU for the water samples, respectively. The removal rate of turbidity increased at first and then decreased with the increase of pH value after the addition of PEX and ferrous/ferric salts, and the removal efficiency of turbidity was better with ferric salts than ferrous salts. The flocculation mechanism when adding only PEX was different from the one when adding both PEX and ferrous/ferric salts, and ferrous/ferric salts played a main role of charge neutralization in the flocculation process.

To explore efficient and rapid method for removing Cd (Ⅱ) from aqueous solution, the prepared graphene oxide-supported ferroferric oxide (Fe₃O₄/GO) nanocomposites were used to remove Cd(Ⅱ) from aqueous solutions. Single factor experiments were used to determine the level of operating factors (initial Cd(Ⅱ) concentration, operating temperature, contact time and initial pH). The operating parameters (4-factor-3-level) of removal Cd(Ⅱ) from aqueous solution were optimized by response surface methodology (RSM) and artificial neural network-genetic algorithm (ANN-GA), the adsorbent performance was researched by isothermal adsorption, kinetics and thermodynamic parameters. Fe₃O₄/GO nanocomposites, the average size of 30.09nm, were successfully prepared by the characterization of X-ray diffraction (XRD), scanning electron microscopy (SEM) and superconducting quantum interference device (SQUID). The predicted and confirmed values of removal Cd (Ⅱ) from aqueous solution were 86.451% and 82.220% with temperature=20.14℃, contact time=57.78min, initial pH=6.41 and initial Cd(Ⅱ) concentration=11.18mg/L using RSM, respectively. However, the predicted and confirmed values were 89.722% and 87.723% using ANN-GA with temperature=29.96℃, initial pH=5.49, initial Cd(Ⅱ) concentration=28.36mg/L and contact time=65.78min. According to R² value, the predicted maximum efficiency and confirmed experiment, the performance and predicted ability of ANN-GA model was better than that of RSM. RSM analysis of variance showed that the effects of four factors on the removal of Cd(Ⅱ) from aqueous solution of Fe₃O₄/GO nanocomposites were as follows:initial Cd(Ⅱ) concentration > temperature > reaction time > pH. The results of adsorption mechanism analysis showed that the adsorption process of Fe₃O₄/GO nanocomposites for removal Cd(Ⅱ) existed simultaneously physical and chemical adsorption. Combined with ANN-GA optimization, Fe₃O₄/GO nanocomposites can be used to remove Cd(Ⅱ) by using magnets to achieve rapid separation.

A magnetic chitosan was prepared by cross linking with glutaraldehyde and Fe₃O₄ for the removal of methylene blue from wastewater. The performance of the magnetic chitosan on methylene blue removal and the characteristics of the adsorption kinetics, isotherms and thermodynamics were investigated. When the magnetic chitosan dose was adjusted to 0.5g/L and the solution pH value was adjusted to 10, after 60 min, removal efficiency of the methylene blue reached 97.6%, and the corresponding adsorption capacity reached 39.0mg/g. Compare to that of 59.8% and 23.9mg/g by the natural chitosan, both removal efficiency and adsorption capacity were improved significantly. Furthermore, the adsorption process of the methylene blue could be well fitted to the pseudo-second-order kinetic model (R²=0.99902) and the Langmuir equilibrium model (R²=0.99961), the adsorption process was a thermodynamic spontaneous process, and the adsorption reaction was an exothermic reaction.

In order to improve the detection accuracy and efficiency for the on-line monitoring device of chemical oxygen demand (COD) by using Ozone in combination with Ultraviolet Radiation (O₃/UV), the relationship between the concentration change rate of the produced carbon dioxide (CO₂) and the digestion rate of organics is analyzed in the digestion of different water samples, a method is further proposed to automatically determine the termination of digestion. Based on the data collected by each sensor during the digestion process, the standard deviation of CO₂ gas concentration change rate is calculated using the moving block standard deviation (MBSD) method, which is applied to automatically determine the termination time of digestion. Digestion experiments with organics of different types and different centration reveal that organics are completely degraded when the standard deviation of CO₂ concentration is less than 0.003, which can be considered as the end point of the reaction. This method can not only improve the detection accuracy and efficiency for the on-line monitoring device of COD, but also has guiding significance to the treatment of wastewater based on O₃/UV method.

The regulated characteristics and mechanism of tellurite bioreduction by bioactive small molecule glutathione (GSH) with Shewanella oneidensis MR-1 were investigated in this study. When 0.1, 0.4 and 1.0mmol/L GSH were added to the bioreduction system, the bioreduction efficiency of the tellurite was increased by 55%, 71% and 78%, respectively, compared with the control. Moreover, the concentration of GSH (0.1~1.0mmol/L) was positively correlated with the bioreduction efficiency of tellurite. The culture conditions were optimized by single factor experiment. Under the conditions of 35℃, pH 8.0, 0.4mmol/L GSH, the bioreduction efficiency of tellurite reached 97% within 24h. In addition, six different respiratory inhibitors were used to investigate the regulated electron transfer pathway of tellurite bioreduction by GSH. It was preliminarily determined that the accelerating sites of GSH in the electron transfer chain were NADH reductase, methylnaphthoquinone and FAD dehydrogenase.

