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2024 Vol. 42, No. 5
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2024, 42(5): 1-9.
doi: 10.13205/j.hjgc.202405001
Abstract:
In the paper, the simultaneous nitrogen and phosphorus removal process (SNDPR) of domestic sewage was accomplished in the anaerobic/aerobic/anaerobic SBR (AAO-SBR) by gradually reducing the external carbon source addition, to reduce the carbon nitrogen ratio (C/N) of influent water, reducing the aerobic aeration rate, and increasing the residence time of aerobic and anoxic stages. The competition between PAOs and GAOs in AOA-SBR under different reaction conditions was investigated by the stoichiometric method, and the nitrogen and phosphorus removal performance, as well as the N2O emission ratio of the system were determined. The results showed that reducing the aerobic aeration rate and increasing the aerobic residence time were conducive to the proliferation of PAOs in AOA-SBR under the condition of low carbon to nitrogen ratio, which promoted denitrification and phosphorus removal. When the C/N ratio decreased from 7.0 to 3.3, the average TN removal rate reached more than 80%, and the average TP removal rate increased from 65.2% to 81.2%. Under different C/N conditions, the changes of microbial endogenous substances in AOA-SBR at anaerobic, anoxic and aerobic stages showed the coexistence characteristics of PAOs-GAO. AOA-SBR tended to enrich the characteristics of GAOs endogenous substances at a higher C/N. Higher C/N condition promoted the endogenous denitrification process of DGAOs and increased the release of N2O, and lower C/N promoted the proliferation of DPAOs. The coupled endogenous denitrification process of DGAOs-DGAOS promoted the reduction of N2O, which reduced the emission of N2O. As the C/N decreased from 7.0 to 3.3, the N2O release decreased from 2.23 to 1.05 mg/L, and the emission ratio decreased from 7.21% to 3.94%. The collaboration between DGAOs endogenous denitrification and DPAOs endogenous denitrification phosphorus removal processes can make full use of carbon sources in raw domestic sewage, which may break the bottleneck of nitrogen removal in urban domestic sewage.
In the paper, the simultaneous nitrogen and phosphorus removal process (SNDPR) of domestic sewage was accomplished in the anaerobic/aerobic/anaerobic SBR (AAO-SBR) by gradually reducing the external carbon source addition, to reduce the carbon nitrogen ratio (C/N) of influent water, reducing the aerobic aeration rate, and increasing the residence time of aerobic and anoxic stages. The competition between PAOs and GAOs in AOA-SBR under different reaction conditions was investigated by the stoichiometric method, and the nitrogen and phosphorus removal performance, as well as the N2O emission ratio of the system were determined. The results showed that reducing the aerobic aeration rate and increasing the aerobic residence time were conducive to the proliferation of PAOs in AOA-SBR under the condition of low carbon to nitrogen ratio, which promoted denitrification and phosphorus removal. When the C/N ratio decreased from 7.0 to 3.3, the average TN removal rate reached more than 80%, and the average TP removal rate increased from 65.2% to 81.2%. Under different C/N conditions, the changes of microbial endogenous substances in AOA-SBR at anaerobic, anoxic and aerobic stages showed the coexistence characteristics of PAOs-GAO. AOA-SBR tended to enrich the characteristics of GAOs endogenous substances at a higher C/N. Higher C/N condition promoted the endogenous denitrification process of DGAOs and increased the release of N2O, and lower C/N promoted the proliferation of DPAOs. The coupled endogenous denitrification process of DGAOs-DGAOS promoted the reduction of N2O, which reduced the emission of N2O. As the C/N decreased from 7.0 to 3.3, the N2O release decreased from 2.23 to 1.05 mg/L, and the emission ratio decreased from 7.21% to 3.94%. The collaboration between DGAOs endogenous denitrification and DPAOs endogenous denitrification phosphorus removal processes can make full use of carbon sources in raw domestic sewage, which may break the bottleneck of nitrogen removal in urban domestic sewage.
2024, 42(5): 10-17.
doi: 10.13205/j.hjgc.202405002
Abstract:
As the largest freshwater lake in China, Poyang Lake has important ecological functions and social values. According to the monitoring data of Poyang Lake from 2012 to 2017, six representative monitoring points in the lake were selected in this study. The trophic status of the lake was evaluated by the Trophic level index method (TLI), and the correlation coefficient method was also used to judge its accuracy based on the bioindicators. The regression equation of Poyang Lake trophic was proposed, and the hydrological characteristics of the lake were included in the calculation, and biological indicators were introduced as reference. The findings were as follows: 1) according to the evaluation result of the TLI method, the average value of TLI in Poyang Lake was within the range of 44.00 to 49.00 during the time period of the study, which means that Poyang Lake was mostly in the medium-rich trophic level. Banghu Lake, shaped like a disc, was in the eutrophic state in 30.56% of the study time, and was at a high trophic level. 2) compared with the seasonal pattern of higher algal cell density in summer and lower algal cell density in winter, the TLI values in Poyang Lake remained stable, with a standard deviation in a range of 3.00 to 5.00. The TLI value could not match the significant difference in algal cell density in the lake, and the TLI value only changed by about 2% in the case of a 300% difference in algal cell density. The reason is that the water physicochemical indicators (TP, TN, SD, COD) in the lake do not well reflect the algal proliferation status, while the TLI method is highly dependent on these indicators. 3) the drivers of algal proliferation in Poyang Lake were highly spatially heterogeneous, among which water temperature had a high positive effect on algal proliferation, and total phosphorus was one of the limiting factors for algal proliferation at monitoring point of Hukou, Banghu, and Kanshan. In contrast, flow volume and water body transparency had different effects at different points due to spatial variability in lake basin morphology. To achieve effective management and protection of lake water, other factors need to be taken into account to achieve a comprehensive master of the mechanisms driving algal proliferation.
As the largest freshwater lake in China, Poyang Lake has important ecological functions and social values. According to the monitoring data of Poyang Lake from 2012 to 2017, six representative monitoring points in the lake were selected in this study. The trophic status of the lake was evaluated by the Trophic level index method (TLI), and the correlation coefficient method was also used to judge its accuracy based on the bioindicators. The regression equation of Poyang Lake trophic was proposed, and the hydrological characteristics of the lake were included in the calculation, and biological indicators were introduced as reference. The findings were as follows: 1) according to the evaluation result of the TLI method, the average value of TLI in Poyang Lake was within the range of 44.00 to 49.00 during the time period of the study, which means that Poyang Lake was mostly in the medium-rich trophic level. Banghu Lake, shaped like a disc, was in the eutrophic state in 30.56% of the study time, and was at a high trophic level. 2) compared with the seasonal pattern of higher algal cell density in summer and lower algal cell density in winter, the TLI values in Poyang Lake remained stable, with a standard deviation in a range of 3.00 to 5.00. The TLI value could not match the significant difference in algal cell density in the lake, and the TLI value only changed by about 2% in the case of a 300% difference in algal cell density. The reason is that the water physicochemical indicators (TP, TN, SD, COD) in the lake do not well reflect the algal proliferation status, while the TLI method is highly dependent on these indicators. 3) the drivers of algal proliferation in Poyang Lake were highly spatially heterogeneous, among which water temperature had a high positive effect on algal proliferation, and total phosphorus was one of the limiting factors for algal proliferation at monitoring point of Hukou, Banghu, and Kanshan. In contrast, flow volume and water body transparency had different effects at different points due to spatial variability in lake basin morphology. To achieve effective management and protection of lake water, other factors need to be taken into account to achieve a comprehensive master of the mechanisms driving algal proliferation.
2024, 42(5): 18-27.
doi: 10.13205/j.hjgc.202405003
Abstract:
To study the distribution of nitrogen forms in sediments of the Poyang Lake, this paper divided Poyang Lake into three parts: the northern lake area, the central lake area, and the river inflow area. The overlying water and sediments were collected from different regions during the wet season, normal water period, and dry season. The ion exchangeable nitrogen (IEF-N), weak acid extractable nitrogen (WAEF-N), strong alkali extractable nitrogen (SAEF-N), and strong oxidant extractable nitrogen (SOEF-N) in sediments were extracted by graded leaching method, and the correlation between various forms of convertible nitrogen in sediments and physical and chemical properties of sediments was analyzed. The results showed that the TN content of sediments was 2.05 to 8.91 g/kg in the wet season, 1885.71 to 4727.27 mg/kg in the normal season, and 480.79 to 3933.00 mg/kg in the dry season, which was the highest in the wet season. The contents of four kinds of convertible nitrogen in sediments were significantly different in different periods; and the content of SOEF-N was the highest in the three periods, inferring SOEF-N was the main species of convertible nitrogen. Spatially, the TN content of the Poyang Lake sediments was in the sequence of the river inflow area>the northern lake area>the central lake area; the spatial distribution of convertible nitrogen content in sediments was related to the water level, and the spatial distribution of four kinds of convertible nitrogen content varied greatly in different periods. The contents of various forms of nitrogen in sediments had a great correlation with the physical and chemical properties of sediments, and were mainly affected by climate and environment.
