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2022 Vol. 40, No. 4
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2022, 40(4): 1-7.
doi: 10.13205/j.hjgc.202204001
Abstract:
Ferrate is a water treatment agent with multi-functions such as oxidation, disinfection and flocculation etc., which has broad application prospect. This paper reviewed the research progress of ferrate in disinfection, including the inactivation characteristics of ferrate to bacteria and viruses and its influencing factors, and compared it with other disinfection technologies in terms of disinfection efficacy, disinfection mechanism and the formation of disinfection byproducts. Ferrate had good inactivation effect on bacteria and viruses in different water bodies within a wide pH range. pH, temperature and organic matters were important factors affecting the disinfection effect of ferrate. The combination of ferrate and other disinfection technologies will be the focus of future research.
Ferrate is a water treatment agent with multi-functions such as oxidation, disinfection and flocculation etc., which has broad application prospect. This paper reviewed the research progress of ferrate in disinfection, including the inactivation characteristics of ferrate to bacteria and viruses and its influencing factors, and compared it with other disinfection technologies in terms of disinfection efficacy, disinfection mechanism and the formation of disinfection byproducts. Ferrate had good inactivation effect on bacteria and viruses in different water bodies within a wide pH range. pH, temperature and organic matters were important factors affecting the disinfection effect of ferrate. The combination of ferrate and other disinfection technologies will be the focus of future research.
2022, 40(4): 8-13,21.
doi: 10.13205/j.hjgc.202204002
Abstract:
In this study antibiotic resistant genes (ARGs) in swine wastewater during the biological treatment was investigated through the methods of laboratory experiment. The ARGs removal during the biological treatment as well as the parameter optimization were explored, in order to provide the theoretical and technological support for control and elimination of ARGs in swine waste. A lab-scale membrane bio-reactor (MBR) was established to treat swine wastewater. The mean removal rate of COD and TN were 95.5% and 92.4%. At the longer SRT of 30, MBR showed the highest removal efficiency of ARGs copy number between 1.5 and 2 logs,but the removal efficiency can reach up to 3.78 logs when the SRT is shortened to 15 days. The effects of environmental factors(DO、pH、T、SS、COD、NH+4-N and TN) on the copy number and abundance of ARGs in MBR effluent showed the same trend. Therefore, by reducing SRT, increasing DO, pH, and temperature, the depletion efficiency of ARGs copy number and abundance can be improved, which has practical application value and guiding significance.
In this study antibiotic resistant genes (ARGs) in swine wastewater during the biological treatment was investigated through the methods of laboratory experiment. The ARGs removal during the biological treatment as well as the parameter optimization were explored, in order to provide the theoretical and technological support for control and elimination of ARGs in swine waste. A lab-scale membrane bio-reactor (MBR) was established to treat swine wastewater. The mean removal rate of COD and TN were 95.5% and 92.4%. At the longer SRT of 30, MBR showed the highest removal efficiency of ARGs copy number between 1.5 and 2 logs,but the removal efficiency can reach up to 3.78 logs when the SRT is shortened to 15 days. The effects of environmental factors(DO、pH、T、SS、COD、NH+4-N and TN) on the copy number and abundance of ARGs in MBR effluent showed the same trend. Therefore, by reducing SRT, increasing DO, pH, and temperature, the depletion efficiency of ARGs copy number and abundance can be improved, which has practical application value and guiding significance.
2022, 40(4): 14-21.
doi: 10.13205/j.hjgc.202204003
Abstract:
With Rhodamine B as the target pollutant, the composite catalytic material CoMn@AC was used to catalyze potassium monopersulfate (PMS) to generate SO-4· for the degradation of Rhodamine B (RhB). Then the composite material was characterized by scanning electron microscopy (SEM), specific surface and aperture analyzer(BET) and other means. The effects of catalyst loading, PMS dosage, pH and reaction temperature on the RhB degradation efficiency were investigated. The results showed that when the RhB at a concentration of 50 mg/L in 100 mL, the Co loading was 7% and the cobalt-manganese ion molar ratio was 5∶1, the composite material CoMn@AC7-5∶1 had better degradation efficiency; when the pH was in the range of 4~10, the reaction temperature was 25 ℃, and the PMS concentration was 0.250 mmol/L, the target pollutant could be removed effectively. In addition, the degradation of RhB by the CoMn@AC/PMS system accelerated significantly with the increase of temperature, and its degradation activation energy was 29.80 kJ/mol.
With Rhodamine B as the target pollutant, the composite catalytic material CoMn@AC was used to catalyze potassium monopersulfate (PMS) to generate SO-4· for the degradation of Rhodamine B (RhB). Then the composite material was characterized by scanning electron microscopy (SEM), specific surface and aperture analyzer(BET) and other means. The effects of catalyst loading, PMS dosage, pH and reaction temperature on the RhB degradation efficiency were investigated. The results showed that when the RhB at a concentration of 50 mg/L in 100 mL, the Co loading was 7% and the cobalt-manganese ion molar ratio was 5∶1, the composite material CoMn@AC7-5∶1 had better degradation efficiency; when the pH was in the range of 4~10, the reaction temperature was 25 ℃, and the PMS concentration was 0.250 mmol/L, the target pollutant could be removed effectively. In addition, the degradation of RhB by the CoMn@AC/PMS system accelerated significantly with the increase of temperature, and its degradation activation energy was 29.80 kJ/mol.
2022, 40(4): 22-28.
doi: 10.13205/j.hjgc.202204004
Abstract:
Ozone-activated carbon (O3-AC) technology can remove pollutants from wastewater through the synergistic effect of adsorption and oxidation, with the size of the AC particle being the key influencing factor. Five different particle sizes in the range of 48~1700 μm were prepared and used for O3-AC treatment of phenol wastewater. The mechanisms of AC particle size effects on pollutant adsorption, oxidation and O3 mass transfer were investigated by adsorption and oxidation kinetics. Experimental results showed that when the particle size of AC was below 150 μm, the exposure of more microscopic pore channels on the surface of AC increased the adsorption and oxidation rates by 189% and 166%, respectively, compared to AC with particle size above 150 μm; the mass transfer and decomposition rates of AC with particle size between 48~150 μm in O3 reached 0.57 min-1 and 0.51 min-1, respectively; after adding tert-butanol (TBA) to O3-AC, the COD removal rate decreased by 20% within 40 min. The decomposition of O3 was related to the catalytic oxidation reaction; after six consecutive O3-AC experiments using 48~150 μm particle size AC, the COD removal rate was maintained at 95% above, showing a good stability.
Ozone-activated carbon (O3-AC) technology can remove pollutants from wastewater through the synergistic effect of adsorption and oxidation, with the size of the AC particle being the key influencing factor. Five different particle sizes in the range of 48~1700 μm were prepared and used for O3-AC treatment of phenol wastewater. The mechanisms of AC particle size effects on pollutant adsorption, oxidation and O3 mass transfer were investigated by adsorption and oxidation kinetics. Experimental results showed that when the particle size of AC was below 150 μm, the exposure of more microscopic pore channels on the surface of AC increased the adsorption and oxidation rates by 189% and 166%, respectively, compared to AC with particle size above 150 μm; the mass transfer and decomposition rates of AC with particle size between 48~150 μm in O3 reached 0.57 min-1 and 0.51 min-1, respectively; after adding tert-butanol (TBA) to O3-AC, the COD removal rate decreased by 20% within 40 min. The decomposition of O3 was related to the catalytic oxidation reaction; after six consecutive O3-AC experiments using 48~150 μm particle size AC, the COD removal rate was maintained at 95% above, showing a good stability.
2022, 40(4): 29-34,70.
doi: 10.13205/j.hjgc.202204005
Abstract:
The promotion of bio-augmentation by filler in a denitrifying sulfide removal process was realized by adding the bacterial agent to regulate the core functional flora, and the efficiency of the denitrification and desulfurization process were improved. It was revealed that the application of filler increased the efficiency of elemental sulfur generation to about 1.5 times of the control group. The dominant bacteria in the biofilm on the filler surface were Pseudomonas and Azoarcus. The combined effect of filler and bacterial agent increased the efficiency of elemental sulfur generation to twice of the control group, and then the dominant bacteria in the biofilm on the filler after bio-augmentation were Pseudomonas and Arcobacter. Expression of sulfur oxidation functional genes was strengthened by bio-augmentation. The artificially added Pseudomonas sp.gs1 improved the impact load resistance of the biofilm on the surface of the filler, and the elemental sulfur generation rate was quickly restored after the impact.