In order to analyze the influence of parameter uncertainly on the numerical model of groundwater pollution, aimed at making a research on Fushun Xishechang and the surrounding area, this paper firstly established a groundwater solute transport numerical simulation model by taking sulfate ion as the simulation factor. For the purpose of reducing computation load, the sensitivity analysis method was used to select the more sensitive parameters as random variables. Then, the paper constructed the Kriging surrogate model of the simulation model, that was used to finish the Monte Carlo simulation. Finally, the output results of the stochastic simulation are statistically analyzed, that was used to construct the pollutant concentration distribution function to estimate the pollution risk of single well. The probability of well 1,2 and 3 that meet the Ⅲ grade of the groundwater quality standard were 0.6%, 97.6% and 0%, respectively, which can provide a more scientific and comprehensive reference for groundwater pollution prevention and control.

The development of shale gas is a state key energy strategy, the potential environmental risks caused by the flowback water have attracted attention. To develop the economical and environmentally friendly biological treatment technology for the flowback water, the activated sludge from the sewage treatment plant was used as the test subject in this study. The inhibitory effects of the organic oxidation activity and the nitrification activity of activated sludge was analyzed through the respiratory measurement experiment. The inhibitory effect of glutaraldehyde, benzalkonium chloride (ADBAC) and salinity on the activated sludge were further identified. The flowback water had very weak inhibition on the organic oxidation activity and very strong inhibition on the nitrification activity, and the 50% inhibitory concentration (IC₅₀) were 75.5% and 10.09%, respectively. The IC₅₀ of glutaraldehyde, ADBAC and salinity to the nitrification activity on activated sludge were 0.0589, 0.0194, 3.63g/L, respectively. The biological treatment of organic pollutants in flowback water was feasible, but it didn¢t work well on denitrification. Salinity, glutaraldehyde and ADBAC had inhibitory effect on the nitrification activity. IC₅₀ of the bactericide was in an order of magnitude difference from the IC₅₀ of the salinity, and the influence of the bactericide need to be paid more attention during biological treatment of the flowback water.

Persulfate (S₂O₈^2-) and its activations were investigated, including ferrous (Fe²⁺), zero-valent iron (ZVI) and ultrasonic (US), on waste activated sludge (WAS) disintegration and acidification. Experimental results showed that S₂O₈^2- effectively disintegrated WAS flocs matrix and further enhanced short-chain fatty acids (SCFAs) production, compared with that obtained from un-pretreated WAS. In addition, activated S₂O₈^2- presented better WAS hydrolysis and acidification performance over un-activated S₂O₈^2- test. The lysis rates of Fe²⁺, ZVI and US activated S₂O₈^2- groups reached to 42.6%, 36.5% and 32.9%, respectively, which were about 10.6%~20.3% higher than that obtained in the non-activated test (22.3%). The maximum SCFAs concentration in the aforementioned three activated tests were 8052, 6613, 4996mg COD/L, respectively, while that was only 3296mg COD/L in non-activated test. Furthermore, the release of organics and the distribution of generated SCFAs were also affected by S₂O₈^2- activations. From the environmental and economic perspective, the S₂O₈^2-+Fe²⁺ system played more significant role for enhancing the SCFAs recovery from WAS fermentation.

The citric acid sludge was conditioned biologically with the separated filamentous fungi Aspergillus niger SS5 before dewatering in the paper. Results showed that fungi concentration and conditioning time both had strong effects on the sludge dewaterability, and the performance of sludge dewatering and settlement were improved significantly. Combined with the analysis of Zeta, particle distribution and bound water concentration, it was observed that negative charge of sludge decreased accompanied by obviously increasing particle size. The concentration of bound water had a reduction of approximate 40% to the control sample without fungi conditioning. Meanwhile, the concentrations of COD in supernatant and protein and polysaccharide in each EPS layer were all decreasing during the sludge conditioning with fungi. There were significant correlations between protein degradation in EPS and bound water content, D₅₀ and Zeta potential, which indicated it was the important factor affecting citric acid sludge dewaterability. Due to the large pH buffering capacity of citric acid sludge, the great pH change was not observed during the decomposition of organic matter in sludge. 71.98% water content of the dewatered sludge cake was obtained with 20mL/g DS Aspergillus niger SS5 conditioning for 3d without chemical additives. It should make for further resource utilization of these food fermentation sludge as citric acid sludge.

