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2022 Vol.42 Issue.2,Published 2022-02-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Ecology
Environmental Impact Assessment and Management
Carbon Emission Control
Advanced Wastewater Treatment Technology Column
Air Pollution Control
497 High aerosol and high ozone pollution and vertical distribution of extinction coefficients in Guangzhou during the dry season
TAO Li-ping, DENG Tao, WU Dui, WU Cheng, HE Guo-wen, ZHANG Xue, SONG Lang, OUYANG Shan-shan, SUN Jia-yin, LIANG Yue, TAN Jian, XIA Rui, ZHOU Zhen
Based on regular surface observation meteorological data, data of six kinds of air quality parameters, actinic radiation data, aerosol scattering and absorption coefficients, single scattering albedo, and aerosol extinction coefficient and depolarization ratio retrieved by lidar data from December 6, 2017 to January 3, 2018 in Guangzhou, this paper analyzed the influence of meteorological parameters variation on pollutant concentration and actinic radiation attenuation by aerosols, studied the formation mechanism of high aerosol and high ozone (double high) pollution, and explored the evolution of extinction coefficient profile in the vertical direction within the boundary layer on double high days. The actinic radiation attenuation on double high days is less than that on haze days during the study period. The scattering and absorption of aerosols has certain attenuation effect on actinic radiation. The scattering components of aerosols have positive feedback on actinic radiation, and the strong actinic radiation on double high days keeps O3 and PM2.5 concentration at a high level. Compared with non-double high days, double high days feature lower wind speed, higher temperature, stronger actinic radiation, higher PM2.5, CO, SO2, and NO2 concentration, higher fine particle ratio, and higher near-surface depolarization ratio during 11:00-16:00. Radar observation shows that the high value area of extinction coefficient is below 0.5km at 8:00 am on four double high days. The mean value area of extinction coefficient appears in the low layer and keeps rising. Actinic radiation flux abates in the afternoon, and its mean value area no longer develops upwards. Extinction coefficient above the mean value area gradually increases vertically as particulate pollution aggravates, and it peaks near the top of the boundary layer. At night, extinction coefficient reduces with the rise of height at the low altitude, increases with the rise of height within a certain altitude range, and decreases exponentially above 1km. The high value area near the top of the boundary layer is more obvious at night.
2022 Vol. 42 (2): 497-508 [Abstract] ( 318 ) [HTML 1KB] [ PDF 2750KB] ( 1605 )
509 Analysis of transportation path and potential sources of atmospheric particulate matter over Gansu Province in spring and winter—Based on HYSPLIT4model and TraPSA analysis platform
ZHANG Qian, PANG Ke, MA Cai-yun, CHENG Heng-rui, MA Ming-yue, KONG Xiang-ru, PAN Feng
The hour-by-hour 72-h air mass back-trajectories of five stations in Gansu province from 2017 to 2018 were calculated using the HYSPLIT4 model and the global data assimilation system. The trajectory clustering method was used to analyze the trajectory characteristics of the backward airflow in Gansu province by combining the time-to-time mass concentration data of particulate matter at each station in spring and winter when the particulate matter pollution was most severe. Based on the analysis method of potential source contribution function (PSCF) and the concentration weighted trajectory (CWT), the result of each station was weighted overlay analyzed using the TraPSA analysis platform, and the potential source areas and their contributions to the mass concentration of particulate matter over Gansu in spring and winter were discussed. The northwest path was the primary path affecting the Gansu province with its rapid movement, long transport distance and severe pollution level; the northeastern path was the next most important with Mongolia and Inner Mongolia being the main sources; southern Gansu was heavily influenced by short-range transportation from the southeastern path and the Qinghai-Tibet Plateau; the transportation distance and height of air mass over Gansu province was longer and higher in spring than in winter, and the mean PM2.5concentration and the ratio of PM2.5/PM10 were both higher in winter than in summer. The PSCF analysis over multi-sites found that the potential contribution source areas of PM10 in spring were mainly distributed in the eastern Xinjiang, Junggar Basin, northeastern Tarim Basin and northwestern Qinghai, with scattered distribution in southern Mongolia, northern Sichuan, northwestern and eastern Qinghai; while in winter it was mainly located in eastern Xinjiang and the Tarim Basin, northwestern and eastern Qinghai, and southern Shanxi; the source area in general shifted southwards in winter and the short-range transportation within the province intensified. The CWT analysis over multi-sites showed that the main contribution areas of PM10concentration in spring were located in the eastern Xinjiang, the Junggar Basin, with linear distribution in southern Mongolia and northern Inner Mongolia and scattered distribution in northern Qinghai and northern Gansu; in winter, it was mainly located in the eastern Xinjiang and northern Gansu; the main contribution area of PM10 was larger and more polluted in spring than in winter, but the short-range transportation and the degree of particulate matter pollution within the province were weakened.
2022 Vol. 42 (2): 509-518 [Abstract] ( 322 ) [HTML 1KB] [ PDF 2100KB] ( 973 )
519 Study on the concentration variation and impact factors of CH4 in Akedala atmospheric background station
ZHAO Zhu-jun, LU Zhong-qi, HE Qing, WANG Jian-lin
The observation data of CH4 concentrations and meteorological elements of Akedala station from 2009 to 2019 were used to analyze the CH4 concentration changes and influencing factors using random forest model and backward trajectory model with clustering analysis methods. The results showed that the CH4 concentrations at Akedala station increased significantly during the recent 10yaers with an annual average concentration of (1934.30±30.94)×10-9 and an average growth rate of 0.45%. The seasonal changes showed high CH4 in autumn and winter and low CH4 in spring and summer, with winter (1973.77±36.72)×10-9>autumn (1935.86±36.14)×10-9>spring (1922.36±26.38)×10-9>summer (1920.92±29.82)×10-9. The CH4 concentration change at Akedala station is influenced by a combination of meteorological factors, with air temperature and relative humidity playing the dominant roles. Backward trajectory clustering analysis based on HYSPLIT model driven by GDAS meteorological data reveals that air mass movement to Akedala station is mostly along the northwestern path paralleling to the Valley of Erchez River, and passing through Alashankou and Old Wind Pass. In addition, the low movement speed in autumn and winter as well as its high speed in spring and summer could affect the seasonal variation of CH4 concentrations.
2022 Vol. 42 (2): 519-527 [Abstract] ( 318 ) [HTML 1KB] [ PDF 719KB] ( 1908 )
528 Spatial differentiation and driving factors of aerosol optical depth in Sichuan Basin from 2003 to 2018
WANG An-yi, KANG Ping, ZHANG Yang, ZENG Sheng-lan, ZHANG Xiao-ling, SHI Juan, LIU Zhi-hong, XIANG Wei-guo, WANG Ke-ke, ZHANG Song-yu, LU Jun-cen
In order to reveal the spatial distribution of aerosol optical depth (AOD) in Sichuan Basin and quantitatively evaluate the driving factors that affect its temporal and spatial differentiation, the geostatistical methods such as Mann-Kendall mutation test, spatial auto-correlation, spatial hot spot detection and geographical detector were used to analyze the data of MODIS aerosol products from 2003 to 2018. There was an overall decreased trend of AOD in Sichuan Basin from 2003 to 2018, and the mutation year was 2015. According to the variation trend, the 16years could be divided into six periods. The characteristics of aerosol regional pollution in Sichuan Basin were obvious. AOD high value areas were mainly concentrated in the middle of the basin, while AOD low value areas were mainly concentrated in the edge of the basin. A significant annual clustering pattern (spatial positive auto-correlation, Moran's I was greater than 0) of the distribution of AOD was showed in Sichuan Basin. The area of the high-high clustering areas had been decreased since 2012, and the variation of the annual clustering areas was consistent with the variation trend of AOD value in different periods. Eight factors were optimized by principal component analysis for geographic detector analysis. And the results showed that the spatial and temporal differentiation of AOD in the basin in the past 16years was mainly caused by the unbalanced development level of urbanization and industrialization. From 2014 to 2015, the driving force of all driving factors decreased 11.2%~59.2% compared with the previous period, which was consistent well with the conclusion that 2015 was a mutation year.
2022 Vol. 42 (2): 528-538 [Abstract] ( 277 ) [HTML 1KB] [ PDF 3980KB] ( 1282 )
539 The impacts of convection on aerosols scavenging and regeneration processes
WEI Shao-han, HU Rong, LI Gu-dong-ze, TANG Xian-bing, XU Wen-hui, CHEN Qian
A squall line occurred during April 23~24, 2007 over Guangdong province, China has been simulated by using the Weather Research and Forecasting (WRF) model in order to investigate the impaction scavenging of aerosol particles by hydrometeors, aerosol regeneration due to complete evaporation of liquid drops, and effects of dynamical transport on the number concentration of aerosols. The results showed that there was a negative correlation between the precipitation and aerosol concentration near surface. By comparing the impaction scavenging rates by different types of hydrometeors and nucleation scavenging rates, it showed that droplet nucleation contributed most to the aerosol scavenging, followed by the impaction scavenging by rain drops at the lower troposphere and snow at the upper troposphere. Droplet nucleation scavenging and ice crystal nucleation scavenging were the dominant scavenging processes for hygroscopic and non-hygroscopic particles respectively. The variation of aerosol number concentration was the result of combined effects of cloud dynamical transport, wet scavenging and regeneration process due to the evaporation of liquid drops. The regeneration process mainly occurred from the surface to the 10km altitude. During the development of convection, the aerosol concentration near surface was significantly reduced whereas the heavy pollution area appeared around the non-precipitation area near the gust front due to the dynamical transport. At the upper troposphere, the number concentration of hygroscopic particles was reduced while that of non-hygroscopic particles was increased.
2022 Vol. 42 (2): 539-549 [Abstract] ( 232 ) [HTML 1KB] [ PDF 2522KB] ( 856 )
550 Study on the transport correlation method of PM2.5 at urban scale—taking Beijing as an example
YIN Hao, HU Dong-mei, YAN Yu-long, PENG Lin, WANG Kai, ZHANG Ke-ke, DENG Meng-jie
Based on data driven, internal environment in city air quality monitoring sites as the research object, multiple linear correlation regression models were established for PM2.5 concentration, wind direction, wind speed, Euclidean distance and other parameters between target stations and surrounding stations. The weight coefficients of each parameter were obtained by gradient descent algorithm, the PM2.5 transmission contribution of surrounding stations to target stations was calculated and the feasibility of the model was evaluated. Taken Feng Tai Garden (FT) in Beijing as the target site, the results showed that the PM2.5 concentration of FT site in 2016 was 82μg/m3, Da Xing (DX), Fang Shan (FS), Yi Zhuang (YZ), Dong Sihuan (DS), Gu Cheng (GC) and Wan Liu (WL) sites were 93, 82, 80, 79, 77和71μg/m3. The correlation between PM2.5 concentration of FT station and WL, GC, DX and YZ of surrounding stations at the last moment was 0.634, 0.631, 0.608 and 0.601, respectively, which indicates the significantly transmitted PM2.5 pollution to FT station. RMSE values of the four seasonal correlation regression models were 13.22, 11.74, 12.51 and 13.22, respectively. The variation trend of PM2.5 simulated concentration was consistent with that of the monitored concentration, which verified the feasibility of the model. WL, DX, YZ and GC were the stations that contribute more to PM2.5 pollution transmission of FT station in spring, summer, autumn and winter respectively, and their contribution values were 1.61%, 1.71%, 2.20% and 8.57%, respectively. The model results can provide a basis for the future urban planning and construction of Beijing. The proposed multiple linear correlation regression method of PM2.5 transmission can also be used to analyze the PM2.5 transmission correlation of other urban scales, providing a basis for the mining of PM2.5 transmission path and accurate traceability within the city.