To study the distribution of nitrogen forms in sediments of the Poyang Lake, this paper divided Poyang Lake into three parts: the northern lake area, the central lake area, and the river inflow area. The overlying water and sediments were collected from different regions during the wet season, normal water period, and dry season. The ion exchangeable nitrogen (IEF-N), weak acid extractable nitrogen (WAEF-N), strong alkali extractable nitrogen (SAEF-N), and strong oxidant extractable nitrogen (SOEF-N) in sediments were extracted by graded leaching method, and the correlation between various forms of convertible nitrogen in sediments and physical and chemical properties of sediments was analyzed. The results showed that the TN content of sediments was 2.05 to 8.91 g/kg in the wet season, 1885.71 to 4727.27 mg/kg in the normal season, and 480.79 to 3933.00 mg/kg in the dry season, which was the highest in the wet season. The contents of four kinds of convertible nitrogen in sediments were significantly different in different periods; and the content of SOEF-N was the highest in the three periods, inferring SOEF-N was the main species of convertible nitrogen. Spatially, the TN content of the Poyang Lake sediments was in the sequence of the river inflow area>the northern lake area>the central lake area; the spatial distribution of convertible nitrogen content in sediments was related to the water level, and the spatial distribution of four kinds of convertible nitrogen content varied greatly in different periods. The contents of various forms of nitrogen in sediments had a great correlation with the physical and chemical properties of sediments, and were mainly affected by climate and environment.
2024, 42(5): 28-34.
doi: 10.13205/j.hjgc.202405004
Abstract:
The Mn-Fe-Ce/GAC catalyst was prepared by impregnation calcination using activated carbon particles as the carrier and loaded with Mn-Fe-Ce polymetallic oxides, and its properties were characterized by SEM, XRD, XPS, and BET, and the results showed that the metal was well dispersed and uniformly loaded on the catalyst surface. The effects of catalyst dosage, initial pH and initial aniline concentration of wastewater on the catalytic ozone oxidation degradation of DOC and TN were investigated, and the reuse and stability of the catalyst were also investigated. The main conclusions were as follows: under the conditions of ozone dosage of 1.9 mg/(L·min), initial pH of wastewater of 6.3 and influent aniline concentration of 19.89 mg/L, the DOC and TN removal rates reached 88.88% and 86.73%, respectively, after 150 min of reaction, and the catalyst was proved to have good treatment effect. After the catalyst was reused five times, the DOC and TN removal rates were maintained more than 75% and 70% respectively, and the performance of the catalyst was stable after reuse.
The Mn-Fe-Ce/GAC catalyst was prepared by impregnation calcination using activated carbon particles as the carrier and loaded with Mn-Fe-Ce polymetallic oxides, and its properties were characterized by SEM, XRD, XPS, and BET, and the results showed that the metal was well dispersed and uniformly loaded on the catalyst surface. The effects of catalyst dosage, initial pH and initial aniline concentration of wastewater on the catalytic ozone oxidation degradation of DOC and TN were investigated, and the reuse and stability of the catalyst were also investigated. The main conclusions were as follows: under the conditions of ozone dosage of 1.9 mg/(L·min), initial pH of wastewater of 6.3 and influent aniline concentration of 19.89 mg/L, the DOC and TN removal rates reached 88.88% and 86.73%, respectively, after 150 min of reaction, and the catalyst was proved to have good treatment effect. After the catalyst was reused five times, the DOC and TN removal rates were maintained more than 75% and 70% respectively, and the performance of the catalyst was stable after reuse.
2024, 42(5): 35-41.
doi: 10.13205/j.hjgc.202405005
Abstract:
The MIL-100 (Fe, Mn) derivative catalyst, with new established active sites and regulated structure, was synthesized by hydrothermal method and calcination method to activate H2O2 for the removal of the typical new pharmaceutical pollutants, butylparaben (BPB) in water. The effects of catalyst dosage and water environmental chemical conditions (such as initial pH, reaction temperature, co-existing ions, etc.) on the degradation of BPB in water by MIL-100 (Fe, Mn) derivatives were detailly investigated, and the active species in the reaction system were also analyzed. The results showed that the MIL-100 (Fe, Mn) derivative catalytic system showed good catalytic performance in a wide range of pH and solution temperature, and increasing the catalyst dosage was conducive to the activation of H2O2 oxidation of BPB in water. Preferably, 96% of BPB could be oxidized within 15 min by the MIL-100 (Fe, Mn) derivative catalytic system under the conditions of pH=7.0, 298 K (25 ℃), 0.2 g/L catalyst and 1 mmol/L H2O2. In addition, the introduction of HCO3- in the reaction system significantly inhibited the degradation of BPB, but different concentration of NO3- and Cl- had little effect on the degradation of BPB in water. The synergistic interaction between Fe/Mn metal ions on the surface of MIL-100 (Fe, Mn) derivative catalyst could promote the decomposition of H2O2 to generate ·OH, and then rapidly oxidize BPB in water.
The MIL-100 (Fe, Mn) derivative catalyst, with new established active sites and regulated structure, was synthesized by hydrothermal method and calcination method to activate H2O2 for the removal of the typical new pharmaceutical pollutants, butylparaben (BPB) in water. The effects of catalyst dosage and water environmental chemical conditions (such as initial pH, reaction temperature, co-existing ions, etc.) on the degradation of BPB in water by MIL-100 (Fe, Mn) derivatives were detailly investigated, and the active species in the reaction system were also analyzed. The results showed that the MIL-100 (Fe, Mn) derivative catalytic system showed good catalytic performance in a wide range of pH and solution temperature, and increasing the catalyst dosage was conducive to the activation of H2O2 oxidation of BPB in water. Preferably, 96% of BPB could be oxidized within 15 min by the MIL-100 (Fe, Mn) derivative catalytic system under the conditions of pH=7.0, 298 K (25 ℃), 0.2 g/L catalyst and 1 mmol/L H2O2. In addition, the introduction of HCO3- in the reaction system significantly inhibited the degradation of BPB, but different concentration of NO3- and Cl- had little effect on the degradation of BPB in water. The synergistic interaction between Fe/Mn metal ions on the surface of MIL-100 (Fe, Mn) derivative catalyst could promote the decomposition of H2O2 to generate ·OH, and then rapidly oxidize BPB in water.
2024, 42(5): 42-52.
doi: 10.13205/j.hjgc.202405006
Abstract:
In this study, the optimal partial nitrification (PN) process was achieved by adjusting the light intensity and algae concentration, and their effects on effluent quality, dissolved oxygen (DO) concentration, the number and enzyme activity of ammonia oxidizing bacteria (AOB), the content of algae photosynthetic pigments, microbial morphology and community structure were investigated. The results of water quality measurement showed that the nitrite accumulation rate reached 88.88% under the condition of 16000 Lux illumination intensity and 1170 mL Chlorella culture solution (OD680=1.6±0.4), achieving a good PN effect. The DO monitoring results showed that the reactor was always in the concentration range of 0.1~0.11 mg/L, and the algae concentration was the main factor affecting the DO concentration in the reactor. The ammonia monooxygenase (AMO) activity and amoA gene copy number of AOB bacteria, and the concentration of three photosynthetic pigments of algae gradually stabilized at the later stage of reactor operation, indicating that AOB bacteria and algae gradually formed a stable symbiotic system in the reactor. High-throughput sequencing results showed that Nitrosomonas and Chlorella were the main functional microorganisms, and the morphologies of two functional microorganisms were observed by scanning electron microscopy. In this paper, the effect of different algal oxygen supply conditions on the activity, quantity of functional microorganisms and microbial community structure in the PN process were investigated, which provided a theoretical reference for regulating algal oxygen supply during the start-up and stable operation of the process.
