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2024, Volume 14,  Issue 2

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Real driving NOx emission characteristics of China Ⅵ heavy-duty diesel vehicles at different altitudes
JI Jianglin, ZHENG Yongming, LI Shifeng, HUANG Congkui, LIU Dianyun, HE Chao
2024, 14(2): 355-361. doi: 10.12153/j.issn.1674-991X.20230322
Abstract(83) HTML (42) PDF(8126KB)(43)

To understand the NOx emission characteristics of China Ⅵ heavy-duty diesel vehicles at different altitudes, a portable emission measurement system (PEMS) was used to conduct real driving emission tests on China Ⅵ heavy-duty diesel vehicles in four cities with different altitudes (including Xiangyang, Kunming, Lijiang and Shangri-la). This study showed that with the increase of altitude, NOx emission showed an increasing trend, and the average NOx emission rate under high altitude was 4.65-20.58 times that of the plain, and NOx emission factor was 2.80-13.75 times that of the plain. NOx emission factors of Shangri-la were 1.27-13.75 times higher than those of Xiangyang, Kunming and Lijiang under different load conditions. NOx emission factors of urban road were 1.05-6.49 times higher than those of suburban road and freeway, and the emission factors of urban road in Shangri-la exceeded 400 mg/km. In the interval of Bin 11-Bin 14 and Bin 21-Bin 28, NOx emission rates showed a trend of increases followed by decreases with the increase of VSP. NOx instantaneous emission rate peaked when the vehicles drove from urban road to suburban road and suburban road to freeway at different altitudes. The high NOx emission area was concentrated in the high speed and high torque range. The coefficient of determination between altitude and the average NOx emission factor was 0.86, which showed a fair positive correlation.

Characteristics and environmental impact of VOCs and greenhouse gas emissions from ground flares of typical petrochemical enterprises
BU Mengya, ZHANG Gangfeng, DU Tianjun
2024, 14(2): 362-370. doi: 10.12153/j.issn.1674-991X.20230677
Abstract(82) HTML (60) PDF(7337KB)(35)

In response to the severe situation of pollution and carbon reduction in China's petrochemical industry, two ground flares in a petrochemical company with millions of tons of ethylene cracking capacity were studied. Through on-site sampling monitoring and model calculation, the emission characteristics of volatile organic compounds (VOCs) and greenhouse gases from the flares during the combustion process were systematically explored. The results showed that VOCs emissions from Flare A and B in 2021 were 310.56 and 77.38 t/a, respectively, with olefins as the main emitted components. Greenhouse gas emissions were dominated by CO2 generated from the conversion of carbon-containing compounds into combustion, accounting for about 99.98% of the total CO2 emissions from flares. The ozone formation potential (OFP) of Flare A and B was 3 011.72 and 628.97 t/a, respectively, and ethylene and propylene were the main contributors to OFP of Flare A and B, with contribution rate of 39.52% and 44.91%, respectively. The global warming potential (GWP) of the two flares was 5 806.92 and 1 148.46 t/a CO2eq, respectively, with CO2 contributing the most, leading to a direct greenhouse effect which was 25.12-35.46 times that of CH4, and 6.64-7.24 times that of the greenhouse effect indirectly caused by VOCs emissions.

Collaborative control of pollution and carbon reduction in the process of onshore oil and gas exploitation
DU Yongliang, WANG Yang, HE Shaolin, YUAN Hongying, XU Wei, SONG Yang, LIU Bo, XU Yingjun
2024, 14(2): 371-378. doi: 10.12153/j.issn.1674-991X.20230478
Abstract(78) HTML (36) PDF(879KB)(28)

The oil and gas industry is an important source of volatile organic compounds (VOCs) emissions and the largest industrial release source of methane (CH4). The coordinated control of VOCs and CH4 in oil and gas exploitation to achieve pollution reduction and carbon reduction is of great significance to China's atmospheric environmental governance and the realization of the "double carbon" goal. Most of the VOCs and CH4 emission sources in the process of oil and gas exploitation have the same root homology, and the organized emission of processes and the torch emission are the largest VOCs emission source and CH4 emission source, respectively. On the basis of adding the collaborative control path of new networked monitoring, selecting appropriate control measures can improve the efficiency of collaborative control of pollutants. The multi-pollutant cost-benefit method in the cost-benefit accounting of pollution control has higher economic benefits. The absorption method and adsorption method are VOCs treatment technologies with higher technical maturity and economy, and reducing the number of compressor and engine start-ups is the most economical CH4 emission reduction measure.

Research on the evaluation of low-carbon development level of industrial parks under carbon peak and carbon neutrality target: taking A park in East China as an example
LIU Qingao, ZHANG Liqiu, JI Yunqing, FENG Li
2024, 14(2): 379-388. doi: 10.12153/j.issn.1674-991X.20230606
Abstract(162) HTML (42) PDF(1529KB)(53)

Under the goal of carbon peak and carbon neutrality, the demand for low-carbon development of industrial parks is becoming more and more urgent. Scientific and reasonable evaluation of the low-carbon development level of industrial parks is a key step to promote the low-carbon development of industrial parks. From the five levels of low-carbon industry, energy resource utilization, pollution reduction and carbon reduction, low-carbon infrastructure, and long-term management, 24 indicators were selected to construct a low-carbon development evaluation index system for industrial parks. The analytic hierarchy process (AHP) combined with the improved criteria importance through intercriteria correlation (CRITIC) method was used to assign weights to indicators, and the technique for order preference by similarity to ideal solution (TOPSIS) - grey correlation analysis model and obstacle degree model were used to analyze the low-carbon development level and obstacle factors of A park in East China from 2018 to 2022. The results showed that the low-carbon development level of A park was increasing year by year from 2018 to 2022, among which the low-carbon development trend of low-carbon industry, energy resource utilization and long-term management criteria was better, while the low-carbon development of pollution reduction and low-carbon infrastructure criteria was hindered. From the perspective of obstacle degree, pollution reduction and carbon reduction, and energy resource utilization in the criterion layer were the key obstacle factors restricting the improvement of the low-carbon development level of A park. Among them, the carbon emission per unit of industrial added value, the comprehensive energy consumption per unit of industrial added value, the reuse rate of industrial water, the wastewater discharge per unit of industrial added value, and the proportion of green buildings in new industrial buildings were more prominent.

Advances in application and reinforced control of Anammox nitrogen removal process based on carbon emission reduction
CHEN Zijian, ZHOU Zhongbo, MENG Fangang
2024, 14(2): 389-397. doi: 10.12153/j.issn.1674-991X.20230649
Abstract(83) HTML (83) PDF(5745KB)(45)

With the proposal of China's "dual carbon" goal and the focus of upgrading the water treatment industry to biological nitrogen removal, sewage treatment plants have shifted from focusing on meeting emission permit limits to realizing carbon neutrality, energy self-sufficiency and resource recovery potential. Anaerobic ammonia oxidation (Anammox) technology, with the advantages of no additional organic carbon source, small footprint, small sludge production and high nitrogen removal efficiency, represents the future development direction of biological nitrogen removal in sewage, with energy saving, consumption reduction and carbon emission reduction. Based on the existing research results, the discovery history of traditional nitrogen removal and Anammox reaction was summarized and compared. The application progress of emerging partial nitrification and Anammox (PN-A), partial denitrification and Anammox (PD-A), and anaerobic methane denitrification and Anammox (DAMO-Anammox) processes in urban mainstream conditions were reviewed. The endogenous and exogenous regulation strategies and their internal mechanisms, which could be implemented when the mainstream Anammox process was confronted with environmental factors such as low temperature, uneven influent load and light, were explored in detail. These strategies include "side-flow sludge supplement to mainstream" "side-flow sewage intermittent supplement to mainstream" and "acclimated biofilm particles", and so so on. Finally, future directions for accelerating the innovative development and application of Anammox nitrogen removal technology were proposed in terms of molecular biology technology, material sciences, digital information technology, and management policies.

