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    25 July 2021, Volume 2021 Issue 4 Previous Issue   
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    Water Pollution Control and Treatment
    Immobilization and efficacy of an aerobic denitrifier
    Chao YIN, Ying LI, Tingyue ZHANG, Jiamin LIU, Tida CHEN, Dan CUI, Minsheng HUANG
    2021, 2021 (4):  1-7.  doi: 10.3969/j.issn.1000-5641.2021.04.001
    Abstract ( 455 )   HTML ( 517 )   PDF (769KB) ( 326 )   Save

    To improve the environmental tolerance and nitrogen removal efficiency of an aerobic denitrifier, polyvinyl alcohol (PVA), sodium alginate (SA), and rice hull powder were used as immobilized carriers for an aerobic denitrifier and the performance was subsequently evaluated. The results showed that the optimal ratio of immobilized particles was a mixture of 12% PVA, 8% sodium alginate (SA), 0.5 g rice hull powder, and 10 mL bacterial solution. The immobilized particles had strong stability and mass transfer capability; the removal efficiency of TN was 89.35% ~ 90.12% over 48h. The immobilized particles had good tolerance to pH and rotating speed. When the pH was 11, the removal efficiency of TN was 90%. The removal efficiency of TN and NH4+-N was the highest (91.29% and 93.30%, respectively) when the speed was 120 r/min. The immobilized particles were not resistant to low temperatures (10℃ and 15℃), and the TN removal efficiency was only about 20% at 10℃. The TN removal efficiency, however, achieved 90.59% at 30℃.

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    Comprehensive evaluation of engineering applications for multi-pond constructed wetlands in Erhai Lake Basin
    Dan LI, Binghui ZHENG, Zhaosheng CHU, Xing WANG, Minsheng HUANG
    2021, 2021 (4):  8-16.  doi: 10.3969/j.issn.1000-5641.2021.04.002
    Abstract ( 354 )   HTML ( 485 )   PDF (1433KB) ( 110 )   Save

    In this study, the rank evaluation method was used to comprehensively assess engineering applications for integrated multi-pond constructed wetlands (MPCWs) using a multi-dimensional evaluation system. We used pollutant purification performance, sewage storage capacity, vegetation ecological restoration, and economic investment as indicators for the evaluation. The results showed that the application of large-scale integrated MPCWs for controlling non-point source pollution was helpful for intercepting pollutants. Accumulated and purified reclaimed water was available for nearby rural agricultural water use. The implementation of MPCWs can result in water savings, pollution reduction, water resource allocation, and sewage reuse. The inclusion of vegetation within MPCWs was beneficial for ecological vegetation restoration and sewage purification. Given the economic investment requirement for MPCWs and the high potential security risks of deep-water MPCWs, we proposed application suggestions for different groups of MPCWs based on functional requirements. Shallow free water surface flow constructed wetlands could be used in populous areas with small volumes of highly polluted water, and eco-floating treatment wetlands could be used in sparsely populated areas with large volumes of highly polluted water. The scientific application of different groups of MPCWs also requires consideration of other factors, such as local special land resource endowments, pollution source structures, and the allocation of rural agricultural water resources.

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    Discussion on LID index model construction framework and its graphical application
    Meiyin QIAN, Kai YANG, Sheng XIE, Lei DING, Lu XU, Ying CHEN
    2021, 2021 (4):  17-25.  doi: 10.3969/j.issn.1000-5641.2021.04.003
    Abstract ( 338 )   HTML ( 483 )   PDF (950KB) ( 128 )   Save

    In this paper, we propose the concept of “LID (low impact development) Index” and “LID Runoff Reduction Efficiency” based on an analysis of runoff cutting efficiency for different LID technical measures. A map was designed to help quickly select the appropriate LID facility and its proportions according to the pollution reduction target in a built-up area. It shows that when the‘LID index’ increases, surface runoff and pollutants exhibit a similar exponential function form; the larger the LID index, the lower the “LID runoff reduction efficiency”. The model data is easy to obtain and flexible, rendering potential applications worthy of exploration.