In this study, the optimal partial nitrification (PN) process was achieved by adjusting the light intensity and algae concentration, and their effects on effluent quality, dissolved oxygen (DO) concentration, the number and enzyme activity of ammonia oxidizing bacteria (AOB), the content of algae photosynthetic pigments, microbial morphology and community structure were investigated. The results of water quality measurement showed that the nitrite accumulation rate reached 88.88% under the condition of 16000 Lux illumination intensity and 1170 mL Chlorella culture solution (OD680=1.6±0.4), achieving a good PN effect. The DO monitoring results showed that the reactor was always in the concentration range of 0.1~0.11 mg/L, and the algae concentration was the main factor affecting the DO concentration in the reactor. The ammonia monooxygenase (AMO) activity and amoA gene copy number of AOB bacteria, and the concentration of three photosynthetic pigments of algae gradually stabilized at the later stage of reactor operation, indicating that AOB bacteria and algae gradually formed a stable symbiotic system in the reactor. High-throughput sequencing results showed that Nitrosomonas and Chlorella were the main functional microorganisms, and the morphologies of two functional microorganisms were observed by scanning electron microscopy. In this paper, the effect of different algal oxygen supply conditions on the activity, quantity of functional microorganisms and microbial community structure in the PN process were investigated, which provided a theoretical reference for regulating algal oxygen supply during the start-up and stable operation of the process.
2024, 42(5): 53-61.
doi: 10.13205/j.hjgc.202405007
Abstract:
To explore health risks and sources of fine particles (PM2.5), we detected the oxidative potential (OP) of PM2.5 in spring in Changzhou using the dithiothreitol (DTT) method, and characterized it by DTTv (volume-normalized DTT consumption) and DTTm (mass-normalized DTT consumption). Two source apportionment methods including positive matrix factorization (PMF) and principal component analysis (PCA) combined with multiple linear regression (MLR), were used to resolve emission sources of DTTv. The results showed that the average daily DTTv and DTTm in PM2.5 were (0.83±0.09) nmol/(min·m3) and (12.52±4.22) pmol/(min·μg) during the sampling period, respectively, which were in the relatively lower exposure levels in China. Organic carbon, secondary ions (SO42-, NO3-, and NH4+), as well as characteristic elements of the traffic sources (Cu, Zn, etc.), correlated moderately with DTTv, suggesting both the secondary sources and traffic sources had some impact on PM exposure related to health. Source apportionment results from PMF showed that vehicle emission (40.1%) and secondary sources (35.6%) were more important contributors to DTTv in PM2.5 than dust sources (18.6%) and combustion sources (5.8%), and MLR-PCA source apportionment method further confirmed significant contribution to DTTv from vehicle emission and secondary sources. The results could provide theoretical and scientific guidance for precise prevention and control of air pollution and health effects.
To explore health risks and sources of fine particles (PM2.5), we detected the oxidative potential (OP) of PM2.5 in spring in Changzhou using the dithiothreitol (DTT) method, and characterized it by DTTv (volume-normalized DTT consumption) and DTTm (mass-normalized DTT consumption). Two source apportionment methods including positive matrix factorization (PMF) and principal component analysis (PCA) combined with multiple linear regression (MLR), were used to resolve emission sources of DTTv. The results showed that the average daily DTTv and DTTm in PM2.5 were (0.83±0.09) nmol/(min·m3) and (12.52±4.22) pmol/(min·μg) during the sampling period, respectively, which were in the relatively lower exposure levels in China. Organic carbon, secondary ions (SO42-, NO3-, and NH4+), as well as characteristic elements of the traffic sources (Cu, Zn, etc.), correlated moderately with DTTv, suggesting both the secondary sources and traffic sources had some impact on PM exposure related to health. Source apportionment results from PMF showed that vehicle emission (40.1%) and secondary sources (35.6%) were more important contributors to DTTv in PM2.5 than dust sources (18.6%) and combustion sources (5.8%), and MLR-PCA source apportionment method further confirmed significant contribution to DTTv from vehicle emission and secondary sources. The results could provide theoretical and scientific guidance for precise prevention and control of air pollution and health effects.
2024, 42(5): 62-69.
doi: 10.13205/j.hjgc.202405008
Abstract:
Deep eutectic solvents (DESs), as a new kind of green solvent, are non-toxic and harmless, hard to evaporate, and have good thermal stability. Using deep eutectic solvents to soak up toxic gases in flue (especially NO) becomes one of the key lookup contents. In this study, methyl urea (MTU) and acetylcholine chloride (AchCl) were used to prepare a deep eutectic solvent (MTU-AchCl DES) to learn about its NO absorption performance, and impact of DESs’ mixing ratio, NO concentration, O2, H2O and carbon dioxide on the absorption performance. The experimental consequences showed that the overall denitrification performance of MTU-AchCl DESs was best when the molar ratio was 1∶2. When there was O2 in the flue gas, the highest absorption capacity of NO by MTU-AchCl DESs was 0.223 g/g. O2 promoted the absorption with the aid of oxidizing NO into NO2. When CO2 was delivered into the flue gas, the absorption of MTU-AchCl DESs on NO had promotion in a certain degree. When H2O was once introduced, the absorption of DESs decreased, and H2O had an inhibitory impact on the absorption of NO in the DESs system. Through FI-IR and Gaussian simulation results, it was discovered that MTU-AchCl DESs and NO were mixed in the structure of nitrogen-oxygen double bond (NO), nitrogen-oxygen single bond (N—O) and nitrogen-nitrogen single bond (N—N). After the addition of O2, CO2 and H2O, the response enthalpy of the DESs machine changed from -53.334 kJ/mol to -56.212 kJ/mol, -55.423 kJ/mol and -50.982 kJ/mol. The simulation result was further verified that the components of flue gas had different effects on the absorption of NO.
Deep eutectic solvents (DESs), as a new kind of green solvent, are non-toxic and harmless, hard to evaporate, and have good thermal stability. Using deep eutectic solvents to soak up toxic gases in flue (especially NO) becomes one of the key lookup contents. In this study, methyl urea (MTU) and acetylcholine chloride (AchCl) were used to prepare a deep eutectic solvent (MTU-AchCl DES) to learn about its NO absorption performance, and impact of DESs’ mixing ratio, NO concentration, O2, H2O and carbon dioxide on the absorption performance. The experimental consequences showed that the overall denitrification performance of MTU-AchCl DESs was best when the molar ratio was 1∶2. When there was O2 in the flue gas, the highest absorption capacity of NO by MTU-AchCl DESs was 0.223 g/g. O2 promoted the absorption with the aid of oxidizing NO into NO2. When CO2 was delivered into the flue gas, the absorption of MTU-AchCl DESs on NO had promotion in a certain degree. When H2O was once introduced, the absorption of DESs decreased, and H2O had an inhibitory impact on the absorption of NO in the DESs system. Through FI-IR and Gaussian simulation results, it was discovered that MTU-AchCl DESs and NO were mixed in the structure of nitrogen-oxygen double bond (NO), nitrogen-oxygen single bond (N—O) and nitrogen-nitrogen single bond (N—N). After the addition of O2, CO2 and H2O, the response enthalpy of the DESs machine changed from -53.334 kJ/mol to -56.212 kJ/mol, -55.423 kJ/mol and -50.982 kJ/mol. The simulation result was further verified that the components of flue gas had different effects on the absorption of NO.
2024, 42(5): 70-74.
doi: 10.13205/j.hjgc.202405009
Abstract:
Waste-activated carbon and K2S2O8 were used to pretreat sludge, and different proportions of activated carbon and K2S2O8 could destroy the sludge structure and enhance the sludge dewatering performance. When 1.00 g/g VS activated carbon and 1.60 mmol/g VS S2O82- were added into the sludge, the sludge was filtered for 60, 120, 180, 240, 300 s after reaction for 20 min. The water loss was (4.95±0.05), (6.65±0.15), (7.45±0.05), (7.90±0.10), (7.90±0.01) g, respectively. Compared with the original sludge, the water loss at the same time increased by 32.00%, 20.91%, 19.20%, 17.04%, and 16.18%, respectively. The moisture content of the sludge cake was (62.63±1.09)%, which was 19.97% lower than that of the original sludge cake. These results showed that activated carbon and K2S2O8 can greatly improve the sludge dewatering performance, accelerate the sludge dewatering rate, and reduce the moisture content of the mud cake. In industrial applications, activated carbon and K2S2O8 have the advantage of low cost. When used for sludge dewatering, they can reduce sludge pretreatment costs, and an efficient sludge treatment effect can reduce sludge comprehensive treatment and subsequent disposal costs.