The effect of goethite on methane production by anaerobic digestion of organic matter was studied with waste activated sludge and tobacco waste as research objects. The addition of goethite increased digestive gas production rate to 359.4mL/g, which was significantly higher than that in the blank. Goethite contributed to the increase of methane content in mixed gases and reduced the volume fraction of CO₂. Goethite was conducive to the dissolution of organic matter during co-digestion of waste activated sludge and tobacco waste, and cellulose decreases to provide sufficient digestive substrate for methanogenesis Archaea. Goethite was beneficial to acidification metabolism. The maximum yield of volatile fatty acids in goethite group was only 56.2mg/g, which was significantly lower than that in blank. In addition, goethite promoted the synthesis of propionic acid. Goethite promoted the degradation of acetic acid. On the first day of digestion, the degradation rate of acetic acid reached 65.5% in the goethite group, which was higher than 56.6% in the blank. Enzyme activity analysis indicated that goethite promoted the key enzymes of hydrolysis, acidification and methanogenesis. Methanothrix and Methanobacterium are the important microorganisms in methanogenesis stage, and 454high-throughput sequencing showed that goethite increased the relative abundance of Methanothrix and Methanobacterium to 59.6% and 23.5%.

In order to investigate the effect of fermentation temperature on the microbial community structure of the rural household biogas digesters in Qinghai Province, twenty-four mud samples from six fermentation temperature periods through the year were collected and analyzed for their changes in microbial community structure using denaturing gradient gel electrophoresis (DGGE). Results showed that fermentation temperature had significant effects on the structure and diversity of microbial communities, and biogas production. Bacteria showed the highest species richness in both the highest (mid-September) and the lowest (mid-March) sampling temperature period, whereas archaea showed the highest species diversity only in mid-September. Firmicutes, Bacteroidetes and Proteobacteria were the most abundant bacterial phyla detected in all samples (total abundance > 72.43%), all of which are important functional bacterial groups in the fermentation system for biogas production. The genera of Petrimas, Clostridium, Tissierella and Pseudomona were the most dominant bacterial groups in all samples, whose total abundance was relatively constant (~32.40%). In archaea, the most dominant group among all samples was the order Methanomicrobiales, with relative abundance of 40.62%~64.74%. The genus Methanogenium was the most dominant species detected for biogas production. Its abundance changed regularly with the fluctuation of fermentation temperature within the range of 32.62%~55.74%, and was consistent with the regularity of biogas production.

In order to explore the effects of slag and biochar application treatment on the community structure and methane emission of iron-reducing bacteria in paddy soil, applied three kinds of treatments, namely biochar, slag and biochar + slag, in a paddy field in Fuzhou to measure early and late paddy. The methane emission flux during the paddy growing season and the number of culturable iron-reducing bacteria were compared, and the difference between the composition of the iron-reducing bacteria and the community composition of the soil in the paddy field was compared. The application of waste could change the quantity of iron-reducing bacteria in paddy soil, and the number of iron-reducing bacteria in the late-season biochar application group was significantly higher than that in the other three groups (P<0.05); the waste was applied to a certain extent. Methane emissions from paddy soils were inhibited, and the early rice mixed application group had the most significant reduction in methane emissions. The iron-reducing bacteria in the paddy soil of Fuzhou Plain are rich in species, distributed in ten gates, of which Firmicutes and Proteobacteria are dominant bacteria, and the sum of abundance is greater than 95%. A total of 20genera were identified, among which the abundance of the genus Bacillus, Anaeromyxobacter, Clostridium and other ten genus, accounting for 62.07%~66.58% of the known iron-reducing genus in the sample; biochar and slag mainly by changing soil pH and water content, the community structure of iron-reducing bacteria in paddy soil was affected, and the effect of mixed application was more significant than single application. The number of Bacillus is significantly negatively correlated with the methane emission flux of paddy soil, and it is the main genus of iron reduction to inhibit methane production and emission.

An incubation experiment was conducted under shallow flooding condition to study the effects of different fertilization treatments on greenhouse gas emissions from black soil. The results showed that application of N fertilizer exert no effect on CO₂ emission compared with the non-fertilizer control treatment under shallow flooding condition, while combined application of N fertilizer with straw or pig manure increased CO₂ emission to one magnitude that of solely application of N fertilizer, with the effect of treatment of N fertilizer with straw was more prominent. In comparison with the non-fertilizer control treatment under shallow flooding condition, application of N fertilizer significantly promoted the emission of N₂O, however, combined application of N fertilizer with pig manure or straw significantly inhibited N₂O emission and promoted slightly absorption of N₂O compared with the treatment of solely application of N fertilizer, with the effect of the treatment of N fertilizer with straw was more remarkable. Application of N fertilizer inhibited CH₄ emission under shallow flooding condition compared with the non-fertilizer control treatment, while combined application of N fertilizer with pig manure or straw significantly increased the emission of CH₄ in comparison with the sole N fertilizer treatment.

