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In order to study the contents, sources, and health risk of PM 2.5 in road fugitive dust in Yunnan, road fugitive dust samples were collected from five typical cities including Kunming, Baoshan, Wenshan, Zhaotong, and Yuxi. Particulate matter resuspension technology was used to levitate the dust samples and collect PM 2.5 . Eight heavy metals including chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), selenium (As), cadmium (Cd), and lead (Pb) in PM 2.5 were detected using ICP-MS. The results showed that the contents of Cr, Ni, Cu, Zn, and Pb in road fugitive dust seriously exceeded the background values of Yunnan soil. The enrichment factors showed that most of the heavy metals in PM 2.5 of road fugitive dust in the five cities of Yunnan were moderately enriched and strongly enriched, which were greatly influenced by human activities. The results of correlation analysis and principal component analysis showed that the heavy metals in PM 2.5 of road fugitive dust in Yunnan were all affected by soil and traffic sources. The other sources varied greatly in different cities:Kunming was affected by iron and steel melting sources, Baoshan and Yuxi were affected by non-ferrous metal smelting sources, and Zhaotong was affected by coal sources. Health risk analysis showed that Cr, Pb, and As in road fugitive dust PM 2.5 had non-carcinogenic risk in children in Kunming, Yuxi, and Zhaotong, respectively, and Cr in Kunming also had a lifetime carcinogenic risk.

To realize a simultaneous partial nitrification, ANAMMOX (anaerobic ammonium oxidation), and denitrification (SNAD) process treating anaerobic digester liquor of swine wastewater (ADLSW) in a continuous-flow biofilm reactor (CFBR), we first gradually increased the influent ammonium (NH 4 + -N) concentration, and then enhanced the ADLSW ratio in the influent during operation; dissolved oxygen (DO) was controlled at (0.4±0.1) mg·L -1 by adjusting the air flow rate, and the temperature was kept at (30±1)℃. Meanwhile, high-throughput sequencing and quantitative PCR (polymerase chain reaction) techniques were used to analyze the bacterial community shifts and the amount of dominant nitrogen removal bacteria. The results demonstrated that a successful start-up of the SNAD process was accomplished in 150 d, and replacement of the actual biogas slurry was completed in 298 d. The effluent (NO 3 - -N+NO 2 - -N)/ΔNH 4 + -N value was less than 0.11, and the average removal rates of NH 4 + -N and TN (total nitrogen) increased to 63.26% and 55.71%, respectively. Moreover, high-throughput sequencing results demonstrated that the dominant microbial populations at phylum level were Chloroflexi (with a relative abundance of 50.78%), Proteobacteria (13.34%), and Planctomycetes (9.26%). The relative abundance of Nitrosomonas increased from 1.55% to 1.98%. In addition, the relative abundance of Candidatus&#95;Brocadia and Candidatus&#95;Kuenenia increased from 0.01% and (<0.01%) to 4.66% and 4.18%, respectively, and the relative abundance of Denitratisoma increased from (<0.01%) to 2.06%. Meanwhile, qPCR analysis showed that the amounts of ammonia-oxidizing bacteria, ANAMMOX, and denitrifying bacteria increased significantly compared with the inoculated sludge. An efficient and stable nitrogen removal rate can be achieved, and the follow-up processing cost can be reduced, by application of the SNAD treatment process for ADLSW.