Waste-activated carbon and K2S2O8 were used to pretreat sludge, and different proportions of activated carbon and K2S2O8 could destroy the sludge structure and enhance the sludge dewatering performance. When 1.00 g/g VS activated carbon and 1.60 mmol/g VS S2O82- were added into the sludge, the sludge was filtered for 60, 120, 180, 240, 300 s after reaction for 20 min. The water loss was (4.95±0.05), (6.65±0.15), (7.45±0.05), (7.90±0.10), (7.90±0.01) g, respectively. Compared with the original sludge, the water loss at the same time increased by 32.00%, 20.91%, 19.20%, 17.04%, and 16.18%, respectively. The moisture content of the sludge cake was (62.63±1.09)%, which was 19.97% lower than that of the original sludge cake. These results showed that activated carbon and K2S2O8 can greatly improve the sludge dewatering performance, accelerate the sludge dewatering rate, and reduce the moisture content of the mud cake. In industrial applications, activated carbon and K2S2O8 have the advantage of low cost. When used for sludge dewatering, they can reduce sludge pretreatment costs, and an efficient sludge treatment effect can reduce sludge comprehensive treatment and subsequent disposal costs.
2024, 42(5): 75-82.
doi: 10.13205/j.hjgc.202405010
Abstract:
In recent years, the preparation of biochar from organic waste has become a research hotspot in many fields. In this paper, biochar (MS-BC) was prepared from municipal sludge (MS) by pyrolysis, and then characterized by FT-IR, SEM, EDS, and BET. The effect of preparation and operation conditions of MS-BC on its adsorption of tetracycline was investigated. The result showed that, the MS-BC1000 prepared by high-temperature pyrolysis has developed a pore structure with a large specific surface area, and can provide abundant adsorption sites and excellent adsorption performance. The removal rate of tetracycline by MS-BC 1000 was about 98.5%, at the MS-BC dosage of 0.3 g, the adsorption time of 4 h, adsorption temperature (T) of 25 ℃, the oscillation frequency (V) of 200 r/min, the initial pH of 6, and the initial tetracycline concentration (c0) of 50 mg/L. Langmuir adsorption isotherm and Lagergren’s quasi-second-order kinetic equation can better explain the adsorption behavior of tetracycline on MS-BC, mainly due to the monolayer adsorption by polar interaction and π-π interaction. The maximum adsorption capacity was 333.3 mg/g. The findings provide a theoretical basis for the reuse of municipal sludge and the treatment of tetracycline antibiotic wastewater.
In recent years, the preparation of biochar from organic waste has become a research hotspot in many fields. In this paper, biochar (MS-BC) was prepared from municipal sludge (MS) by pyrolysis, and then characterized by FT-IR, SEM, EDS, and BET. The effect of preparation and operation conditions of MS-BC on its adsorption of tetracycline was investigated. The result showed that, the MS-BC1000 prepared by high-temperature pyrolysis has developed a pore structure with a large specific surface area, and can provide abundant adsorption sites and excellent adsorption performance. The removal rate of tetracycline by MS-BC 1000 was about 98.5%, at the MS-BC dosage of 0.3 g, the adsorption time of 4 h, adsorption temperature (T) of 25 ℃, the oscillation frequency (V) of 200 r/min, the initial pH of 6, and the initial tetracycline concentration (c0) of 50 mg/L. Langmuir adsorption isotherm and Lagergren’s quasi-second-order kinetic equation can better explain the adsorption behavior of tetracycline on MS-BC, mainly due to the monolayer adsorption by polar interaction and π-π interaction. The maximum adsorption capacity was 333.3 mg/g. The findings provide a theoretical basis for the reuse of municipal sludge and the treatment of tetracycline antibiotic wastewater.
2024, 42(5): 83-89.
doi: 10.13205/j.hjgc.202405011
Abstract:
At present, research on improving the hydrogen production efficiency of cellulose waste fermentation mostly focuses on comparing different pretreatment methods and optimizing experimental conditions. While there is little research on the experimental design and application analysis of low-temperature pretreatment technology. In this study, the pretreatment temperature and time of temperature pretreatment on peanut shell were optimized for further biohydrogen production. The pretreatment conditions were designed using orthogonal experiment design (OED) and central composite design (CCD) and optimized using the direct measurement and response surface methods. The modified Gompertz model (MGM) and a logistic function model (LFM) were employed to determine the kinetics of hydrogen-rich bioenergy production from the peanut shell. The OED results showed that peanut shell pretreated for 12 h at 50 ℃ produced the maximum TRS of 3.16%, exhibiting a better result than CCD. A maximum hydrogen yield of 109.2 mL was obtained when the PSP was pretreated at -80 ℃ for 12 h, which was 54.46% higher than the control. Model simulation indicated that the LFM predicted hydrogen production more accurately than the MGM, as evidenced by the high correlation coefficient and high Pearson’s correlation between predicted and actual values. The high hydrogen yield promotion and the realization of no energy consumption of the temperature pretreatment in some peanut shell planting areas, can provide a potential application for cost-efficient and stabilized bioenergy recovery from peanut shell with temperature pretreatment.
At present, research on improving the hydrogen production efficiency of cellulose waste fermentation mostly focuses on comparing different pretreatment methods and optimizing experimental conditions. While there is little research on the experimental design and application analysis of low-temperature pretreatment technology. In this study, the pretreatment temperature and time of temperature pretreatment on peanut shell were optimized for further biohydrogen production. The pretreatment conditions were designed using orthogonal experiment design (OED) and central composite design (CCD) and optimized using the direct measurement and response surface methods. The modified Gompertz model (MGM) and a logistic function model (LFM) were employed to determine the kinetics of hydrogen-rich bioenergy production from the peanut shell. The OED results showed that peanut shell pretreated for 12 h at 50 ℃ produced the maximum TRS of 3.16%, exhibiting a better result than CCD. A maximum hydrogen yield of 109.2 mL was obtained when the PSP was pretreated at -80 ℃ for 12 h, which was 54.46% higher than the control. Model simulation indicated that the LFM predicted hydrogen production more accurately than the MGM, as evidenced by the high correlation coefficient and high Pearson’s correlation between predicted and actual values. The high hydrogen yield promotion and the realization of no energy consumption of the temperature pretreatment in some peanut shell planting areas, can provide a potential application for cost-efficient and stabilized bioenergy recovery from peanut shell with temperature pretreatment.
2024, 42(5): 90-97.
doi: 10.13205/j.hjgc.202405012
Abstract:
To investigate the working conditions and design parameters of excavation of the existing municipal solid waste (MSW) from the landfill, a large-scale study of excavation was conducted on the landfill in southern China after the pilot-scale study. The results showed that: 1) the continuity of operations of the bucket wheel excavator was poor with an efficiency lower than 50 t/h; 2) the densities of waste samples after excavation were decreased by about 34%, compared to 1.04 t/m3 of that in the original condition; 3) the average efficiency of load was about 6 vehicles per hour, which composed 46% of the design value, and continuity of operations was mainly affected by the dispatch of the MSW incineration plant; 4) within 1 to 18 hours, with the extension of continuous operation time, the excavation efficiency generally increased and then decreased, with a maximum value appearing near 10 hours, and there were differences in the distributions of excavation efficiency among day, night and crossing-day-night, and it was advisable to choose crossing-day-night operation; 5) the concentration levels of six pollutants in the air of the monitoring points of the landfill boundary and the excavation area were generally low, but the data were not enough to analyze the impact of excavation, and the rapid monitoring of air should be strengthened when the weight of waste excavated on one hour exceeding 180 t; 6) the amount of leachate and rainfall changed synchronously after excavation, and the amount of leachate after excavation was consistent with the amount of the two months before excavation, indicating that excavation did not cause an increase in the amount of leachate. The above results could provide a reference for the formal design of excavation engineering.