2022 Vol. 42 (2): 550-556 [Abstract] ( 233 ) [HTML 1KB] [ PDF 2093KB] ( 1090 )
557 Analysis of PM2.5 pollution transportation path in winter in Southeast Shanxi Province
PEI Kun-ning, GAO Xing-ai, WANG Shu-min, YAN Shi-ming, WANG Yan
Based on the hourly concentration data of PM2.5 and surface wind field data in winter of Jincheng and Changzhi from 2017 to 2019, combined with HYSPLIT trajectory model and mesoscale numerical model WRFV4.2, the characteristics and transmission characteristics of PM2.5 pollution in winter in Southeast Shanxi were analyzed. The results showed that the pollution degree of PM2.5 in Jincheng in winter was higher than that in Changzhi. Affected by the terrain, southerly wind, northerly wind and northwest wind prevail on the ground in Jincheng, and the pollution direction was mainly southerly wind and northerly wind; The southerly wind prevails near the ground in Changzhi, and this wind direction had the highest frequency of pollution. The potential pollution source areas affecting Jincheng and Changzhi were mainly distributed in the west, northeast and southeast. The westward airflow came from central Shaanxi Province, the northeast airflow came from southwestern Hebei Province, and the southeast airflow came from central and eastern Henan Province. Pollution passing through the southeastern part of Shanxi mainly affected the central and southern parts of Shanxi Province and the southern part of Beijing. Through the numerical simulation of flow field, combined with the analysis results of potential source area and influence area, under the weather situation behind the pressure equalizing field or high pressure, the pollution transport path in the southeast of Shanxi included:Airflow from the Northeast (southwest of Hebei Province), transporting pollutants along the Fukou Xing in the northeast of Changzhi to the southeast of Shanxi, and the same northeast air flow continued southward along the eastern foot of the Taihang Mountain and then turned to the Taihang Xing at the junction of Shanxi and Henan to transport pollutants to the southeast of Shanxi; Airflow from the southeast (northern and east of Henan) transported pollutants; And airflow from the west (central and southern Shaanxi) transported pollutants. The pollutants were transported northward to the central and southern Shanxi Province through the southeast of Shanxi Province, and some were transported to the south of Beijing through Jingxing in the Middle East of Shanxi Province.
2022 Vol. 42 (2): 557-567 [Abstract] ( 221 ) [HTML 1KB] [ PDF 10535KB] ( 846 )
568 Emissions of biogenic volatile organic compounds (BVOCs) from fargesia nanlingensi in Nanling mountains, southern China
LIU Yun-feng, GONG Dao-cheng, LIN You-jin, WANG Hao, WANG Yu-jin, LI Qin-qin, DENG Shuo, XU Qiao, LIU Shi-wei, ZHOU Zhi-ping, ZENG Qing-tuan, WANG Bo-guang
In this study, we obtained the emission characteristics and emission rates of 20 biogenic volatile organic compounds (BVOCs) of fargesia nanlingensi from September to November 2018, by using a dynamic headspace sampling and thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) analysing technique. The results showed that isoprene was the dominant BVOCs emitted from fargesia nanlingensi, its emission rate ((1.36 ±0.99)×104 μgC/(m2×h)) was significantly higher than those of monoterpenes ((32.59 ±35.39) μgC/(m2×h)), sesquiterpenes ((2.62 ±2.91) μgC/(m2×h)) and other BVOCs. Compared with other bamboo species in Asia, the isoprene emission rate of fargesia nanlingensi was at an upper-middle level. There was an obvious diurnal variation of the BVOCs emitted from fargesia nanlingensi. The BVOCs emission rates gradually rose after sunrise, peaked at 12:00 to 13:00, and then started falling. In addition, the emission rates of isoprene had significant positive correlations with temperature and weak correlations with light.
2022 Vol. 42 (2): 568-574 [Abstract] ( 249 ) [HTML 1KB] [ PDF 554KB] ( 1395 )
575 A new particle source apportionment method based on single particle mass spectrometry dataset
XU Jiao, ZHANG Deng-yi, ZHANG Ying-lei, FENG Yin-chang
As an important online source apportionment method, apportioning particle matter (PM) sources using single particle mass spectrometry (SPAMS) can't obtain the source contributions based on mass concentration. To solve this problem, a new online source apportionment method ArtPMF is proposed in this work. PM were collected and analyzed by SPAMS from February to March 2021 in an industrial city in Huaihe plain. The ArtPMF model was employed on the SPAMS dataset to quantify the source contributions to PM2.5. During the observational period, PM2.5 was contributed by secondary source, industrial source, vehicle exhaust source, coal combustion, crustal dust, biomass burning, and firework source, with contributions of 23%, 22%, 20%, 12%, 10%, 6%, and 6% respectively. The directional distributions of coal combustion, biomass burning, firework source, industrial source and vehicle exhaust source contribution are consistent with the actual situation of industrial enterprises and functional zoning, conforming that the ArtPMF can provide reliable source apportionment supporting for pollution control.
2022 Vol. 42 (2): 575-584 [Abstract] ( 257 ) [HTML 1KB] [ PDF 1413KB] ( 1933 )
585 Fine source tracing of typical VOCs pollution episodes around industrial park
WANG Dong-fang
A chemical industrial park in Shanghai was selected as the target area. Aiming at the typical process of atmospheric VOCs pollution, sources of small-scale atmospheric VOCs were traced by coupling high-time resolution GC-MS measurement, Lagrange atmospheric dispersion model, VOCs source profiles and similarity analysis. The Lagrange atmospheric dispersion model can track the direction of the main air masses and the potential contribution of the enterprise with a spatial resolution of 110m×110m; Based on the similarity analysis between the receptor and source profiles, the potential sources can be furtherly identified. The cosine similarity coefficient of high similarity enterprises can reach more than 0.8 (maximum of 1), indicating high accuracy and credibility of the source apportionment results.
2022 Vol. 42 (2): 585-592 [Abstract] ( 495 ) [HTML 1KB] [ PDF 1267KB] ( 8388 )
593 Influence of end-of-pipe treatment on VOCs emission in industrial coating industries
WANG Rui-peng, WANG Xiao-qi, CHENG Shui-yuan, CHENG Long, CAI Bin, SHEN Ze-ya
VOCs samples from workshops and outlets were collected from four types of typical industrial coating industries in Hebei Province, 102 VOCs species were detected and analyzed, and the VOCs emission characteristics of workshops and outlets in four industries were obtained. The results showed that VOCs emission concentrations vary greatly among different industries due to the influence of type of coating, usage amount and other factors. Aromatics and oxygenated VOCs were the main components in furniture manufacturing, vehicle manufacturing and special equipment manufacturing industries, accounting for 14.7%~88.3% and 10.1%~64.7%, respectively. The proportion of halo-hydrocarbons in metal products industry was 59.2%~86.9%. The end-of-pipe treatment had the greatest effect on aromatics, and the proportions of toluene, ethylbenzene, xylene, trimethylbenzene, butyl acetate and 2-butanone at the outlets were significantly lower than that in the workshops. The contributions of aromatics to ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAP) were the highest, and the end-of-pipe treatment had a significant reduction effect on OFP, SOAP and source reactivity (SR). The differences in the SR of various sources were obvious, and it is suggested to strengthen the control of industries with high SR value.
2022 Vol. 42 (2): 593-600 [Abstract] ( 268 ) [HTML 1KB] [ PDF 605KB] ( 1209 )
Water Pollution Control
601 Start-up of endogenous partial denitrification and performance of EPD-ANAMMOX coupling process
ZHANG Xiao-ling, ZHANG Meng, CHEN Zi-wei, ZHANG Zhuo
This study was designed to evaluate performances of the start-up of endogenous partial denitrification and EPD-ANAMMOX process. The glycogen accumulation bacteria (GAO) were enriched in the anaerobic/aerobic sequence batch reactor (SBR) using the activated sludge as inoculum sludge and the acetate acted as carbon source by regulating the influent COD/P ratio as 150:1. Then, the GAOs were induced into denitrifying glycogen accumulation bacteria (DGAO) by means of gradually boosting the concentration of added nitrate at the end of anaerobic phase in SBR. Correspondingly, the level of chemical oxygen demand (COD) at the end of anoxic period was almost the same as that at the distal end of anaerobic stage, the total nitrogen removal efficiency and the average COD removal efficiency were over 98% and 86.74% at the end of anaerobic period of SBR, respectively. Furthermore, the endogenous partial denitrification system was successfully formed by shortening the anaerobic and anoxic time, the ratio of nitrite translated from nitrate (NTR) at the end of anoxic period was up to 65.96%. The average total nitrogen and COD removal load in the 30days operation of the coupled process were 0.222kgN/(m3×d) and 0.337kgCOD/(kgMLVSS.d) with an efficiency of 86.12% and 87.21%, respectively. Typically, the effluent NO3--N concentration was lower than 4.2mg/L and both NO2--N and NH4+-N levels were near to 0mg/L in the same phase. Compared with inoculated sludge, the relative abundance of competibacter increased from 0.001% to 25.06% in the sludge of EPD-SBR during the stable operation period, and the total abundance of Defluviicoccus, Contendobacter, Sphingobium,and Amaricoccus increased from 0.14% to 0.431%, implying that the competibacter was the dominated functional bacteria for the endogenous partial denitrification system.