Based on the published data during 2005 to 2015, the spatial and temporal variation of sea surface DMS and chlorophyll a (Chl-a) was discussed in the Yellow Sea and the East China Sea. DMS and Chl-a concentration in summer were higher than those during winter, and annual concentration of DMS and Chl-a rose from south to north, and the seasonal variation of DMS and Chl-a concentration got bigger with an increase of latitude. Statistical analysis showed that Chl-a had an exponential relation with DMS concentration during spring and summer, while there was a linear relationship during winter. And under conditions of different Chl-a concentration levels, the impact of temperature on DMS concentration were different. A multivariate statistical model was established in this work, in which the sea surface temperature and the surface Chl-a concentration was used to estimate the surface DMS concentration. The DMS concentration rose with the increase of the Chl-a concentration. The DMS concentration was relatively high within a range of temperature with the central temperature of 21.31℃, and the higher the Chl-a concentration was, the narrower the range of temperature could be.

In order to clarify the regularity of Dongting Lake blooms, the changing rule of water area and its influencing factors, the MODIS02HKM images were used as the main data sources in the study. The Floating Algae Index (FAI) and a Multi-band Water Index (MBWI) were adopted to identify and extract the water and the scope of algal bloom in Dongting Lake. the temporal and spatial distribution data of water and algal bloom in Dongting Lake in the past 2001~2015 years were analyzed. The research conclusions were as follows:Firstly, the water area of Dongting Lake presented obvious seasonal change in years and a inter-annual reduced trend. The area of water was in order of summer, autumn, spring and winter. In the 2001~2015 year, the average area of water was 2.2times that of the dry season. Secondly, the area shrinkage rate of Dongting Lake in 2001~2015 was-14.574km²/a, and the largest rate was -38.678km²/a in summer. Thirdly, from 2001 to 2015, algal bloom occurred annually in the Dongting Lake area, large-scale algal blooms were usually found in the western part of Dongting Lake. The algal bloom of the West Dongting Lake and the South Dongting Lake were scattered along the river bank. Fourthly, the seasonal and inter-annual seasonal variations of blooms in Dongting Lake were significant. The area of water bloom basically presented normal distribution every year. The minimum value appeared in winter and the maximum value appeared in summer and autumn. The minimum value of algal boom was appeared in winter time, whilst, the maximum value of algal boom appeared in summer and autumn. Its maximum value reached to 681.43km². The largest algal bloom in 2001~2015 years accounted for 16.693% of the total Lake area. The annual average change rate of algal bloom area was -8.657km²/a. Algal blooms showed a trend of area reduction.

To evaluate characteristics of phytoplankton community structure and main environmental impact factors in the "Sankou" of Yangtze River and the Western Dongting Lake, phytoplankton from 18 sampling sites which distributed in "Sankou" and Western Dongting Lake were investigated in November 2016, March and August 2017. 72 species of six phyla was detected, and the phytoplankton density was in a range from 1.32 to 275×10⁴cells/L with the lowest in November and the highest in August, which the average density was 32.75×10⁴cells/L. The average density in Sankou of Yangtze River and the West Dongting Lake were 35.39×10⁴cells/L and 25.88×10⁴cells/L, respectively. In terms of dominant groups, Synedra acus, Navicula pupula and Stauroneis smithii Grun dominated in "Sankou" of the Yangtze River, and the West Dongting Lake is dominated by the Phormidium tenue of Cyanophyta, Chlorella, vulgaris and Scenedesmus quadricauda of Chlorophyta. In terms of diversity, the Shannon-Wienner index and the Margalef index of the "Sankou" of the Yangtze River were 1.31 and 1.01, while that were 1.40 and 1.10 in the West Dongting Lake, respectively. The CCA analysis of phytoplankton and water environmental factors indicated that, water temperature (WT), total nitrogen (TN) and total phosphorus (TP) were the main factors affecting the distribution of phytoplankton in "Sankou" of Yangtze River, while WT and pH were main factors of distribution phytoplankton in the Western Dongting Lake.

Based on the field investigation data of surface seawater along the Hainan Island coastal water in dry, wet and normal flow seasons of 2016 year, the spatiotemporal distribution characteristics of dissolved inorganic phosphorus (DIP) were studied. The DIP pollution level, nutrient composition and eutrophication were evaluated. Meanwhile, the main source of DIP and the relationship between DIP and environmental factors were also discussed. The results showed that the average concentration of DIP was (0.008±0.006) mg/L, ranged from 0.000mg/L to 0.062mg/L in the surface seawater along the Hainian Island coastal area. The high concentration of DIP was distributed around the Xiaohai adjacent coastal water of Wanning city in all seasons. The pollution level of DIP in normal flow season was higher than that in wet and dry flow seasons. The eutrophication index ranged between 0.00 and 3.94, with an average value (0.21±0.46). The overall eutrophication of Hainan Island adjacent seawater was relatively low, but the eutrophication problem in some local coastal water areas was still outstanding.