To investigate the working conditions and design parameters of excavation of the existing municipal solid waste (MSW) from the landfill, a large-scale study of excavation was conducted on the landfill in southern China after the pilot-scale study. The results showed that: 1) the continuity of operations of the bucket wheel excavator was poor with an efficiency lower than 50 t/h; 2) the densities of waste samples after excavation were decreased by about 34%, compared to 1.04 t/m3 of that in the original condition; 3) the average efficiency of load was about 6 vehicles per hour, which composed 46% of the design value, and continuity of operations was mainly affected by the dispatch of the MSW incineration plant; 4) within 1 to 18 hours, with the extension of continuous operation time, the excavation efficiency generally increased and then decreased, with a maximum value appearing near 10 hours, and there were differences in the distributions of excavation efficiency among day, night and crossing-day-night, and it was advisable to choose crossing-day-night operation; 5) the concentration levels of six pollutants in the air of the monitoring points of the landfill boundary and the excavation area were generally low, but the data were not enough to analyze the impact of excavation, and the rapid monitoring of air should be strengthened when the weight of waste excavated on one hour exceeding 180 t; 6) the amount of leachate and rainfall changed synchronously after excavation, and the amount of leachate after excavation was consistent with the amount of the two months before excavation, indicating that excavation did not cause an increase in the amount of leachate. The above results could provide a reference for the formal design of excavation engineering.
2024, 42(5): 98-106.
doi: 10.13205/j.hjgc.202405013
Abstract:
Under the background of the Dual Carbon goal of China, to achieve the recycling of steel slag and reduce the energy consumption and carbon emissions of the transportation industry, this paper took the waste steel slag of Pingxiang Steel Plant as the research object, designed the steel slag asphalt mixture AC-13 test group based on the characteristics of the waste steel slag, and conducted road performance tests under various environmental conditions, and compared it with the diabase asphalt mixture AC-13 control group. Based on the life cycle analysis (LCA), the article analyzed its energy consumption and CO2 emissions. The results showed that the steel slag asphalt mixture had better road performance under all tested environmental conditions than the diabase asphalt mixture, and its energy consumption and CO2 emissions were effectively reduced, which proved the steel slag asphalt mixture a sustainable cleaner pavement material.
Under the background of the Dual Carbon goal of China, to achieve the recycling of steel slag and reduce the energy consumption and carbon emissions of the transportation industry, this paper took the waste steel slag of Pingxiang Steel Plant as the research object, designed the steel slag asphalt mixture AC-13 test group based on the characteristics of the waste steel slag, and conducted road performance tests under various environmental conditions, and compared it with the diabase asphalt mixture AC-13 control group. Based on the life cycle analysis (LCA), the article analyzed its energy consumption and CO2 emissions. The results showed that the steel slag asphalt mixture had better road performance under all tested environmental conditions than the diabase asphalt mixture, and its energy consumption and CO2 emissions were effectively reduced, which proved the steel slag asphalt mixture a sustainable cleaner pavement material.
2024, 42(5): 107-113.
doi: 10.13205/j.hjgc.202405014
Abstract:
To study the effect of this technology on the removal of different chlorinated hydrocarbons, a chlorinated hydrocarbon polluted site in the Pearl River Delta was selected, and laboratory experiments and pilot-scale field experiments were carried out using the room temperature desorption technology enhanced by chemical oxidation. The results showed that after room temperature desorption, the average removal rates of contaminants such as vinyl chloride, trichloroethylene, and tetrachloroethylene in the soil were all above 80%. After alkaline activation and sodium persulfate chemical oxidation, except for tetrachloroethylene in heavily polluted soil, the removal rates of contaminants in the soil were all above 90%. Different levels of pollution in the soil had achieved the remediation target values for vinyl chloride, trichloroethylene, and tetrachloroethylene. After on-site remediation, the soil chloroethylene, trichloroethylene, and tetrachloroethylene all reached the remediation target values. The initial concentration of contaminants has a great influence on the removal of chlorinated hydrocarbons. The higher the initial concentration, the higher the desorption rate of chlorinated hydrocarbons. Engineering practice has shown that the enhanced normal temperature desorption proposed in this study is feasible for the remediation of chlorinated hydrocarbon polluted soil.
To study the effect of this technology on the removal of different chlorinated hydrocarbons, a chlorinated hydrocarbon polluted site in the Pearl River Delta was selected, and laboratory experiments and pilot-scale field experiments were carried out using the room temperature desorption technology enhanced by chemical oxidation. The results showed that after room temperature desorption, the average removal rates of contaminants such as vinyl chloride, trichloroethylene, and tetrachloroethylene in the soil were all above 80%. After alkaline activation and sodium persulfate chemical oxidation, except for tetrachloroethylene in heavily polluted soil, the removal rates of contaminants in the soil were all above 90%. Different levels of pollution in the soil had achieved the remediation target values for vinyl chloride, trichloroethylene, and tetrachloroethylene. After on-site remediation, the soil chloroethylene, trichloroethylene, and tetrachloroethylene all reached the remediation target values. The initial concentration of contaminants has a great influence on the removal of chlorinated hydrocarbons. The higher the initial concentration, the higher the desorption rate of chlorinated hydrocarbons. Engineering practice has shown that the enhanced normal temperature desorption proposed in this study is feasible for the remediation of chlorinated hydrocarbon polluted soil.
2024, 42(5): 114-121.
doi: 10.13205/j.hjgc.202405015
Abstract:
The screening of remediation technologies is a multi-objective decision-making process, that requires considering not only the preferences of decision makers, but also the performance of remediation technology. Based on 596 site cases remediated in China in recent years, this research constructed a screening index system for remediation technology as well as a quantitative approach for these indices. Moreover, the AHP (analytic hierarchy process) and entropy method were combined to determine index weights, and the TOPSIS (technique for order preference by similarity to ideal solution) was conducted to rank remediation technologies. An organic contaminated site in Shenyang was selected as the study area. To compare their performance, the AHP method, the Entropy method, and the AHP-Entropy combination method were carried out respectively to calculate the index weights, and then the optimal remediation technology was screened. Results showed that the index weights calculated by the three weighting approaches were significantly different, and the AHP-Entropy combination method can balance the subjective preference of the decision makers and the contribution of system information. The applicable remediation technology screened by AHP-Entropy TOPSIS is consistent with what was applied at the site.
The screening of remediation technologies is a multi-objective decision-making process, that requires considering not only the preferences of decision makers, but also the performance of remediation technology. Based on 596 site cases remediated in China in recent years, this research constructed a screening index system for remediation technology as well as a quantitative approach for these indices. Moreover, the AHP (analytic hierarchy process) and entropy method were combined to determine index weights, and the TOPSIS (technique for order preference by similarity to ideal solution) was conducted to rank remediation technologies. An organic contaminated site in Shenyang was selected as the study area. To compare their performance, the AHP method, the Entropy method, and the AHP-Entropy combination method were carried out respectively to calculate the index weights, and then the optimal remediation technology was screened. Results showed that the index weights calculated by the three weighting approaches were significantly different, and the AHP-Entropy combination method can balance the subjective preference of the decision makers and the contribution of system information. The applicable remediation technology screened by AHP-Entropy TOPSIS is consistent with what was applied at the site.
2024, 42(5): 122-130.
doi: 10.13205/j.hjgc.202405016
Abstract:
The monitoring of the dynamic change of regional vegetation is one of the important means of mine ecological environment restoration and its effect assessment. Based on the GEE (Google Earth Engine) cloud platform, this study extracted the normalized difference vegetation index (NDVI) dataset of the non-ferrous metal mining areas in Dexing year by year from 2012 to 2022 based on MODIS remote sensing data, and used Sen slope analysis, Mann-Kendall test and Hurst index to analyze the characteristics of spatial and temporal dynamic changes and future trends of NDVI in the historical legacy areas before and after the mine production, ecological restoration projects. The results showed that: 1) before the implementation of the ecological restoration project from 2012 to 2017, the historical area was in a natural re-greening state, and the rate of change of NDVI was 0.0024/a, and after the implementation of the ecological restoration project from 2018 to 2022, the rate of increase of NDVI was significant and reached 0.0135/a. The change of NDVI in the in-production mining area from 2012 to 2022 generally showed a fluctuating and stable low-level state; 2) the highest proportion of significant regional decrease of NDVI in the historical mining area from 2012 to 2017 reached 51.52%, and the highest proportion of increase of NDVI in this area from 2018 to 2022 reached 99.09%. The NDVI in the in-production mining area was dominated by a slightly significant increase from 2012 to 2022; 3) through predictive analysis, the historical legacy areas will undergo significant ecological restoration and governance, and continue to show strong and sustained positive development in the future; a certain proportion of the mining areas in the southwest of Dexing will show a reverse trend. This study can provide a reference for the construction of ecological restoration projects and environmental management in mining areas.