Exploration of regional governance paths for pollution reduction and carbon reduction based on territory spatial planning practice
LIU Guili, WANG Yi, YOU Yingqi, YAN Nan, NIU Haipeng, LI Mingkui
2024, 14(2): 398-406. doi: 10.12153/j.issn.1674-991X.20230680
Abstract(157) HTML (42) PDF(2264KB)(45)

The purpose of this paper is to explore the pollution reduction and carbon reduction governance path that combines spatial use zoning in existing territory spatial planning practice. On the basis of systematically sorting out the relevant research on pollution reduction and carbon reduction at this stage, the significance of implementing pollution reduction and carbon reduction zoning management was explained, including promoting green and low-carbon development, implementing and supervising territory spatial planning as a key measure, and promoting the modernization of the ecological environment. The main problems faced by the current management of pollution reduction and carbon reduction zones were analyzed, such as insufficient standards and technical specifications, the urgent need to build the coordination system, the need to improve the coordination mechanism, and the need to strengthen the guarantee system, especially the lack of a strong grasp at the spatial implementation level. Although the implementation plan, zoning design, institutional framework and important indicators of pollution reduction and carbon reduction were involved in the content of territory spatial planning at the national, provincial, municipal, county and township levels, the zoning management system, standard system, planning transmission, and coordination and guarantee mechanism were still insufficient. Finally, the main countermeasures for the zoning management of pollution reduction and carbon reduction at this stage were put forward, including the formulation of a carbon emission zoning standard system, the establishment of a pollution reduction and carbon reduction collaborative zoning system connected with the territory spatial planning, the construction of a synergistic benefit enhancement mechanism of carbon reduction and pollution reduction integrating center, conduction, amplification, early warning feedback, incentive and examination, and the improvement of the source, zoning and practice link of pollution reduction and carbon reduction zoning governance guarantee mechanism.

Study on the distribution characteristics of air particle concentration in urban agglomeration in China
LIU Ying, HE Jinmei, GUO Min, TAN Yufei, ZHAO Yanyun, WANG Zongshuang
2024, 14(2): 407-415. doi: 10.12153/j.issn.1674-991X.20230707
Abstract(55) HTML (30) PDF(7211KB)(35)

Based on the monitoring data of particulate matter (PM2.5 and PM10) from 2015 to 2022, the concentration distribution characteristics and similarities and differences of particulate matter in 10 urban agglomerations (169 cities) in China were analyzed from the perspectives of daily average concentration, annual average concentration, compliance from a probability theory angle, and the required concentration reduction for compliance. The results indicated that the pollution levels of particulate matter within urban agglomerations in China tend to stabilize, while significant differences existed among different urban agglomerations. The concentration of particulate matter within urban agglomerations in China exhibited a stratified pattern. Based on the concentration levels, the 10 urban agglomerations were categorized into three groups: high, medium, and low concentrations. This classification remained consistent when viewed from a statistical distribution perspective, except for the Guanzhong Plain urban agglomeration, which was classified as a high-concentration urban agglomeration. The differences in the required concentration reduction for compliance (secondary standard of Ambient Air Quality Standard (GB 3095-2012)) were significant among urban agglomerations. The PM2.5 and PM10 levels in the Western Taiwan Strait urban agglomerations and the PM10 levels in the Pearl River Delta urban agglomeration have already met the standards. However, in order for the Central Plains, Guanzhong Plain, Beijing-Tianjin-Hebei, and Shandong Peninsula urban agglomerations to meet the standards, the concentration of PM2.5 and PM10 needed to be reduced by more than 50% and 27%, respectively. It was recommended to scientifically establish regional stage target values for particulate matter in line with China's national conditions, to accelerate compliance in urban agglomerations in stages based on their own conditions.s.

Assessment of the contribution of factors affecting ozone pollution in Tianjin based on meteorological composite index
LI Minjiao, WEN Juan, YIN Lifeng, ZHANG Leibo, SUN Rui, FENG Zhenzhen, LI Huaiming
2024, 14(2): 416-424. doi: 10.12153/j.issn.1674-991X.20230544
Abstract(45) HTML (46) PDF(3547KB)(42)

By using the near-ground ozone concentrations and simultaneous meteorological data in Tianjin from 2017 to 2021, a localized ozone meteorological composite index was constructed based on statistical methods, and the contributions of meteorological and anthropogenic factors to changes in ozone concentration and exceedance days were assessed. The results showed that the ozone meteorological composite index could be well established based on the daily maximum temperature, sea level pressure, average wind speed, relative humidity, boundary layer thickness and short-wave radiation flux, and the correlation coefficient with the actual ozone concentration could reach 0.86 (P<0.01), which was higher than any single meteorological factor. Based on the evaluation of this index, the ozone concentration in Tianjin showed an increasing trend at first and then a decreasing trend from 2017 to 2021, with a decrease of 15.9% in 2021 compared to 2017. Anthropogenic factors played a dominant role in the concentration change, contributing 10.0%, while meteorological factors contributed 5.9%. The change in the number of exceedance days in the five years was consistent with the trend of concentration change, and mild pollution was the main type of exceedance days. The high proportion of mild pollution in 2018 was the main reason for the highest number of ozone exceedance days in that year. The number of ozone exceedance days in Tianjin decreased by 36 days from 2017 to 2021, with meteorological conditions contributing to a decrease of 20 days and anthropogenic factors contributing to a decrease of 16 days. The analysis of the factors affecting changes in the number of exceedance days at different pollution levels showed that meteorological conditions were the main factor leading to a decrease in mild pollution days, while the contribution of anthropogenic control measures was mainly reflected in the reduction of moderate pollution weather.

Review of research on VOCs treatment by gliding arc plasma
ZHENG Huan, JIANG Longjin, ZHANG Shun, NI Guohua
2024, 14(2): 425-436. doi: 10.12153/j.issn.1674-991X.20230370

Gliding arc plasma combines the advantages of both thermal and cold plasma, showing great application prospects in volatile organic compounds (VOCs) removal. Various types of gliding arc generators and their characteristics were introduced based on the exposition of the generation principle and basic properties of gliding arc plasma. By summarizing and collating the relevant literature at home and abroad, the key factors affecting the removal efficiency of VOCs and the differences in the performance of different gliding arc reactors in VOCs abatement were summarized. Finally, the mechanism of VOCs purification by gliding arc plasma was discussed and the future research directions of this technology were prospected.

Quantitative effect evaluation on dust control measures of construction sites
CHEN Ke, ZHOU Jun, NIE Chunxiao, FENG Xiyong, LONG Xingyue, SUN Yang, JIA Tianjiao
2024, 14(2): 437-445. doi: 10.12153/j.issn.1674-991X.20230639

With the urban planning and construction, large-scale construction projects have produced amounts of atmospheric pollutants represented by coarse particulate matter (PM10) in the process of foundation excavation, main construction and exterior wall decoration. In order to minimize PM10 caused by dust at construction sites, relevant departments require to take dust suppression measures at construction sites such as bare soil covering, stereoscopic spraying and enclosure isolation. The dust suppression effect of each measure was explored based on the on-site dust suppression measure controlled experiments and high-precision numerical wind tunnel experiments. The results showed that PM10 concentration decreased by 5.1% when only using enclosure spraying, the concentration decreased by 12.3% when only using construction spraying, and when both measures were used, the concentration decreased by 11.4%. When the wind speed was high, the dust suppression effect of bare soil cover was more significant than that of low wind, and the mean PM10 concentration of bare soil cover under third-level wind (>2 m/s) was 10.7% lower than that without bare soil cover. PM10 concentration of bare soil spray decreased by 21.3% compared with that of no spray. On the whole, the dust reduction rates during the foundation excavation stage were 3.6%, 10.5%, 18.4% and 29.0% for enclosure heights of 2, 3, 4 and 5 m, respectively. In the main construction stage, the influence distance of dust diffusion gradually decreased with the increase of emission source. When the source height was 10 m, the maximum influence distance was 75 m outside the construction site; when the source height was 30m, the maximum influence distance was 50 m. When the source height was 50 and 90 m, the dust dissipation rate was less than 10% as soon as the dust source left the site, which means that the impact outside the site could be ignored.