2022 Vol. 42 (2): 601-611 [Abstract] ( 338 ) [HTML 0KB] [ PDF 919KB] ( 1546 )
612 pH coupling model of denitrifying anaerobic methane oxidation (DAMO) system
LU Jiao, LOU Ju-qing, XU Fan
This study tried to couple the pH value with the reaction kinetics of the denitrification-type methane anaerobic oxidation process. The Denitrifying Anaerobic Methane Oxidation (DAMO) reaction rate and pH value were coupled and evaluated in three reactors with different dominant bacteria. The results show that the Anammox-DAMO maximum denitrification rate and the initial inhibition concentration of nitrate ammonium at 25℃ were 3.95mg/(L×d), 182.63mg/L and 196.40mg/L, respectively. The maximum denitrification rate and the initial inhibition concentration of nitrate in Nitrate-DAMO system were 4.30mg/(L×d) and 367.69mg/L, respectively. The maximum denitrification rate and the initial inhibition concentration of nitrite in Nitrite-DAMO system were 4.04mg/(L×d) and 293.35mg/L, respectively. The denitrification rate of the systems increased first and then decreased with the increase of pH. The optimum pH was 7.5±0.2, 7.2±0.2, 7.8±0.2, respectively. The bacterial growth rate, nitrate affinity constant and inhibition constant of Nitrate-DAMO system were 1291.21cfu/(L×d), 295.23mg/L and 72.63mg/L, respectively; The bacterial growth rate, nitrite affinity constant and inhibition constant of Nitrite-DAMO system were 4040.42cfu/(L×d), 264.51mg/L and 5.02mg/L, respectively. All the three DAMO systems could be described by the coupled Haldane pH model; the denitrification process of Nitrate-DAMO system and Nitrite-DAMO system could also be described by Monod-pH coupling equation.
2022 Vol. 42 (2): 612-619 [Abstract] ( 218 ) [HTML 0KB] [ PDF 1113KB] ( 2447 )
620 Effect of influent C/N rations on nitrite accumulation and microbial community in the partial denitrification process
ZHANG Miao, ZHU Chen-jie, FAN Ya-jun, LV Xiao-fan, JI Jun-jie, GE Li-ying, WU Jun
Using the anoxic/aerobic intermittent operation mode, the influence of influent C/N ratios (C/N=5.0, 3.3, 2.5, 2.0) on nitrite (NO2-) accumulation and pollutant degradation in partial denitrification process was investigated, and the microbial diversity and functional bacteria evolution were explored with high-throughput sequencing. At the C/N ratio of 2.5, the system achieved the best treatment performance, and the effluent NO2- concentration was 27.18mg/L with the nitrite transformation ratio (NTR) of 67.96%. The analysis of the degradation rules of each pollutant in typical cycle revealed that the degradation rate of COD directly affected the process of denitrification and the stable NO2- accumulation can only be maintained under the condition of lower C/N ratios (C/N=2.0~2.5), although NO2-accumulation peaked at 30min of anoxic stage in all the four operations with the highest NO2- values of 4.86(C/N=5.0), 16.52(C/N=3.3), 30.16(C/N=2.5), and 20.28 (C/N=2.0) mg/L, respectively. High-throughput sequencing results showed that in addition to traditional functional bacteria of Thauera(2.67%~24.04%), Terrimonas(4.94%~21.19%) and Saprospiraceae(5.34%~13.50%), Flavobacterium(28.23%) was the dominant bacteria that maintained high NO2- accumulation when the C/N ratio was 2.5. Combined with the operational characteristics of partial denitrification process, the application feasibility of related coupling processes with NO2-as intermediate product was discussed.
2022 Vol. 42 (2): 620-628 [Abstract] ( 265 ) [HTML 0KB] [ PDF 810KB] ( 1105 )
629 Intermittent aeration-internal circulation biological filter performance and biofilm characteristics
REN Wu-ang, CAO Feng-feng, JU Kai, JIN Peng-kang, LI Si-min, CHAI Bei-bei, LEI Xiao-hui
The mechanism of enhanced denitrification by intermittent aeration-coupled internal circulation biofiltration is still not clear. We therefore investigated the pollutant removal in a biofiltration reactor. Several methods were used to analyze the biomass, biological activity, and nitrification and denitrification rates of the system, and the microbial population in the reactor was analyzed. The intensity of protein-like fluorescence gradually decreased throughout the system, and no protein-like peak was detected in the effluent. The decrease of NH4+-N along the 10-50cm section of the reactor did not cause a significant increase in NO3--N, and the NO3--N content decreased at 50cm. This section showed obvious denitrification. The dissolved oxygen and biomass levels throughout the system indicated an anoxic/anaerobic environment and significant denitrification. In addition, the low oxygen uptake rate (OUR) but high TTC-dehydrogenase activity at 50cm and the significantly higher denitrification rate compared to the nitrification rate indicated enhanced denitrification in this region. Based on 16S rRNA high-throughput sequencing analysis, the system had a higher abundance of microorganisms involved in denitrification at the phylum level, mainly Firmicutes (10.64%) and Bacteroidetes (22.29%). Denitrification was also evident at the genus level in Comamonas (3.11%) and Hydrogenophaga (2.43%). Our results suggest that the BAF system with intermittent aeration coupled with internal circulation enhanced denitrification in the bottom zone and thus improved the denitrification efficiency.
2022 Vol. 42 (2): 629-636 [Abstract] ( 289 ) [HTML 0KB] [ PDF 1545KB] ( 1459 )
637 Simultaneous removal of domestic wastewater and nitrate wastewater by three-stage anammox system
HAN Ke-xin, ZHANG Qiong, FENG Yan, LI Xi-yao, PENG Yong-zhen
To further utilize carbon source, endogenous denitrification reactor (ED-SBR)、partial nitrification reactor (PN-SBR) and anammox reactor (AMX-UASB) were used to treat low C/N domestic wastewater and industrial wastewater rich in nitrate. The feasibility of simultaneous denitrification of domestic wastewater and nitrate wastewater was discussed. 77.5% of the organic matter in the influent could be converted into internal carbon source in the ED-SBR anaerobic stage, and endogenous denitrification was carried out in the anoxic stage. The average NO3--N concentration in the effluent was 3.4mg/L, reaching an average removal rate of 90.4%; PN-SBR can achieve stable half shortcut nitrification under low do (0.1~0.3mg/L), Nitrite Accumulation Ratio (NAR) is 96.3%, and the ratio of NO2--N/NH4+-N in effluent is about 1.01, which can provide stable substrate for anammox; AMX-UASB reduces NH4+-N and NO2--N in influent is converted to N2 and NO3--N. The average effluent of NO3--N was 7.12mg/L. The average TIN concentration of inlet and outlet water was 77.5 and 8.2mg/L respectively, and the average TIN removal rate was 89.2%. In order to couple domestic sewage with high NO3--N content, providing an effective way to remove nitrogen from wastewater simultaneously.
2022 Vol. 42 (2): 637-643 [Abstract] ( 204 ) [HTML 0KB] [ PDF 636KB] ( 1233 )
644 Cost-benefit analysis of different non-membrane based technologies for the treatment of bio-stabilized leachate
LIU Wan-ying, Lü Fan, QIU Jun-jie, HUANG Yü-long, ZHANG Hua, SHAO Li-ming, HE Pin-jing
In this paper, four non-membrane based techniques, including activated carbon adsorption, coagulation, Fenton and electrolysis, were applied to treat the anaerobic-aerobic stabilized leachate. The respective water quality parameters, such as dissolved organic carbon (DOC), chemical oxygen demand (COD), dissolved nitrogen (DN) and specific ultraviolet absorbance at 254nm (SUV254), were determined for comparison. Cost change curve of removing unit COD was also depicted. When activated carbon adsorption, Fenton and coagulation were employed, the removal efficiencies of COD, DOC and DN increased with enhancing the dosages of agents. Fenton and electrolysis as chemical oxidation techniques shows superior performance on the removal of aromatized organics, resulting in 60%~70% reduction of SUV254. In addition, the removal efficiency linearly increased with the current density. For every unit of COD removal, the cost for applying activated carbon adsorption is highest among all the tested techniques while the expense of Fenton will be minimal. To make these techniques economical, it is recommended that 5g/L of activated carbon, 0.605g/L of Fenton reagent and 4.92mmol/L Fe of coagulant were used for each process. When applied in practical application, it is worth noting that the actual dosage need be optimized on basis of the properties of on-site leachate and the local discharge standards.
2022 Vol. 42 (2): 644-653 [Abstract] ( 217 ) [HTML 0KB] [ PDF 825KB] ( 1145 )
654 The degradation mechanism study of 17α-ethinylestradiol by TiO2 nanobelt/pg-C3N4 photocatalyst under visible light irradiation
LUO Li-jun, MENG De-mei, DAI Jian-hui, LI Jun-Hong, ZHENG Li-bo, XIA Li-hong, JIANG Feng-zhi
TiO2-NB/pg-C3N4 photocatalysts were prepared using prepared porous C3N4 nanosheets and TiO2 nanobelts via grinding and followed calcination, and the preparation conditions were optimized. The prepared materials were used to remove 17α-ethynylestradiol(EE2) under visible light irradiation, which has most potent estrogenic activity. The structure and surface physical-chemical properties of them were comprehensively investigated by scanning electron microscope (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption isotherms (BET). The results showed that the B-type TiO2 nanobelts were anchored onto porous C3N4 nanosheets to form TiO2-NB/pg-C3N4 composite photocatalyst. The degradation rate constants of EE2 on TiO2-NB/pg-C3N4 (0.02537min-1) was 12.88 times and 3.29 times than those on pure TiO2-NB(0.00197min-1) and pg-C3N4(0.0077min-1). Active species capture experiments showed that ·O2- was the main active specie in the EE2 degradation process on TiO2-NB/pg-C3N4. The HPLC-high resolution mass spectrum (HPLC-HRMS) measurement results showed that there were 4 intermediates and possible degradation route was proposed. Moreover, the estrogenic activity measurement by MCF-7method during degradation process showed that TiO2-NB/pg-C3N4 can effectively eliminate the estrogenic activity without producing by-products with more estrogenic activity.
2022 Vol. 42 (2): 654-664 [Abstract] ( 256 ) [HTML 0KB] [ PDF 2201KB] ( 1444 )
665 Effects of solution characteristics and coexisted substances on the removal of perfluorooctanoic acid from water by nanofiltration membrane
WANG Jia-xuan, HU Yu-ning, YUE Xiang-lei, WANG Lei, LIU Zhe
Polyamide composite nanofiltration (NF) membrane was used to remove persistent organic pollutant-perfluorooctanoate acid (PFOA) from water. This research investigated the influence of PFOA concentration, ionic strength, pH value, typical macromolecular organic matter-bovine serum albumin (BSA), and the coexistence of BSA and Na+ in feed solution on PFOA rejection, respectively. The filtration experiments were conducted at an operating pressure of 0.8MPa for 24h. Results showed that the retention of PFOA increased with increasing PFOA concentration. The higher the ionic strength or pH of the feed solution, the higher the rejection rate of PFOA was. When BSA presented in PFOA feed solution, BSA could not only block some membrane pores, but also form an organic fouling layer on the membrane surface which increased the negative charge of the membrane surface. Thus, both size exclusion and electrostatic repulsion abilities of the NF membrane were enhanced. When BSA coexisted with Na+ in the feed water, the pore blocking degree of the NF membrane was more serious. The presence of Na+ made the organic fouling layer much thicker. Therefore, the sieving capacity of the NF membrane was enhanced.