The promotion of bio-augmentation by filler in a denitrifying sulfide removal process was realized by adding the bacterial agent to regulate the core functional flora, and the efficiency of the denitrification and desulfurization process were improved. It was revealed that the application of filler increased the efficiency of elemental sulfur generation to about 1.5 times of the control group. The dominant bacteria in the biofilm on the filler surface were Pseudomonas and Azoarcus. The combined effect of filler and bacterial agent increased the efficiency of elemental sulfur generation to twice of the control group, and then the dominant bacteria in the biofilm on the filler after bio-augmentation were Pseudomonas and Arcobacter. Expression of sulfur oxidation functional genes was strengthened by bio-augmentation. The artificially added Pseudomonas sp.gs1 improved the impact load resistance of the biofilm on the surface of the filler, and the elemental sulfur generation rate was quickly restored after the impact.
2022, 40(4): 35-42.
doi: 10.13205/j.hjgc.202204006
Abstract:
In view of the different coordination modes of different metal ions, it is difficult to synthesize bimetallic organic framework (MOFs) materials, and obtain bimetal oxides by directly calcining MOFs. In this paper, Cu3(BTC)2 was used as a material template to prepare metal oxide CuO, and Zn2+ calcination was introduced by light deposition to synthesize a bimetal oxide catalyst CuO/ZnO. And then the photocatalytic degradation performance for rhodamine B (RhB) was studied under visible light condition. The main active species of the rhodamine B was determined in the degradation process. The degradation mechanism of dyes was investigated by liquid phase in-situ infrared technology. The result showed the MOFs derivative CuO/ZnO catalyst had an excellent photocatalytic degradation ability. The degradation efficiency of 10 mg/L rhodamine B reached 67.56% above after 150 min of visible light response. Among them, superoxide radical·O2- played a major role. After 5 cycles, the degradation rate was still above 50%, which proved that the material had good reusability. A method of liquid phase in-situ infrared technology was established. The analysis result inferred that, during the degradation process, the destruction of the ethyl, carboxyl and benzene ring aromatic ring structure took place on the rhodamine B molecule, as well as the release of the amino by-products. The research results provide references for the development of high-efficiency photocatalytic system and researches on pollutant degradation mechanism.
In view of the different coordination modes of different metal ions, it is difficult to synthesize bimetallic organic framework (MOFs) materials, and obtain bimetal oxides by directly calcining MOFs. In this paper, Cu3(BTC)2 was used as a material template to prepare metal oxide CuO, and Zn2+ calcination was introduced by light deposition to synthesize a bimetal oxide catalyst CuO/ZnO. And then the photocatalytic degradation performance for rhodamine B (RhB) was studied under visible light condition. The main active species of the rhodamine B was determined in the degradation process. The degradation mechanism of dyes was investigated by liquid phase in-situ infrared technology. The result showed the MOFs derivative CuO/ZnO catalyst had an excellent photocatalytic degradation ability. The degradation efficiency of 10 mg/L rhodamine B reached 67.56% above after 150 min of visible light response. Among them, superoxide radical·O2- played a major role. After 5 cycles, the degradation rate was still above 50%, which proved that the material had good reusability. A method of liquid phase in-situ infrared technology was established. The analysis result inferred that, during the degradation process, the destruction of the ethyl, carboxyl and benzene ring aromatic ring structure took place on the rhodamine B molecule, as well as the release of the amino by-products. The research results provide references for the development of high-efficiency photocatalytic system and researches on pollutant degradation mechanism.
2022, 40(4): 43-49,146.
doi: 10.13205/j.hjgc.202204007
Abstract:
To investigate the impact of surrounding heterogenous media on the remediation efficiency of the multi-screen wells, two-dimensional numerical simulations were performed. In the numerical model, high-permeable lenses were constructed around the well and the location, size and hydraulic conductivity of the lenses were changed in different setups. The results showed that the surrounding high-permeable lenses and their position, size and hydraulic conductivity had impact on the remediation efficiency of the multi-screen wells, and its value depended on the effect of flow focusing and meandering introduced by the high-permeable lenses. The high-permeable porous media surrounding the well could significantly enhance remediation efficiency. The optimal injection interval changed due to the existence of heterogeneity surrounding the well. In general, optimal injection interval was enhanced with the surrounding high-permeable porous media. This study provides theoretical instruction for the groundwater remediation using multi-screen wells in heterogeneous aquifer. Furthermore, it offers a new idea on further enhancing remediation efficiency by the multi-screen wells.
To investigate the impact of surrounding heterogenous media on the remediation efficiency of the multi-screen wells, two-dimensional numerical simulations were performed. In the numerical model, high-permeable lenses were constructed around the well and the location, size and hydraulic conductivity of the lenses were changed in different setups. The results showed that the surrounding high-permeable lenses and their position, size and hydraulic conductivity had impact on the remediation efficiency of the multi-screen wells, and its value depended on the effect of flow focusing and meandering introduced by the high-permeable lenses. The high-permeable porous media surrounding the well could significantly enhance remediation efficiency. The optimal injection interval changed due to the existence of heterogeneity surrounding the well. In general, optimal injection interval was enhanced with the surrounding high-permeable porous media. This study provides theoretical instruction for the groundwater remediation using multi-screen wells in heterogeneous aquifer. Furthermore, it offers a new idea on further enhancing remediation efficiency by the multi-screen wells.
2022, 40(4): 50-56,78.
doi: 10.13205/j.hjgc.202204008
Abstract:
Aiming at small-scale quench tower in limited space, the effect of operation parameters of spray nozzle on the evaporation process was studied by using computational fluid dynamics (CFD), such as atomization droplet size, jet relocity and spray angle. The results showed that with the increase of the droplet size, the evaporation time, axial and radial evaporation distance of the droplet increased accordingly, and the evaporation time increased by 293% when droplet size increased from 40 μm to 80 μm. When the jet velocity of droplet increased, the evaporation time, axial and radial evaporation distance of the droplet decreased, but the effect was weakened when the jet velocity increased to a certain value. The increase of spray angle caused the decrease of the evaporation time and axial evaporation distance of the droplet, but there was no obvious trend on the radial evaporation distance. The small atomizing droplet size nozzle below 70 μm could directly and effectively improve the operation safety. By comparison, it was found that a turbulence intensified area was formed in the upper part of the quench tower with volute inlet, and that led to better cooling characteristic and operational safety than quench tower with upper vertical inlet, when the space of quench tower was limited. The axial safety margin could be increased by 7% with a droplet size of 80 μm. The simulation results could provide optimal design scheme and operation guidance for engineering application of miniaturized quench tower.
Aiming at small-scale quench tower in limited space, the effect of operation parameters of spray nozzle on the evaporation process was studied by using computational fluid dynamics (CFD), such as atomization droplet size, jet relocity and spray angle. The results showed that with the increase of the droplet size, the evaporation time, axial and radial evaporation distance of the droplet increased accordingly, and the evaporation time increased by 293% when droplet size increased from 40 μm to 80 μm. When the jet velocity of droplet increased, the evaporation time, axial and radial evaporation distance of the droplet decreased, but the effect was weakened when the jet velocity increased to a certain value. The increase of spray angle caused the decrease of the evaporation time and axial evaporation distance of the droplet, but there was no obvious trend on the radial evaporation distance. The small atomizing droplet size nozzle below 70 μm could directly and effectively improve the operation safety. By comparison, it was found that a turbulence intensified area was formed in the upper part of the quench tower with volute inlet, and that led to better cooling characteristic and operational safety than quench tower with upper vertical inlet, when the space of quench tower was limited. The axial safety margin could be increased by 7% with a droplet size of 80 μm. The simulation results could provide optimal design scheme and operation guidance for engineering application of miniaturized quench tower.