Sulfur isotopic values of riverine sulfate and dissolved heavy metal (DHM) contents were adopt to illustrate the effect of different human activities on the DHM contents in the Yiluo River (YLR). The results indicated that dissolved components in the upstream of YRB were heavily affected by the sulfide minerals exploration. In the upstream of Luo River, high average SO₄^2- content of (173±108)mg/L (n=8) and low average δ³⁴S_SO4 value of (3.1±2.1)‰ (n=8) were detected in the river water, and heavy metals as Co, Fe, Mn, Ni, Zn, Mo, Cd, Pb and U had high concentrations in this reach. While in the upstream of Yi River, high mean SO₄^2- content of (169±89) mg/L (n=6) and low mean δ³⁴S_SO4 value of (3.7±1.2) ‰ (n=6) were also detected, and heavy metals as Cr, Co, Fe, Ni, Zn, Mo, Cd, W, Hg, Pb and U had relatively high contents. Dissolved contents in the downstream of YRB were primarily affected by sewage and industrial wastewater. Average SO₄^2- content of (121±30) mg/L and δ³⁴S_SO4 value of (9.4±0.8) ‰ (n=4) were monitored in the downstream of Luo River along with the increasing concentrations of V, Cr, Ni, As, W and Hg. Correspondingly, in the downstream of Yi River, average SO₄^2- content of (122±22) mg/L and δ³⁴S_SO4 value of (10.5±2.4) ‰ (n=3) with the increasing concentrations of V, U, Ni, and As were found. Dissolved components in the source water of YLR were mainly derived from atmospheric deposition, and the river water was characterized with low level of DHMs and moderate δ³⁴S values ranging from 6.7‰ to 8.2‰. The contents of DHMs and δ³⁴S_SO4 values in YRB had the same spatial variations, so that the δ³⁴S_SO4 can well interpret the sources of dissolved heavy metals and sulfate in the river water.

The growth of Microcystis aeruginosa and Scenedesmus obliquus was investigated using sodium nitrate, ammonium chloride and urea as nitrogen (N) source; dipotassium hydrogen phosphate, sodium glycerophosphate and adenosine triphosphate as phosphorus (P) source. The N concentrations of culture media were 1.00, 4.00, 8.00mg/L, respectively, and the P concentrations were 0.20, 2.00mg/L, respectively. Bulk culture experiment was conducted to investigate the growth response of Microcystis aeruginosa and Scenedesmus obliquus to different forms and concentrations of N and P under N and P starvation. The results showed that different forms of N and P can stimulate the growth of two species of algae, but there was a bit difference. There was no significant difference in growth rates of M. aeruginosa between different concentrations of sodium nitrate, while the growth rates of S. obliquus reached the highest growth rate when N concentration of sodium nitrate increased to 4.00mg/L. It indicated that 1.00mg/L sodium nitrate has saturated the N requirement of M. aeruginosa, and the nitrogen demand of S. obliquus was higher than that of M. aeruginosa. The growth rates of M. aeruginosa was same when cultured with 1.00 and 4.00mg/L of ammonium chloride and urea, and the growth rates and maximal cell densities were higher than that cultured with same concentration of sodium nitrate. Compares with sodium nitrate, indicating M. aeruginosa prefers to use ammonium chloride and urea. However, the growth rates of M. aeruginosa cultured by 8.00mg/L ammonium chloride was lower than that cultured with same concentrations of urea and sodium nitrate, and also lower than that cultured with low concentration ammonium chloride, indicating high concentration of ammonium chloride was harmful to the growth of M. aeruginosa. There was no significant difference in growth rate and maximal cell densities of S. obliquus between 8.00mg/L of ammonium chloride and 8.00mg/L of urea. And both were higher than that using sodium nitrate to culture. It indicated that the tolerance of S. obliquus to ammonium chloride was higher than that of M. aeruginosa. All three forms of P can be utilized by M. aeruginosa and S. obliquus. However, the maximal cell densities of M. aeruginosa was higher with high concentration of organic phosphorus, and S. obliquus grew better under high concentration of inorganic phosphorus, indicating that availability of different forms of P were different among different algae. The ammonium concentration declined significantly, and inorganic phosphorus concentration was lower than organic phosphorus in recent years in Lake Taihu, which will benefit dominance of cyanobacteria. At present, the concentration of ammonium nitrogen in Taihu Lake is significantly reduced, the proportion of inorganic phosphorus in water is very low, and the concentration of dissolved organic phosphorus is relatively high, which is more favorable to the formation of cyanobacteria.

The enhanced removal rate (RR) of Microcystis aeruginosa and Anabaena flos-aquae as a result of the combination of chitosan (CTS) and polyaluminum chloride (PAC) was observed. In order to reveal the effects of CTS, PAC, initial pH and dosing order on coagulation, single factor experiment and response surface methodology were used. In the condition of CTS 0.40mg/L, PAC 1.19mg/L, raw water pH 7.5and PAC/CTS (PAC and CTS premixed), M. aeruginosa(chlorophyll-a (chl-a) 45~55μg/L) could achieve a chl-a RR of 95.7% (close to the prediction of 96.1%). As for A. flos-aquae (chl-a 80~90μg/L), in the condition of CTS 0.25mg/L, PAC 2.00mg/L, raw water pH 7.9and CTS+PAC (CTS added first), could achieve a chl-a RR of 97.0% (close to the prediction of 97.9%). At pH 9.0(a simulation of alkaline algae-containing water), compared with the other two dosing orders, the type of PAC/CTS was the most effective in removing algae, leading to a chl-a RR of 94.9% for M. aeruginosa and 95.3% for A. flos-aquae. The cost of 0.40mg/L CTS and 2.00mg/L PAC for M. aeruginosa removal would be ¥0.0215/m³ and that of 0.24mg/L CTS and 2.00mg/L PAC for A. flos-aquae would be ¥0.0149/m³.