Research and industrial testing of truck road moisturizing dust suppressant for North Open-pit Coal Mine
ZHAO Xiaoliang, DU Jing, XIA Shiyang, SONG Ziling, YANG Guohua, WANG Chuang, GUO Meng, MA Zhimin
2024, 14(2): 446-454. doi: 10.12153/j.issn.1674-991X.20230355

Truck road transport is one of the largest sources of dust in open-pit coal mines, especially in the high-temperature environment in summer where road moisture evaporation is extremely high and truck disturbance intensity is extremely high. Taking truck pavement of Horin River North Open-pit Coal Mine as the research background, the stress state and dust production mechanism of NET200 dump truck tire adhesion dust were analyzed; the moisture content, chemical functional groups and particle size distribution of the road soil were collected and tested, and the functional positioning of moisture, wetting and coagulation of the developed dust suppressant was determined. Monomer preference experiments were carried out to determine the humectant glycerol (B), wetting agent sodium dodecylbenzene sulfonate (T) and coagulant polyacrylamide (N) as the orthogonal test materials, with evaporation as the main control index. The range method was used to determine the best formulation of humectant dust suppressant as 3.0% glycerol, 0.25% sodium dodecylbenzene sulfonate and 0.05% polyacrylamide. Through the observation of the dust surface film-forming state and water content changes under different spraying volumes, the best spraying volume was determined to be 1.6-2.0 L/m2 per unit of road surface. The results of the 12 d dust suppression industrial test in North Open-pit Coal Mine showed that the concentrations of total dust and respirable dust in all sections of the single test cycle were gradually increasing, and the concentrations of total dust and repairable dust in the dust suppressant sprayed load-bearing and non-load-bearing sections during the three tests were significantly lower than the corresponding sections of conventional water sprinkling, and they were lower than the specified limits of 4 mg/m3 of total dust and 2 mg/m3 of respirable dust, respectively, indicating that the independently developed moisturizing type dust suppressant spraying effective dust suppression time of single time was 3-4 d. Spraying dust suppressant could effectively increase the proportion of large particles in the dust, and condensation and agglomeration effect was significant. The average water content of the soil in spraying dust suppressant load-bearing and non-load-bearing section was 14% and 12%, respectively, more than 2 times the conventional sprinkling section. The research shows that the moisturizing dust suppressant can significantly extend the effective dust suppression time of a single spraying, and has significant applicability to dynamic working conditions such as mining roads.

Optimization of secondary air injection angle for garbage incineration boiler based on CFD
CHEN Weijing, SUN Jiakang, ZHENG Minfeng, GONG Lingzhu, TANG Fangzhou
2024, 14(2): 455-463. doi: 10.12153/j.issn.1674-991X.20230489
Abstract(41) HTML (16) PDF(3378KB)(20)

In order to study the influence of the secondary air injection angle on the temperature, speed, flue gas residence time and exhaust heat loss in the furnace of the incineration boiler and the correlation between the secondary air injection angle and the NOx concentration at the incinerator outlet, the UDF compiler boundary condition and Fluent coupling method were adopted. The secondary air injection angle of front and rear walls of a 600 t/d municipal solid waste incineration boiler was numerically simulated. The simulated variation range of the front wall secondary air injection angle was 68°-80°, the variation range of the rear wall secondary air injection angle was 61°-73°, the secondary wind speed was 42 m/s, and the secondary air temperature was 301.15 K. The results showed that when the secondary air injection angle of the rear wall was constant, the NOx concentration increased first and then decreased with the increase of the secondary air injection angle of the front wall. The minimum concentration of NOx was 142.23 mg/m3, the heat loss of exhaust smoke from the incineration furnace was reduced, and the minimum heat loss of exhaust smoke was 7.12%. When the secondary air injection angle of the front wall remained unchanged, the NOx concentration increased first and then decreased with the increase of the secondary air injection angle of the rear wall. The minimum concentration of NOx was 149.15 mg/m3, the heat loss of exhaust smoke from the incineration furnace increased first and then decreased, and the minimum heat loss of exhaust smoke was 7.46%. When the secondary air injection angle of front and rear walls was 80° and 67°, respectively, the average temperature between the two layers of SNCR spray guns was 1 229.59 K, and the residence time was 1.63 s, which was closer to the optimal reaction temperature and residence time of SNCR denitrification compared with other conditions. The average temperature at the exit of the first flue was 1 211.36 K, and the residence time was greater than 2 s, which helped to inhibit the formation of dioxins.

Study on microbial community structure and functional characteristics of typical rural black and odorous water bodies in Qingdao
MA Jiwei, WANG Hongbo, FENG Huijuan, LI Ao, GUO Xiaoya, BAI Yang
2024, 14(2): 464-473. doi: 10.12153/j.issn.1674-991X.20230477

Microorganisms play a significant role in the formation process of rural black and odorous water bodies. It is of great significance to fully understand their community structure and functional characteristics in order to clarify the mechanism of black and odorous water formation and implement effective governance measures. To this end, a total of 29 rural black and odorous water bodies, including pit-pond type and ditch type, in Jiaozhou City, Pingdu City, and Laixi City were studied. The water quality characteristics and black odor levels in different types of water bodies were analyzed. Based on the 16S rRNA high-throughput sequencing, the microbial community characteristics of the water bodies and their response relationship with the water quality characteristics were described, and the ecological functions of microbial communities were predicted. The results showed that the average values of ammonia nitrogen (NH3-N), dissolved oxygen (DO), and transparency were 17.4 mg/L, 5.63 mg/L, 13.9 cm and 9.3 mg/L, 6.25 mg/L, 15.5 cm in the water bodies of the pit-pond type and the ditch type, respectively, and the degree of black and odorous was higher in the former type. Microorganisms of the two types were dominated by chemoenergetic heterotrophs, and the diversity of the microbial community was greater in the pit-pond type. As a dominant phylum, the average relative abundance of phylum Firmicutes in pit-pond type water bodies was 32.10% higher than that of 18.29% in ditch type water bodies, while as a dominant class, the class γ-Proteobacteria had an average relative abundance of 27.86% in pit-pond type water bodies lower than that of 42.74% in ditch type water bodies, and there was not much difference in the relative abundance of Psychrobacter and Flavobacterium as dominant genera in the two types of water bodies. NH3-N and DO concentrations were significantly correlated (P<0.05) with the dominant genera of the two types of water bodies, which were the key factors influencing the microbial community characteristics. FAPROTAX predictions indicated that aerobic metabolism of organic matter and urea decomposition fermentation were the main functions of microbial communities in typical rural black and odorous water bodies in the region, and a higher nitrogen metabolism potential was found in the pit-pond type.

Research progress on tracing and characterization of dissolved organic matter in water environment
WU Hanhong, GAO Sijia, LIU Tingting, CHU Zhaosheng
2024, 14(2): 474-486. doi: 10.12153/j.issn.1674-991X.20230651
Abstract(238) HTML (64) PDF(4380KB)(55)

Dissolved organic matter (DOM) in water has a wide range of sources and complex components, which can participate in the migration and transformation of heavy metals and biogeochemical cycles in water. Some technical means can be used to identify the source of DOM in water, and realize the characterization of DOM components and properties, so as to understand its ecological environmental effects. The composition, characteristics and current research hotspots of DOM in water environment were briefly introduced. The application characteristics, important characterization parameters, influencing factors and limitations of UV-Vis absorption spectroscopy, three-dimensional fluorescence spectroscopy, stable isotopes, biomarkers and FT-ICR-MS in the tracing and characterization of DOM in water environment were summarized and compared. The results showed that both UV-Vis absorption spectroscopy and three-dimensional fluorescence spectroscopy had the advantages of convenient operation, fast analysis speed and no sample destruction, but their emphasis on DOM characterization was different. Stable isotope technology focused on the isotopic composition and content of carbon, nitrogen and other elements in DOM, biomarkers could record the information of DOM molecular structure, while FT-ICR-MS could characterize DOM from the molecular level. All the above technologies have broad application prospects for DOM research. However, due to the complexity of DOM components and elements as well as the limitations of each technology, the combined use of multiple technologies has become the development trend of DOM characterization and analysis. Therefore, the conditions, objectives and advantages of multi-technology co-application were described, and the research progress and cases of water environment DOM based on multi-technology integration were summarized. Finally, the future development direction of DOM traceability and representation was prospected.