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    Research on the integration and application of aquatic vegetation restoration technology in the lakeshore zone of Taihu Lake
    Xueyan YIN, Guanghan YAN, Xing WANG
    2021, 2021 (4):  26-38.  doi: 10.3969/j.issn.1000-5641.2021.04.004
    Abstract ( 464 )   HTML ( 34 )   PDF (2399KB) ( 233 )   Save

    Since the eleventh five-year plan, the National Major Science and Technology Program for Water Pollution Control and Treatment (referred to as the “Water Program”) has developed more than 20 key technologies to assist in restoring the lakeshore zone of Taihu Lake Basin. These solutions overcome the application limitations of a single technology in ecological restoration of the lakeshore zone. This includes technologies for: rebuilding the upwind bank slope to eliminate wave and algae in the ecological restoration area; rapid settlement of sediment for lasting improvements in water quality; multi-level reconstruction technology for aquatic vegetation in an open water area; large-scale cultivation and community construction for optimal allocation and stabilization of aquatic plants; and utilization of aquatic vegetation resources for long-term operation and management, based on the technical requirements for improving soil stability, improving the wetland habitat, and restoring the aquatic vegetation in the restoration area. Hence, a comprehensive technology solution for ecological restoration of different lakeshore zones in Taihu Lake Basin (titled “investigation and assessment of lakeshore zone status, wetland habitat improvement, wetland aquatic vegetation restoration, and long term management”) was formed. The complete technology solution for vegetation restoration in the dike-type lakeshore zone has been successfully applied in Zhushan Bay of Taihu Lake, with the wind wave reduced by 64% and the vegetation coverage rate exceeding 30%. The complete technology solution for vegetation restoration in a gentle slope lakeshore zone was also successfully applied in Gonghu Bay of Taihu Lake; the implementation resulted in coverage of aquatic plants reaching 57%, water depth transparency of more than 110 cm, and a greatly improved biodiversity index. In summary, the research results provide a practical basis for aquatic vegetation restoration and water quality improvement.

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    Research on the integration and application of industrial point source emission permit management technology in Taihu Basin
    Xiaochun GUO, Zhenyang HAN, Shaoyong LU, Binghui ZHENG, Zebin TIAN
    2021, 2021 (4):  39-45.  doi: 10.3969/j.issn.1000-5641.2021.04.005
    Abstract ( 385 )   HTML ( 47 )   PDF (607KB) ( 111 )   Save

    In this paper, we provide an overview of the development of emission permit systems domestically and globally, and analyze the problems and technology requirements for an emission permit management system at the initial stage of the National Major Science and Technology Program for Water Pollution Control and Treatment (referred to hereinafter as the “Water Program”) in the Taihu Basin. Based on a summary of technical achievements from the 11th and 12th Five-Year Plans for the Taihu Basin Water Program, a comprehensive set of industrial point source emission permit management technology methods was developed for unit division, control unit pollution load verification, control unit water environmental capacity calculation, assessment of water pollution control and management for key industries, allocation of emission permits, and dynamic monitoring. Furthermore, the effects of implementing a complete set of technologies in Taihu Lake Basin were explored and will serve as a reference for the implementation of a pollution permit management system.

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    Characteristics of dissolved organic matter and its effects on denitrification in urban river sediments
    Rui WENG, Zheng WEI, Yanmei YANG, Jing HAN, Yan HE, Minsheng HUANG
    2021, 2021 (4):  46-54.  doi: 10.3969/j.issn.1000-5641.2021.04.006
    Abstract ( 414 )   HTML ( 35 )   PDF (1032KB) ( 83 )   Save

    Understanding the impact of dissolved organic matter (DOM) on the denitrification process is critical to addressing the challenges associated with nitrogen removal in urban river treatment. In this paper, we show that DOM in urban rivers are mainly comprised of small-molecule fulvic acids. The humic acid content and aromaticity of the DOM, moreover, were found to be low. Compared with the control case, DOM can promote the denitrification process; specifically, the removal efficiency of TN and NO3-N in the DOM-added group increased by 7.24% ± 0.36% and 23.52% ± 1.17%, respectively. DOM with an acetate group had an even better effect on the removal of TN and NO3-N, reaching 74.48% ± 1.29% and 98.62% ± 0.07%, respectively. Microbiological analysis showed that the DOM-added group can significantly increase the diversity and richness of the bacteria community compared with the control case. However, the relative abundance of the heterotrophic denitrifiers Pseudomonas and Brevundimonas as well as the nirK-type denitrifier Paracoccus in the DOM-added group was less than that of the DOM with an acetate group. Additionally, a relatively high concentration of NH4+-N (> 3.7 mg/L) was observed in the DOM-added group. The addition of DOM can significantly increase the relative abundance of Anaeromyxobacter related to dissimilatory nitrate reduction to ammonium (DNRA) functional genes. It is speculated that DOM promotes the denitrification process and induces the DNRA process simultaneously.