2022 Vol. 42 (2): 665-671 [Abstract] ( 305 ) [HTML 0KB] [ PDF 629KB] ( 1115 )
672 Ammonia nitrogen prediction in surface water based on bidirectional gated recurrent unit
REN Yong-qin, KIM Ju-song, YU Jin-won, WANG Xiao-li, Peng Shi-tao
For more accurate prediction of NH4+-N, this paper proposes a novel hybrid forecast model (CCB) that uses complementary complete ensemble empirical mode decomposition with adaptive noise (CCEEMDAN) and bidirectional gated recurrent unit (BiGRU) neural network. Firstly, the original NH4+-N data is decomposed into several relatively simple components by CCEEMDAN. Subsequently, BiGRU neural network is employed to predict each component. The final forecast result is obtained by the summation of all the prediction results for the decomposed components. NH4+-N data of Poyang Lake that was monitored from June, 2017 to February, 2020 is used to evaluate the proposed forecast model. Mean absolute percentage error (MAPE) of the forecast result by our model is 3.38% for 1day ahead forecast, 6.82% for 7days ahead forecast and 9.41% for 15days ahead forecast. Moreover, CCB model shows better forecast performance than the competitor models. Results demonstrate that CCB model has a powerful forecast capacity, and it can be effectively used for the analysis and decision-making in water resource management.
2022 Vol. 42 (2): 672-679 [Abstract] ( 205 ) [HTML 0KB] [ PDF 1346KB] ( 855 )
680 Leaching properties of phosphorus and fluorine in hemihydrate phosphogypsum as underground filiing materials and geochemical simulation
ZHU Xue-tao, DU Bing, A Man-jiao, KANG Ti, CHEN Deng-mei, SHI Jian-hua, LIU Jian-guo
The HPG as backfill material was selected as the research subject. The leaching characteristics and long-term release of phosphorus and fluorine in four kinds of HPG and HPGB cemented paste filling materials were evaluated by pH-dependent and semi-dynamic leaching tests under simulated groundwater leaching conditions. The controlling mechanisms of phosphorus and fluorine leaching characteristics was discussed by geochemical simulation analysis. The results showed that 99.97% soluble phosphorus and 95.92% fluoride were solidified as Ca3(PO4)2 and CaF2 in HPGB which was modified by quicklime. According to the pH-dependent leaching test, the leaching concentration of total phosphorus had no significant relationship with pH under neutral and alkaline conditions. The geochemical simulation results of the semi-dynamic leaching test indicated the controlling phase of phosphorus in HPGB is fluoroapatite. The major controlling phase of fluorine leaching was fluorite and fluoroapatite, and the proportion of fluorite controlling phase decreased from 95% to 90% after long term leaching test.
2022 Vol. 42 (2): 680-687 [Abstract] ( 295 ) [HTML 0KB] [ PDF 639KB] ( 1282 )
688 Groundwater pollution and health risks under exemption of cyanide residue disposal scenarios
NAI Chang-xin, QIU Pan-pan, XU Ya, LAI Kai-lun, CHANG Jing-run
Exempted disposal is a means to dispose of hazardous waste using non-hazardous waste disposal facilities under risk-controlled conditions, which is of great significance to enhance the national hazardous waste hierarchical classification management and precise pollution control capability, but quantitative risk assessment studies under exempted disposal conditions are still scarce. In this paper, nine general industrial solid waste landfills (NISWL) in North China were selected as typical hazardous waste-cyanide slag as an example, and the groundwater contamination characteristics and health risks of cyanide slag under the exempted disposal conditions of NISWL were predicted by systematic sampling, leaching characteristics analysis and process model simulation. The results showed that, except for NISWL A and NISWL B, the exposure concentrations of the other seven NISWLs due to the aging and long-term leakage of landfill materials exceeded the groundwater Class III water quality limits by 0.64~29 times, and the health risks were mainly due to the carcinogenic risk of As and non-carcinogenic risk of T-CN, which exceeded the acceptable risk levels by 31~270 times and 17.2~305.5 times, respectively. The health risks mainly came from the carcinogenic hazards of As and non-carcinogenic hazards of T-CN, which exceeded the acceptable risk level by 31~270 and 17.2~305.5 times respectively. The main reason is that cyanide in cyanide residue degrades slowly, resulting in higher residual toxicity, higher leaching concentration, and higher health risk due to serious contamination of HDPE film after deterioration and leakage.The study of admission leaching toxicity control based on risk control shows that there are differences in the control limits of T-CN admission concentration of different NISWLs, which are distributed between 1.15~3.25mg/L, and all of them are strictly higher than the limit (5mg/L) specified in the Technical Specification for Cyanide Residue Pollution Control in Gold Industry (HJ 943-2018). The above research results suggest that (1) admission leaching concentration limits should be set considering the long-term risk caused by the aging of landfill engineering materials, and more stringent admission concentration control limits should be set. (2) The size of the risk is affected by the scale of the site, regional meteorology, hydrology and geology, so the entry leaching concentration control limit should also take into account the above-mentioned differences and determine the zoning classification.
2022 Vol. 42 (2): 688-696 [Abstract] ( 232 ) [HTML 0KB] [ PDF 634KB] ( 1543 )
Advanced Wastewater Treatment Technology Column
697 Removing of COD and NH3-N from blue-coke wastewater by electrochemical oxidation
LI Jin-cheng, SONG Yong-hui, TANG Jie-li
Electro-chlorination and oxidation method was applied to treat the high concentration harmful components in blue-coke wastewater. The influence of dosage of sodium chloride bearing, external voltage, and initial pH on removal efficiency of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) were investigated, the processing and pollutant oxidation mechanism of electrochemical oxidation were systematical analyzed. The results indicated that the removal efficiency of COD and NH3-N both increased with the increasing of the addition of dosage of sodium chloride, applied voltage, and electrolysis time. Under the processing condition of sodium chloride 60g/L, voltage 6V, electrode distance 10mm, initial pH 9, and 3h electrolysis time, the COD and NH3-N removal efficiency reached 84.31% and 95.77% respectively, which extremely exceeded the removal efficiency 41.18% and 34.10% without NaCl as the electrolyte. The degradation of COD and NH3-N mainly depended on indirect oxidation of anode, the chlorine gas produced on the anode would occur hydrolysis reaction to produce active chlorine such as ClO- in the solution. During electrolysis, most of ammonia nitrogen were converted to N2at the action of ClO-, and a small part existed in form of the compounds of containing nitrogen in the bulk solution. The major organic pollutants, phenolic substances in blue-coke wastewater decreased greatly after treatment, part of them could be converted into ethers or alkanes.
2022 Vol. 42 (2): 697-705 [Abstract] ( 204 ) [HTML 0KB] [ PDF 508KB] ( 2389 )
706 Degradation of organic pollutants by modified titanium based PbO2 electrode: Taking methyl orange and 4-nitrophenol as examples
YUE Wen-qing, NI Yue, SUN Ze-peng, LIU Fen-wu, BI Wen-long, CHEN Zi-ming, WEI Yi-wen
Ti/SnO2-Sb/Ce-PbO2 electrode was prepared by sol-gel method and electrochemical deposition method. The surface morphology, crystal structure and electrochemical performance of the prepared electrode were analysed, and the degradation effect of the electrode on methyl orange and 4-nitrophenol was further investigated. The results showed that the Ti/SnO2-Sb/Ce-PbO2 electrode has a more stable structure, has a better electrochemical activity compared with other electrodes, and that its oxygen evolution potential can reach 1.56V. The optimal operating conditions were set at an interelectrode spacing of 2cm, at a current density of 30mA/cm2, at a concentration of the target pollutant of 100mg/L, and at an electrolyte concentration of 0.10mol/L. As electrolysis time reached 120min with the Ti/SnO2-Sb/Ce-PbO2 electrode, the removal efficiency of methyl orange and 4-nitrophenol reached 99.59% and 96.16%, respectively. After 180min of degradation, the TOC removal efficiency reached 56.71% and 54.87%, respectively. The results provide a technical support for the Ti/SnO2-Sb/Ce-PbO2 electrode to degrade organic pollutants.
2022 Vol. 42 (2): 706-716 [Abstract] ( 239 ) [HTML 0KB] [ PDF 1354KB] ( 1139 )
717 Simultaneous removal of norfloxacin and Pb(II) via Fe3O4-activated persulfate oxidation
SU Bing-qin, LIU Yi-qing, LIN Yu-ting, WANG Jian, QUAN Xiao-hui, LI Rui, RUI Chuang-xue
This study employed the advanced oxidation process of persulfate, activated with Fe3O4 magnetic nanoparticles (Fe3O4/PS), for simultaneous removal of NOR (norfloxacin) and Pb(II) in wastewater. The effects of Fe3O4 dosage, PS concentration, initial pH value and Pb(II) concentration on the degradation of NOR were investigated. Experimental results indicated that the degradation of NOR followed the pseudo-first-order kinetics. The degradation of NOR and the removal of Pb(II) reached to 90.2% and 99.5%, respectively, under the reaction conditions of temperature of 30℃, initial NOR concentration of 5.0mg/L, Fe3O4 dosage of 2.0g/L, PS concentration of 1.5mmol/L, initial pH value of 7.0, and reaction time of 120minutes. Free radical quenching experiments confirmed that SO4-· was the dominant free radical in the degradation of NOR. The possible degradation pathways and intermediate products of NOR were inferred using LC-MS. This study indicated that the Fe3O4-activated PS oxidation process could be served as a novel technique for the simultaneous removal of organic pollutants and heavy metals.
2022 Vol. 42 (2): 717-727 [Abstract] ( 237 ) [HTML 0KB] [ PDF 1282KB] ( 1242 )
728 Treatment of effluent from MBR by Fenton cathode-electrocoagulation ozone air flotation process
DIAO Yue, YANG Chao, JIN Xin, SUN Hui, JIN Peng-kang
In order to remove organic matter in landfill leachate MBR effluent, the Fenton cathode-electrocoagulation ozone air flotation process was constructed with aluminum (Al) as anode and carbon polytetrafluoroethylene (C-PTFE) as cathode. The removal characteristics of this process for landfill leachate MBR membrane effluent were investigated by comparing with the conventional electrocoagulation cathode (Al and SS). When the pH5 and ozone flow were 300mL/min, the COD removal rate of Fenton cathode system was increased by 30.03% and 15.16%, respectively, compared with that of SS and Al cathode systems. According to the analysis of three-dimensional fluorescence characteristics, the C-PTFE cathode system had a good removal effect on humic acids. A typical refractory organic compound IBP (ibuprofen) was selected in MBR effluent to clarify the mechanism of organic degradation. The results showed that compared with SS cathode and Al cathode, the H2O2 production of C-PTFE cathode system was increased by 63.27% and 122.22%, respectively. The quenching experiment showed that ·OH was generated not only through the reaction of H2O2 and O3, but also through the reaction of O3-and H2O, it was proved that THE C-PTFE cathode had a certain strengthening effect on the electrocoagulation ozone flotation process, and was more conducive to the removal of organic matter.