Soil microbial metabolism is vital for nutrient cycling and stability of an ecosystem. To elucidate the long-term effects of biochar application on nutrient limitations and carbon use efficiency (CUE) of soil microbial metabolisms, biochars pyrolyzed at 450℃ from trunks and branches of fruit trees under an oxygen-limited condition were mixed with the top Lou soils (0-20 cm) with application amounts of 0, 20, 40, 60, and 80 t·hm -2 in 2012. Corn-wheat rotation was carried out afterwards for seven years. The nutrient limitations of soil microbial metabolisms were analyzed quantitatively through ecoenzymatic stoichiometry in 2019. The results indicated that:① With an increase in the biochar application amount, soil moisture, organic carbon, total nitrogen, C:N, C:P, and N:P significantly increased, whereas there were no clear patterns for the active components of carbon, nitrogen, and phosphorus, microbial biomass carbon, nitrogen, phosphorus and total phosphorus. In contrast, the activities of five extracellular enzymes ( β -1,4-glucosidase, cellobiohydrolase, leucine aminopeptidase, β -1,4- N -acetylglucosaminidase, and phosphatase) were significantly reduced. ② The soil microorganisms suffered from the phosphorus limitation under all treatments in this study. In the treatments of biochar application, the carbon and phosphorus limitations of microbial metabolisms increased significantly with increasing application amount, whereas the microbial CUE decreased significantly. When the application amount was 20 t·hm -2 , the carbon limitation (0.625±0.022) and phosphorus limitation (62.153°±0.892°) were lowest, and the microorganism CUE (0.511±0.007) was highest. ③ Partial least-squares path modeling (PLS-PM) showed that soil carbon, nitrogen, phosphorus, and their stoichiometry had a very direct positive effect on phosphorus limitation ( P <0.01), and there was a positive correlation between carbon limitation and phosphorus limitation ( R 2 =0.242, P <0.001); in contrast, the carbon and phosphorus limitations had a very significant negative effect on CUE ( P <0.001). It was revealed that the excessive application of biochar had caused a soil element stoichiometry imbalance, which deteriorated the phosphorus limitation of the soil microbial metabolism and further led to carbon limitation and reduction of CUE. When the biochar application amount was 20 t·hm -2 , C and P limitations were lowest, and microbial CUE was highest. Therefore, 20 t·hm -2 was optimal for regulating soil microbial metabolism, maintaining ecological functions, and reducing carbon dioxide emission produced by microbial metabolism.

Aeolian sandy soil was collected at depths of 0 to 100 cm at intervals of 0-10, > 10-20, > 20-30, > 30-40, > 40-60, > 60-80, and > 80-100 cm from under the cover of psammophilous shrubs Ammopiptanthus mongolicus, Hedysarum scoparium, Oxytropis aciphylla, Nitraria tangutorum and Haloxylon ammodendron and from a mobile dune in the Ulan Buh Desert. Multi-fractal theory was used to determine the soil particle size distribution (PSD), which measured the fractions of ω (Mn), ω (Zn), ω (Cr), ω (Cu), ω (Pb), ω (Ni), ω (As), and ω (Cd), as well as their distribution status in the laboratory and analyzed correlations between the PSD and heavy metal content to identify the relationship between soil structure and heavy metal pollution. This result shows that a range of different types of shrubs can increase the distribution of fine soil particles, and specifically Ammopiptanthus mongolicus and Hedysarum scoparium can increase range, heterogeneity and degree of dispersion of the PSD. The heavy metal content in the soil under the different shrubs is ranked as ω (Mn) > ω (Zn) > ω (Cr) > ω (Cu) > ω (Pb) > ω (Ni) > ω (As) > ω (Cd). In the first 10 cm of the soil under the shrubs, the concentration of all heavy metals are higher than samples from the mobile dune except for Cr and Cu. Average value of ω (Mn) and ω (Cd) is 354.899 and 1.429 mg·kg -1 under Ammopiptanthus mongolicus and Hedysarum scoparium respectively. Concentrations of Mn and Cd under Ammopiptanthus mongolicus and Hedysarum scoparium shrubs are significantly higher than those of mobile dune ( P <0.05), and the concentration of both is significantly various between each soil layers ( P <0.05). The highest value for ω (Mn) is in soil layer between 30 and 40 cm below the surface and the highest for ω (Cd) appears between 10 and 20 cm below the surface. The average ω (Pb) under Hedysarum scoparium is 13.556 mg·kg -1 which is the highest among all the shrubs, exceeding 3.24% under Ammopiptanthus mongolicus and higher than samples from mobile dune. However, average ω (As) under Hedysarum scoparium is exceeded 0.37% under Ammopiptanthus mongolicus but still higher than samples from mobile dune. The grain size of φ (silt) and φ (medium coarse sand) are determining factors for heavy metal concentrations in fine and coarse particles of aeolian sandy soil. Heavy metal measurements all positively correlate with φ (silt) and φ (clay), however, they negatively correlate with φ (medium coarse sand), except for ω (Cr). The correlation coefficients between heavy metal contents and the multifractal parameters are similar for φ (clay), φ (silt), and φ (medium coarse sand). Therefore, multifractal parameters can describe the correlation between heavy metals and their determinant soil grain size. This study shows that, Ammopiptanthus mongolicus and Hedysarum scoparium can entrap and deposit fine particles from the sand flow to surface soil layers around shrubs and improve the condition of PSDs for different soil layers with respect to heavy metals. Hence, in aeolian sandy soil these concentrations are higher than for mobile dunes after planting Ammopiptanthus mongolicus and Hedysarum scoparium . Therefore both should be used to promote good soil structure of particular areas to entrap and in-situ control heavy metals to decrease heavy metal pollution in downwind cities.