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    A review of the upgrading technology for the A2/O process of municipal wastewater treatment plants under high discharge standards in China
    Zheng WEI, Yanmei YANG, Rui WENG, Yan HE, Minsheng HUANG
    2021, 2021 (4):  55-63.  doi: 10.3969/j.issn.1000-5641.2021.04.007
    Abstract ( 386 )   HTML ( 34 )   PDF (827KB) ( 132 )   Save

    This paper provides an overview of the technical achievements in A2/O upgrading during the 11th and 12th Five-Year Plans as well as the current successful operation of the improved A2/O process. We summarize the measures used for upgrading the A2/O process of municipal wastewater treatment plants under high discharge standards with respect to in-situ optimization and advanced treatment. Finally, we review the operating state of representative A2/O upgrade demonstration projects and offer suggestions for optimization and promotion of the A2/O process.

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    Investigation of the environmental status of water at the Dalian Lake demonstration area in the Jinze water source area of Taipu River
    Yang ZHA, Difang WANG, Chengjin CAO, Minsheng HUANG, Xing WANG, Bowen YU, Chang LIU, Haochen DU, Mengzhuo LI
    2021, 2021 (4):  64-71.  doi: 10.3969/j.issn.1000-5641.2021.04.008
    Abstract ( 402 )   HTML ( 32 )   PDF (4975KB) ( 113 )   Save

    In this paper, we use hydrology and water quality survey data around Dalian Lake to assess the environmental status of the water and surface runoff pollution in the Dalian Lake demonstration area. The results show that the water quality of the Jinze water source can largely satisfy class Ⅲ standards for surface water; however, given seasonal differences for some indicators, the water quality of the Jinze water source fails to meet the standard on a consistent basis. The water body surrounding the Dalian Lake demonstration area is predominantly slow flow (flow rate: 0 - 0.03 m/s), with low transparency and neutral or slightly alkaline water (pH = 6.63 - 9.67); these conditions render the area susceptible to forming water bloom. Pollution from nitrogen and phosphorus nutrients at each sampling point was significant, and seasonal differences were noticeable; the water quality in spring and summer is generally better (class Ⅱ—Ⅲ), and some water bodies meet class Ⅴ standards in autumn and winter. The concentration of rainwater runoff in the Dalian Lake demonstration area has a noticeable initial effect. The average concentration of nitrogen and phosphorus in the underlying water is higher than the class Ⅴ standard for surface water, and the pollution is likewise more significant.

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    Coastal structure and environmental resources of the Jinze water source area of Taipu River
    Chang LIU, Bowen YU, Chengjin CAO, Minsheng HUANG, Xing WANG, Difang WANG, Yang ZHA, Mengzhuo LI, Haochen DU
    2021, 2021 (4):  72-80.  doi: 10.3969/j.issn.1000-5641.2021.04.009
    Abstract ( 322 )   HTML ( 31 )   PDF (11842KB) ( 60 )   Save

    In this paper, we consider the rainwater runoff prevention and control technology demonstration area of the Jinze water source area in Qingpu District, Shanghai - Dalian Lake; the research area is a national major water project from the “13th Five-Year Plan”. Our study includes systematic research analysis on the type and slope of the riparian zone, the nature of the riparian soil, and the species of indigenous plants in the demonstration area; the study provides essential data to support subsequent research on the use of experimental rainwater gradient control technology in the riparian zone. The analysis shows that the riparian zone in the demonstration area is comprised of near-natural and rigid riparian, with gentle slopes. The aquatic and terrestrial plants in the zone with the largest population include lotus, reed, and herbaceous plants, respectively. Among the sampling sites in the study area, the average total nitrogen content of the soil in the adjacent farmland fluctuated around 0.95 g/kg, while the soil near the inlet gate was measured at 0.42 g/kg. The total phosphorus content of the soil in the adjacent residential living area, fish pond culture, and farmland area was more than 1.58 g/kg, while the soil at the lakeshore berm was measured at 1.10 g/kg. The average organic matter content was 11.30 g/kg, with higher values recorded in the densely planted area. These results confirm that local fishpond farming and agriculture have contributed to pollution of the soil environment.

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    Changes in water quality and land use structure in the green-belt area around Shanghai
    Tida CHEN, Dan CUI, Yuxin YUAN, Jiamin LIU, Minsheng HUANG, Ying Li
    2021, 2021 (4):  81-89.  doi: 10.3969/j.issn.1000-5641.2021.04.010
    Abstract ( 330 )   HTML ( 31 )   PDF (1463KB) ( 76 )   Save

    In this paper, we study land use change and its effects on water quality for 30 water bodies in the green-belt area of Shanghai; the analysis is based on the Markov transfer matrix and Pearson correlation analysis of field data and interpreted land use types. The results show that: the water quality is dominated by Grade Ⅳ and lower Grade Ⅴ; the proportion of water bodies with lower Grade Ⅴ is decreasing year by year; the buffer zone is dominated by construction land, forest, and grassland, with a total proportion of about 84.37%; the increase in construction land and decrease in bare land, accounted for 48.95% of the total reduced area and 50.85% of the total increased area, respectively; on the 300 m buffer scale, grassland had a positive effect on DO and Chla; on the 500 m scale, bare land was the main factor for CODMn deterioration; and cultivated land was positively correlated with multiple pollution indicators at two scales.