2022 Vol. 42 (2): 728-735 [Abstract] ( 196 ) [HTML 0KB] [ PDF 854KB] ( 1011 )
736 Adsorption and aerobic degradation of water pollutants by laterite nickel ore-based materials
WANG Bing-ning, LIU Shou-jun, YANG Song, CHEN Liang-yu, LIU Xing-yang, LI Jin, SHANGGUAN Ju
Taking laterite nickel ore as the research object, the removal efficiencies of rhodamine B(RhB) with the raw ore (HT) and the modified ore (HT-FeNi) were investigated systematically. The adsorption mechanism of RhB was studied by X-ray diffraction, specific surface area analyser, infrared spectrum, and the kinetic and isothermal adsorption characteristic analyses. The results show that the HT possesses a relatively rich pore structure and a good adsorption performance on RhB. When added 0.2g/Lof HT, a RhB removal efficiency of 39.03% and a adsorption capacity of 93.80mg/g were reached. The RhB removal efficiency was enhanced, while the equilibrium adsorption capacity was decreased with the increasing dosage of HT. The adsorption kinetics and isotherms of RhB were well fitted by pseudo-second-order kinetic and Freundlich equation, respectively. The adsorption process might include two steps:surface diffusion and intra-particle diffusion. The 1/n was less than 0.5, which indicated that the adsorption process occurred more easily. The adsorption capacity of 39.67mg/g was still remained after 5cycles of experiments, indicating a good recycling performance of HT. The adsorption of RhB by HT was mainly attributed to the adsorption site of Si-O. The modified ore (HT-FeNi) was prepared by gas reduction of raw ore (HT). SEM、XRD、BET and XPS were used to characterize HT-FeNi and the degradation efficiency of RhB with this material was investigated. The specific surface area of HT-FeNi was smaller (14.374m2/g), and its main component was Fe-Ni bimetallic. HT-FeNi could not remove RhB by adsorption. However, the degradation efficiency of RhB could reach 94% in HT-FeNi/Air/pH=3system within 40min. The reactive oxygen species capture experiments indicated that the hydroxyl radical (·OH) played a major role for the RhB degradation. HT-FeNi could activate O2 under acidic condition and ·OH formed. The Fe2+/Fe3+ cycle induced by Ni0 promoted the production of ·OH. Then HT-FeNi/Air/pH=3system was applied to the removal of MO and DNCB, the removal efficiencies were 47% and 78%, respectively.
2022 Vol. 42 (2): 736-744 [Abstract] ( 228 ) [HTML 0KB] [ PDF 1513KB] ( 728 )
745 Synthesis of magnetic cationic chitosan flocculant by low-pressure UV light for the removal of Cr(Ⅵ)
ZHENG Huai-li, ZHONG Zheng, ZOU Hong, BAI Ying, ZHAO Rui, DING Wei, JIANG Jun-yi
A new magnetic chitosan flocculant FSCAD was synthesized by using magnetic Fe3O4 coated with silica and silane coupling agent (KH-570) as magnetic core, chitosan, acrylamide and acryloyloxyethyl trimethylammonium chloride as graft monomers and low-pressure ultraviolet light as initiator, the Cr(Ⅵ) removal properties of the material were studied. The flocculants were characterized by fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffractometer and vibration sample magnetometer, showing the materials were successfully prepared and have good magnetic response. The effects of pH, dosage, reaction time and interference ions on flocculation properties were explored and fitted to the flocculation dynamics model. The flocculation kinetics accorded with the pseudo second order kinetic equation and the removal effect of FSCAD on low concentration Cr(Ⅵ) wastewater reached 90.48% at the added amount of 900mg/L, pH of 3 and the reaction time of 60min.
2022 Vol. 42 (2): 745-752 [Abstract] ( 261 ) [HTML 0KB] [ PDF 543KB] ( 1908 )
Solid Waste
753 Pollution characteristics and toxicity assessment of PAHs in coal gangue from mine aera in Huaibei
CHEN Xue, XU Dan-dan, QIAN Ya-hu, HONG Xiu-ping, LIANG Han-dong
In this paper, we collected 13 gangue samples (7 fresh samples and 6 weathered samples) from Liuqiao Mine in Huaibei, and 16 parent polycyclic aromatic hydrocarbons (16 PAHs) and alkyl-polycyclic aromatic hydrocarbons (a-PAHs) were analyzed by GC-MS/MS on qualitative and quantitative. The results showed that 16PAHs and a-PAHs were generally contained in coal gangue, and the content level of a-PAHs (∑a-PAHs average 587.88ng/g, n=13) was generally higher than that of 16PAHs (∑16PAHs average 505.23ng/g, n=13). The most abundant substance was naphthalene, phenanthrene and chrysene, accounted for 15%, 33% and 15% of ∑16PAHs, respectively. Alkyl-naphthalene and alkyl-phenanthrene in the content of the advantage, accounted for 22% and 40% of ∑a-PAHs. The contents of ∑16PAHs and ∑a-PAHs in the weathered samples was higher than those in the fresh samples. Only the contents of Benzoapyrene and C2-phenanthrene decreased after weathering, and the corresponding contents of C1-Benzoapyrene and phenanthrene increased after weathering. The characteristic ratio shown that the coal gangue samples satisfy 0<C0/(C0+C1-C4) PHE<0.25 and 0.2<C0/(C0+C1-C5) NAP<0.55; apply these ratios to PAHs of coal, petroleum, sediment also have a good dispersion. Therefore, these ratios can be used for identify PAHs from coal gangue. Through the toxicity evaluation of coal gangue, the average Benzoapyrene toxicity equivalent concentration reached 194.60ng/g, in which a-PAH contributed most of the toxicity equivalent concentration. This study provides basic experimental data for the source of PAHs and reveals the possible ecological risks of PAHs in coal gangue.
2022 Vol. 42 (2): 753-760 [Abstract] ( 317 ) [HTML 0KB] [ PDF 470KB] ( 1595 )
761 Regulating PVC and PET floatability based on surface reconstruction induced by environments
ZHANG Ying-shuang, YANG Ya-bin, JIANG Hong-ru, WANG Hui
The hydrophobic conversion of hydrophilic polyethylene terephthalate (PET) and polyvinyl chloride (PVC) plastics in different environments was researched on the basis of surface reconstruction and thermodynamics, aiming at the floatability fluctuation of waste plastics. It was revealed that 82%, 47% and 0.2% of PET hydrophobicity was recovered in air, ethanol, and water at temperature 70℃, and 100%, 37%, and 2% of PVC hydrophobicity was recovered. A non-polar air environment with high temperature favoured surface reconstruction and hydrophobicity restoration, while a polar water environment with low temperature induced hydrophilic plastic surfaces. Compared with the surface coating, the surface alcoholysis was more conducive to maintaining the hydrophilicity of the plastic. This study proposed that changing the molecules structure of plastic surface was beneficial to maintaining their hydrophilicity, and a low-temperature-entire-immersion process assisted plastic flotation in stability.
2022 Vol. 42 (2): 761-769 [Abstract] ( 287 ) [HTML 0KB] [ PDF 3061KB] ( 1022 )
770 Effects of metal catalysts on pyrolysis products of painted plywood
ZHANG Jia-wen, CHEN Qin-dong, XU Qi-yong
Five catalysts, including CaCO3, CaO, Fe2O3, iron powder and Na2CO3 were used as catalytic agents in the catalytic pyrolysis of painted wood. Solid and liquid products of pyrolysis were collected separately for yield calculation and products characterization. The results showed that all five catalysts effectively improved the yield of solid products. In addition, CaCO3, Na2CO3 and iron powder also increased the yield of liquid products. The content of titanium in all solid products was in a high level, which may cause potential environmental pollution. The liquid products of pyrolysis mainly included esters, ketones, alcohols, phenols and acids, and a small amount of nitrogen-containing substances. The introduction of CaCO3, CaO, Fe2O3 and Na2CO3 could reduce the content of acids in the liquid products. In summary, CaCO3 was more efficient at improving the quality of both solid and liquid pyrolysis products.
2022 Vol. 42 (2): 770-776 [Abstract] ( 269 ) [HTML 0KB] [ PDF 1759KB] ( 1120 )
777 Metagenomic analysis on the responses of microbial community to ammonia stress
PENG Yun, LI Lei, WU Di, YANG Ping-jin, PENG Xu-ya, WANG Xiao-ming
A series of batch experiments were conducted to investigate the responses of anaerobic digestion (AD) microbial community exposed to ammonia (TAN) stress. In combination with Metagenomic sequencing analysis, this paper investigated the responses of process parameters, community structure/composition and functional gene/metabolic pathways of AD to the process disturbance induced by different TAN concentrations. The overall performance of AD system was gradually optimized at the concentration of 3000mg/L TAN while when TAN reached 6000mg/L, an accumulation of propionate and butyrate was observed with a concomitant decrease of methane yield. At both concentration levels, the resistance and redundancy of hydrolytic and acidogenic bacteria can ensure their metabolic performance for substrate degradation. However, the total relative abundance of acetogens and methanogens at the low concentration level continued to increase, whereas a low increase rate and even a decrease in the total relative abundance was observed at the high level, suggesting the potential process inhibition. By further analyzing the functional gene changes in the two process stages, The methanogenesis and syntrophic acetate oxidation pathways showed resistance and redundancy under the ammonia stress, but the high concentration of TAN (6000mg/L) inhibited the expression of key genes ACADS and PCCA in the syntrophic degradation of butyrate and propionate. Therefore, the key contributor to the ammonia inhibition turned out to be acetogenesis.
2022 Vol. 42 (2): 777-786 [Abstract] ( 318 ) [HTML 0KB] [ PDF 535KB] ( 1295 )
Soil Pollution Control
787 The effect of iron-rich biochar on microorganisms dominated by methanotrophs in landfill cover
BAI Xin-yue, CHEN Yu-ke, HUANG Dan-dan, XU Qi-yong
To further clarify the relationship between methanotrophs and its environment in landfill cover soils, the impact of environmental differences caused by different substrate concentrations and biochar groups on microorganisms were investigated by comparing the two important microbial activities, including methane oxidation and EPS generation. Substrate concentrations had the greatest impact on microbial diversity and population differences. With sufficient carbon source and oxygen, the amount of methane oxidation was mainly contributed by type I methanotrophs; otherwise, type Ⅱ methanotrophs dominated. Under high methane and low oxygen conditions, adding iron-rich biochar may effectively alleviate EPS blockage and facilitate the growth of Methylocystis.