In this paper, 1.5 g·L -1 of magnetic activated carbon with different particle sizes being 80, 140, 200, and 300 mesh (numbered 2, 3, 4, 5) were inoculated into the same sequencing batch reactor (SBR). The sludge volume index (SVI), particle size distribution characteristics, changes of extracellular proteins (PN), polysaccharide (PS), and polymeric substances (EPS) and their decontamination capability were studied and compared with a control group without addition (numbered 1). The results show that different particle diameters of magnetic activated carbon have certain influences on the granulation process. For example, it is easier for activated sludge to form aerobic granular sludge (AGS) when particle size are 140 mesh and 200 mesh acting as an inner core. Under these conditions, the AGS has a close structure and good sedimentation characteristics. Gaussian distribution was adopted to analyze the characteristics of Tparticle size distribution and standard deviations. The average diameter of the sludge in 3# and 4# all reached 780 μm within 50 days, which was higher than other reactors, with the same standard deviations being 318.9 μm and 362.3 μm respectively, which is lower than 2# and 3#. Besides, the granular sludge formed in both reactors was uniform in size and stable in operation. Different particle sizes of magnetic activated carbon were beneficial for the enhancement of proteins (PN), especially those with appropriate diameters (140 and 200 mesh), but had little effects on polysaccharides (PS). The formation of aerobic granular sludge based-magnetic activated carbon was in accordance with the inert kernel model. Meanwhile, the PN/PS in 3# and 4# were obviously higher than other SBRs with the same removal rate of TN and TP reaching 50% and 60% respectively.

Bisphenol A (BPA) is widely known as a typical synthetic environmental hormone. Effects of BPA concentrations and aerations on soil microbial communities were rarely reported. This paper presented the studies on effects of various concentrations of BPA (0, 0.25 mg·kg -1 , 0.50 mg·kg -1 , 1.00 mg·kg -1 , 2.00 mg·kg -1 ) and soil aertaiton (aerobic and anaerobic) on characteristics of paddy soil microbial communites by technology of qPCR (fluorescence quantitative PCR) and PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis). The results lined out that: ① the microbial abundance index was significantly different among different BPA concentrations under the same condition of soil aeration (anaerobic or aerobic). However, the index of microbial evenness, Shannon-Wiener-diversity and evenness-indices were insignificantly different under these conditions. At a concentration of 0.50 mg·kg -1 , the microbial abundance index reached a maximum value under anaerobic conditions; while under aerobic conditions the opposite result was found, the microbial abundance index dropped to a minimum value. ② The two-way analysis of variance (ANOVA) showed that: the concentration of BPA, soil aeration and their interaction significantly affected the abundance of bacteria, whereas the abundance of fungi was only affected by soil aeration. The study results showed that: the abundance index was a sensitive indicator for the variation of soil microbial diversity; it was a critical value for the change of soil microbial abundance when the BPA concentration was 0.50 mg·kg -1 ; as for the abundance of fungi, the response of bacteria abundance was more sensitive to BPA and soil aeration conditions.

This study utilized the sequencing batch activated sludge reactor (SBR) inoculated aerobic granular sludge (AGS) to treat the low COD/N ratio (<4.0) domestic wastewater under low DO (0.5-1.0 mg·L -1 ) concentration condition. Long-term performance of simultaneous nitrogen and phosphorus removal and bacterial community composition of AGS-SBR were studied. The results showed that the AGS-SBR system had good and stable decontamination abilities in its 180-day operation. The average removal rates of COD, NH 4 + -N, TN and TP were 87.17%, 95.21%, 77.05%, and 91.11%, respectively. At the same time, the AGS showed good settling performance, and always kept its integrated and compact structure. No obvious granular sludge disintegration phenomenon occurred in 180 days. Meanwhile, by using Illumina 16S rRNA gene MiSeq sequencing, we investigated the bacterial abundance in AGS-SBR reactor. Proteobacteria, Firmicutes, Chlorobi, Chloroflex, and Bacteroidetes were the dominant microbial communities in the simultaneous nitrogen and phosphorus removal reactor. Denitratisoma , Planctomycetaceae , Thauera , Comamonas , Nitrosomonas and Nitrospira were suggested to be the primary organisms responsible for the nitrogen removal. Clostridium and Anaerolinea were the main bacterial communities of phosphorus removal.