The monitoring of the dynamic change of regional vegetation is one of the important means of mine ecological environment restoration and its effect assessment. Based on the GEE (Google Earth Engine) cloud platform, this study extracted the normalized difference vegetation index (NDVI) dataset of the non-ferrous metal mining areas in Dexing year by year from 2012 to 2022 based on MODIS remote sensing data, and used Sen slope analysis, Mann-Kendall test and Hurst index to analyze the characteristics of spatial and temporal dynamic changes and future trends of NDVI in the historical legacy areas before and after the mine production, ecological restoration projects. The results showed that: 1) before the implementation of the ecological restoration project from 2012 to 2017, the historical area was in a natural re-greening state, and the rate of change of NDVI was 0.0024/a, and after the implementation of the ecological restoration project from 2018 to 2022, the rate of increase of NDVI was significant and reached 0.0135/a. The change of NDVI in the in-production mining area from 2012 to 2022 generally showed a fluctuating and stable low-level state; 2) the highest proportion of significant regional decrease of NDVI in the historical mining area from 2012 to 2017 reached 51.52%, and the highest proportion of increase of NDVI in this area from 2018 to 2022 reached 99.09%. The NDVI in the in-production mining area was dominated by a slightly significant increase from 2012 to 2022; 3) through predictive analysis, the historical legacy areas will undergo significant ecological restoration and governance, and continue to show strong and sustained positive development in the future; a certain proportion of the mining areas in the southwest of Dexing will show a reverse trend. This study can provide a reference for the construction of ecological restoration projects and environmental management in mining areas.
2024, 42(5): 131-138.
doi: 10.13205/j.hjgc.202405017
Abstract:
To explore the accumulation of nitrogen and phosphorus in bioretention facilities in practical projects, four types of typical bioretention facilities in the Yuelai Sponge City in Chongqing were taken as research objects to investigate the contents of TN, NH4+-N, NO3--N,TP and available phosphorus (AP) at different depths of soil media, and study the distribution of nitrogen and phosphorus in the medium layer. The results showed that the contents of TN and TP in the surface soil (0 to 10 cm) of ecological tree pond, rain garden, biological retention zone and biological parterre were the highest. In particular, the contents of TN in the surface soil of rain gardens were the highest, reaching 885 mg/kg. NH4+-N was mainly distributed in the middle layer of soil, accounting for about 28% of the total content. NO3--N content in different soil layers had little difference and fluctuated in the range of 0.31~1.25 mg/kg. Water content (WC) can affect the distribution of NO3--N and AP in soil, and NO3--N content in the middle and upper soil of ecological tree pool was significantly negatively correlated with WC at the level of 0.05, and higher water content can weaken the accumulation of NO3--N. pH effected the distribution of NO3--N, TP, TN and AP in soil, and the contents of AP and NO3--N in soil were negatively correlated with pH. Higher pH can reduce the accumulation of NO3--N and AP in soil.
To explore the accumulation of nitrogen and phosphorus in bioretention facilities in practical projects, four types of typical bioretention facilities in the Yuelai Sponge City in Chongqing were taken as research objects to investigate the contents of TN, NH4+-N, NO3--N,TP and available phosphorus (AP) at different depths of soil media, and study the distribution of nitrogen and phosphorus in the medium layer. The results showed that the contents of TN and TP in the surface soil (0 to 10 cm) of ecological tree pond, rain garden, biological retention zone and biological parterre were the highest. In particular, the contents of TN in the surface soil of rain gardens were the highest, reaching 885 mg/kg. NH4+-N was mainly distributed in the middle layer of soil, accounting for about 28% of the total content. NO3--N content in different soil layers had little difference and fluctuated in the range of 0.31~1.25 mg/kg. Water content (WC) can affect the distribution of NO3--N and AP in soil, and NO3--N content in the middle and upper soil of ecological tree pool was significantly negatively correlated with WC at the level of 0.05, and higher water content can weaken the accumulation of NO3--N. pH effected the distribution of NO3--N, TP, TN and AP in soil, and the contents of AP and NO3--N in soil were negatively correlated with pH. Higher pH can reduce the accumulation of NO3--N and AP in soil.
2024, 42(5): 139-146.
doi: 10.13205/j.hjgc.202405018
Abstract:
Point source pollution, such as rivers (seas) sewage outfalls, is closely related to the environmental quality of surface water. It is also the main cause of ecological environment pollution. Scientific and effective monitoring, evaluation and remediation of water environment pollution, systematically mastering the data of the rivers (seas) outfalls, and combining it into the water ecological environment intelligent monitoring and supervision system database is essential. In this paper, for the objective problem that submerged outfalls are difficult to investigate and review, a set of multi-source data fusion technology systems for secondary investigation of submerged outfalls was established based on acoustic, optical and other detection means. Taking a survey in a Town in Shanghai as an example, 51 suspected submerged outfalls were identified and located within a total of 35.5 km of shoreline survey area by multi-method collaboration. Among them, 49 locations were reviewed and confirmed to be present, with a success rate of 96.1%. After the review, 18 new submerged outfalls were found, and 31 registered submerged outfalls were also identified, i.e. the success rate of the known underwater outfalls reached 100%, which further verified the reliability of the secondary survey technology system. This also provides detailed basic data for the transparent regulation of emissions, scientific and precise pollution control and ecological environmental protection.
Point source pollution, such as rivers (seas) sewage outfalls, is closely related to the environmental quality of surface water. It is also the main cause of ecological environment pollution. Scientific and effective monitoring, evaluation and remediation of water environment pollution, systematically mastering the data of the rivers (seas) outfalls, and combining it into the water ecological environment intelligent monitoring and supervision system database is essential. In this paper, for the objective problem that submerged outfalls are difficult to investigate and review, a set of multi-source data fusion technology systems for secondary investigation of submerged outfalls was established based on acoustic, optical and other detection means. Taking a survey in a Town in Shanghai as an example, 51 suspected submerged outfalls were identified and located within a total of 35.5 km of shoreline survey area by multi-method collaboration. Among them, 49 locations were reviewed and confirmed to be present, with a success rate of 96.1%. After the review, 18 new submerged outfalls were found, and 31 registered submerged outfalls were also identified, i.e. the success rate of the known underwater outfalls reached 100%, which further verified the reliability of the secondary survey technology system. This also provides detailed basic data for the transparent regulation of emissions, scientific and precise pollution control and ecological environmental protection.
2024, 42(5): 147-153.
doi: 10.13205/j.hjgc.202405019
Abstract:
The escalating concern over global warming has prompted a heightened focus on the dynamics of carbon storage within forest ecosystems. Remote sensing technology has emerged as the favored approach for estimating carbon storage across extensive forested regions. Leveraging hyperspectral remote sensing technology enhances the precision of forest carbon storage estimation. Consequently, this study undertook the task of hyperspectral remote sensing to estimate carbon storage within Pinus Massoniana forests and compared the results with estimates derived from Landsat TM multispectral remote sensing. The spectral attributes of Pinus Massoniana forests and their correlation with carbon storage were subjected to analysis. Subsequently, models for estimating carbon storage employing hyperspectral and multispectral remote sensing data were established. The findings indicated a significantly improved accuracy in carbon storage estimation through hyperspectral remote sensing when compared to multispectral remote sensing data. Specifically, the R-squared (R2) value for the model, based on the normalized difference vegetation index data derived from hyperspectral imagery at sensitive wavelengths, approached approximately 0.8, while the root mean square error (RMSE) was notably low at 0.968 t/hm2. Hyperspectral remote sensing data excelled in capturing nuanced spectral variations within vegetation. This capability enhances the retrieval of vital parameters such as vegetation biomass and carbon storage, as well as other biochemical characteristics. Consequently, hyperspectral remote sensing contributes substantially to the enhancement of carbon storage estimation accuracy within Pinus Massoniana forests.