2022 Vol. 42 (2): 787-793 [Abstract] ( 199 ) [HTML 0KB] [ PDF 1183KB] ( 784 )
794 Mechanism of heavy metal uptake and transport in soil-rice/wheat system and regulation measures for safe production
WANG Cheng-chen, TIAN Wen, XIANG Ping, XU Wu-mei, GUAN Dong-xing, Lena Q. MA
To master the heavy metal pollution in rice and wheat crops from main production regions in China, we collected the data from existing literature and analyzed the concentrations of arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb) in soil-rice/wheat system, summarized their underlying mechanisms of target heavy metals absorption, transport, and accumulation. In addition, effective remediation measures for safe production were also introduced. The results showed that 31.3% and 22.2% of Cd, 26.2% and 32.1% of Pb in rice and wheat grains are over the value of China National Standard (GB2762-2017). Reducing the bioavailability of As, Cd, Cr and Pb and controlling their absorption in the soil-rice/wheat system could effectively decrease their accumulation in grains. The heavy metals uptake in soils-crop systems can be effectively decreased by water and fertilizer management, chemical modification, phytoremediation, bioremediation and genetic methods to achieve safe production. In the future, we should form a multi-disciplinary and integrated all factor pattern to improve the soil pollution research in China. Furthermore, developing the contaminated soil utilization technology for the safe production of agricultural products, so as to better ensure the national food safety production.
2022 Vol. 42 (2): 794-807 [Abstract] ( 348 ) [HTML 0KB] [ PDF 385KB] ( 1297 )
808 Effect of co-metabolism by polycyclic aromatic hydrocarbon on the microbial degradation of benzo[a]anthracene and its mechanism
ZHU Qing-he, ZENG Jun, WU Yu-cheng, YANG-Jie, LIN Xian-gui
In this study, the effect of three co-metabolic substrates (phenanthrene, anthracene, pyrene) on environmental distribution of benzo[a]anthracene (BaA) was studied by using 14C isotope tracer. High-throughput sequencing and co-occurrence network analysis were used to evaluate bacterial community responses. The results demonstrated that all the three co-metabolic substrates promoted degradation of BaA. The mineralization of BaA increased by 2.5% in the anthracene treatment compared to the control. In the treatments of phenanthrene and pyrene, the bound residue of 14C was 4% higher than in the control, amounting to 31% of the total addition. The topological characteristics of bacterial co-occurrence network changed with the supplementation of co-metabolic substrates. Anthracene significantly raised the proportion of positive links, which indicated mutualistic interactions. In contrast, the competition between bacterial taxa was strengthened in the treatments of phenanthrene and pyrene, as evidenced by increased negative links after incubation. It was likely that anthracene and BaA degraded through common metabolic pathways, which caused mutualistic interactions and higher mineralization rate of BaA in the soil microcosms. Overall, co-metabolism could be an important factor influencing the fate of BaA in soil and changing the interaction among bacterial species.
2022 Vol. 42 (2): 808-814 [Abstract] ( 289 ) [HTML 0KB] [ PDF 744KB] ( 1229 )
Environmental Ecology
815 Hydrochemical characteristics and sources of the upper Yarlung Zangbo River in summer
YAN Yu-peng, NIU Feng-xia, LIU Jia, LIU Xin-ting, LI Ying, PENG Hui, YAN Deng-hua, XIAO Shang-bin
To explore inorganic hydrochemical characteristics of the upper Yarlung Zangbo River, water samples were collected from the main stream and different tributaries in this region in August 2020. The chemical compositions and spatial variations as well as the sources of the main ions were analyzed. Results showed that the main anions in the river were HCO3- and SO42-, accounted for 71.1% and 23.2% of the total anions, respectively; the main cations were Ca2+ and Na+, accounted for 47.9% and 34.8% of the total cations, respectively; the total dissolved solids (TDS) ranged between 43.5~187.3mg/L, with an average of 116.4mg/L (this indicated a low salinity of water). The dominate pattern of hydrochemical type in the Yarlung Zangbo River Upstream Basin was HCO3·SO4-Ca·Na, while exhibited HCO3-Ca·Na pattern in some headwater (i.e., Jiemayangzong river and Kubi river). Then, there existed drastically changes of HCO3-, SO42-, and Ca2+ along the mainstream, which was mainly affected by glacier melt water and the inflow water from different tributaries. In general, in the upper Yarlung Zangbo River, the hydrochemical characteristics was controlled by rock weathering with the ions mainly originated form the carbonate rock and silicate, and the evaporite (sulfate) dissolution was also another source. In contrast, this area was less affected by human activities.
2022 Vol. 42 (2): 815-825 [Abstract] ( 255 ) [HTML 0KB] [ PDF 938KB] ( 1423 )
826 Water quality inversion and eutrophication assessment of The South China Sea based on GEE
WANG Feng-xia, XIA Zhuo-yi, GUO Yu-hui, YANG Zi-qing, LI Jia-xin, CHEN Yin-xiao
Based on the Google Earth Engine (GEE) platform, this study took MODIS data to build water quality inversion models by constructing multivariate feature. The response degree of water quality to MODIS features was SD>COD>TN>Chl-a, and polynomial fitting of water quality parameters was the best model. The spatial and temporal heterogeneity of the four water quality parameters (SD, TN, Chl-a and COD) in the South China Sea was obviously different. The high SD values were mainly distributed in the western Philippines and eastern Vietnam sea areas, and gradually decreased from 2006 to 2018. During 2006 to 2018, the distribution range of TN high values expanded year by year, while the concentration of Chl-a gradually decreased. COD gradually spread from 2006 to 2018. Through three-dimensional trend surface analysis, the spatial variation trend of SD was similar to those of COD, TN and Chl-a, while the spatial variation trend of Chl-a was completely opposite to those of SD and COD. The eutrophication degree of the South China Sea showed an increasing trend from 2006 to 2018, different countries should carry out regional cooperation to manage the marine environment.
2022 Vol. 42 (2): 826-833 [Abstract] ( 1076 ) [HTML 0KB] [ PDF 1889KB] ( 2600 )
834 Spatial heterogeneity of dissolved methane in a plateau lake: a case study in Yangzonghai Lake in autumn
ZHENG Xiang-wang, CHEN Min, XIAO Shang-bin, WANG Sheng-rui, WANG Xue-zhu, CHEN Wei, LIU Jia, XU Hao-ting
Near-surface and vertical profiles of dissolved CH4 concentrations were measured at a high resolution using the new fast-response automated gas equilibrator (FaRAGE) connected to a greenhouse gas analyzer at Yangzonghai Lake in November 2020, to investigate the spatial pattern of dissolved CH4 and its driving factors. Results showed that dissolved CH4 concentrations of surface water ranged between 0.02 and 0.97μmol/L, indicating a net source of atmosphere CH4. The dissolved CH4 was relatively higher in the north and south parts of the lake, but lower in the middle area, which was mainly influenced by aquatic plants distribution, discharge from inflow rivers and topographical conditions. Vertical profiles of dissolved CH4 at different spots of the lake exhibited relatively consistent pattern, while CH4 was more significantly oxidized in the middle section. The bootstrap analysis suggested that estimates of CH4 emission derived from fewer measurements were subjected to potentially large biases, and the minimum number of sampling sites that guaranteed an accurate estimation of diffusive CH4 flux at Yangzonghai Lake was 3.7per km2. It was necessary to perform high-resolution observations of CH4 concentration for an accurate estimation of carbon emission from lakes or reservoirs.
2022 Vol. 42 (2): 834-842 [Abstract] ( 264 ) [HTML 0KB] [ PDF 1110KB] ( 1498 )
843 Spatio-temporal distribution and influencing factors of stable carbon and nitrogen isotopes of phytoplankton in Dianchi Lake
CHEN Rong, WANG Ming-guo, HUANG Lin-pei, GUO Wen, LI Rui, WANG Jiao-yuan, CHEN Guang-jie
A comparative study of δ13C and δ15N values of phytoplankton in Dianchi during the dry, transitional and rainy seasons showed that the δ13C and δ15N levels of phytoplankton were characterized by significant spatial and temporal fluctuations. During the dry, transitional and rainy seasons, the δ13C of phytoplankton were respectively at -20.44‰±0.72‰, -17.32‰±1.09‰ and -15.92‰±1.74‰, showing a gradually increasing trend. However, the opposite trend was recorded for the seasonal variation of δ15N levels in phytoplankton, because in rainy season the level was significantly lower (13.55‰±0.85‰) than in the transitional period (15.02‰±1.12‰), and in the dry season (15.02‰±1.12‰). The average of the spatial distribution of the δ13C levels in phytoplankton is 13.17‰, with an upper level in the south basin and a lower level in the north basin. For the δ15N levels of spatial distribution in phytoplankton, the average was 11.37‰, with a high value n the central basin and lower values in the southern and northern basins of the lake. About the level influencing factors, the statistical analyses showed that the δ13C value of phytoplankton in Dianchi was strongly related to multiple factors such as water temperature, precipitation, electrical conductivity and pH value, indicating that δ13C level of phytoplankton was significantly affected by cell growth rate and inorganic carbon sources. The seasonal variation in the δ15N values of phytoplankton in the lakes was mainly related to precipitation, and to the total nitrogen, and total phosphorus levels in the waters. The spatial variation in the δ15N was consistent with the spatial pattern of catchment land uses in Dianchi. This indicated that urban domestic sewage still remains an important pollution source of Dianchi, while agricultural fertilizer and other non-point source pollution played an important role in modulating both spatial and temporal variation of the phytoplankton δ15N levels. Therefore, spatial patterns of land use and seasonal variations in precipitation, were importantly affecting the ecosystem nutrient cycling and isotopic levels in the biota of the Dianchi lake.
2022 Vol. 42 (2): 843-853 [Abstract] ( 342 ) [HTML 0KB] [ PDF 1518KB] ( 1572 )
854 Lining promotes the homogenization of bacterial communities in sediments
ZHAO Jun-ying, ZHANG Wei, GUO Xiao-yu, SU Zhen-hua, DI Yan-ming, DONG Zhi
Taking the North Canal in Beijing-Tianjin-Hebei Basin as research area., a comparative analysis of bacterial community diversity, composition and pattern of environmental factors between the upstream and the mid-down stream samples was carried out. The results showed that engineering projects of bottom and bank in the mid-down stream of the North Canal of Beijing-Tianjin-Hebei Basin promoted the homogeneity of the bacterial community. Comparing to the spatial scaling patterns of upstream samples (0.0002), the value of bacterial communities in the mid-down stream (0.00002) was significantly lower and the distribution pattern of samples in the NMDS plot was more intensive. The homogenized community in the mid-down stream showed the lower richness due to the higher fragment type of the non-abundant species, lower fragment type and lower relative abundance of the abundant species. The analysis of RDA model (P=0.002) showed that the engineering projects, the total phosphorus and the antibiotics of macrolide and tetracycline were the key environmental factors. Engineering projects of bottom and bank was closely related to the diversity of Fibrobacteres, Gracilibacteria, Acidobacteria, Acidothermia and the relative abundance of Fischerbacteria, Kiritimatiellaeota, Actinobacteria, Cyanobacteria.