In this study, natural zeolite was modified by HDTMA. Effects of the modified conditions, HDTMA-modified zeolite doses, solution pH values, and reaction time on nitro-phenol removal were investigated, and the adsorption kinetics and isotherms were discussed. Compared with natural zeolite, HDTMA-modified zeolite showed better performance in nitro-phenol removal. An adsorption capacity of 2.53 mg · g⁻¹ was achieved when the concentration of HDTMA solution (pH = 10) was 1.2% in preparation of modified zeolite. This adsorption capacity was higher than that obtained by natural zeolite (0.54 mg · g⁻¹). In adsorption tests, when HDTMA- modified zeolite dose was adjusted to 8 g · L⁻¹, the removal efficiency of nitro-phenol reached 93.9% after 90 min reaction, with wastewater pH of 6. Furthermore, the nitro-phenol adsorption process could be well fitted to the pseudo-first-order kinetics model (R² > 0.90), whereas the adsorption isotherm results indicated that Langmuir model provided the best fitting for the equilibrium data at different temperatures, with R² of higher than 0.90.

In this study, simultaneous nitrification and denitrification (SND) coupled Phosphorus removal process through gradually decreasing DO concentration was investigated by treating wastewater with a low COD/TN ratio (C/N = 3 : 1-4: 1) in a sequencing batch reactor (SBR) inoculated with aerobic granular sludge (AGS). Successful SND coupled Phosphorus phenomenon occurred after 20d at the DO concentration of 0.50-1.0 mg x L(-1). In the following 40 days, the average removal rates of COD, NH4(+) -N, TN and TP were 84.84% , 93.51%, 77.06% and 85.69%, and the NO3(-) -N and NO2(-) -N average accumulations in the effluent were only 4.01 mg x L(-1) and 3.17 mg x L(-1), respectively. The AGS had complete forms and good settling performances, and the sludge volume index (SVI) was about 55.22 mL x g(-1) at the end of starting-up stage. The results of different nitrogen sources showed that the removal rate of TN was in the order of NH4(+) -N > NO2(-) -N > NO3(-) -N, and the removal rate of TP was in the order of NO3(-) -N > NO2(-) -N > NH4(+) -N. The nitrogen and phosphorus removal of wastewater were mainly realized by simultaneous nitrification and denitrification and denitrifying phosphorus removal, respectively.

A greenhouse pot experiment was conducted to investigate the effects of arbuscular mycorrhizal (AM) fungi Claroideoglomus etunicatum (CE), Rhizophagus intraradices (RI), Funneliformis mosseae (FM) and Glomus versiforme (GV) on AM colonization rate, biomass, mineral nutrient uptake, C: N: P ratios and Na and Cl- concentrations of reeds (Phragmites australis) grown in saline and non-saline wetland soils. The aim was to provide a technical basis for the ecological revegetation and salinity restoration of wetland ecosystem. The results indicated that symbiotic associations were successfully established between the four isolates and reeds grown in the two types of wetland soils. The average AM colonization rates ranged from 2.5% to 38%. The mean root colonization rate of CE was significantly higher than those of the other three isolates. There were no significant differences in root colonization rates between saline and non-saline wetland soils. The biomass and nutrient contents of reeds grown in non-saline wetland soils were significantly higher than those grown in saline wetland soils. However, Na+ and Cl- concentrations of reeds grown in non-saline wetland soils were significantly lower than those grown in saline wetland soils. In non-saline wetland soils, inoculation with GV significantly increased the shoot dry weight and the shoot N, P, K, Ca and Mg contents of reeds. Inoculation with GV and RI significantly improved the root P and K contents of reeds. Inoculation with the four AM fungi significantly reduced the shoot N: P ratios. Inoculation with FM and GV significantly reduced the root C : N and C : P ratios. Inoculation with the four AM fungi significantly reduced the shoot Cl- concentrations. Inoculation with RI significantly reduced the shoot Na+ concentrations. In saline wetland soils, inoculation with AM fungi had no significant effect on the biomass, mineral nutrient uptake and Na+ and Cl- concentrations of reeds. The results demonstrated that the four AM fungi isolates had different effects on the growth of reeds in wetland soils with different salt contents. Inoculation with AM fungi played a more positive role in improving the growth of reeds in non-saline wetland soil than those in saline wetland soil. Further experiments should be conducted to screen optimal AM fungi isolates under field conditions and to evaluate the practical effects of AM fungi on the growth of reeds in wetland soils with different salt contents.