2022, 40(4): 57-63,105.
doi: 10.13205/j.hjgc.202204009
Abstract:
NOx is one of the main pollutants that cause acid rain and photochemical smog. PCDD/Fs are the most toxic substance known to mankind so far. The coordinated control of multiple pollutants has become the focus of air pollution control in the new era because it can greatly reduce the cost of treatment. In this paper, the MnO2 catalyst was prepared by hydrothermal method, and the simultaneous catalytic removal of nitrogen oxides and chlorobenzene was investigated. Meanwhile, the effect of different precursors on the catalytic performance was investigated. The results showed that the main formation of manganese sulfate as the precursor was α-MnO2, which exhibited the best catalytic performance for catalytic removal of nitrogen oxides and chlorobenzene, and had good catalytic stability. It still maintained 98% of NO conversion and 88% of chlorobenzene conversion after 16 h continuous reaction. The α-MnO2 had a large specific surface area, a high Mn3+ concentration on the surface, and richer surface active oxygen species, so it exhibited excellent redox performance at medium and low temperatures. Therefore, the α-MnO2 catalyst with manganese sulfate as the precursor exhibited the best catalytic performance.
NOx is one of the main pollutants that cause acid rain and photochemical smog. PCDD/Fs are the most toxic substance known to mankind so far. The coordinated control of multiple pollutants has become the focus of air pollution control in the new era because it can greatly reduce the cost of treatment. In this paper, the MnO2 catalyst was prepared by hydrothermal method, and the simultaneous catalytic removal of nitrogen oxides and chlorobenzene was investigated. Meanwhile, the effect of different precursors on the catalytic performance was investigated. The results showed that the main formation of manganese sulfate as the precursor was α-MnO2, which exhibited the best catalytic performance for catalytic removal of nitrogen oxides and chlorobenzene, and had good catalytic stability. It still maintained 98% of NO conversion and 88% of chlorobenzene conversion after 16 h continuous reaction. The α-MnO2 had a large specific surface area, a high Mn3+ concentration on the surface, and richer surface active oxygen species, so it exhibited excellent redox performance at medium and low temperatures. Therefore, the α-MnO2 catalyst with manganese sulfate as the precursor exhibited the best catalytic performance.
2022, 40(4): 64-70.
doi: 10.13205/j.hjgc.202204010
Abstract:
In response to the requirements of building indoor purification in the post-COVID-19 era, six kinds of different filter units were selected (No.1—G4 carbon cloth, No.2—G4 polyester, No.3—F7 glass fiber, No.4—F7 electrostatic melt blown cloth, No.5—G4 polyester+F7 glass fiber, No.6-micro static charge electric module+G4 Polyester), and the PM2.5 purification performance of different filter units were analysed through experiments. The primary filtration efficiency, PM2.5 purification efficiency, resistance, CADR and CEE of the different filter units were tested. The results showed that: 1) No.5 and No.6 composed filter unit could effectively improve the primary filtration efficiency of the filter unit and PM2.5 purification efficiency. 2) At the rated wind speed, the resistance of the No.2 filter unit was the lowest, and the resistance of the No.5 filter unit was the highest. 3) In the maximum air volume condition, CADR and CEE of the No.2 filter unit was the smallest, and CADR and CEE of the No.4 filter unit was the largest. The CADR and CEE of No.2 filter unit was about 7.13% and 6.54% of that of No.4 filter unit, respectively. Compared with No.2 filter unit, CADR and CEE of No.6 filter unit was increased by approximately 150% and 247%, respectively. The micro static charge electric module could promote the primary filtration efficiency and the PM2.5 purification efficiency, and shorten the purification time effectively without increasing the resistance.
In response to the requirements of building indoor purification in the post-COVID-19 era, six kinds of different filter units were selected (No.1—G4 carbon cloth, No.2—G4 polyester, No.3—F7 glass fiber, No.4—F7 electrostatic melt blown cloth, No.5—G4 polyester+F7 glass fiber, No.6-micro static charge electric module+G4 Polyester), and the PM2.5 purification performance of different filter units were analysed through experiments. The primary filtration efficiency, PM2.5 purification efficiency, resistance, CADR and CEE of the different filter units were tested. The results showed that: 1) No.5 and No.6 composed filter unit could effectively improve the primary filtration efficiency of the filter unit and PM2.5 purification efficiency. 2) At the rated wind speed, the resistance of the No.2 filter unit was the lowest, and the resistance of the No.5 filter unit was the highest. 3) In the maximum air volume condition, CADR and CEE of the No.2 filter unit was the smallest, and CADR and CEE of the No.4 filter unit was the largest. The CADR and CEE of No.2 filter unit was about 7.13% and 6.54% of that of No.4 filter unit, respectively. Compared with No.2 filter unit, CADR and CEE of No.6 filter unit was increased by approximately 150% and 247%, respectively. The micro static charge electric module could promote the primary filtration efficiency and the PM2.5 purification efficiency, and shorten the purification time effectively without increasing the resistance.
2022, 40(4): 71-78.
doi: 10.13205/j.hjgc.202204011
Abstract:
Aiming at the problems of long traditional composting cycle, low dehydration efficiency, and poor insulation preservation effect, this research used kitchen waste and sawdust as raw materials, based on a composting reactor with external heat source, the effect of ventilation modes (natural ventilation and high-temperature ventilation with external heat source) and ventilation rates on temperature, moisture content, oxygen content, maturity index (pH, electric conductivity, germination index) and nitrogen form transformation during high-temperature composting of food waste were studied. The results showed that: 1) the high-temperature ventilation mode was helpful to maintain high temperature of the reactor, significantly prolonged the high temperature period, improved the water removal rate and maturity of the reactor. Compared with natural ventilation, the high temperature period (≥50 ℃) under high temperature ventilation was extended for 6 days, the cumulative temperature increased by 51.77%, the water removal rate increased by 62.37%, and the seed germination rate increased by 14.75%; 2) compared with natural ventilation, the ammonia volatilization and nitrogen loss under high temperature ventilation treatment increased by 131.46% and 74.87% respectively; 3) the increase of ventilation rate could improve the water removal rate. When the aeration rate reached 0.75 L/(kg DM·min), the water removal rate reached the peak value of 80.31%; 4) in the high-temperature ventilation mode, ammonia volatilization and nitrogen loss increased with the increase of ventilation rate, and ammonia volatilization accounted for 55.48%~70.73% of nitrogen loss, which was the main way of nitrogen loss.
Aiming at the problems of long traditional composting cycle, low dehydration efficiency, and poor insulation preservation effect, this research used kitchen waste and sawdust as raw materials, based on a composting reactor with external heat source, the effect of ventilation modes (natural ventilation and high-temperature ventilation with external heat source) and ventilation rates on temperature, moisture content, oxygen content, maturity index (pH, electric conductivity, germination index) and nitrogen form transformation during high-temperature composting of food waste were studied. The results showed that: 1) the high-temperature ventilation mode was helpful to maintain high temperature of the reactor, significantly prolonged the high temperature period, improved the water removal rate and maturity of the reactor. Compared with natural ventilation, the high temperature period (≥50 ℃) under high temperature ventilation was extended for 6 days, the cumulative temperature increased by 51.77%, the water removal rate increased by 62.37%, and the seed germination rate increased by 14.75%; 2) compared with natural ventilation, the ammonia volatilization and nitrogen loss under high temperature ventilation treatment increased by 131.46% and 74.87% respectively; 3) the increase of ventilation rate could improve the water removal rate. When the aeration rate reached 0.75 L/(kg DM·min), the water removal rate reached the peak value of 80.31%; 4) in the high-temperature ventilation mode, ammonia volatilization and nitrogen loss increased with the increase of ventilation rate, and ammonia volatilization accounted for 55.48%~70.73% of nitrogen loss, which was the main way of nitrogen loss.