Development, application and prospect of cyanobacteria blooms control technology in lakes and reservoirs
CAO Jing, YUAN Jing, ZHAO Li, PAN Zhengguo, YAN Guokai, GAO Sijia, CHU Zhaosheng, ZHENG Binghui
2024, 14(2): 487-500. doi: 10.12153/j.issn.1674-991X.20230453
Abstract(273) HTML (176) PDF(3405KB)(78)

Cyanobacteria blooms will cause a series of ecological environment problems such as the water supply system blockage, water odor, aquatic death, etc., and even threaten the safety of drinking water. Therefore, effective control technology is very important for the prevention and control of cyanobacteria blooms. The development history of cyanobacteria blooms control technology at home and abroad was summarized through literature research, and application scope, application situation, advantages and disadvantages of typical cyanobacteria blooms control technology were reviewed. The algal bloom control technology can be divided into physical algal control technology, chemical algal control technology and biological algal control technology. From the perspective of the time development of key words in technical literature, before 2010, foreign cyanobacteria bloom control technology mainly focused on chemical algal control technology such as flocculation and coagulation, and after 2010, it developed to biological algal control technology such as aquatic plant algal suppression. Before 2010, China's cyanobacteria bloom control technologies mainly focused on biological algal control technologies such as silver carp bighthys algae control and aquatic plant algae suppression. After 2010, physical algal control technologies such as ultrasonic and mechanical algal removal and chemical algal control technologies such as flocculation developed rapidly. After 2015, physical algal control technology further developed. Foreign cyanobacteria bloom control technology started from chemical algal control technology in the 1950s, and developed physical algal control technology such as ultrasonic wave and light wave after 2000, and mainly biological algal control and chemical algal control technology after 2010. Domestic cyanobacteria bloom control technology started from biological algal control technology for small water bodies in the 1980s, and gradually developed into mechanical algal removal technology (physical algal control technology) for large lakes and reservoirs after 2000. Physical algal control technology and chemical algal control technology have significant emergency effects, but physical algal control technology has disadvantages such as high cost and insufficient long-term performance, and chemical algal control technology has secondary pollution risk. However, the biological algal control technology has some ecological security problems, such as slow effect, risk of invasion of alien species, and risk of disturbance of ecosystem, so there are few practical application cases. In the future, the optimization, screening and demonstration application of cyanobacteria bloom control technology should be accelerated, and the integrated application of cyanobacteria bloom control technology with internal and external pollution control and water ecological restoration technologies should be carried out to improve the effect of cyanobacteria bloom control.

Distribution and migration characteristics of 1,2,4-trichlorobenzene pollution in a dye factory plot
WANG Shuo, QIAO Pengwei, DAI Xiaoli, LI Jiabin, WEI Yan, WEI Wenxia, LI Peizhong
2024, 14(2): 501-509. doi: 10.12153/j.issn.1674-991X.20230450

Taking a contaminated plot of a dye factory in Beijing as an example, statistical analysis was carried out on the concentration data of five chlorobenzene volatile organic pollutants (chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene) in soil and groundwater. 1,2,4-trichlorobenzene with high detected concentrations and exceedance multiples in soil and groundwater samples was selected, its vertical distribution characteristics in soil and horizontal distribution characteristics in groundwater were analyzed, and the solute migration law of 1,2,4-trichlorobenzene in groundwater was simulated by using MT3D in GMS software. This result indicated that the maximum detectable concentrations of the five chlorobenzene organic pollutants in soil samples all exceed the corresponding screening values, the maximum detectable concentrations of chlorobenzene and 1,2-dichlorobenzene in groundwater samples did not exceed the corresponding screening values, and the maximum detectable concentrations of 1,4-dichlorobenzene, 1,2,3-trichlorobenzene and 1,2,4-trichlorobenzenene exceed the corresponding screening values. High concentration of 1,2,4-trichlorobenzene in soil was mainly concentrateded in the range of 0-10 m depth. The concentration of 1,2,4-trichlorobenzene in groundwater in the northwest was significantly higher than that in the southeast. There was a slight northward movement of the groundwater level line on the north side of the plot, and the groundwater level of each monitoring well was in a slow downward trend. 1,2,4-trichlorobenzene in the block migrated to the southern boundary of the block at 540 d, with a migration distance of 96.2 m. The research results could provide a theoretical reference for precise control and reasonable restoration of polluted plots.

Research on the effect of atmospheric pressure fluctuation on the migration and transformation of benzene in soil based on TMVOC simulation
XU Xin, SUN Yuanyuan, XI Beidou, ZHENG Mingxia, DING Hongyu, SU Jing
2024, 14(2): 510-519. doi: 10.12153/j.issn.1674-991X.20230302

In order to explore the migration and transformation law of benzene series (BTEX) under the fluctuation of atmospheric pressure, and improve the control level of soil and groundwater pollution in petrochemical-polluted sites, a refinery site in northwest China was taken as the research object and, combined with indoor soil column experiment and TMVOC software simulation, BTEX leakage simulation was carried out to explore the migration and transformation law of benzene in the vadose zone and aquifer under different amplitude of atmospheric pressure fluctuation. The results show that the atmospheric pressure cycle fluctuation can cause the gaseous benzene in the vadose zone to migrate to the non-equilibrium state, resulting in the increase of the gaseous mass fraction by 0.1%-0.5%. The conversion of non-aqueous liquid (NAPL) phase pollutants into vapor phase pollutants and their volatilization through the atmosphere is the main way of leakage quality loss, and this transformation will cause atmospheric pollution in the site and its surroundings. At the same time, the amplitude of atmospheric pressure fluctuation is negatively correlated with the time of gaseous transition. The study shows that the atmospheric pressure fluctuation significantly affects the phase transformation and migration process of benzene, promotes the phase transformation of benzene, and makes more benzene transform into gas, resulting in atmospheric environmental pollution.

Research of technical specification system for the overall process of pollution control in metal-related historic abandoned mines
ZOU Tianyuan, QIAO Xiongbiao, ZHANG Zongwen, SUN Ning
2024, 14(2): 520-527. doi: 10.12153/j.issn.1674-991X.20230434
Abstract(92) HTML (39) PDF(949KB)(38)

Heavy metal pollution from metal-related historical abandoned mines is a long-standing ecological and environmental problem in China that still has not been well resolved, and is an important source of risk affecting ecological security in China. Although the pollution prevention and control of metal-related historical abandoned mines has been rapidly developed since the 12th Five-Year Plan period, the remediation technology is still immature and the relevant standards are lacking because of the relatively short overall remediation process in China. Therefore, the urgency and systematic requirements of pollution prevention and control are more prominent. At present, there are few technical specification documents directly aimed at historical abandoned mines in China and there is a lack of systematic and effective engineering technical specification standard system, resulting in poor pollution prevention and risk control effect of metal-related historical abandoned mines. Typical ecological and environmental problems in pollution prevention and control of heavy metal mines were analyzed firstly, the technical specifications for reference in pollution prevention and control projects of historical abandoned mines were sorted out, and then the differences between current technical documents and actual needs were compared. According to the principles of comprehensiveness, pertinence, systematisms and coordination, the framework of technical specification system for pollution prevention and control of historical abandoned mines involved in metal was constructed from seven main dimensions, including investigation and monitoring, assessment and evaluation, program preparation, engineering investigation and design, implementation of treatment and restoration projects, project acceptance and effectiveness evaluation, and information system construction. The requirements for formulating technical normative documents were put forward, in order to provide decision-making reference for environmental managers and standard researchers. It was suggested that on the basis of comprehensively carrying out the investigation of historical abandoned mines, the technical standards for pollution prevention and control of all kinds of historical abandoned mines should be established as soon as possible, so as to provide guarantee for implementing the ecological environmental protection plan and deepening the battle for pollution prevention and control during the 14th Five-Year Plan period.