Microbial genes encoding aromatic ring-hydroxylating oxygenase (ARHOs) have been selected as molecular markers for evaluating the potential of microbial degradation ability in environment. The development of culture-independent metagenomic technology has greatly accelerated the research of functional genes and functional groups on aromatic hydrocarbon degradation in recent years. This article summarized the ARHOs related databases, introduced various functional genes and corresponding primers applied to environment samples in microbial degradation of different types of aromatic hydrocarbons (benzene series, naphthalene as well as other polycyclic aromatic hydrocarbons). It also reviewed the applications of this technology in various complex environment samples. Furthermore, the future development of microbial degradation of aromatic compounds using metagenomics technologies was prospected.

The research was conducted in the Luanhe, Chaohe and Baihe river basins, which were the important water conservation areas of Beijing-Tianjin-Hebei region. By analyzing the changes of land use and landscape pattern in 2010 and 2015, the spatial and temporal distribution and characteristics of land use transfer and landscape pattern were studied. The distribution and change of water conservation in the study area during this period were simulated by SWAT model and compared with precipitation. Also, the influence of landscape pattern change on water conservation were calculated by partial correlation analysis method. The results showed that the correlation coefficients between water conservation and PLAND, NP, LPI, LSI, COHESION indices were -0.846, -0.635, 0.468, 0.523, 0.918, respectively. The relationships between landscape pattern and water conservation were concluded as followed:Water conservation would be increased when the higher landscape diversity, higher degree of aggregation, more complex, irregular and dominant of the landscape shape were shown, Fragmentation of the landscape might cut down the water conservation capacity significantly.

The dry deposition fluxes of total inorganic nitrogen (TIN) to the China Seas during one dust (April 26~May 3, 2011) and one haze event (January 1~7, 2016) were calculated by WRF-CMAQ model. Contributions of the TIN deposition to the marine primary productivity during two events were also analyzed. Two inland polluted regions were selected to explore their contributions to the deposition of TIN over China Seas during the haze event. The results showed that TIN dry deposition flux over China Seas were 6.77 and 3.01mg N/(m²·d) during the dust and haze event respectively, which were about 6.84 and 3.04 times higher than that of the nonevent days. The nitrogen deposition during two events can be converted to new primary biological productivities of 38.5 and 17.1mg C/(m²·d) over China Seas, respectively. Reduced nitrogen (NH₃ and NH₄⁺, accounting for 62.2% of TIN dry deposition flux) was the main component of TIN deposition during dust event while the oxidized nitrogen (HNO₃ and NO₃^-, accounting for 84.3% of TIN dry deposition flux) was main components during the haze event. Highest deposition fluxes during dust event was found in Yellow Sea while the lowest fluxes was in Bohai Sea. During the haze days, dry deposition of TIN over Yellow Sea and East China Sea were roughly the same, which were higher than that in Bohai Sea. During this haze event, TIN deposition over the Bohai Sea, Yellow Sea and East China Sea from Beijing-Tianjin-Hebei & Northwest of Shandong (Region 1) were higher than that from Yangtze River Delta (Region 2). The contribution to TIN dry deposition flux over China adjacent seas from Region 1was in the range of 38.7%~74.6% and about 1.14%~12.1% from Region 2.

The correlation of distribution characteristics, regulations of propagation of tetracyclines and sulfonamide resistance genes (ARGs), and the microbial community structure of the contaminated rivers were studied by using the Miseq sequencing and real-time PCR techniques. The tetracycline resistance genes tetA and tetB and the sulfonamide resistance genes sul1and sul2 were both detected in water and sediment. And the absolute abundances of tetracycline resistance gene and sulfonamide resistance gene were 5.09×10³~1.26×10⁷ and 3.94×10⁵~1.32×10⁹copics/L, respectively. The abundances of sul1antibiotic resistance gene was significantly higher than other genes. The main dominant bacteria in the river were Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria and Cyanobacteria. The relative abundance accounted for 95.62% of the total proportion, and there was little difference in overall of the examples. The analysis of resistance gene and microbial community redundancy showed that Methylotenera was the main factor affecting the abundance of tetA resistance gene, Dechloromonas and Clostridium. Sensu stricto 1were the main factors affecting the abundance of tetB resistance gene, and Dechloromonas, Clostridium sensu stricto 1and Methylotenera were the main factors affecting of the abundance of sul1 and sul2 resistance gene distribution.