2022, 40(4): 79-88.
doi: 10.13205/j.hjgc.202204012
Abstract:
Cow manure biochar (BC) were prepared by low-limit oxygen pyrolysis of cow manure at 400 ℃, 500 ℃ and 600 ℃, and then sulfur-modified cow manure biochar (BCS) were prepared by co-pyrolysis of sublimated sulfur and BC at different mass ratios. The BC and BCS were characterized by elemental analyzer, SEM, FTIR, XPS and BET, and the adsorption characteristics of each BC and BCS sample for Hg2+ were studied. The results showed that with the increase of pyrolysis temperature, BC and BCS became coarse and porous, and Hg2+ was adsorbed on the surface and pore of biochar. Kinetic experiments showed that the adsorption process of BC and BCS could be better described by the pseudo-second-order model than the pseudo-first-order model. The equilibrium time of BCS for Hg2+ adsorption was only 30 min, and the adsorption process was not affected by pH. The results of isothermal experiments showed that Langmuir model could better describe the adsorption process of BC, and the adsorption capacity decreased when increasing pyrolysis temperature. The isothermal adsorption of BCS to Hg2+ conformed to the Freundlich equation, the adsorption capacity of BCS was significantly higher than BC, and the maximum adsorption capacity was 407.81 mg/g. The desorption experiments showed that the adsorption stability of BCS was higher than BC, and the desorption rate was lower than 5% in each desorption agent. The results of FTIR and XPS showed that the main adsorption mechanisms of BC and BCS were functional group complexation and HgS precipitation, respectively. Therefore, BCS is a highly efficient and stable mercury adsorption material.
Cow manure biochar (BC) were prepared by low-limit oxygen pyrolysis of cow manure at 400 ℃, 500 ℃ and 600 ℃, and then sulfur-modified cow manure biochar (BCS) were prepared by co-pyrolysis of sublimated sulfur and BC at different mass ratios. The BC and BCS were characterized by elemental analyzer, SEM, FTIR, XPS and BET, and the adsorption characteristics of each BC and BCS sample for Hg2+ were studied. The results showed that with the increase of pyrolysis temperature, BC and BCS became coarse and porous, and Hg2+ was adsorbed on the surface and pore of biochar. Kinetic experiments showed that the adsorption process of BC and BCS could be better described by the pseudo-second-order model than the pseudo-first-order model. The equilibrium time of BCS for Hg2+ adsorption was only 30 min, and the adsorption process was not affected by pH. The results of isothermal experiments showed that Langmuir model could better describe the adsorption process of BC, and the adsorption capacity decreased when increasing pyrolysis temperature. The isothermal adsorption of BCS to Hg2+ conformed to the Freundlich equation, the adsorption capacity of BCS was significantly higher than BC, and the maximum adsorption capacity was 407.81 mg/g. The desorption experiments showed that the adsorption stability of BCS was higher than BC, and the desorption rate was lower than 5% in each desorption agent. The results of FTIR and XPS showed that the main adsorption mechanisms of BC and BCS were functional group complexation and HgS precipitation, respectively. Therefore, BCS is a highly efficient and stable mercury adsorption material.
2022, 40(4): 89-96,120.
doi: 10.13205/j.hjgc.202204013
Abstract:
In order to clarify the effects of antibiotics on anaerobic digestion of pig manure, this study focused on methane production potential, metabolism, and byproducts of anaerobic digestion under the treatment of three typical antibiotics. The methane production potential of tetracycline and sulfadiazine treatment groups was about 60.92~67.00 mL/ g TS and 55.88~62.13 mL/g TS respectively, higher than that in control group, 58.15 mL/g TS. The methane production potential of oxytetracycline treatment group was 42.27~50.43 mL/g TS, while 16%~19% of COD in the system was converted into CH4. The addition of oxytetracycline promoted the hydrolysis stage, while the acidogenesis stage and methanogenesis stage were inhibited. Addition of the three antibiotics promoted the transformation of dissolved proteins while inhibited that of the dissolved polysaccharides. Further analysis of dissolved organic matter showed that humic acid content after oxytetracycline treatment was lower than others. The addition of different antibiotics affected the metabolites and pathways of anaerobic digestion, resulting in positive or negative effect on CH4 production and degradation of organic components.
In order to clarify the effects of antibiotics on anaerobic digestion of pig manure, this study focused on methane production potential, metabolism, and byproducts of anaerobic digestion under the treatment of three typical antibiotics. The methane production potential of tetracycline and sulfadiazine treatment groups was about 60.92~67.00 mL/ g TS and 55.88~62.13 mL/g TS respectively, higher than that in control group, 58.15 mL/g TS. The methane production potential of oxytetracycline treatment group was 42.27~50.43 mL/g TS, while 16%~19% of COD in the system was converted into CH4. The addition of oxytetracycline promoted the hydrolysis stage, while the acidogenesis stage and methanogenesis stage were inhibited. Addition of the three antibiotics promoted the transformation of dissolved proteins while inhibited that of the dissolved polysaccharides. Further analysis of dissolved organic matter showed that humic acid content after oxytetracycline treatment was lower than others. The addition of different antibiotics affected the metabolites and pathways of anaerobic digestion, resulting in positive or negative effect on CH4 production and degradation of organic components.
2022, 40(4): 97-105.
doi: 10.13205/j.hjgc.202204014
Abstract:
In a small-scale experiment, four groups of self-made composting reactors were used to explore the effect of compound microbial agents on the aerobic biological treatment process and composting effect of food wastes. Using sawdust as an auxiliary material, the heterotrophic bacteria from BIOFORM ® Waste Digester (WD), the composite thermostable bacteria screened and prepared in previous study (TB), and the mixture of WD+TB were added separately. The no bacteria group was selected as the control (CK). The total weight of pile, temperature, moisture, organic matter content of dry matter, pH value and seed germination index (GI) were determined to study the treatment process. The results showed that when the initial moisture content, organic matter content of dry matter, C/N, amount of auxiliary materials (weight ratio of food waste) and amount of bacteria were (63.5±0.5)%, (96.6±0.9)%, 34.9±2.7, 20% and 25 mL/kg respectively, (WD+TB) group had the longest high temperature period and the highest temperature peak. During the 15-day trial period, (WD+TB) group performed best in terms of total weight loss rate (80.7%), the organic matter loss rate (64.3%) and the daily mean organic matter reduction rate (2.13 times of CK), with the lowest water soluble ammonia nitrogen content and E4/E6, and the highest germination rate index (96.3±26.7)%. This composite microbial agent (WD+TB) could effectively improve the aerobic biological treatment effect of food waste and significantly improve the composting efficiency.
In a small-scale experiment, four groups of self-made composting reactors were used to explore the effect of compound microbial agents on the aerobic biological treatment process and composting effect of food wastes. Using sawdust as an auxiliary material, the heterotrophic bacteria from BIOFORM ® Waste Digester (WD), the composite thermostable bacteria screened and prepared in previous study (TB), and the mixture of WD+TB were added separately. The no bacteria group was selected as the control (CK). The total weight of pile, temperature, moisture, organic matter content of dry matter, pH value and seed germination index (GI) were determined to study the treatment process. The results showed that when the initial moisture content, organic matter content of dry matter, C/N, amount of auxiliary materials (weight ratio of food waste) and amount of bacteria were (63.5±0.5)%, (96.6±0.9)%, 34.9±2.7, 20% and 25 mL/kg respectively, (WD+TB) group had the longest high temperature period and the highest temperature peak. During the 15-day trial period, (WD+TB) group performed best in terms of total weight loss rate (80.7%), the organic matter loss rate (64.3%) and the daily mean organic matter reduction rate (2.13 times of CK), with the lowest water soluble ammonia nitrogen content and E4/E6, and the highest germination rate index (96.3±26.7)%. This composite microbial agent (WD+TB) could effectively improve the aerobic biological treatment effect of food waste and significantly improve the composting efficiency.