Temporal changes of heavy metals in sludge under the condition of straw charcoal assisted earthworm composting
WANG Xingming, ZHANG Zhen, CHU Zhaoxia, DONG Peng, LIANG Shuying, DENG Ruilai
2024, 14(2): 528-537. doi: 10.12153/j.issn.1674-991X.20230416
Abstract(44) HTML (21) PDF(3376KB)(23)

In order to reduce the migration and availability of heavy metals in domestic sludge and improve its utilization rate, the residual sludge of a municipal domestic sewage treatment plant was taken as the research object, the sludge by composting alone was set as the control group, and the earthworms and different proportions of corn straw charcoal (0%, 2%, 4%, 6% and 8%) were added, to study the time variation of heavy metal concentrations and their effective state in sludge under the condition of straw charcoal assisted earthworm composting. The results showed that with the increase of composting time (0-30 d), the pH and TN concentrations of sludge first increased and then decreased, the TOC concentration gradually decreased, the EC concentration first decreased and then increased, and the TP and TK concentrations gradually increased. At the end of composting, the pH, TOC and TN concentrations decreased by 6.38%, 20.24% and 13.44% on average compared with the initial values, respectively. The concentrations of heavy metals Cd, Zn and Pb decreased first and then increased, while the concentrations of Cu, Ni and Cr increased first and then decreased. The effective concentrations of heavy metals Cd, Cu, Ni and Zn decreased first and then increased, and the effective concentrations of Cr and Pb increased first and then decreased. After 10 days of composting, the effective concentrations of Cd, Cu, Ni and Zn decreased the most compared with the initial values, with an average decrease of 40.99%, 30.65%, 16.23% and 3.17%, respectively. The addition of straw carbon could improve the weak acid environment of sludge, increase the concentration of TK, and decrease the concentrations of EC, TOC, TN and TP. The concentrations of heavy metals in sludge (except Pb) and their effective state concentrations (except Cu and Pb) decreased with the increase of the proportion of carbon added to straw. Through correlation and stepwise regression analysis, it was concluded that straw charcoal assisted earthworm composting mainly affected the effective concentration of heavy metals by changing the sludge pH and the concentrations of EC, TOC and TP, and the addition of 8% corn straw charcoal had the best effect on reducing the concentrations and effective concentrations of heavy metals in the sludge.

Experimental research on the preparation of expansion cementitious materials using municipal solid waste incineration fly ash
ZHANG Yuanxin, WANG Zhen, LU Qianming, LIU Longyu, MU Yueting, QIN Hualin
2024, 14(2): 538-544. doi: 10.12153/j.issn.1674-991X.20230405
Abstract(55) HTML (22) PDF(3267KB)(22)

In order to realize large-scale resource utilization of municipal solid waste (MSW) incineration fly ash in the field of building materials, the effect of the addition ratio of fly ash, water-solid ratio and addition of admixtures on the performance of fly ash-cement expansion cementitious system was investigated, and the hydration products were analyzed microscopically. The results indicated that with the increasing content of MSW incineration fly ash, the dispersion degree of fly ash-cement slurry decreased, the setting time was prolonged, and the compressive strength decreased continuously. The expansion rate increased first and then decreased and reached maximum when the fly ash content was 60%. As the water-solid ratio of slurry increased, the dispersion degree, the setting time and the expansion rate of fly ash-cement slurry all increased, a more reasonable water-solid ratio between 0.37 and 0.40 should be considered. Al and aluminium nitride (AlN) in fly ash reacted with water to generate gas, leading to expansion of the cementitious material, NaOH increased the alkalinity of the solution, promoting the generation of more bubbles, and improved expansion of cementitious materials. CaCl2 promoted the hydration reaction of the fly ash-cement cementitious system, leading to the formation of "cloud" shaped C—S(A)—H gel, the gel micropores were filled with clusters of hydrated calcium aluminate chloride crystals, making the structure of the solidified body more compact, the compressive strength of the solidified body was improved, and the leaching content of heavy metals and dioxine concentration decreased.

Optimization of supporting design for medical waste incineration process and testing analysis of incineration system performance
REN Dejie
2024, 14(2): 545-550. doi: 10.12153/j.issn.1674-991X.20230598
Abstract(54) HTML (11) PDF(1512KB)(24)

In order to realize efficient, safe incineration of medical waste, meeting with the environmental standards, the design calculation for the main incineration process supporting equipment (including primary combustion chamber and secondary combustion chamber) was carried out and the design parameters were reviewed. Sawdust and wood blocks were used as substrates for test waste. The parameters of the incineration process, including hydrogen chloride removal rate, heavy metal mercury removal rate, combustion efficiency, residual heat removal rate, soot removal rate, dioxin emission concentration, and overall system performance score, were studied. The volumes of the primary combustion chamber and secondary combustion chamber were determined using methods of thermal engineering theory. Performance metrics were monitored during the incineration process, and correlation analysis was conducted using SPSS 22. The results showed that the volumes of the primary combustion chamber and secondary combustion chamber were inversely calculated as 1.20 and 3.30 m³, respectively, both of which were smaller than the actual furnace volume and met the requirements. The performance score exhibited a strong positive correlation with the removal rates of hydrogen chloride, heavy metal mercury, soot, and combustion efficiency (R=0.965, 0.966, 0.982, 0.997, respectively). Conversely, the performance score was significantly negatively correlated with thermal degradation rate (R=−0.986) and dioxin emission concentration (R=−0.957).

Research progress and future trend of retired power battery recycling: CiteSpace-based visual analysis
LIU Fang, LI Anqi
2024, 14(2): 551-561. doi: 10.12153/j.issn.1674-991X.20230536
Abstract(98) HTML (39) PDF(9777KB)(43)

Based on CNKI and WoS databases, the publishing trend, high-yield authors, high-yield institutions, keyword co-occurrence and clustering of research on retired power battery recycling during 2000-2023 were analyzed using the bibliometrics software CiteSpace. The results show that the study on retired power battery recycling has shown a continuous upward trend since 2000. The foreign high-prolific authors gather and cooperate tightly, while domestic high-prolific authors are scattered and have weak cooperative relations. Foreign high-yield institutions are concentrated in developed countries, and domestic high-yield institutions are mostly from cities with higher economic development levels. The keywords co-occurrence and clustering analysis show that the recycling process, echelon utilization and the recycling system construction of retired power batteries are the research focus. In the future, cross-regional, cross-industry and interdisciplinary cooperation should be positively developed. The research on the construction of the efficient, intelligent and safe retired power battery recycling system and echelon utilization industrial chain should be strengthened to promote the healthy development of the new energy vehicle industry chain.

Study on spatial and temporal evolution of ecological risk and ecological zoning identification in Guangdong-Hong Kong-Macao Greater Bay Area under the background of urbanization
LI Chao, NIU Wenhao, HUANG Huaiyu, YAO Shunbo, GONG Zhiwen
2024, 14(2): 562-573. doi: 10.12153/j.issn.1674-991X.20221130
Abstract(305) HTML (189) PDF(13563KB)(54)

In order to reveal the transfer and change rule of land use types in the urban agglomeration of Guangdong-Hong Kong-Macao Greater Bay Area (GBA) in the past 30 years, based on four Landsat remote sensing images from 1990 to 2020, the spatial and temporal evolution characteristics of ecosystem service value (ESV) and ecological risk value in the study area were analyzed and the ecological function zoning was constructed. The results showed that in the past 30 years, the cumulative increase in construction land area in GBA was 5 616 km2, with an increase of 179%, mainly due to the transfer of forest land and cultivated land. ESV generally increased first and then decreased in time, and was spatially low in the middle and high in the surrounding area. Ecological risks were increasing in time, and the risk level was shifting to medium and high-risk types. The ecological risk was spatially characterized by high distribution in the middle and low in the surrounding area and showed a certain spatial agglomeration phenomenon. According to the distribution of ESV and ecological risk value, the research area could be divided into four functional ecological zones: strict control zone, key control zone, general control zone and ecological protection zone. The strict control zone was expanding, the key control zone was increasing first and then decreasing, and the ecological protection zone was shrinking continuously.

Quantitative analysis of the impact of human activities on habitat quality and their spatial relationship: Shijiazhuang as an example
YAN Yu, QIN Yaowei, PING Yurong, DONG Jiaqi, LI Shuangjiang, CAO Jiansheng, XIAO Jieying
2024, 14(2): 574-582. doi: 10.12153/j.issn.1674-991X.20230710
Abstract(123) HTML (33) PDF(17603KB)(28)

Quantitative analysis and revealing of the impact and the correlation of human activities on habitat quality can provide a scientific basis for the management and restoration of the regional eco-environment. Taking Shijiazhuang City as a case study, the temporal and spatial evolution of habitat quality was evaluated by InVEST model based on land use results from remote sensing images of 2010, 2015 and 2021. The spatial correlation between human activities and habitat quality and the impact of human activities on habitat quality were analyzed by bivariate spatial autocorrelation and multiscale geographically weighted regression (MGWR) models, and the human activity intensity index was constructed in combination with the land use, night light and population density data. The results showed that from 2010 to 2021, the human activity intensity in the study area was generally at a stable lower level, showing an increasing trend, with a spatial distribution of low in the western parts and high in the eastern parts. The average value of habitat quality was in the medium level, with a "V" type fluctuation, decreasing first and then increasing. In the spatial distribution, habitat quality level was high in the west and low in the central and eastern parts. There was a significant spatial heterogeneity in the impact of human activity on habitat quality, with a predominantly negative correlation and a decreasing impact, while a positive correlation appeared along rivers and in parts of mountain areas. It was suggested that the spatial correlation between human activity intensity and habitat quality should be considered for eco-environment protection and restoration measures in Shijiazhuang, focusing on the areas in the east-central parts. The measures included controlling the expansion of construction land, protecting basic farmland, and strengthening the ecological restoration along the Hutuo River to improve the habitat quality.