To reveal the structure characteristics of microbial communities in regional groundwater at different depths and the interaction between microbial communities and groundwater environment, Liuli River district located in the southwestern Beijing was selected to collect different deep groundwater samples for the hydrochemical analysis and the high-throughput sequencing of the V4-V5region of microbial 16S rRNA. The results of hydrochemistry showed that the concentration of eight main ions decreased with the increase of depth in groundwater, especially Cl^-, SO₄^2- and NO₃^- varied obviously. In industrial area, the highest concentrations of NO₃^- and SO₄^2- were up to 155.30mg/L and 321.00mg/L, respectively, where shallow groundwater was contaminated with NO₃^- and SO₄^2-. Microbial analysis showed that the diversity of microbial community was strongly affected by groundwater depth, and microbial abundance increased with the increase of groundwater depth. Proteobacteria(26.2%~95.2%)was the dominant phylum and Pseudomonas (1.5%~32.2%)was the dominant genus. The microbial community at different depths of groundwater was significantly different. The number of the specific genera of shallow, middle and deep aquifer were 74, 60 and 54, respectively. NO₃^-, SO₄^2-and depth were the main factors affecting the microbial community. In addition, the concentrations of NO₃^- and SO₄^2- were closely related to depth. Groundwater depth was an important control factor to microbial community structure.

Based on the monitoring data of the national urban air quality real-time release platform, this study used the spatial interpolation method to simulate the exposure level of China PM_2.5 on the spatial grid scale of 10kmx10km, and used the BenMap model to estimate the health loss of China's PM_2.5 pollution in 2017. Then this study conducted a spatial analysis of the health economic losses of PM_2.5 pollution on a city scale. In terms of statistical significance, the total PM_2.5 pollution in 2017 caused 321435 premature deaths, 746078 hospital admissions, and 14877551 morbidity in China. The health economic loss was about 126.25 billion yuan, accounting for 1.53% of the national GDP. From the perspective of urban scale, the health effect showed a certain spatial agglomeration effect, and the cities in Beijing-Tianjin-Hebei region were more serious. In terms of spatial distribution, the main distributions were "high-high" and "low-low", that was, high-value cities of health economic loss gathered with each other, and low-value cities of health economic loss gathered with each other, too. And there existed a phenomenon that the high-value cities influenced each other and gradually spread around, and then affected the low-value cities around.

In order to study adaptative mechanisms of sliver carp and tilapia on harmful algal blooms and provide scientific methods of fish species selection in biological manipulation, systematic research was conducted on bioaccumulation, degradation of microcystin and the differences in resistance and detoxification mechanisms on sliver carp (Hypophthalmichthys molitrix) and tilapia (Oreochromis niloticus). In toxic Microcystis feeding experiment, the daily intake of microcystin by sliver carp and tilapia was up to 10mg/kg body weight. Both fishes show strong resistance to MC. Microcystin concentrations in feces of sliver carp and tilapia after Microcystis intake were significantly decreased to 71.5% and 6.0% respectively (P<0.05). The degradation ability of tilapia to toxic Microcystis and microcystin is much higher than silver carp. The hepatosomatic index of sliver carp and tilapia was significantly decreased from (1.19±0.21)% and (2.24±0.19)% to (0.79±0.06)% and (1.72±0.07)% respectively (P<0.05). Bioaccumulations of MC of the two species were (1.57±0.31) and (10.81±6.52)μg/kg (fresh weight) in the muscle, (4.28±1.64) and (2.48±0.15)mg/kg (fresh weight) in the liver. There were significant differences between MC accumulation in the muscle and liver of each species (P<0.05). Microcystin concentration in the muscle of tilapia was 6.9 times higher than that of silver carp. During the toxic experiment, LD₅₀ of microcystin-LR was 270µg/kg on sliver carp and 790µg/kg on tilapia, which suggested microcystin tolerance of tilapia is stronger than that of sliver carp. Enormous lipid droplets were observed in the liver cell of the two species whether fed with Microcystis or intraperitoneally injected with microcystin. After intraperitoneal injection with microcystin-LR, the content of GSH in the two species showed a significant decrease in 6h and then increased gradually. Significant difference of GSH content was found between the two species (P<0.05). The results showed that the degradation ability of tilapia to microcystin is much higher than silver carp. Silver carp mainly feeds on the mucilage sheath and adhesion bacteria of colonial Microcystis with small amount of intracellular microcystin released. This mechanism can effectively protect silver carp fed with Microcystis to less damage. The digestive enzymes in tilapia have strong digestion and degradation ability to Microcystis and microcystin, and the high level of GSH content and related enzyme activity ensure efficient detoxification of toxins in vivo. From the view of food safety, compared with tilapia, silver carp is the species which is more suitable and to be widely used for cyanobacteria bloom control.