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    A review of applications and research progress on the use of nanoparticles for the inhibition of harmful algal bloom
    Yuxin YUAN, Jiamin LIU, Ling PAN, Lihong WANG, Xueli ZHANG, Minsheng HUANG
    2021, 2021 (4):  90-98.  doi: 10.3969/j.issn.1000-5641.2021.04.011
    Abstract ( 423 )   HTML ( 30 )   PDF (670KB) ( 116 )   Save

    This review summarizes the latest research progress on the inhibition mechanism of different nanoparticles on algal bloom. We systematically analyze the influence of environmental factors on migration and transformation of nutrients and the cytotoxicity process regulated by nanoparticles. The future prospects for the immobilization of nanoparticles are explored, and the paper proposes ideas to realize the functional performance of nanomaterials while controlling environmental risks. This research sheds light on new strategies for the inhibition of algal bloom.

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    Geography
    The impacts of climate and land use changes on water yield in the Beisan River Basin
    Wenjing LI, Sheng WANG, Qing LI, Taoli WU, Xinyue ZHAO
    2021, 2021 (4):  99-108.  doi: 10.3969/j.issn.1000-5641.2021.04.012
    Abstract ( 493 )   HTML ( 59 )   PDF (1255KB) ( 159 )   Save

    The Beisan River Basin is an important water source for the Jing-Jin-Ji region. It is important to analyze the temporal and spatial changes in basin water yield and the corresponding driving factors to maintain the security and stability of the ecosystem. Based on meteorology, land use, and soil data, the water production module of the InVEST model was used to analyze the temporal and spatial change characteristics of water yield in the Beisan River Basin from 2000 to 2017. The contribution of climate and land use change to the change in water yield was explored through scenario simulation. The results showed that from 2000 to 2017, the average annual water yield of the Beisan River Basin was 17.8 × 108 m3; the annual change showed an increasing trend at a rate of 1.03 × 108 m3/a. The spatial distribution pattern of water yield was high in the south and low in the north. The average depth of water production in the south and north was 70.85 mm and 8.83 mm, respectively. The high value area of water yield was transferred from the southeast Juhe River and Huanxiang River Basin to the southwest Wenhe River and Yongdingbei River Basin. The water supply per unit area, ranked from high to low, across different land use types showed the following order: construction land > cultivated land > water area > unused land > forest land > grassland. From 2000 to 2015, the water yield of cultivated land was the highest, accounting for 51.3% of the total water yield of the basin, while that of construction land increased the most, reaching 144.3%. Scenario simulation results showed that climate and land use change contributed 70.7% and 29.3%, respectively, to the water yield increase, and the surge in precipitation played a leading role.

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    Response of soil greenhouse gas emissions to temperature and moisture across different land-use types
    Wenxiu SANG, Hualei YANG, Jianwu TANG
    2021, 2021 (4):  109-120.  doi: 10.3969/j.issn.1000-5641.2021.04.013
    Abstract ( 532 )   HTML ( 61 )   PDF (1000KB) ( 171 )   Save

    In this paper, soil samples were collected from the red soil region of southern China (namely, the Sunjiaba small watershed in Yingtan, Jiangxi) across four different land-use types. Laboratory incubation experiments were subsequently carried out from June 2019 to October 2019. We used a closed chamber to measure soil greenhouse gases (CO2, CH4, N2O) simultaneously with the help of an advanced greenhouse gas analyzer (Picarro-G2508). The aim was to explore the response of soil greenhouse gas emissions across different land-use types to changes in temperature and soil moisture levels under the premise of global climate change. The results showed that the global warming potential (GWP) of the four land-use types increases with paddy, orangery, forest, and upland, respectively. This suggests that greenhouse gas emissions from paddy soils have the greatest relative impact on global warming. In a temperature-controlled experiment, soil CO2 emissions were shown to have a significant positive correlation with soil temperature. The Q10 values of soil respiration coefficients for the four land-use types were: 2.61 (forest), 2.51 (upland), 3.12 (orangery), and 3.17 (paddy). Thus, paddy soil respiration has the highest temperature sensitivity, indicating that paddy soil has a higher CO2 emission potential. Correlations were not significant between CH4 and N2O emissions to soil temperature. In the moisture-controlled experiment, the results indicated that soil CO2 emissions increased at the beginning and then decreased with increasing soil moisture, with the maximum emission rate at 20% GWC (gravity water content). CH4 emissions from paddy soils increased with soil moisture (R2 = 0.8875); CH4 fluxes from the other three land-use types, however, were not significantly related to soil moisture. The soil N2O emissions increased at the beginning and then decreased across the soil moisture range measured; all land-use types had the highest N2O fluxes at 25% GWC.