A new strain of high ammonia nitrogen tolerant and heterotrophic nitrification-aerobic denitrification bacterium TN-14 was isolated from the environment. Its physiological and biochemical characteristics and molecular identification, performences of heterotrophic nitrification-aerobic, the abilities of resistance to ammonia nitrogen as well as the decontamination abilities were studied, respectively. It was preliminary identified as Acinetobacter sp. according to its physiological and biochemical characteristics and molecular identification results. In heterotrophic nitrification system, the ammonia nitrogen and total nitrogen removal rate of the bacterial strain TN-14 could reach 97.13% and 93.53% within 24 h. In nitrates denitrification system, the nitrate concentration could decline from 94.24 mg · L(-1) to 39.32 mg · L(-1) within 24 h, where the removal rate was 58.28% and the denitrification rate was 2.28 mg · (L · h)(-1); In nitrite denitrification systems, the initial concentration of nitrite could be declined from 97.78 mg · L(-1) to 21.30 mg x L(-1), with a nitrite nitrogen removal rate of 78.22%, and a denitrification rate of 2.55 mg · (L· h)(-1). Meanwhile, strain TN-14 had the capability of flocculant production, and the flocculating rate could reach 94.74% when its fermentation liquid was used to treat 0.4% kaolin suspension. Strain TN-14 could grow at an ammonia nitrogen concentration as high as 1200 mg · L(-1). In the aspect of actual piggery wastewater treatment by strain TN-14, the removal rate of COD, ammonia nitrogen, TN and TP cloud reached 85.30%, 65.72%, 64.86% and 79.41%, respectively. Strain TN-14 has a good application prospect in biological treatment of real high- ammonia wastewater.

A greenhouse pot experiment was conducted to investigate the influence of arbuscular mycorrhizal (AM) fungi Glomus etunicatum (GE) and Glomus versiforme (GV) on the plant growth, nutrient uptake, C: N: P stoichiometric, uptake of heavy metals by maize (Zea mays L.) grown in three types of coal mine spoil banks. The aim was to provide a technical basis for the revegetation of coal mine spoil banks in grassland ecosystem. The results indicated that the symbiotic associations were successfully established between two isolates and maize grown in the three substrates, with an average mycorrhizal colonization rate ranging from 36% to 54%. The colonization of two AM fungi significantly increased the dry weight of maize grown in recent discharged and weathered coal mine spoils and GE increased those grown in weathered coal mine spoil. Inoculation with AM fungi promoted the uptake of N, P and K by maize to varying degrees. In addition, inoculation with GE and GV also decreased C: N: P ratios, supporting the growth rate hypothesis, and had significantly differences on concentrations of Cu, Fe, Mn and Zn in shoots and roots of maize. The results indicated that GE and GV had different mycorrhizal effects on maize in the three types of substrates. GV was more suitable for the revegetation of recent discharged coal mine spoil and weathered coal mine spoil, while GE was more suitable for the revegetation of spontaneous combusted coal mine spoil. The experiment demonstrates that AM fungi have a potential role for maize to enhance the ability to adapt the composite adversity of different types of coal mine spoil and play a positive role in the revegetation of different coal mine spoil banks. Further field experiments should be conducted to evaluate the practical effects of AM fungi on the vegetation restoration of different types of coal mine spoil under field conditions.