2022 Vol. 42 (2): 854-862 [Abstract] ( 250 ) [HTML 0KB] [ PDF 842KB] ( 1253 )
863 Recent progress of the effect of suspended sediment movement on the transport of microplastics in rivers
WANG Xin-jie, WANG Yi-ning, ZHAO Jian, LIU Sheng-dong, XIA Xing-hui, LI Yang
This review summarized the occurrence and abundance of microplastics (MPs) firstly and then the main transformation processes of MPs in rivers, including aggregation, settling, rising, resuspension, horizontal migration, and hyporheic exchange. In this paper, we critically evaluated the transportation of MPs in sediment-laden river, such as the heteroaggregation and co-settling of MPs with suspended sediments, influence of sediments on the resuspension and infiltration of MPs. The interaction mechanisms between suspended sediments and MPs concerning influencing factors of MP transportation have been discussed. Finally, recommendations for future research were discussed:(1) reliable models for predicting the migration process and flux of MPs in rivers are needed to develop; (2) researchers are suggested to use aged-MPs to conduct experiments, and consider the effect of turbulent water and organisms on the transportation behavior of MPs during laboratory work.
2022 Vol. 42 (2): 863-877 [Abstract] ( 481 ) [HTML 0KB] [ PDF 947KB] ( 2595 )
878 The bioaccumulation characteristics of quinolones (QNs) in macrobenthos-A case study of Baiyangdian Lake
FU Yu, JU Ze-jia, CHEN Hui, ZHAO Xin-yu, SONG Yuan-meng, WANG Guang-zhi, ZHANG Lu-lu, CUI Jian-sheng
The concentrations of quinolones (QNs) in water and macrobenthos samples were detected by high performance liquid chromatography tandem mass spectrometry (HPLC-MS). Correlation analysis was conducted between the characteristics of bioaccumulation for QNs in macrobenthos and environmental parameters in Baiyangdian Lake. The results showed that:The concentrations of ΣQNs in water varied from 0.7380 to 2004ng/L, the average concentrations of FLU (168.0ng/L) were the highest and the detection frequency of ofloxacin (OFL) and norfloxcin (NOR) in macrobenthos was the highest (Freq=100%), followed by flumequine (FLU) and enrofloxa (ENR) (Freq350%), while the detection rate of other QNs was less than 40% (Freq￡40%), While in the macrobenthos, the concentrations of ΣQNs varied from 23.70ng/g to 289.4ng/g, thereinto, the average concentrations of FLU(29.43ng/g) and CIP(40.38ng/g) were the highest; The bioaccumulation factors (BCF) of QNs in macrobenthos were in the range of 219.6 (BCFMAR)~1754 (BCFENR) L/kg, which indicated that the bioaccumulation of QNs was high in macrobenthos; The trophic magnification factors (TMF) of OFL, ENR, and NOR varied from 0.1299 (TMFFLU) to 6.426 (TMFENR), indicating NOR and ENR appeared trophic magnification, while FLU and OFL appeared trophic dilution; Through correlation analysis, the results showed that the BCF of ENR、CIP、FLU and ORB were significant positively correlated with water depth (WD), temperature (T), secchi depth (SD), dissolved oxygen (DO), and total organic carbon (TOCs), while significant negatively correlated with chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3--N), PO43-, total carbon (TCs), total phosphorus (TNs), and NH3-Ns; TMFOFL was significantly positive correlation to COD, TP, TN, NO3-N, PO43-, TCs, TNs and NH3-Ns, while significant negatively correlated with WD, T, SD, DO and TOCs, indicating that domestic sewage and aquaculture wastewater contributed the most to QNS.
2022 Vol. 42 (2): 878-888 [Abstract] ( 293 ) [HTML 0KB] [ PDF 2377KB] ( 1136 )
889 Relationship between microplastics occurrence and environmental factors and risk assessment during ice-covered period of the Daihai Lake
WANG Zhi-chao, DOU Ya-Jiao, ZHOU Xin, YANG Wen-huan, YAO Zhi, LI Wei-ping
In order to investigate the contamination and potential risks of microplastics in the ice cap of inland lakes, microplastics were sampled during the ice-covered period of the Daihai Lake, Inner Mongolia, northwest. The relationship between microplastics and environmental factors was analyzed by microscopic observation, redundancy analysis and pollutant risk index evaluation. The results showed that the abundance of microplastics in the Daihai ice cap ranged from 283 to 1055n/L, and the main detectable forms and colors were fibrous and black, and the particle size was mainly <0.5mm. Vertically, the abundance of microplastics in the upper and lower ice layers was higher than that in the middle ice layer. The abundance of microplastics was significantly correlated with the concentration of total nitrogen, ammonia nitrogen and salinity, but not with other environmental factors. The risk assessment results showed that the microplastics pollution in the Daihai Lake during the ice-covered period has reached a moderate level, and the potential risk should be taken seriously.
2022 Vol. 42 (2): 889-896 [Abstract] ( 228 ) [HTML 0KB] [ PDF 1081KB] ( 1287 )
897 The effects of microorganisms on the migration and transformation of nitrogen in the polyculture system of Plagiogathops microlepis Bleeker, Hypophthalmichthys molitrix and Aristichthys nobilis
ZHANG Zhe, GAO Yue-xiang, ZHANG Yi-min, CHENG Ling-ling, GUO Yan-min, ZHU Yue-ming, YU Jiang-hua
The polyculture system of Plagiogathops microlepis Bleeker (Xenocypris microlepis), Hypophthalmichthys molitrix (Silver carp) and Aristichthys nobilis (bighead carp) was set up in simulated eutrophic water. The dynamics of microbial communities and their effects on the migration and transformation of nitrogen in the sediments were investigated by applying isotopic labeling and microbial analysis to reveal the underlying mechanism of the polyculture system. The results showed that:The polyculture of Xenocypris microlepis, silver carp and bighead carp could increase the proportion of Pseudomonas and Bacillus involved in the ammonification process in the sediments. Comparing with the silver carp and bighead carp group, the total proportion of Bacillus and Pseudomonas in the polyculture group was the highest (31.2%) at the end of experiment, showing that it enhanced ammonification process and thus, reduced the content of organic nitrogen in the sediments. Consequently, the δ15N(substrate sediment) of the polyculture group decreased to 726.8‰. The polyculture of Xenocypris microlepis, silver carp and bighead carp could increase the proportion of denitrifying bacteria (Zoogloea and Bacillus) in the sediments. The proportion of Zoogloea and Bacillus in the polyculture group was significantly higher than that in the silver carp and bighead carp group (P<0.05), reaching 8.17% and 33.7%, respectively. Therefore, the denitrification process was enhanced in the system, converting more nitrate into nitrogen gas in the water and finally releasing this gas from this water. At the end of the experiment, in the polyculture group, the δ15N(nitrate nitrogen)decreased to 96.3‰ and the total content of 15N decreased to 6.94μmol.
2022 Vol. 42 (2): 897-906 [Abstract] ( 219 ) [HTML 0KB] [ PDF 757KB] ( 1023 )
907 Microbial photoelectric reduction of CO2 to acetate and its response mechanism to external applied voltage
ZHOU Mei-zhou, LUO Hai-ping, ZENG Cui-ping, LIU Guang-li, ZHANG Ren-duo
For evaluating the performance of microbial photoelectric synthesis (MPES) to reduce CO2 to synthesize acetic acid and its limiting factors, this study tried to construct a novel double-chamber microbial photo-electrosynthesis system (MPES)by coupling TiO2 photoanode with biocathode and using solar energy as main energy. The replacement of pure electrochemical anodes by photoanodes significantly reduced the external voltage requirements of MPES biocathodes, and MPES could continue to operate stably, with an average acetic acid production rate of (1.18 ±0.11) mmol/(L·d) and a Faraday efficiency of 45.75% ±3.97%. The photoanode drives the cathode to produce hydrogen, suggesting that the cathodic microorganisms tend to use H2-mediated electron transfer. The external voltage influenced the performance of the MPES significantly by affecting the electron donating ability of the photoanode. When the external voltage was increased from 0.4~0.6V, the MPES current, acetate production and Faraday efficiency were significantly improved, and the performance of the MPES was mainly limited by the photoanode. When the external voltage was higher than 0.6V, the system current and the output of acetic acid increased mildly, and Faraday efficiency reached the maximum value at 0.8V, and then declined, indicating that the electron-acceptting ability of biocathode was saturated at 0.8V and the performance of the MPES was mainly limited by the biocathode. As an electron intermiate, H2 was incompletely utilized during the operation of MPES, explaining why the Faraday efficiency was not further improved with an increase in external voltage.
2022 Vol. 42 (2): 907-913 [Abstract] ( 265 ) [HTML 0KB] [ PDF 771KB] ( 1172 )
914 Review on modeling the transport and retention of colloids in saturated porous media
LIN Dan-tong, HU Li-ming, SHEN Chong-yang
The research progress on the modeling of colloid transport and retention in saturated porous media is reviewed. Colloids transport in porous media due to convection and dispersion but retain in porous media due to surface deposition and straining. The advection dispersion equation with retention term can effectively describe the form of the breakthrough curves and the retention profiles in the one-dimensional column tests, and the macroscopic transport and retention parameters of the colloid can be obtained through fitting. However, the convection dispersion equation is a macroscopic description of the test curves and cannot explain the microscopic mechanism behind them. The micromechanical analysis of colloid decides its transport and retention behavior, including the Brownian motion of the colloid itself, the interaction between colloid- colloid/colloid-solid surface, and the force of the flow field acting on the colloid. Macroscopic parameters of colloidal movement in porous media can be predicted based on colloidal filtration theory and its subsequent modification methods. However, existing methods are usually based on a simplified structure and internal flow field of porous media, ignoring the influence of pore structure and surface characteristics of porous media. The pore structure model is a simplified model of porous media pore structure. Based on this model, the macroscopic transport and retention behavior of colloids can be predicted considering the micromechanical analysis of colloids. However, the various effects of colloid transport and retention in porous media have not been fully considered in current studies. The problems to be solved in this field are summarized, including the establishment of convection dispersion equation considering microscopic mechanism, the development of colloid filtration theory considering pore structure of porous media, and the improvement of colloid transport and retention simulation method based on pore structure model.