The escalating concern over global warming has prompted a heightened focus on the dynamics of carbon storage within forest ecosystems. Remote sensing technology has emerged as the favored approach for estimating carbon storage across extensive forested regions. Leveraging hyperspectral remote sensing technology enhances the precision of forest carbon storage estimation. Consequently, this study undertook the task of hyperspectral remote sensing to estimate carbon storage within Pinus Massoniana forests and compared the results with estimates derived from Landsat TM multispectral remote sensing. The spectral attributes of Pinus Massoniana forests and their correlation with carbon storage were subjected to analysis. Subsequently, models for estimating carbon storage employing hyperspectral and multispectral remote sensing data were established. The findings indicated a significantly improved accuracy in carbon storage estimation through hyperspectral remote sensing when compared to multispectral remote sensing data. Specifically, the R-squared (R2) value for the model, based on the normalized difference vegetation index data derived from hyperspectral imagery at sensitive wavelengths, approached approximately 0.8, while the root mean square error (RMSE) was notably low at 0.968 t/hm2. Hyperspectral remote sensing data excelled in capturing nuanced spectral variations within vegetation. This capability enhances the retrieval of vital parameters such as vegetation biomass and carbon storage, as well as other biochemical characteristics. Consequently, hyperspectral remote sensing contributes substantially to the enhancement of carbon storage estimation accuracy within Pinus Massoniana forests.
2024, 42(5): 154-162.
doi: 10.13205/j.hjgc.202405020
Abstract:
The Chinese government proposes to strive to achieve peak carbon dioxide emissions by 2030, so it is necessary to actively explore the time and peak of carbon emissions in typical regions under different development models. Combining the threshold regression model with the STIRPAT model, a threshold-STIRPAT extension model was constructed to analyze the carbon emissions of seven provinces and cities in East China from 2005 to 2019, and combined with the scenario analysis method, the carbon emissions of provinces and cities in East China from 2020 to 2040 were predicted respectively. The forecast results show that: under the development model of the benchmark scenario, all provinces and cities in East China can achieve the peak of carbon emissions target in 2030; under the model of the energy-saving development scenario and the green development scenario, all provinces and cities can achieve the peak of carbon emissions target 4 to 5 years ahead of schedule. It is suggested that the 7 provinces in East China: Shanghai, Jiangsu and Zhejiang should use the energy-saving development scenario as the standard for industrial development planning; while Anhui, Fujian, Jiangxi and Shandong should select the benchmark scenario and strive to use the energy-saving development scenario as the standard, to layout their industrial development in the future.
The Chinese government proposes to strive to achieve peak carbon dioxide emissions by 2030, so it is necessary to actively explore the time and peak of carbon emissions in typical regions under different development models. Combining the threshold regression model with the STIRPAT model, a threshold-STIRPAT extension model was constructed to analyze the carbon emissions of seven provinces and cities in East China from 2005 to 2019, and combined with the scenario analysis method, the carbon emissions of provinces and cities in East China from 2020 to 2040 were predicted respectively. The forecast results show that: under the development model of the benchmark scenario, all provinces and cities in East China can achieve the peak of carbon emissions target in 2030; under the model of the energy-saving development scenario and the green development scenario, all provinces and cities can achieve the peak of carbon emissions target 4 to 5 years ahead of schedule. It is suggested that the 7 provinces in East China: Shanghai, Jiangsu and Zhejiang should use the energy-saving development scenario as the standard for industrial development planning; while Anhui, Fujian, Jiangxi and Shandong should select the benchmark scenario and strive to use the energy-saving development scenario as the standard, to layout their industrial development in the future.
2024, 42(5): 163-171.
doi: 10.13205/j.hjgc.202405021
Abstract:
The modified Ca-based sorbent particles were prepared by the extrusion-spheronization method. The cyclic CO2 capture capacity was tested using the dual fixed bed reaction system. After 20 cycles, the CO2 uptake of the sorbents with 5% cement and 10% cellulose added was 0.19 g/g. The modified Ca-based absorbents were treated with separate hydration after the calcination under different steam volume fraction and temperature, to regenerate the CO2 capture performance. The CO2 sorption of the modified sorbent was 0.59 g/g after 20 cycles, which was realized by the hydration with 30% steam of 300 ℃. The 1st, 10th, 20th carbonation of the sorbent treated with steam hydration was examined by using the thermal gravimetric analyzer, in order to investigate the effect of hydration treatment on the reaction kinetics of the carbonation stage of the sorbent. It was found that steam hydration reactivation improves the reaction rate of the product layer diffusion control stage of carbonation. Furthermore, the test results of the micro-morphology, pore structure, and mechanical properties of the sorbent particles before and after hydration reactivation showed significant cracks on the surface of the adsorbents after activation, and the crushing force and anti-abrasion properties also decreased remarkably.
The modified Ca-based sorbent particles were prepared by the extrusion-spheronization method. The cyclic CO2 capture capacity was tested using the dual fixed bed reaction system. After 20 cycles, the CO2 uptake of the sorbents with 5% cement and 10% cellulose added was 0.19 g/g. The modified Ca-based absorbents were treated with separate hydration after the calcination under different steam volume fraction and temperature, to regenerate the CO2 capture performance. The CO2 sorption of the modified sorbent was 0.59 g/g after 20 cycles, which was realized by the hydration with 30% steam of 300 ℃. The 1st, 10th, 20th carbonation of the sorbent treated with steam hydration was examined by using the thermal gravimetric analyzer, in order to investigate the effect of hydration treatment on the reaction kinetics of the carbonation stage of the sorbent. It was found that steam hydration reactivation improves the reaction rate of the product layer diffusion control stage of carbonation. Furthermore, the test results of the micro-morphology, pore structure, and mechanical properties of the sorbent particles before and after hydration reactivation showed significant cracks on the surface of the adsorbents after activation, and the crushing force and anti-abrasion properties also decreased remarkably.
2024, 42(5): 172-182.
doi: 10.13205/j.hjgc.202405022
Abstract:
With the progress of industrialization, human living standards have been greatly improved. With the rapid economic development, a large quantity of fossil fuel combustion of CO2 is emitted into the atmosphere, aggravating global warming. At present, the development of CO2 capture and storage technology (CCS) is an effective way to reduce CO2 emissions from industrial production. Due to the huge carbon sequestration potential of steel slag and the low economic cost, from the perspective of the economy and environment, steel slag carbon sequestration technology will have a bright future. In this paper, the research status and future development of steel slag carbon sequestration technology are reviewed. The composition and resource utilization of steel slag are briefly introduced, and then the reaction mechanism, the existing problems and future development of steel slag carbon sequestration technology are put forward.
With the progress of industrialization, human living standards have been greatly improved. With the rapid economic development, a large quantity of fossil fuel combustion of CO2 is emitted into the atmosphere, aggravating global warming. At present, the development of CO2 capture and storage technology (CCS) is an effective way to reduce CO2 emissions from industrial production. Due to the huge carbon sequestration potential of steel slag and the low economic cost, from the perspective of the economy and environment, steel slag carbon sequestration technology will have a bright future. In this paper, the research status and future development of steel slag carbon sequestration technology are reviewed. The composition and resource utilization of steel slag are briefly introduced, and then the reaction mechanism, the existing problems and future development of steel slag carbon sequestration technology are put forward.
2024, 42(5): 183-191.
doi: 10.13205/j.hjgc.202405023
Abstract:
As an important initiative to reuse and reduce municipal solid waste, municipal solid waste classification and disposal is a key component in reducing greenhouse gas (GHG) emissions in the waste disposal process and achieving the goal of carbon neutrality and carbon peaking. After a pilot study in Shanghai, the "Two Networks Integration" model, which effectively combines the recycling network and the city sanitation network shows its advantage in reducing carbon emissions. However, the current research on carbon emissions from China’s domestic waste is only limited to the regional scale. Fewer greenhouse gas emission accounting systems, most of which lack accuracy and uniformity, are available in a national spatial and temporal framework. Meanwhile, most of the accounting indicators and parameters need to be updated. This project was based on a "1+4+8" urban research approach, combining fieldwork, policy, and literature research, to establish a GHG accounting system for domestic waste classification and disposal in China. The research explored the carbon emissions of domestic waste in each province and city during the 13th Five-Year Plan period through data analysis, and predicted the carbon reduction potential of the application of the "Two Networks Integration" model during the 14th Five-Year Plan period. The results showed that the carbon reduction effect (in terms of carbon emission factor) of waste treatment before and after the "Two Networks Integration" changed from 0.71 kg CO2-eq/t to 1.56 kg CO2-eq/t. It was expected that, if the coverage rate of the "Two Networks Integration" reaches 10% in China, the carbon reduction potential contributed by all regions would reach 13.1 million tons in 2025. The research also provided targeted recommendations based on the "Shanghai Experience" for different levels of city clusters to reduce energy consumption and increase synergies in the whole process of domestic waste disposal nationwide.