2022, 40(4): 106-111,133.
doi: 10.13205/j.hjgc.202204015
Abstract:
A statical bio-drying process of kitchen waste mixed with returned material and landscaping waste was proposed. The variation of temperature and moisture content during the static bio-drying process were investigated. Metagenomic technology was used to deeply explore the succession of the microbial community in the pile during the bio-drying process of kitchen waste. It was found that the static bio-drying technology had fast heating rate, which made the material pile reach a high temperature above 65 ℃ within 4 hours. The moisture content of the stockpile can be quickly reduced from 36% to about 20% within 48 hours. The main functional bacteria in the process was Firmicutes and Actinomycetes. Analysis at the genus level revealed that the dominant genera were Bacillus, Saccharomonas, Staphylococcus and Thermoactinomycetes. The statical bio-drying process mainly used the thermophilic phase to ensure the stability of the microbial community and metabolism function, thereby ensured the stability and high efficiency of industrialized operation. It was a new bio-drying strategy with good application potential and prospects.
A statical bio-drying process of kitchen waste mixed with returned material and landscaping waste was proposed. The variation of temperature and moisture content during the static bio-drying process were investigated. Metagenomic technology was used to deeply explore the succession of the microbial community in the pile during the bio-drying process of kitchen waste. It was found that the static bio-drying technology had fast heating rate, which made the material pile reach a high temperature above 65 ℃ within 4 hours. The moisture content of the stockpile can be quickly reduced from 36% to about 20% within 48 hours. The main functional bacteria in the process was Firmicutes and Actinomycetes. Analysis at the genus level revealed that the dominant genera were Bacillus, Saccharomonas, Staphylococcus and Thermoactinomycetes. The statical bio-drying process mainly used the thermophilic phase to ensure the stability of the microbial community and metabolism function, thereby ensured the stability and high efficiency of industrialized operation. It was a new bio-drying strategy with good application potential and prospects.
2022, 40(4): 112-120.
doi: 10.13205/j.hjgc.202204016
Abstract:
In order to reduce the biological activity of heavy metals in soil, composites were made using fulvic acid (FA) extracted from selenium-enriched soil and nano-zero-valent iron (NZVI) prepared by conventional methods with different FA mass ratios. The composites were characterized by SEM, FTIR and XRD. Trough soil cultivation experiments, the effect of each compound on the occurrence of DTPA with lead added externally in soil under different dosages and reaction times were studied, and analyzed the morphological changes with Tessier method to discuss its passivation consequent. The results showed that FA and NZVI formed composites successfully with different FA mass ratios; under the same dosage, the effective state of DTPA of lead in the soil decreased with the increase of the FA mass ratio in the composites; when the composites with 10% FA mass was added to the soil in 2% (20.0 g/kg), the DTPA effective state of lead in the soil was reduced by 83.01% on the 10th day; after adding the composites, the lead in the soil transformed significantly from the exchangeable state and the carbonate combined state to Fe-Mn oxide combined state and the residual state, and the organic bound state was unchanged basically. These changes were especially significant when the compound with 1% FA mass was added, making the exchangeable state and the carbonate bound state reduced respectively by 50.61% and 66.90%. Therefore, based on different morphological characterization methods, the active forms of soil lead showed a downward trend, indicating that the prepared composite had a certain passivation effect on soil lead, but the mechanism was different, and the passivation laws shown were different.
In order to reduce the biological activity of heavy metals in soil, composites were made using fulvic acid (FA) extracted from selenium-enriched soil and nano-zero-valent iron (NZVI) prepared by conventional methods with different FA mass ratios. The composites were characterized by SEM, FTIR and XRD. Trough soil cultivation experiments, the effect of each compound on the occurrence of DTPA with lead added externally in soil under different dosages and reaction times were studied, and analyzed the morphological changes with Tessier method to discuss its passivation consequent. The results showed that FA and NZVI formed composites successfully with different FA mass ratios; under the same dosage, the effective state of DTPA of lead in the soil decreased with the increase of the FA mass ratio in the composites; when the composites with 10% FA mass was added to the soil in 2% (20.0 g/kg), the DTPA effective state of lead in the soil was reduced by 83.01% on the 10th day; after adding the composites, the lead in the soil transformed significantly from the exchangeable state and the carbonate combined state to Fe-Mn oxide combined state and the residual state, and the organic bound state was unchanged basically. These changes were especially significant when the compound with 1% FA mass was added, making the exchangeable state and the carbonate bound state reduced respectively by 50.61% and 66.90%. Therefore, based on different morphological characterization methods, the active forms of soil lead showed a downward trend, indicating that the prepared composite had a certain passivation effect on soil lead, but the mechanism was different, and the passivation laws shown were different.
2022, 40(4): 121-126.
doi: 10.13205/j.hjgc.202204017
Abstract:
In the experiment, the removal efficiencies of As(Ⅴ) and Sb(Ⅴ) by coagulation process were comparatively studied when ferric chloride (FeCl3) and aluminum chloride (AlCl3) were used as coagulant separately, while the effects of the reaction endpoint pH, EDTA concentration, Fe/Al dosage and the coexistence of heavy metals on removal of As(Ⅴ) and Sb(Ⅴ) from spent EDTA soil washing solution were mainly discussed. The results showed that: 1) aluminum salt was more effective than iron salt in the removal of As(Ⅴ) and Sb(Ⅴ) from spent EDTA washing solution by coagulation process; 2) the presence of EDTA not only reduced the removal of As(Ⅴ) and Sb(Ⅴ) by the adsorption of iron/aluminum flocs, but also inhibited the formation of iron arsenate, iron antimonite precipitates, in which the removal of As(Ⅴ) and Sb(Ⅴ) decreased simultaneously. Larger size and quantity of stable crystalline precipitate was formed during iron coagulation process with EDTA; 3) when c(EDTA)=0.05 mg/L, the removal efficiency of As(Ⅴ) and Sb(Ⅴ) in the spent EDTA washing solution by aluminum coagulation was up to 98.00% and 93.09%, respectively, with pH=5 and ρ(Al)=2000 mg/L; 4) the formation of Al(OH)3 flocs was enhanced to promote the removal of As(Ⅴ) and Sb(Ⅴ) when the coexisting heavy metals complexed with EDTA. The effective removal of As(Ⅴ) and Sb(Ⅴ) from spent EDTA soil washing solution by iron/alumiaum coagulation will promote the development and application of EDTA-based soil washing technologies.
In the experiment, the removal efficiencies of As(Ⅴ) and Sb(Ⅴ) by coagulation process were comparatively studied when ferric chloride (FeCl3) and aluminum chloride (AlCl3) were used as coagulant separately, while the effects of the reaction endpoint pH, EDTA concentration, Fe/Al dosage and the coexistence of heavy metals on removal of As(Ⅴ) and Sb(Ⅴ) from spent EDTA soil washing solution were mainly discussed. The results showed that: 1) aluminum salt was more effective than iron salt in the removal of As(Ⅴ) and Sb(Ⅴ) from spent EDTA washing solution by coagulation process; 2) the presence of EDTA not only reduced the removal of As(Ⅴ) and Sb(Ⅴ) by the adsorption of iron/aluminum flocs, but also inhibited the formation of iron arsenate, iron antimonite precipitates, in which the removal of As(Ⅴ) and Sb(Ⅴ) decreased simultaneously. Larger size and quantity of stable crystalline precipitate was formed during iron coagulation process with EDTA; 3) when c(EDTA)=0.05 mg/L, the removal efficiency of As(Ⅴ) and Sb(Ⅴ) in the spent EDTA washing solution by aluminum coagulation was up to 98.00% and 93.09%, respectively, with pH=5 and ρ(Al)=2000 mg/L; 4) the formation of Al(OH)3 flocs was enhanced to promote the removal of As(Ⅴ) and Sb(Ⅴ) when the coexisting heavy metals complexed with EDTA. The effective removal of As(Ⅴ) and Sb(Ⅴ) from spent EDTA soil washing solution by iron/alumiaum coagulation will promote the development and application of EDTA-based soil washing technologies.