2022 Vol. 42 (2): 914-924 [Abstract] ( 476 ) [HTML 0KB] [ PDF 1026KB] ( 1989 )
925 A numerical simulation study on remediation efficiency of Multi-Phase Extraction (MPE) in petrochemical contaminated sites of low permeability
TIAN Lei, HU Li-tang, ZHANG Meng-lin
This paper utilized the software TOUGH3/TMVOC to build a conceptual model of a typical contaminated site in North China, and simulated the transport and distribution of Volatile Organic Chemicals (VOCs) in layered low-permeability strata. In addition, simulation scenarios under diffident conditions were set up to understand the effect of the permeability in the medium to efficiency of multi-phase extraction (MPE). VOCs mainly occurred in form of non-aqueous phase liquid (NAPL), and the maximum saturation of NAPL was located in the aquifer underneath the leakage position. When the maximum depth of extraction well was -8.75m, VOCs in NAPL phase could be effectively removed, which occupied the maximum mass fraction in the medium, and the total organic matter removal rate reached 89.8%. Besides, multi-phase extraction wells promoted the desorption of adsorption phase VOCs, and reduced the content of adsorbed VOCs in the medium effectively. After a period of extraction, the contents of residual VOCs in liquid and adsorption phase increased, which could become a potential secondary pollution source to groundwater. With the decreasing of the permeability in layered medium, the efficiency of MPE was reduced, and the residual VOCs in NAPL phase were difficult to extract in low permeability layer, which resulted in the decreasing of total organic removal rates.
2022 Vol. 42 (2): 925-935 [Abstract] ( 257 ) [HTML 0KB] [ PDF 1738KB] ( 1158 )
936 Effects of dicyandiamide, hydroquinone and phosphorus additives on greenhouse gas emissions during composting
YANG Yan, LI Guo-xue, LUO Yi-ming, YANG Jia, YUAN Jing
In order to reduce the emission of N2O, CH4 and NH3 simultaneously during composting, this study explored the effects of phosphogypsum (PG) and superphosphate (SP) on NH3 andgreenhouse gases emissions based on the dicyandiamide (DCD) and hydroquinone (HR) addition during pig manure composting. Pig manure and cornstalks were used and mixed as raw materials, and three treatments were carried out for 40days in the 60L composting vessel. In the HD treatment, DCD and HR were added; for the HD+P and HD+S treatment, the PG and SP were added together, separately, on the basis of DCD and HR addition. The results showed that the phosphorus additives amendment promoted the compost maturity and reduced carbon (7.58%~11.33%) and nitrogen losses (25.03%~33.42%) based on the addition of dicyandiamide and hydroquinone. The combined use of those additives could reduce NH3 emission by 15.21%~16.91% and CH4 emission by 23.75%~38.30%, while increased N2O emissions by 0.14%~20.57%. The phosphorus-containing additives could fix ammonium nitrogen and reduce NH3 emissions due to its lower pH and phosphoric acid. At the same time, the CH4 emissions was reduced by sulfuric acid ions through inhibiting the methanogens activity. In general, adding dicyandiamide, hydroquinone and phosphorus simultaneously decreased the total greenhouse emission of 7.60%~24.30%, and the HD+P treatment had the best performance in greenhouse gas emissions during composting.
2022 Vol. 42 (2): 936-944 [Abstract] ( 271 ) [HTML 0KB] [ PDF 433KB] ( 1522 )
945 China's surface urban heat island drivers and its spatial heterogeneity
NIU Lu, ZHANG Zheng-feng, PENG Zhong, JIANG Ya-zhen, LIU Meng, ZHOU Xiao-min, TANG Rong-lin
Based on satellite remote sensing data acquired through Moderate Resolution Imaging Spectrometer (MODIS), not only was the annual mean surface urban heat island intensity of 284prefecture-level cities in 2018 figured out, but spatial distribution patterns and spatial agglomeration models of surface urban heat islands in China were analyzed. Combining multivariate remote sensing data, meteorological data and socioeconomic statistics, a geographically weighted regression model was utilized to analyze spatial heterogeneity in main drivers for surface urban heat island intensity during daytime and nighttime. As demonstrated by relevant results, an obvious spatial autocorrelation existed in spatial distribution of China's surface urban heat island intensity. Compared with the traditional global ordinary least squares (OLS) model, interpretation of the drivers was significantly improved according to the geographically weighted regression model. Moreover, determination coefficients for daytime and nighttime increased from 0.651 and 0.189 in the OLS model to 0.876 and 0.659 respectively. In addition, both the residual sum of squares and the Akaike information criterion were calculated to be lower by the geographically weighted regression model. In terms of the drivers, vegetation placed a significantly negative influence on surface urban heat island intensity during the daytime, while structural differences were proved to exist in directions of influence that was applied by other factors along with geographic position changes. On the whole, surface urban heat island intensity was most significantly affected by differences in urban and rural vegetation in daytime; but at night, it was susceptible to socio-economic factors.
2022 Vol. 42 (2): 945-953 [Abstract] ( 395 ) [HTML 0KB] [ PDF 2791KB] ( 1529 )
954 Coupling analysis of urban thermal environment and landscape characteristics based on optimal granularity
SU Wang-xin, ZHANG Liu-kuan, CHANG Qing
We obtained land surface temperature and landscape components from Landsat and GF-2 within the inner Fifth Ring area in Beijing. The polygon grid approach has been applied for analyzing the relationship between urban landscape components and pattern characteristics and thermal environment characteristics. These various size polygon grids division was from 100m×100m to 1000m×1000m. With the increase of grid size, the correlation between IS/GWS and average LST first decreases and then gradually increases, trending to be flat at 600m. The optimal grid size range of IS and GS affected by LST was 600m×600m within the inner Fifth Ring area of Beijing. Among the 1796grids based on the optimal granularity, the mean temperature (Tm) was significantly correlated with impervious (0.723) and vegetation & water (-0.715), the standard deviation of temperature (Ts) was significantly correlated with impervious (-0.051) and water (0.054); when the proportion of vegetation was more than 55%, Tm decreased rapidly. When the proportion of dominant landscape types in the grid reaches a certain level, an increase or decrease in its proportion will cause rapid changes in the thermal environment. Based on the correlation analysis of vegetation & water, impervious landscape pattern, and thermal environment, Tm and LPI_IS (0.665), COHENSION_GWS (-0.547) were significantly correlated. When the proportion of GWS in the grid is more than 40%, the larger the vegetation water patch area and the higher the spatial connectivity, the more conducive to improving the thermal environment.
2022 Vol. 42 (2): 954-961 [Abstract] ( 227 ) [HTML 0KB] [ PDF 1926KB] ( 697 )
Carbon Emission Control
962 Risk measurement of China's carbon emissions trading market in different circumstances
LIU Hong-qin, HU Shu-hui
Based on the daily trading data of 5 carbon trading centers in Shenzhen, Hubei, Guangdong, Shanghai, and Beijing from 2015 to 2020, four trading scenarios of Ave, Med, Max, and Min are set up, and the TGARCH-VaR model is used to analyze carbon in different scenarios. The market risk of emissions trading has been studied. The results show that there are differences in carbon emissions trading market risks in different scenarios, and there are certain laws in the market stability and policy response of each scenario:The fluctuation range of the carbon spot yield in the Ave scenario is the smallest, while the Max scenario and the Min scenario have fluctuations in the carbon spot yield. The larger fluctuation of the spot yield means that the risk of the carbon market in the Ave scenario is minimal. The carbon market in the four scenarios has a risk leverage effect, and the impact of bad news on market volatility is greater than that of good news. The Med and Min scenarios are highly dependent on policies, and are susceptible to greater volatility risks due to external factors; the carbon market in the Max scenario is the least sensitive to news, and it is difficult to reflect the market's proper regulatory role; The Ave scenario market is more stable and can better reflect the regulatory effect of the policy. The VaR value variance of the carbon market under the Ave scenario is the smallest, and the VaR value variance of the carbon finance market under the Max scenario is significantly higher than the other three markets, indicating that the carbon market price volatility risk is small in the Ave scenario; the carbon market risk is the smallest in the Ave scenario and the market is stable It is highly sexual and can better reflect the regulatory role of the policy. When China is unifying the carbon emission market, it should take into account the differences in various regions and enthusiasm of enterprises to participate in carbon trading, helps to implement the dual carbon goals.
2022 Vol. 42 (2): 962-970 [Abstract] ( 317 ) [HTML 0KB] [ PDF 621KB] ( 1538 )
Environmental Impact Assessment and Management
971 The spatial effect of innovation on provincial green growth in China
CHEN Yong-zhi, LIANG Wen-ming, LIN Ying-xing
In this paper, the global principal component analysis method was utilized to measure the green growth level of 30 provinces (excluding Tibet) in mainland China from 2003 to 2016, and a Spatial Panel Durbin Model was constructed to empirically investigate the spatial impact of knowledge innovation, technology innovation, institution innovation, and culture innovation on provincial green growth. It was showed that knowledge innovation had a significant positive spatial impact on the level of green growth, with a direct effect of 2.35×10-5 and an indirect effect of 3.75×10-5. The local green growth level was significantly affected by the level of local technology innovation, with an influence coefficient of 0.1590, and was not significantly affected by the spatial level of technology innovation in the surrounding areas. Besides, it was significantly affected by the local institution innovation with an impact coefficient of 0.00733, whereas an impact coefficient of -0.01617 was for the surrounding areas' institution innovation. Meanwhile, the spatial impact of culture innovation on green growth level was not significant. Therefore, it was recommended to focus on knowledge production, knowledge accumulation and knowledge spillover of the regional green growth-orientation, aiming at promoting the coordinated green development and developing the key role of technology innovation in green growth. It was also suggested to further perfect the intellectual property protection system supporting inter-provincial green growth, intensify the promotion and popularization of green culture. Meanwhile, more human capital should be devoted and industrial structure should be optimized, thus promoting high-level opening up.
2022 Vol. 42 (2): 971-981 [Abstract] ( 244 ) [HTML 0KB] [ PDF 717KB] ( 1325 )
982 Rural households income-enhancing effect of wetland restoration based on the Lashihai watershed, Yunnan
YU Yuan-he, WU Jian
Using household level panel data in the Lashihai watershed in Yunnan Province from 2005 to 2016, this paper exploits the Difference-in-Differences (DID) model, Propensity Score Matching (PSM)-DID approach and placebo test to empirically investigate the income-enhancing effect of wetland restoration for local residents. The results suggest that wetland restoration has had a significant positive impact on households' income growth, raising total and per capita income by 39.2% and 43.5% respectively. Such findings are valid through multiple robustness tests. Wetland restoration has effectively improved the income structure such that the income growth stems mainly from government transfer like subsidies for wetland restoration and off-farm employment such as ecotourism. The income-enhancing effects of wetland restoration are heterogenous. On the one hand, the effect is significantly stronger for non-poverty households than for poverty households, and thus there may be a risk of enlarging income inequality within rural communities; on the other hand, social capital within rural communities such as information sharing and general trust improved the income-enhancing effect of wetland restoration.
2022 Vol. 42 (2): 982-992 [Abstract] ( 239 ) [HTML 0KB] [ PDF 493KB] ( 1134 )
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