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    Numerical simulation and analysis of the spatial and temporal variations in residual water levels of the Changjiang Estuary
    Yunping SONG, Jianrong ZHU
    2021, 2021 (4):  121-133.  doi: 10.3969/j.issn.1000-5641.2021.04.014
    Abstract ( 388 )   HTML ( 40 )   PDF (4817KB) ( 104 )   Save

    Residual water level is an important factor affecting water depth; the water level depends primarily on river discharge, tidal conditions, and wind stress, and it can change significantly with time and space. Studying the temporal and spatial variations in residual water levels—and the respective influencing factors—is of great scientific significance and can be applied to estuarine water level prediction, water resources utilization, seawall design, flood protection, and navigation. In this paper, we used a validated three-dimensional numerical model of the estuary and coast to: simulate the temporal and spatial variations in the residual water levels of the Changjiang Estuary; analyze the impacts of river discharge, tidal conditions, and wind stress on residual water levels; and determine the dynamic mechanisms for its change. The spatial and temporal variations in residual water levels of the Changjiang Estuary is driven primarily by the fact that upstream residual water levels are higher than downstream levels because of runoff force. The highest residual water level appears in September, reaches 0.861, 0.754, 0.629, 0.554, and 0.298 m at Xuliujing, Chongxi, Nanmen, Baozhen, and the easternmost section of the northern dike of the Deepwater Navigation Channel, respectively. The lowest residual water level appears in: January for Xuliujing (0.420 m) and Chongxi (0.391 m), February for Nanmen (0.313 m) and Baozhen (0.291 m), and April for the easternmost section of the northern dike of the Deepwater Navigation Channel (0.111 m). The residual water level in the North Branch is lower than the level in the South Branch, because a small amount of river water flows into the North Branch. The residual water level is higher in the South Channel than the one in the North Channel. Within the South Channel itself, furthermore, the water level is higher on the south side than the north due to the Coriolis force, which makes the water turn to the right. By using numerical experiments to compare the impact of different factors, we found that runoff has the largest impact on residual water levels, tidal conditions have the second largest impact, and wind has minimal impact. The monthly mean river discharge is largest in July, which should lead to the highest residual water level, but southeasterly winds prevail in the same period leading to small residual water levels. The river discharge in September remains high and northerly winds prevail, driving the Ekman water transport landward and resulting in a residual water level rise in the estuary. The interaction between the river discharge and the northeasterly wind makes the residual water level highest in September rather than in July. In conclusion, this study revealed the dynamic mechanism explaining the highest residual water level observed in September.

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    Simulation analysis for remote sensing inversion of ocean wavelength and water depth by the Complex Morlet Wavelet method
    Shanling CHENG, Shouxian ZHU, Gui ZHANG, Wenjing ZHANG
    2021, 2021 (4):  134-144.  doi: 10.3969/j.issn.1000-5641.2021.04.015
    Abstract ( 390 )   HTML ( 32 )   PDF (3298KB) ( 81 )   Save

    Using the wave-shaped features of remote sensing images, the wavelength of ocean waves can be determined based on the wavelet method. Shallow water depths can then be estimated from the wavelength because the wavelength becomes shorter as the water depth decreases. In this paper, remote sensing data were replaced by ideal elevation data, and numerical simulation data were used to study the performance of the Complex Morlet Wavelet method in estimating wavelength and water depth. In particular, the effects of data resolution and sub-image size on water depth estimation were explored. The results from the ideal elevation data shows that: when the wavelength has no spatial change and the size of the sub-image is greater than the wavelength, the data resolution has no substantial effect on the wavelength estimation if there are more than nine evenly distributed data grids in one image. This phenomenon can be explained by the wavelength-energy spectrum. When the wavelength changes spatially, accurate estimation of the wavelength requires that the sub-image size is larger than twice the wavelength and there are four data grids in one wavelength. The estimation of wavelength by numerical simulated data requires a similar size for sub-images and the data number. The error of water depth estimation increases slightly if the sub-image size is too large, and also increases slightly as the resolution of the data decreases.

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