2022, 40(4): 127-133.
doi: 10.13205/j.hjgc.202204018
Abstract:
The study on the migration and transformation of petroleum pollutants is of great significance to environmental protection and human health. Because of their different adsorption behaviors in soils with different textures, the static adsorption test method was adopted, and the adsorption kinetics and adsorption thermodynamics of petroleum hydrocarbons on three kinds of soils (silty soil, silty sand and silty clay) in Ganquanbao industrial area of Xinjiang were studied. The effects of soil particle size, organic matter content, pH value and salt content on the adsorption of petroleum hydrocarbons were analyzed. The results showed that the adsorption of petroleum hydrocarbons by silty soil, silty sand and silty clay reached adsorption equilibrium in 240 minutes. The adsorption capacity from large to small was silty soil, silty clay, and then silty sand, and the equilibrium adsorption capacity was 0.7765 mg/g, 0.6763 mg/g and 0.7173 mg/g respectively. The quasi-second-order kinetic model (R2=0.9967~0.9989) could more accurately describe the process of soil adsorption of petroleum hydrocarbons. The isotherm was of Langmuir type, and their adsorption equilibrium constants (Ka) were 0.6126 (silty soil), 3.1310 (silty sand) and 0.1180 (silty clay), indicating that the adsorption of petroleum hydrocarbons in different texture soils was monolayer adsorption. The amount of soil adsorbed to petroleum hydrocarbons gradually increased with the decrease of soil particle size and pH, and the increase of organic matter content and salt content.
The study on the migration and transformation of petroleum pollutants is of great significance to environmental protection and human health. Because of their different adsorption behaviors in soils with different textures, the static adsorption test method was adopted, and the adsorption kinetics and adsorption thermodynamics of petroleum hydrocarbons on three kinds of soils (silty soil, silty sand and silty clay) in Ganquanbao industrial area of Xinjiang were studied. The effects of soil particle size, organic matter content, pH value and salt content on the adsorption of petroleum hydrocarbons were analyzed. The results showed that the adsorption of petroleum hydrocarbons by silty soil, silty sand and silty clay reached adsorption equilibrium in 240 minutes. The adsorption capacity from large to small was silty soil, silty clay, and then silty sand, and the equilibrium adsorption capacity was 0.7765 mg/g, 0.6763 mg/g and 0.7173 mg/g respectively. The quasi-second-order kinetic model (R2=0.9967~0.9989) could more accurately describe the process of soil adsorption of petroleum hydrocarbons. The isotherm was of Langmuir type, and their adsorption equilibrium constants (Ka) were 0.6126 (silty soil), 3.1310 (silty sand) and 0.1180 (silty clay), indicating that the adsorption of petroleum hydrocarbons in different texture soils was monolayer adsorption. The amount of soil adsorbed to petroleum hydrocarbons gradually increased with the decrease of soil particle size and pH, and the increase of organic matter content and salt content.
2022, 40(4): 134-139,187.
doi: 10.13205/j.hjgc.202204019
Abstract:
Taking the clay in Northeastern China as the research object, the contaminated soil was simulated, and the effects of extraction rate, soil water content and thermal enhancement on the remediation of benzene-contaminated soil by soil vapor extraction were studied. At the same time, the heat transfer effect of soil with different water content and the variation law of soil temperature under the heating condition of central heat source were explored. The results showed that: 1) the best pumping rate for the remediation of benzene-contaminated soil by soil vapor extraction was 10 L/min; 2) in the clay soil with water content of 5%~20%, the remediation effect of soil vapor extraction decreased with the increase of soil water content, but under the effect of thermal enhancement, the repair effect decreased and then increased with the increase of soil water content, and the repair effect was the best when the water content was 5%; 3) under the condition of central heat source heating, the soil temperature showed nonlinear attenuation along the radial direction from the heat source, and the attenuation was more obvious near the heat source point; 4) when thermal enhanced soil vapor extraction was used to repair benzene-contaminated clay, the restoration performance were best when the temperature of the central heat source was 160 ℃.
Taking the clay in Northeastern China as the research object, the contaminated soil was simulated, and the effects of extraction rate, soil water content and thermal enhancement on the remediation of benzene-contaminated soil by soil vapor extraction were studied. At the same time, the heat transfer effect of soil with different water content and the variation law of soil temperature under the heating condition of central heat source were explored. The results showed that: 1) the best pumping rate for the remediation of benzene-contaminated soil by soil vapor extraction was 10 L/min; 2) in the clay soil with water content of 5%~20%, the remediation effect of soil vapor extraction decreased with the increase of soil water content, but under the effect of thermal enhancement, the repair effect decreased and then increased with the increase of soil water content, and the repair effect was the best when the water content was 5%; 3) under the condition of central heat source heating, the soil temperature showed nonlinear attenuation along the radial direction from the heat source, and the attenuation was more obvious near the heat source point; 4) when thermal enhanced soil vapor extraction was used to repair benzene-contaminated clay, the restoration performance were best when the temperature of the central heat source was 160 ℃.
2022, 40(4): 140-146.
doi: 10.13205/j.hjgc.202204020
Abstract:
Heavy metal pollution in farmland soil attracted broad attention in China due to its harm to human health and ecological environment. In order to explore the feasibility of biochar on remediating soil heavy metals in pilot-scale, the long-term stabilization effect and ecological risk of soil cadmium and lead was studied by using the nitric acid and potassium permanganate modified coconut shell biochar. With application of different dosages of biochar, the long-term variation of soil cadmium and lead bioavailability was discussed, in combination with the results of soil-agricultural product comprehensive quality impact index, to evaluate the possible ecological risk after the remediation. The results showed that the modified biochar could significantly improve the stability of soil cadmium and lead. When the applied amount of modified bichar was higher than 20 g/kg, soil cadmium and lead were mainly in residual fraction after 12 weeks and the immobilization rates were increased by 8%~23% and 11%~24%, respectively, compared with the control group. After 15~18 weeks’ remediation, the contents of bioavailable cadmium and lead in soil were maintained within the safety threshold, and no excessive metals were detected in the planted vegetables. This study indicated that it might be desirable to use modified coconut shell biochar for large-scale remediation of soil heavy metals.
Heavy metal pollution in farmland soil attracted broad attention in China due to its harm to human health and ecological environment. In order to explore the feasibility of biochar on remediating soil heavy metals in pilot-scale, the long-term stabilization effect and ecological risk of soil cadmium and lead was studied by using the nitric acid and potassium permanganate modified coconut shell biochar. With application of different dosages of biochar, the long-term variation of soil cadmium and lead bioavailability was discussed, in combination with the results of soil-agricultural product comprehensive quality impact index, to evaluate the possible ecological risk after the remediation. The results showed that the modified biochar could significantly improve the stability of soil cadmium and lead. When the applied amount of modified bichar was higher than 20 g/kg, soil cadmium and lead were mainly in residual fraction after 12 weeks and the immobilization rates were increased by 8%~23% and 11%~24%, respectively, compared with the control group. After 15~18 weeks’ remediation, the contents of bioavailable cadmium and lead in soil were maintained within the safety threshold, and no excessive metals were detected in the planted vegetables. This study indicated that it might be desirable to use modified coconut shell biochar for large-scale remediation of soil heavy metals.
2022, 40(4): 147-152.
doi: 10.13205/j.hjgc.202204021
Abstract:
To solve the problem of high nitrate content of groundwater, bimetal Pd-Cu@UiO-66 catalyst was prepared for the catalytic reduction of nitrate in water for the first time. The influence of the carrier synthesized with different regulator and process conditions on denitrification performance was investigated. The results showed that the nitrate removal rate was 97.4%, and N2 selectivity was 95.2% when the UIO-66 carrier was prepared by hydrochloric acid with the loading of 1% Pd and 1% Cu and the hydrogen flow rate was 70 mL/min. The carrier prepared with the modulator of lower pKa had the smaller particle size, which was conducive to the formation and dispersion of smaller active metal particles. The high dispersion of active metal was beneficial to the generation of activated hydrogen and the electron transport of Cu, and to improve the selectivity of nitrogen in denitration reaction. During the reaction, the bimetallic synergic effect was the key factor affecting the catalytic performance.
To solve the problem of high nitrate content of groundwater, bimetal Pd-Cu@UiO-66 catalyst was prepared for the catalytic reduction of nitrate in water for the first time. The influence of the carrier synthesized with different regulator and process conditions on denitrification performance was investigated. The results showed that the nitrate removal rate was 97.4%, and N2 selectivity was 95.2% when the UIO-66 carrier was prepared by hydrochloric acid with the loading of 1% Pd and 1% Cu and the hydrogen flow rate was 70 mL/min. The carrier prepared with the modulator of lower pKa had the smaller particle size, which was conducive to the formation and dispersion of smaller active metal particles. The high dispersion of active metal was beneficial to the generation of activated hydrogen and the electron transport of Cu, and to improve the selectivity of nitrogen in denitration reaction. During the reaction, the bimetallic synergic effect was the key factor affecting the catalytic performance.