Coupling relation between ecosystem services and people's well-being from the perspective of human-land symbiosis and simulation prediction: a case study of southwestern Guangxi Karst-Beibu Gulf
XIE Weiwei, HU Baoqing, ZHANG Lili
2024, 14(2): 583-591. doi: 10.12153/j.issn.1674-991X.20230408
Abstract(118) HTML (56) PDF(6824KB)(37)

The coupling and coordinated development of ecosystem services and people's well-being is crucial for the management and sustainable development of regional ecosystems. Taking the Karst-Beibu Gulf in southwestern Guangxi as an example, based on the modified model, comprehensive evaluation model and coupling coordination model, the coupling relationship between ecosystem services value (ESV) and the level of people's well-being was analyzed. The results showed that from 2005 to 2020, the ESV of the Karst-Beibu Gulf in southwestern Guangxi decreased, showing a spatial characteristic of "higher in the northwest and lower in the southeast", achieving a high level of people's well-being. The coupling and coordination between ecosystem services value and people's well-being had been enhanced, and the spatial distribution was consistent with the characteristic of ESV "high in the northwest and low in the southeast". From 2025 to 2035, the ESV shows a decreasing trend, while people's well-being and the coupling of the two will increase. However, measures should be taken to address the risk of ecosystem service value reduction. The research results have enriched the analytical perspective of people's well-being, proposing suggestions for implementing the adjustment of the occupation and compensation of construction land and ecological land, strengthening the construction of coastal protective forests, and guiding capital to fully convert the ecological value into economic and cultural value, to achieve ecological sustainability and stable growth of people's income.

Study on zoning of ecological protection and restoration based on ecological assessment: taking Qinghai Lake Basin as an example
CUI Tengyu, ZHAO Jun, GUAN Mengluan, HAO Haiguang, WANG Baoliang
2024, 14(2): 592-600. doi: 10.12153/j.issn.1674-991X.20230311

In view of the ecological protection and restoration in China's ecologically vulnerable areas, taking Qinghai Lake Basin as an example, key ecological spaces were identified by evaluating the importance of ecosystem services and ecological sensitivity. At the same time, ecological protection and restoration zones were delimited based on the ecological security pattern and typical ecological problems of the basin, and the restoration strategies for different zones were proposed. The results showed that: 1) The area of extremely important ecosystem services in the basin accounted for about 63.2% of the total basin area, and the area of extremely sensitive ecological zones accounted for 6.55% of the total basin area. 2) The area of core ecological space in Qinghai Lake Basin was 18 746.72 km2 and the area of priority ecological space was 5 324.26 km2, which together constituted the critical ecological space area accounting for 81.15% of the total area of the basin. 3) According to the natural geographic features of the upper, middle and lower reaches of the basin and the topography, the ecological security pattern of the basin was constructed as "one network and four zones". Based on the ecological security pattern, key ecological space and typical ecological problems, Qinghai Lake Basin was divided into six ecological protection and restoration sub-zones, and engineering measures such as biodiversity protection, construction of wetland ecosystem network and soil and water conservation were put forward.

Research on the relationship between landscape pattern changes and human disturbance in urban agglomeration around Poyang Lake
PENG Jinchen, YE Changsheng, GAN Feng
2024, 14(2): 601-611. doi: 10.12153/j.issn.1674-991X.20230510
Abstract(135) HTML (54) PDF(13440KB)(32)

Exploring the relationship between landscape pattern evolution and human disturbance can provide theoretical basis for regional landscape pattern optimization and ecological sustainable development. Taking the urban agglomeration around Poyang Lake as an example, the spatial and temporal changes of land use landscape pattern during 2000-2020 were analyzed, and the spatiotemporal changes of human disturbance degree and its spatial coupling relationship with landscape pattern change process were explored by using landscape pattern index, human disturbance degree model, bivariate spatial autocorrelation and other methods. The results showed that from 2000 to 2020, the land use types of the urban agglomeration around Poyang Lake were mainly cultivated land and forest land, and the construction land expanded rapidly, increasing by 188 500 hm2. The patch density, Shannon diversity index and fractal dimension showed an increasing trend, while the average patch area, spread index and aggregation index showed a decreasing trend, and the landscape fragmentation degree increased. From 2000 to 2020, the average anthropogenic disturbance degree of the urban agglomeration around Poyang Lake increased from 0.462 3 to 0.468 9, and the areas with strong anthropogenic disturbance were located in Poyang Lake plain, especially in Nanchang urban area, Nanchang County and Yingtan urban area, and the range of areas with high disturbance degree continued to expand, and the disturbance intensity gradually weakened from the middle to the edge. The low value was distributed in Poyang Lake, and construction land and cultivated land were the main types of disturbance. The degree of human disturbance was positively correlated with patch density, spread index and Shannon diversity index, and negatively correlated with average patch area and aggregation index, showing obvious spatial heterogeneity.

Traits of seven medicinal plants in Taihang Mountains and their responses to soil factors
GUO Wenfang, CHEN Yanmei, GAO Fei, WANG Jiale
2024, 14(2): 612-621. doi: 10.12153/j.issn.1674-991X.20230694
Abstract(143) HTML (46) PDF(7439KB)(22)

In order to understand the trait differences of plants gradually formed during the process of adapting to the environment and their influencing factors, seven medicinal plants commonly found in Taihang Mountains were selected as the research objects, including Alkekengi officinarum, Houttuynia cordata, Artemisia argyi, Glechoma longituba, Lycium chinense, Lonicera japonica and Mentha canadensis. The plant photosynthesis, structural traits and soil physicochemical properties were measured to analyze the trait differences and their responses to soil factors. The results showed that among the seven medicinal plants, Mentha canadensis and Lycium chinense showed superior trait combinations, with higher photosynthetic rate and leaf dry matter content, and lower transpiration rate and specific leaf area; the root-to-shoot ratio of Lycium chinense was significantly higher than other plants. Spearman correlation analysis showed that leaf transpiration rate and stomatal conductance were significantly negatively correlated with leaf dry matter content and plant biomass per plant. There was a significant positive correlation between intercellular CO2 concentration and leaf relative water content, while there was a significant negative correlation between water use efficiency and specific leaf area. The changes in the traits of the seven medicinal plants on Taihang Mountain slope mainly came from interspecific variation, with the variation coefficient of photosynthetic and structural traits ranging from 11.08% to 164.42%. Except for strong variation in plant biomass per plant and root-to-shoot ratio, all other traits showed moderate variation. The average intraspecific variation coefficient of different traits was 28.75%, which was at a low level. The RDA analysis of plant traits and soil factors showed that the sum of the explanatory rates of soil pH and clay content on plant trait variation was 72.30%, which was the main soil factor affecting the traits of the seven medicinal plants, and the soil conductivity was significantly positively correlated with soil pH and clay content. Through factor analysis, the organic carbon, total nitrogen, and C/N ratio were more correlated with the changes of the traits of Alkekengi officinarum, Mentha canadensis, Artemisia argyi and Lycium chinense, and the soil moisture was more correlated with that of Glechoma longituba. In summary, the traits of the seven medicinal plants were obviously different in Taihang Mountains, which could be affected by soil pH, soil particle composition, soil conductivity, and so on. Differentiated soil improvements should be carried out for specific plant varieties.