As an important initiative to reuse and reduce municipal solid waste, municipal solid waste classification and disposal is a key component in reducing greenhouse gas (GHG) emissions in the waste disposal process and achieving the goal of carbon neutrality and carbon peaking. After a pilot study in Shanghai, the "Two Networks Integration" model, which effectively combines the recycling network and the city sanitation network shows its advantage in reducing carbon emissions. However, the current research on carbon emissions from China’s domestic waste is only limited to the regional scale. Fewer greenhouse gas emission accounting systems, most of which lack accuracy and uniformity, are available in a national spatial and temporal framework. Meanwhile, most of the accounting indicators and parameters need to be updated. This project was based on a "1+4+8" urban research approach, combining fieldwork, policy, and literature research, to establish a GHG accounting system for domestic waste classification and disposal in China. The research explored the carbon emissions of domestic waste in each province and city during the 13th Five-Year Plan period through data analysis, and predicted the carbon reduction potential of the application of the "Two Networks Integration" model during the 14th Five-Year Plan period. The results showed that the carbon reduction effect (in terms of carbon emission factor) of waste treatment before and after the "Two Networks Integration" changed from 0.71 kg CO2-eq/t to 1.56 kg CO2-eq/t. It was expected that, if the coverage rate of the "Two Networks Integration" reaches 10% in China, the carbon reduction potential contributed by all regions would reach 13.1 million tons in 2025. The research also provided targeted recommendations based on the "Shanghai Experience" for different levels of city clusters to reduce energy consumption and increase synergies in the whole process of domestic waste disposal nationwide.
A MODELING METHOD OF DIGITAL ELEVATION MODEL FOR A LARGE GARBAGE LANDFILL BASED ON LiDAR POINT CLOUD
2024, 42(5): 192-198.
doi: 10.13205/j.hjgc.202405024
Abstract:
To solve the technical difficulties of using unmanned aerial vehicle (UAV) inspection for monitoring the stability of domestic waste landfills, the largest Xingfeng landfill in South China was taken as the research object to collect point cloud data. Four methods, namely radial basis function, nearest neighbor, triangulated irregular network, and inverse distance weighting were used to establish the digital elevation model. By analyzing the model parameters of the stack shadow map, terrain correlation, contour map, and maximum drainage length map, the suitable point cloud collection and modeling method for landfill sites were studied. The research results show that the landfill’s surface is covered with resin coatings with strong reflection directionality, which has an obvious directionality for the reflection of LiDAR rays and a strong inhibitory effect on the testable range of UAV. At an altitude of 50 meters on a flight route, a distance of no more than 60 meters between flights is required to ensure a data collection volume above 100 points/m2. In areas with high film gradients, separate air routes must be arranged. Through modeling and application effect comparison, the triangulated irregular network method has the best comprehensive performance, with a terrain elevation accuracy deviation of no more than 2 cm, and can effectively handle tasks such as terrain contour drawing and water flow simulation.
To solve the technical difficulties of using unmanned aerial vehicle (UAV) inspection for monitoring the stability of domestic waste landfills, the largest Xingfeng landfill in South China was taken as the research object to collect point cloud data. Four methods, namely radial basis function, nearest neighbor, triangulated irregular network, and inverse distance weighting were used to establish the digital elevation model. By analyzing the model parameters of the stack shadow map, terrain correlation, contour map, and maximum drainage length map, the suitable point cloud collection and modeling method for landfill sites were studied. The research results show that the landfill’s surface is covered with resin coatings with strong reflection directionality, which has an obvious directionality for the reflection of LiDAR rays and a strong inhibitory effect on the testable range of UAV. At an altitude of 50 meters on a flight route, a distance of no more than 60 meters between flights is required to ensure a data collection volume above 100 points/m2. In areas with high film gradients, separate air routes must be arranged. Through modeling and application effect comparison, the triangulated irregular network method has the best comprehensive performance, with a terrain elevation accuracy deviation of no more than 2 cm, and can effectively handle tasks such as terrain contour drawing and water flow simulation.
2024, 42(5): 199-205.
doi: 10.13205/j.hjgc.202405025
Abstract:
To achieve dynamic scheduling for a domestic waste transfer system, an optimization method based on digital twin technology was proposed. This scheduling framework comprises the physical transfer system, virtual transfer system, digital twinning center for the transfer system, and a scheduling control system specifically designed for domestic waste management. Utilizing a genetic algorithm, a corresponding virtual transfer system model was established, enabling day-to-day dynamic scheduling of domestic waste through virtual-real interactions. The effectiveness of this method was demonstrated by its application in the scheduling of the waste sorting transfer system in Wuchang District, Wuhan.
To achieve dynamic scheduling for a domestic waste transfer system, an optimization method based on digital twin technology was proposed. This scheduling framework comprises the physical transfer system, virtual transfer system, digital twinning center for the transfer system, and a scheduling control system specifically designed for domestic waste management. Utilizing a genetic algorithm, a corresponding virtual transfer system model was established, enabling day-to-day dynamic scheduling of domestic waste through virtual-real interactions. The effectiveness of this method was demonstrated by its application in the scheduling of the waste sorting transfer system in Wuchang District, Wuhan.
2024, 42(5): 206-214.
doi: 10.13205/j.hjgc.202405026
Abstract:
In this study, a simulation model of cement kiln co-processing municipal sludge technology was developed by Aspen Plus. Based on the case that the daily production of clinker was 10000 t/d, the model aimed to analyze the effect of the changes in feed rate and sludge moisture content on flue gas emission law, the calciner’s temperature and coal consumption. The results showed that when the moisture content of sludge remained at 60%, and the feed rate of sludge ranged from 1 t/d to 20 t/d, the concentration of NO and SO2 in flue gas changed from 205.5 mg/m3 and 26.5 mg/m3 to 56.7 mg/m3 and 26.8 mg/m3, respectively. When the feed rate of sludge remained at 10 t/d, and the moisture content of sludge ranged from 10% to 90%, the concentration of NO decreased from 136.5 mg/m3 to 133.1 mg/m3 and then increased to 134.6 mg/m3, while the concentration of SO2 decreased from 27.4 mg/m3 to 26.2 mg/m3. 50% was the critical moisture content of sludge for the changes in the calciner’s temperature and coal consumption. Higher moisture content decreases the temperature and increases consumption, while the opposite is true for lower moisture content. According to simulation results, it is proposed that by maintaining the calciner temperature within the range of 880~905 ℃, the moisture content of sludge can be controlled at 45%~63%, thereby ensuring a sludge feed rate of 20 t/h. The optimized production parameters are proposed to provide a reference for current technology optimization.
In this study, a simulation model of cement kiln co-processing municipal sludge technology was developed by Aspen Plus. Based on the case that the daily production of clinker was 10000 t/d, the model aimed to analyze the effect of the changes in feed rate and sludge moisture content on flue gas emission law, the calciner’s temperature and coal consumption. The results showed that when the moisture content of sludge remained at 60%, and the feed rate of sludge ranged from 1 t/d to 20 t/d, the concentration of NO and SO2 in flue gas changed from 205.5 mg/m3 and 26.5 mg/m3 to 56.7 mg/m3 and 26.8 mg/m3, respectively. When the feed rate of sludge remained at 10 t/d, and the moisture content of sludge ranged from 10% to 90%, the concentration of NO decreased from 136.5 mg/m3 to 133.1 mg/m3 and then increased to 134.6 mg/m3, while the concentration of SO2 decreased from 27.4 mg/m3 to 26.2 mg/m3. 50% was the critical moisture content of sludge for the changes in the calciner’s temperature and coal consumption. Higher moisture content decreases the temperature and increases consumption, while the opposite is true for lower moisture content. According to simulation results, it is proposed that by maintaining the calciner temperature within the range of 880~905 ℃, the moisture content of sludge can be controlled at 45%~63%, thereby ensuring a sludge feed rate of 20 t/h. The optimized production parameters are proposed to provide a reference for current technology optimization.