A greenhouse pot experiment was conducted to investigate the influence of arbuscular mycorrhizal (AM) fungi Glomus versiforme on the plant growth, nutrient uptake, C: N: P stoichiometric, uptake of heavy metals and rare earth elements by soybean (Glycine max) grown in rare earth mine tailings. The aim was to provide a basis for the revegetation of rare earth mine tailings. The results indicated that soybean had a high mycorrhizal colonization and symbiotic associations were successfully established with G. versiforme, with an average rate of approximately 67%. The colonization of G. versiforme significantly promoted the growth of soybean, increased P, K contents, and decreased C: N: P ratios, supporting the growth rate hypothesis. Inoculation with G. versiforme significantly decreased shoots and roots La, Ce, Pr and Nd concentrations of soybean compared to the control treatment. However, inoculation with G. versiforme had no significant effect on the heavy metal concentrations, except for significantly decreased shoot Fe and Cr concentrations and increased root Cd concentrations. The experiment demonstrates that AM fungi have a potential role for soybean to adapt the composite adversity of rare earth tailings and play a positive role in revegetation of rare earth mine tailings. Further studies on the role of AM fungi under natural conditions should be conducted.

The pollution status and distribution characteristic of rare earth elements in soil were analyzed around Bayan Obo mining area and Baotou tailing reservoir located in Inner Mongolia grassland ecosystem, aiming at grasping the overall situation of grassland ecosystem pollution caused by rare earth elements and providing basic information as well as theoretical basis. The results indicated that seven rare earth elements in soils from different directions of Baotou tailing reservoir accumulated to a certain extent compared to the soil background value of Inner Mongolia. The pollution degree was Ce > La > Nd > Pr > Sm > Y > Eu. Within 50 m from the edge of tailing reservoir, soil rare earth contamination was the most serious, with the concentrations of La, Ce, Pr, Nd, Sm, Eu and Y reaching 11,45.0 mg x kg(-1), 23,636.0 mg x kg(-1), 4568.16 mg x kg(-1) , 6855.51 mg x kg(-1), 582.18 mg x kg(-1), 94.21 mg x kg(-1)), and 136.25 mg x kg(-1), respectively. Owing to the dominant wind direction of northwest, soils from the southeast were contaminated most seriously. For Bayan Obo mining area, the concentrations of seven rare earth elements in soil from the mining area were significantly higher than those of other areas investigated, with the concentrations of La, Ce, Pr, Nd, Sm, Eu and Y reaching 3112.56 mg x kg(-1), 7142.12 mg x kg(-1), 1467.12 mg x kg(-1), 2552.80 mg x kg(-1), 210.80 mg x kg(-1), 36.20 mg x kg(-1) and 63.22 mg x kg(-1), respectively. The soils of six areas of Bayan Obo mining area were all contaminated by rare earth elements, and the contamination degree was in the order of mining area > outside the dump > east side of the railway > the dump > outside the urban area > west side of the railway. Besides, the transportation of rare earth ore led to the soil rare earth contamination along the railway, and the distribution characteristic of rare earth elements in soils along the railway was affected by the dominant wind direction of northwest. Baotou tailing reservoir and Bayan Obo mining area had the same contamination characteristic, and the concentrations of rare earth elements were in accordance with those in the tailings. The health and stabilization of local grassland ecosystem are being threatened by excessive soil rare earth elements.

Under intermittent aerated and continuous fed operation where the biofilm system was subjected to alternated anaerobic/aerobic condition, the effect of influent volatile fatty acids (VFAs) concentrations, operation cycle and backwash on the biological phosphorus removal performance of the biofilter was studied. In the experiment, synthetic domestic wastewater was used, and the influent velocity was 5 L x h(-1) with gas versus liquid ratio of 8:1 and hydraulic retention time (HRT) of 1.3 h, resulting in average COD, ammonium and phosphorus load of 4.7, 0.41 and 0.095 g x (L x d) (-1) respectively. Results show that, (1) effective release and uptake of phosphorus was achieved in a operation cycle; (2) when influent VFAs was 100 mg x L(-1) (calculated by COD value) and operation cycle was 6 h the filter performed best in phosphorus removal, the phosphorus loading removal rate can be as much as 0.059 g x (L x d)(-1) at the aerated phase with those of COD and ammonium being 3.8 g x (L x d)(-1) and 0.28 g x (L x d)(-1) respectively, and with average effluent phosphorus, COD and ammonium concentrations being 1.8, 43.6 and 8.7 mg x L(-1), which shows nitrogen loss also happened; (3) the pause of backwash decreased the phosphorus removal performance rapidly with the removal efficiency lower than 40% in two days, but the consequent daily backwash operation gave a short improvement on the phosphorus removal, which disappeared in another two days. Thus, it is shown that biological phosphorus removal achieved with better phosphorus loading removal performance in the biofilter under intermittent aerated and continuous fed operation, and that sufficient and stable influent VFAs concentration, proper operation cycle, and more frequent backwash favored the performance.