Ecological restoration of abandoned mines within giant panda habitat based on Maxent model and circuit theory
FEI Yongqiang, HUANG Aimin, LUO Yi, ZHAO Li
2024, 14(2): 622-632. doi: 10.12153/j.issn.1674-991X.20230754
Abstract(114) HTML (32) PDF(20600KB)(33)

In order to improve the efficiency and pertinence of ecological restoration of abandoned mines in the habitat of giant pandas, based on Maxent model and circuit theory, the ecological restoration demonstration project area of abandoned mines within Giant Panda National Park (Ya'an region, Sichuan) was taken as the research zone. The suitable habitats for giant pandas and the main environmental variables affecting the habitat of giant pandas were analyzed, the ecological sources and ecological corridors were identified, and the corresponding ecological restoration strategies were proposed. The results showed that the distribution of bamboo for giant pandas, elevation, soil type, and soil thickness were the four main environmental variables affecting the habitat of giant pandas in the area, and the most suitable habitat conditions were the existence of bamboo for giant pandas, an elevation of 2 290-3 250 m, a soil type of dark brown soil or brown soil, and a soil thickness of 65-86 cm. The area of unsuitable and low-suitable areas accounted for 75.96% of the study area, and the area of unsuitable and low-suitable areas within the abandoned mines accounted for 92.23%. The suitable habitat of giant pandas was relatively fragmented. The study area had a large number of scattered ecological sources and long ecological corridors, and their distribution was affected by abandoned mines and other factors. During the ecological restoration of the abandoned mines in the area, it is necessary to start from the overall situation and environmental variables of the area, focusing on the restoration of the primary ecological sources and corridors in the Baoxing area and the Yingjing and Shimian areas. During the restoration process, it is necessary to consider the environmental variables that have a greater impact on the habitat of giant pandas, such as bamboo for food, elevation, soil type, and thickness, and refer to the most suitable habitat conditions as the target for restoration. After the restoration is completed, it is necessary to strengthen monitoring and management. This method can obtain the environmental conditions and distribution range of the suitable habitat of giant pandas, determine the key ecological restoration areas and restoration strategies, and improve the efficiency and quality of restoration, thus promoting the recovery and reproduction of rare wild animal populations such as giant pandas.

Kinetic control of sodium hypochlorite electrolysis process and disinfection effect in sewage treatment
GAO Feng, GAO Sheng, CHEN Tao, LI Yu, NIAN Zheng, YAN Cheng, WANG Chongyang
2024, 14(2): 633-641. doi: 10.12153/j.issn.1674-991X.20230572
Abstract(99) HTML (27) PDF(4624KB)(23)

In order to increase the chlorine production of sodium hypochlorite electrolysis process and meet the disinfection requirements of effluent from the advanced treatment unit in township sewage treatment station, from the perspective of reaction kinetics, the influence of electrolytic parameters such as saline concentration, current density and electrolytic temperature on the production process of sodium hypochlorite was investigated, and the influence of effluent quality of the advanced treatment unit on the disinfection effect of sodium hypochlorite was analyzed, to clarify the influence mechanism of electrolytic parameters and effluent quality. The results showed that the temperature effect, chlorine evolution potential, disproportionation reaction and activation energy could be effectively controlled by adjusting the saline concentration, current density, electrolytic temperature and time to 40 g/L, 20 A/dm2, 32 ℃ and 2.5 h, respectively, and then the yield of sodium hypochlorite could be increased to 9.28 g/L. When the dosage of sodium hypochlorite was at least 5 mg/L and the contact reaction time was 5 min, the sterilization performance of sodium hypochlorite against fecal coliform groups in denitrification filter effluent was more competitive than its oxidation performance of COD and ammonium, and could reduce the number of fecal coliform groups in water samples to 102.97 L-1, and finally meet the bacteria index requirements of A-level standard of Discharge Standard of Pollutants for Municipal Waste-water Treatment Plant (GB 18918-2002).

Research progress of advanced oxidation technology based on persulfate activation for the treatment of sulfonamides in water
LIU Shiyue, Peng Xiangtian, MA Ruirui, ZENG Ping, LI Juan, ZHU Xingyun
2024, 14(2): 642-650. doi: 10.12153/j.issn.1674-991X.20230529
Abstract(44) HTML (29) PDF(3804KB)(30)

Sulfonamide drugs (SAs) are one of the most frequently detected antibiotics in water, traditional biological treatment cannot effectively degrade sulfonamides, and thus the development of technology for efficient degradation of SAs has practical significance. In recent years, the advanced oxidation processes that generate sulfate radicals ($\mathrm{SO}_4^{-}\cdot $) by activating persulfate (PS) have received widespread attention. Various methods for the activation of PS were focused on, including thermal, ultraviolet light, metal ion and metal oxides, carbon materials and MOFs activation and so on; and their possible activation mechanisms, advantages and disadvantages were summarized. The application of advanced oxidation processes based on persulfate activation (PS-AOPs) in the degradation of sulfonamides was reviewed and the mechanism of degradation of SAs by PS-AOPs was summarized. The results showed that the activation mechanism of PS was to break O—O bond in the molecular structure, which led to the decomposition of PS to form $\mathrm{SO}_4^{-}\cdot $ or other active substances. The efficiency of PS-AOPs in degrading SAs was determined by the activation method. The degradation pathways of SAs were divided into free radical and non-free radical pathways, in which the free radical pathways mainly included partial oxidation of aniline, cleavage of sulfonamide groups and adjacent sites (${\mathrm{C—NH—}}{\mathrm{SO}}_2—{\mathrm{C}} $), and the non-free radical pathways included electron transfer, surface activation, and the role of single linear oxygen (1O2). Finally, it was suggested that the future research focus should be on the development of catalysts for stable and efficient activation of PS, as well as the synergistic effect of multiple treatment technologies. Meanwhile, research on the mechanism of SAs degradation and the actual wastewater containing SAs should be strengthened.

Research status and development trend of livestock and poultry wastewater treatment based on bibliometrics
YANG Yangyang, DING Qian, ZHOU Zizhen, LIU Jiaqiang, ZHAO Minglei, FAN Xiulei, HOU Jun
2024, 14(2): 651-662. doi: 10.12153/j.issn.1674-991X.20230495
Abstract(65) HTML (135) PDF(15878KB)(37)

To comprehensively understand the progress of academic research in the field of livestock and poultry wastewater, VOSviewer was used to statistically and visually analyze the literature related to livestock and poultry wastewater in the Web of Science (WoS) Core Collection database from 2003 to 2023 and, through keyword clustering analysis, to understand the main lines of research in this field and the changes over the years. The results showed that the number of publications in the field of livestock and poultry wastewater research had grown rapidly in the past three years, the number of publications had reached 4 117 by 2023, and Chinese and American scholars had contributed more to the research in this field and cooperated closely. Organic matter, nutrients, pathogenic bacteria, heavy metals and antibiotics were the main pollutants in livestock and poultry wastewater treatment, of which heavy metals and antibiotics had attracted more attention in recent years. It was urgent to strengthen the supervision and treatment of antibiotics in livestock and poultry wastewater. The mapping on the time scale revealed that livestock and poultry wastewater was mainly treated with biological treatment technology, and the average occurrence year of the keyword microalgae-based wastewater treatment was 2022, indicating that it was a new technology for the treatment of livestock and poultry wastewater. Besides, the research deficiencies and future development trends of livestock and poultry wastewater treatment were discussed in terms of pollutant types and treatment technologies, and it was proposed that low-energy consumption, shock-resistant, and high-value-added treatment technologies based on the concept of sustainable development may be the focus of future research, and that new water treatment technologies and applied research should be developed on this basis.

Influencing factors of partial denitrification to enhance nitrogen removal and its coupled process application progress
XUE Tongzhan, QUAN Zhidao, LI Weihua, YANG Houyun, YAN Xiangyu, YANG Xinlei
2024, 14(2): 663-671. doi: 10.12153/j.issn.1674-991X.20230621
Abstract(78) HTML (87) PDF(1443KB)(23)

As a front-end process for nitrogen removal, partial denitrification (PD) has been favored due to its advantages, such as high efficiency, low energy consumption, and low greenhouse gas emission. It has become a research hotspot in recent years. Partial denitrification coupled anammox process (PD/A) is a new biological nitrogen removal process, which not only plays an important role in the nitrogen cycle, but also holds high economic and practical value in terms of energy saving and environmental protection. The research status of PD process was introduced, and the influence of different inoculated sludge on PD process start-up was analyzed, based on existing research results. The magnetic effect, carbon source, C/N and iron-carbon ratio were reviewed to elucidate the mechanism of the influence of key factors on microbial community structure, key enzyme activity and cell metabolic pathways during enhanced nitrogen removal by PD process. The characteristics of different coupling forms of PD/A process were analyzed, and the research and application progress of the coupling process in treating practical wastewater such as municipal sewage, aquaculture wastewater and landfill leachate were summarized. Finally, the outlook of PD/A process in wastewater nitrogen removal treatment was prospected, and the potential engineering application scheme of PD/A process in landfill leachate treatment was proposed. It was considered that the key direction of future research was to overcome the influencing factors of PD and optimize the parameters of PD/A to enhance the efficiency and stability of the process.