2022, 40(4): 153-158,208.
doi: 10.13205/j.hjgc.202204022
Abstract:
A membrane-cathode electro-Fenton process based on cathodic steel mesh membrane module was established and pilot-scale for the pretreatment of semiconductor wastewater reuse was conducted. The organic matters’ removal efficiency was investigated, and the operation parameters (including aeration, applied voltage and Fe2+ dosage) were also optimized. The continuous-flow pilot-scale experiment was carried out under optimal conditions and then compared with Fenton process. The results showed that the membrane-cathode electro-Fenton process could continuously produce ·OH exhibiting high potential in eliminating refractory organic compounds. Under HRT=120 min, the optimal operation parameters were found to be 0.6 m3/h of air flux, 3 V of applied voltage and 0.3 mmol/L of Fe2+ dosage, with removal rates of COD, TOC and H2O2 at (73.6±18.3)%, (51.2±12.7)% and (83.7±13.0)%, respectively. The corresponding treatment cost per unit COD was RMB 1.93/g COD. In conclusion, the membrane-cathode electro-Fenton process showed higher organic removal rate and lower cost, cimparing to the Fenton process.
A membrane-cathode electro-Fenton process based on cathodic steel mesh membrane module was established and pilot-scale for the pretreatment of semiconductor wastewater reuse was conducted. The organic matters’ removal efficiency was investigated, and the operation parameters (including aeration, applied voltage and Fe2+ dosage) were also optimized. The continuous-flow pilot-scale experiment was carried out under optimal conditions and then compared with Fenton process. The results showed that the membrane-cathode electro-Fenton process could continuously produce ·OH exhibiting high potential in eliminating refractory organic compounds. Under HRT=120 min, the optimal operation parameters were found to be 0.6 m3/h of air flux, 3 V of applied voltage and 0.3 mmol/L of Fe2+ dosage, with removal rates of COD, TOC and H2O2 at (73.6±18.3)%, (51.2±12.7)% and (83.7±13.0)%, respectively. The corresponding treatment cost per unit COD was RMB 1.93/g COD. In conclusion, the membrane-cathode electro-Fenton process showed higher organic removal rate and lower cost, cimparing to the Fenton process.
2022, 40(4): 159-165.
doi: 10.13205/j.hjgc.202204023
Abstract:
Temperature affects the existent forms of substances and the rate of biochemical reaction in environmental mediums. Based on this, boron selective chelating resin was used to treat the groundwater with boron concentration exceeding the standard in an alpine region. The operation parameters and performance of the process were determined by field pilot test. And the mechanism of resin boron removal was explored by FTIR, SEM and BET characterization. The results showed that the inlet velocity of 16 BV/h (bed volume; 1 BV=22.5 L) was suitable for the project, and the effluent water quality met the Hygiene Standard for Drinking Water (GB 5749—2006). The penetration point of resin column was 871.11 BV, and the exchange capacity of resin was 3.58 mg/g; the boron content of wastewater generated during resin regeneration was 342.81 mg/L, which could be used as the raw material for boron production. After the boron removal test, the hydroxyl functional group content and pore volume on the surface of the resin were reduced, and obvious wrinkles appeared on the surface, indicating that boron was removed by intra-particle diffusion and chelation process. The results of this experiment can provide theoretical support and technical reference for the treatment of boron in alpine region.
Temperature affects the existent forms of substances and the rate of biochemical reaction in environmental mediums. Based on this, boron selective chelating resin was used to treat the groundwater with boron concentration exceeding the standard in an alpine region. The operation parameters and performance of the process were determined by field pilot test. And the mechanism of resin boron removal was explored by FTIR, SEM and BET characterization. The results showed that the inlet velocity of 16 BV/h (bed volume; 1 BV=22.5 L) was suitable for the project, and the effluent water quality met the Hygiene Standard for Drinking Water (GB 5749—2006). The penetration point of resin column was 871.11 BV, and the exchange capacity of resin was 3.58 mg/g; the boron content of wastewater generated during resin regeneration was 342.81 mg/L, which could be used as the raw material for boron production. After the boron removal test, the hydroxyl functional group content and pore volume on the surface of the resin were reduced, and obvious wrinkles appeared on the surface, indicating that boron was removed by intra-particle diffusion and chelation process. The results of this experiment can provide theoretical support and technical reference for the treatment of boron in alpine region.
2022, 40(4): 166-173.
doi: 10.13205/j.hjgc.202204024
Abstract:
To evaluate the activated sludge PHA synthesis yield prediction under the condition of mixed carbon sources, genetic algorithms were proposed to optimize the weights and thresholds of the BP artificial neural network, and the research established the prediction model based on the GA-BP network. Food waste fermentation liquid was applied as the substrate and activated sludge was used to synthesize PHA under the ADD mode. Based on experimental data, the comparison between the measured data and the model predictions was carried out, to verify the accuracy of the network prediction model and the prediction of the long-term PHA synthesis ability. Results showed that the GA-BP network model improved based on the genetic algorithm had high prediction accuracy than the traditional BP neural network model, and the model explored a feasible method to evaluate the long-term variation of the maximum PHA production yield in mixed microbial cultures and determined the reasonable enrichment time.
To evaluate the activated sludge PHA synthesis yield prediction under the condition of mixed carbon sources, genetic algorithms were proposed to optimize the weights and thresholds of the BP artificial neural network, and the research established the prediction model based on the GA-BP network. Food waste fermentation liquid was applied as the substrate and activated sludge was used to synthesize PHA under the ADD mode. Based on experimental data, the comparison between the measured data and the model predictions was carried out, to verify the accuracy of the network prediction model and the prediction of the long-term PHA synthesis ability. Results showed that the GA-BP network model improved based on the genetic algorithm had high prediction accuracy than the traditional BP neural network model, and the model explored a feasible method to evaluate the long-term variation of the maximum PHA production yield in mixed microbial cultures and determined the reasonable enrichment time.
2022, 40(4): 174-181,201.
doi: 10.13205/j.hjgc.202204025
Abstract:
Slurry bioreactor can be applied in the remediation of high-concentration contaminated soils, and resist harsh condition by implementing oxygen and nutrients. It also shows advantages in high treatment efficiency and easy control of bioremediation process. This study introduced the removal ratios of non-biodegradable organics, i.e., polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pentachlorophenol (PCP) and total petroleum hydrocarbons (TPH), by the slurry bioreactor. The effects of pollutants characteristics, biodegradation pathways, water-soil ratio and operational parameters (such as pH, temperature, dissolved oxygen, etc.) in the contaminants’ removal process were compared. The related techniques, engineering cases and application costs of slurry bioreactors were also reviewed. Due to its relevant high cost and complex biodegradation mechanisms, slurry bioreactor was mainly studied in the laboratory nowadays in China. As a promising bioremediation technology, it is necessary to further improve the treatment efficiency of slurry bioreactor and reduce the application cost in the future to promote the application.
Slurry bioreactor can be applied in the remediation of high-concentration contaminated soils, and resist harsh condition by implementing oxygen and nutrients. It also shows advantages in high treatment efficiency and easy control of bioremediation process. This study introduced the removal ratios of non-biodegradable organics, i.e., polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pentachlorophenol (PCP) and total petroleum hydrocarbons (TPH), by the slurry bioreactor. The effects of pollutants characteristics, biodegradation pathways, water-soil ratio and operational parameters (such as pH, temperature, dissolved oxygen, etc.) in the contaminants’ removal process were compared. The related techniques, engineering cases and application costs of slurry bioreactors were also reviewed. Due to its relevant high cost and complex biodegradation mechanisms, slurry bioreactor was mainly studied in the laboratory nowadays in China. As a promising bioremediation technology, it is necessary to further improve the treatment efficiency of slurry bioreactor and reduce the application cost in the future to promote the application.