The USEPA 16 priority pollutant dominated polycyclic aromatic hydrocarbons (PAHs) in the surface river sediments of Sichuan Province and Chongqing City in southwest China were determined using GC-MS. The result showed the content of PAHs in the sediment ranged from 48.2 ng/g to 723.1 ng/g, with an average value of 276.1 ng/g. Among which, the maximum content was found in Shimenzi of Yangtze River, the minimum content was found in Baiqing of Fujiang River. The content order of PAHs in the sediments followed Yangtze River (358.6 ng/g) > Minjiang River (322.2 ng/g) > Tuojiang River (292.7 ng/g) > Qujiang River (260.6 ng/g) > Jialing River (240.2 ng/g) > Fujiang River (82.4 ng/g). The vertical profiles of c(An)/c(An + Phe), c(FlA)/c(FlA + Pyr) and c(InP)/c (InP + BghiP) suggested the PAHs in this zone were mainly originated from pyrogenic source, the main sources of PAHs were petroleum combustion, biomass combustion, and coal burning. Risk assessment suggested that the PAHs in the sediment of this zone had no significantly biological impairment and low toxicological risk.

In order to reconstruct the chronology of 2,2-his (4-Chlorophenyl)-1,1,1-trichloroethane (DDT) input into the Hongfeng reservoir and assess the pollution issues, the temporal distribution of DDT in sediment core from Hongfeng reservoir was measured using GC/MS method, and the possible sources and potential risk assessment also had been identified. The DDTs (sum of p,p'- and o,p'-DDT, DDE and DDD) in sediment core were ranged from 7.6 to 23.7 ng/g, and roughly, ever decreased from the bottom to the surface sediment. In detail, a sharp decline of DDTs concentration in sediment was found from 1981 to 1983, followed by a tardy decrease trend to the present. The DDTs in sediment were mainly composed of p,p'-DDTs (sum of p,p'-DDT, DDE and DDD). The ratio of p,p'-DDTs to o,p'-DDTs (sum of o,p'-DDT, DDE and DDD) ranged from 5.1 to 8.4, which suggests that the DDTs in sediment were chiefly originated from the technical DDT. Meanwhile, the DDTs in sediments were dominated by the metabolites of DDT (DDD and DDE) and the ratio of DDT/(DDD + DDE) were between 0.31 and 0.84, indicating the DDTs in sediment were mostly stemmed from the historical usage. Besides, the vertical profile of the ratios of DDT/( DDD + DDE) and DDE/DDD indicate that possible usage of technical DDT still occurred in the drainage area of Hongfeng reservoir around 1990, although the usage of technical DDT in agriculture has been banned in 1983. The residue levels of DDE, DDD, DDT, and DDTs in surface sediment from Hongfeng reservoir were all between ERL and ERM, suggesting potential risk could occur, and the contamination of DDT in Hongfeng reservoir deserving more concerns.

The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was measured in sediment core from Miyun reservoir, and the possible sources and the potential risk assessment also have been identified. The aim of the present work is to understand the temporal trend of PAHs in Miyun reservoir recently. The concentrations of sigma PAH16 in sediment ranged from 618.5 ng/g to 1087.9 ng/g, and roughly, increased continuously from the bottom (16 cm under the surface) to the surface sediment. The PAHs in sediment core were mainly composed of phenanthrene and fluorene. The concentrations of phenanthrene and fluorene in sediment core were 236.1-417.9 ng/g and 91-130.8 ng/g, respectively. Both of them accounted for 47.2%-58.1% of the sigma PAH16 in sediments. Nevertheless, high-rings aromatic hydrocarbons (5-6 rings) were increased steadily in recent years. PAHs compositional profile indicated that the main source of PAHs was originated from the combustion of coal and biomass. However, the vertical profiles of Flu/Flu + Pyr and INP/INP + BghiP ratios suggested that the vehicles emission was increased very recently. Risk assessment suggested that PAHs in sediment from Miyun reservoir was no significant biological impairment, and low toxicological risk of PAHs was found up to now.