As an effective soil amendment, biochars have attracted increasing research attention, while their environmental risks have not been fully explored. Studies on the effects of biochars on ecosystem, especially on soil invertebrates, are still scarce. The model organism, Caenorhabditis elegans (C. elegans, nematode), was used to assess the potential neurotoxicity of biochar. The neurobehaviors of C. elegans, including their body bends, relative move length, defecation, touch response and chemical index, were investigated after 24h-exposed in biochars, the washed biochars and biochar supernatants. The contents of metallic and non-metallic elements, biochar physicochemical properties and the environmentally persistent free radicals (EPFRs) were characterized. The results showed a hormesis behavior of C. elegans when exposed in biochar particles with high EPFRs intensity. No significant effect to C. elegans was observed when exposed in supernatants. Compared to the other endogenous pollutants in biochars, EPFRs have a potential neurotoxic effects to nematodes. This study provides a new angle to assess the potential environmental risks of biochar application.

The toxicity of polychlorinated biphenyls (PCBs) and their transformation have been intensively investigated in recent years. However, the potential mechanisms of biotransformation in a lake food web remain unclear. In current study, the distribution characteristics of PCBs and δ¹⁵N values in different tissues of six species of fishes, collected in Dongting Lake, were analysed with gas chromatography-high resolution mass spectrometer and stable isotope mass spectrometer, respectively. The correlation between PCBs and the trophic level were explored based on the concentrations and δ¹⁵N values. The concentration of ∑PCBs₁₁₅ranged from 0.04 to 9.77ng/g wet weight (ww), and the highest level was found in the gonad of Cyprinus carpio. The concentration of toxicity equivalent (TEQ) varied from 0.003 to 2.39pg/g, with highest level detected in the fat of Silurus asotus. And the PCB levels in fish collected from Dongting Lake were at low level comparing with previous study. PCB28, 52, 95, 99, 101, 105, 110, 118, 138, 153, 155 and 209 were found in all tissues. The coplanar PCBs (Co-PCBs), Ind-PCBs (Indicator PCBs) and PCB209 was in a tissue-specific manner. The significant positive correlation (P<0.05) between the PCB congeners and δ¹⁵N values varied depending on the calculation mode of PCB concentrations (such as, ng/g ww, ng/g dry weight and lipid- normalized).

This paper empirically analyzed the inertial characteristics, structural changes and amplification effects of PM_2.5 sequences using AR model and TAR model, using hourly PM_2.5 mass concentration monitoring data from 2009 to 2017 in Beijing, Chengdu, Guangzhou, Shanghai and Shenyang. There existed relatively strong inertia of PM_2.5 sequences in the five cities, especially in Chengdu. It was also found that there were structural changes from 2009 to 2017 in Beijing, Shanghai, and Guangzhou. The PM_2.5 sequences of the five cities are obviously nonlinear. The PM_2.5 in the five cities were running at a low level, and the inertial characteristics were obvious. In addition, there was no obvious amplification effect, suggesting that the haze pollution prevention was not necessary to consider the amplification effect of the PM_2.5 sequence. The inertial characteristics of the PM_2.5 sequences at the low regime required more attention in policy-making in the future.

The four-stage analysis framework of NSUSBM-SFA-NSUSBM-Tobit was constructed in this paper. Based on the cross-section data of 213 cities in China, NSUSBM model was used to calculate the environmental efficiency of cities under the separable and inseparable assumptions. Then the three-stage DEA model was used to introduce natural factors. And combined with the new development concept, The Tobit model was used to analyze the influencing factors of urban environmental efficiency. Research showed, The average urban environmental efficiency in China was 0.49, the overall efficiency was not high, and regional differences were obvious. For some high-quality development cities, the relatively excellent natural environment compensated for the inefficiency of management to a certain extent, and there was still a room for improvement in its management inefficiency. For low-quality cities, the inseparability of GDP and environment pollution were the main causes of environmental inefficiency. Innovation ability had obvious promoting effect on urban environmental efficiency. The proportion of secondary industry was negatively related to environmental efficiency. The greater the difference between urban and rural areas, the lower the environmental efficiency. Government's environmental investment and regulation helped to improve urban environmental efficiency. Opening up and introducing foreign capital had a significant effect on improving urban environmental efficiency. Urbanization helped to improve environmental efficiency.

Based on the subdivision on the main business of enterprises, firstly, efficiency of carbon emission was analyzed by way of the ZSG-SBM method using the samples from the public-listed industrial enterprises during 2014~2016 and industrial enterprises as a whole during 2011~2016. Secondly, using SEM, potentials and capabilities of carbon emission reduction was quantified. Lastly, by way of four-quadrant matrix method, differences on the paths of carbon emission reduction were discussed after evaluating status of carbon emission reduction. During 2011~2016, the status improved annually. It was noted that combined effect existed in manufactures, therein, efficiency on the heavy industries was above 0.65 in general whilst on the light industries was irregular. There were relations among the enterprises with heterogeneity, corporate governance and technology played a very important role, especially external environment have been incentive effects and crowding-out effects. Therefore, carbon emission reduction of enterprises with heterogeneity should be paid more attention by the policy-maker through planning different paths and avoiding repeated construction.