Effectiveness, management experience and optimization suggestions for the Water Pollution Prevention and Control Fund projects in China
CHEN Qiang, DONG Jiao, ZHAO Shaoyan, ZHAO Li, JIANG Xia
2024, 14(2): 672-680. doi: 10.12153/j.issn.1674-991X.20230839
Abstract(52) HTML (28) PDF(4977KB)(25)

Since the establishment of the Water Pollution Prevention and Control Fund in 2015, both central and local government entities have undertaken extensive efforts to strengthen and standardize the management of fund projects, which has led to a significant improvement in the efficiency of fund utilization. Currently, there is limited research on water pollution prevention and control fund projects, and there is a lack of pertinent experience and practice summaries. Based on the data of the environmental status bulletin and performance evaluation, the effectiveness of the projects in promoting water quality improvement and ecological restoration, establishing long-term mechanisms, and driving social input were analyzed. The management experience of the water pollution prevention and control fund projects was summarized, from the aspects of fund investment, project planning, fund allocation, fund use, and performance evaluation. Through investigation, typical practices in system construction, project planning, process supervision, and performance management in some provinces were extracted. At the same time, the existing problems in the management of water pollution prevention and control fund projects, such as the need to expand the scope of fund support, improve the systematic planning of the projects, strengthen the technical support, and optimize the performance management. To further elevate the standard of fund management and enhance the efficiency of fund utilization, it was suggested to reasonably expand the scope of fund support based on the key tasks of water ecological environmental protection in the new era and local practical needs, adhere to basin coordination and improve the systematic planning of projects, formulate comprehensive technical guidance documents to reinforce technical support, and enhance performance management systems to strengthen effective monitoring of project outcomes.

Research progress on aquatic environmental behavior and aquatic toxicity of sulfonamide drugs
LI Xia, WANG Chen, LIU Li, ZHANG Xinyi, WEI Jian, SONG Yonghui
2024, 14(2): 681-691. doi: 10.12153/j.issn.1674-991X.20230658

Sulfonamides (SAs) are commonly found in aquatic environment, and most of them are released into the environment in the form of parent molecules or metabolites. Low concentrations of SAs can be detected in surface water, groundwater, seawater, and even drinking water, and they pose potential risks to the aquatic eco-environment and human health due to their high emissions and strong pseudo persistence in the environment. Focusing on the fate of SAs in the aquatic environment, the typical behavioral patterns of SAs in adsorption, migration, transformation, degradation and bioconcentration in the aquatic environment were summarized. Moreover, an analysis was conducted on the toxic effects of SAs on aquatic plants, aquatic animals and aquatic microorganisms. The results showed that studies on the behavior of SAs in the aqueous environment had mostly focused on its adsorption characteristics and patterns on the surface of environmental media. However, there were fewer studies on the transport transformation and bioconcentration patterns of SAs under hydrodynamic conditions. Previous studies revealed that the adsorption of SAs on the surface of environmental media mainly occurred in the form of cation exchange and molecular binding, and the charge density of the adsorbent surface was an important factor determining the adsorption amount. SAs existed widely in the aquatic environment. Although the concentration level of SAs was low, the negative impact on aquatic organisms would produce potential ecological risks, mainly manifested as interfering with the growth and development process of aquatic plants, causing the characteristic deformities of aquatic animals, interfering with the community structure and function of aquatic microorganisms, and ultimately causing macro impacts on the entire water environment and its circulation. In the future, the study on the concentration and contribution rate of SAs attenuation process in water environment and the standardized toxicity test of aquatic organisms should be strengthened, so as to further study SAs ecotoxicology and solve SAs pollution problem.

Changes of the coastal oil spill risk regime in China from 2014 to 2020
ZHANG Liguo, CHENG Jinxiang, HAN Zhaoxing, ZHENG Chaohui, XU Honglei, LI Yue
2024, 14(2): 692-698. doi: 10.12153/j.issn.1674-991X.20230496
Abstract(71) HTML (34) PDF(7121KB)(22)

In order to study the spatial and temporal distribution pattern of oil spill risk of large-scale oil transportation in marine, the spatial analysis model of marine oil spill risk was established by applying the methods of geospatial analysis, big data analysis and mathematical statistics. The changes of oil spill risk regime from 2014 to 2020 were analyzed based on the national coastal ship AIS data, historical oil spill accident data, and ecological environment sensitive area data. The results showed that compared with 2014, the average value and the maximum value of oil spill accident risk index in 2020 increased by about 27.8% and 26.8%, respectively. The change of oil spill accident risk index was about -0.46-0.40. The oil spill accident risk increasing areas were mainly in the north-south channel, Chengshantou, the mouth of the Yangtze River, Taiwan Strait, and the Pearl River estuary sea area. The oil spill accident risk decreasing areas were mainly distributed in the near-shore sea area. The high-risk concentration areas of coastal oil spill accident risk were mainly located in the Bohai Sea - North Yellow Sea, the mouth of the Yangtze River, Taiwan Strait and the Pearl River estuary sea area. There were localized adjustments within the high-risk concentration areas in 2020 compared with 2014, but the distribution pattern of high-risk concentration areas remained unchanged. The research results could provide support for risk control and emergency equipment.

Working principle of microbial fuel cell and strategies for enhancing power generation performance
JIANG Jinyuan, ZHANG Yue, HE Xuwen, TAN Wei, SONG Haoyang, SHI Dongni, ZHAO Hongbing
2024, 14(2): 699-709. doi: 10.12153/j.issn.1674-991X.20230563
Abstract(228) HTML (24) PDF(7805KB)(29)

Microbial fuel cell (MFC) is a new technology that addresses the environmental deficiencies of other energy sources. At present, low energy output is a key bottleneck in the practical application of MFC. Based on the working principle of MFC, it was proposed that poor microbial activity, resistance to electron migration, proton transfer resistance, slow cathodic reduction reaction were the limiting factors for the energy output of MFC. The strategies for improving MFC electricity production performance were summarized from the following five aspects: adjusting pH and selecting the optimal salinity to enhance microbial metabolic activity; modifying anode materials to reduce electron migration resistance; enhancing electrolyte conductivity, optimizing membrane materials, and shortening electrode spacing to reduce proton transfer resistance; preparing efficient cathode catalysts and selecting excellent electron acceptors to accelerate the cathodic reduction reaction rate; and improving the configuration of MFC reactor to improve overall power generation performance. In the future, key research could be carried out in five areas, including synthesis of new cathode catalysts, reduction of membrane pollution, optimization of microbial growth environment, preparation of excellent electrode materials, and improvement of MFC reactor configuration.

Research and application of cleaner production evaluation index system for electrolytic manganese industry
SHI Feifei, DAN Zhigang, FANG Lin, YUAN Wen, YIN Shu, YAO Yang
2024, 14(2): 710-718. doi: 10.12153/j.issn.1674-991X.20230619
Abstract(129) HTML (80) PDF(2420KB)(73)

The research on the evaluation index system of cleaner production is of great significance for various industries to further promote cleaner production. A cleaner production evaluation framework model for the whole process of “pollution source control-process emission reduction-end treatment-recycling” suitable for general industries was put forward. The evaluation index system of cleaner production in electrolytic manganese industry was constructed, which was composed of 9 first-level indicators such as production process and equipment, and 45 second-level indicators. Expert consultation and analytic hierarchy process were used to determine the index weights, and among them, the weights of harmless treatment rate and direct current consumption index of electrolytic manganese slag were 0.092 and 0.050, respectively, which reflected the emphasis and key points of cleaner production in the industry. The evaluation results of the cleaner production level of three typical enterprises showed that the score of the case enterprises was 40.78-77.26, which was lower than the Ⅰ-level of cleaner production. The index system can effectively reflect the cleaner production level of electrolytic manganese enterprises. Combined with the actual condition of Enterprise 1, 10 targeted cleaner production transformation measures were proposed from the aspects of production process and equipment and so on, which could provide a feasible reference for enterprises to promote cleaner production, and also provide a basis for the formulation of green and low-carbon policies in the industry.