2022, 40(4): 188-195,223.
doi: 10.13205/j.hjgc.202204027
Abstract:
In recent years, groundwater pollution is becoming more and more serious in China. Domestic waste landfill has become one of the most important sources of groundwater pollution in China. In this paper, the groundwater environment of Chifeng landfill site and its surroundings were systematically tested. Single factor index method and comprehensive evaluation method were used to evaluate the quality of present groundwater. The causes of groundwater pollution were analyzed by factor analysis and Pearson correlation analysis. Based on the historical detection data, the substances exceeding the standard including ammonia nitrogen, sulfide, fluoride, total coliform and part of the sensory traits in contrast to the limit value of Ⅲ water body in China’s national standard Groundwater Quality Standard (GB/T 14848—2017). The exceedance frequency was between 11% and 90%. The exceedance multiple ranged from 1.01 to 120. In addition to ammonia nitrogen and fluoride, the concentration of superstandard substances showed a decreasing trend. The main excess substances were fluoride and total coliformsat at present. The overshoot multiple was between 1.03 and 1.37. According to factor analysis and Pearson correlation analysis, combined with the characteristics of total coliforms, the excessive total coliform population was mainly caused by inadequate well cleaning and human activities around the site. Combined with literature research and formation lithology, superstandard fluoride was mainly determined by hydrogeological condition. The concentration of ammonia nitrogen fluctuated greatly, and all points exceeded the historical standard. For the concentration of ammonia nitrogen, there was a positive correlation between the background point and other monitoring points (P<0.01, R≥0.655). The contribution rate of leachate to the nitrogen in groundwater was 30.37%. The non-point source pollution in the upstream area and the influence of landfill leachate were the main reasons.
In recent years, groundwater pollution is becoming more and more serious in China. Domestic waste landfill has become one of the most important sources of groundwater pollution in China. In this paper, the groundwater environment of Chifeng landfill site and its surroundings were systematically tested. Single factor index method and comprehensive evaluation method were used to evaluate the quality of present groundwater. The causes of groundwater pollution were analyzed by factor analysis and Pearson correlation analysis. Based on the historical detection data, the substances exceeding the standard including ammonia nitrogen, sulfide, fluoride, total coliform and part of the sensory traits in contrast to the limit value of Ⅲ water body in China’s national standard Groundwater Quality Standard (GB/T 14848—2017). The exceedance frequency was between 11% and 90%. The exceedance multiple ranged from 1.01 to 120. In addition to ammonia nitrogen and fluoride, the concentration of superstandard substances showed a decreasing trend. The main excess substances were fluoride and total coliformsat at present. The overshoot multiple was between 1.03 and 1.37. According to factor analysis and Pearson correlation analysis, combined with the characteristics of total coliforms, the excessive total coliform population was mainly caused by inadequate well cleaning and human activities around the site. Combined with literature research and formation lithology, superstandard fluoride was mainly determined by hydrogeological condition. The concentration of ammonia nitrogen fluctuated greatly, and all points exceeded the historical standard. For the concentration of ammonia nitrogen, there was a positive correlation between the background point and other monitoring points (P<0.01, R≥0.655). The contribution rate of leachate to the nitrogen in groundwater was 30.37%. The non-point source pollution in the upstream area and the influence of landfill leachate were the main reasons.
2022, 40(4): 196-201.
doi: 10.13205/j.hjgc.202204028
Abstract:
In view of the difference between GF-6 and Landsat-8 images in water quality monitoring, the eutrophication assessment of water quality in Chao Lake was taken as the research content, the water quality parameters were inversed, and the water quality assessment model was constructed by using the method of integrated nutritional state index. Using ENVI 5.3 and ArcGIS 10.3 software, the visualization of water quality parameters and TLI was realized. Compared with the measured data, the accuracy of the inversion result was evaluated by using Pearson correlation model. The main conclusions were as follows: the nutrient status of the water quality in Chao Lake at the time of imaging was medium nutrient; the comprehensive nutrient status index TLI derived from GF-6 and Landsat-8 were 42.75 and 42.13 respectively, and there was no significant difference between them, however, the coefficients of GF-6 and Landsat-8 were 0.988 and 0.965, respectively, indicating that GF-6 was more accurate and reliable. The conclusion could provide reference for selecting remote sensing image data in water quality monitoring.
In view of the difference between GF-6 and Landsat-8 images in water quality monitoring, the eutrophication assessment of water quality in Chao Lake was taken as the research content, the water quality parameters were inversed, and the water quality assessment model was constructed by using the method of integrated nutritional state index. Using ENVI 5.3 and ArcGIS 10.3 software, the visualization of water quality parameters and TLI was realized. Compared with the measured data, the accuracy of the inversion result was evaluated by using Pearson correlation model. The main conclusions were as follows: the nutrient status of the water quality in Chao Lake at the time of imaging was medium nutrient; the comprehensive nutrient status index TLI derived from GF-6 and Landsat-8 were 42.75 and 42.13 respectively, and there was no significant difference between them, however, the coefficients of GF-6 and Landsat-8 were 0.988 and 0.965, respectively, indicating that GF-6 was more accurate and reliable. The conclusion could provide reference for selecting remote sensing image data in water quality monitoring.
2022, 40(4): 202-208.
doi: 10.13205/j.hjgc.202204029
Abstract:
Based on the results of the air quality model and the 0~1 integer programming algorithm, the multi-scenario rapid response decision model of emission factors and pollutants’ environmental concentration was established, which realized the rapid decision of the adjustment plan of air pollutant emission sources under the air pollution control target. The model was applied to the high-speed enclosed area of Cangzhou, Hebei. Based on the AERMOD simulation results of atmospheric primary PM10 in 2018, the contribution of each emission source to the national controlled point pollution in the enclosed area was analyzed, and the optimal source group control solution was obtained when the total contribution concentration value was adjusted. The results showed that among the particulate matter emission sources in Cangzhou expressway enclosed area, the contribution of road sources to national controlled points pollution was the highest, followed by non-road mobile sources. In addition, it was optimal to control the source groups of provincial road in Xinhua Distric and soil dust in Yunhe District under the goal of minimizing the total emission in the confined area and reducing the contribution concentration of national control points (Municipal Environmental Protection Bureau Station, Cangxian Urban Construction Bureau Station and TV Transmission Station) by at least 1.5 μg/m3, the total emission of source groups was 791.30 t/a, with a decrease of 15.66 t/a; the average annual contribution concentration of each control point was 7.80 μg/m3, 10.09 μg/m3 and 7.87 μg/m3, decreased by 1.75 μg/m3, 2.00 μg/m3 and 1.52 μg/m3, respectively. This research method realized the rapid effect evaluation under the given air pollution source adjustment plan, and gave the optimal emission reduction plan.
Based on the results of the air quality model and the 0~1 integer programming algorithm, the multi-scenario rapid response decision model of emission factors and pollutants’ environmental concentration was established, which realized the rapid decision of the adjustment plan of air pollutant emission sources under the air pollution control target. The model was applied to the high-speed enclosed area of Cangzhou, Hebei. Based on the AERMOD simulation results of atmospheric primary PM10 in 2018, the contribution of each emission source to the national controlled point pollution in the enclosed area was analyzed, and the optimal source group control solution was obtained when the total contribution concentration value was adjusted. The results showed that among the particulate matter emission sources in Cangzhou expressway enclosed area, the contribution of road sources to national controlled points pollution was the highest, followed by non-road mobile sources. In addition, it was optimal to control the source groups of provincial road in Xinhua Distric and soil dust in Yunhe District under the goal of minimizing the total emission in the confined area and reducing the contribution concentration of national control points (Municipal Environmental Protection Bureau Station, Cangxian Urban Construction Bureau Station and TV Transmission Station) by at least 1.5 μg/m3, the total emission of source groups was 791.30 t/a, with a decrease of 15.66 t/a; the average annual contribution concentration of each control point was 7.80 μg/m3, 10.09 μg/m3 and 7.87 μg/m3, decreased by 1.75 μg/m3, 2.00 μg/m3 and 1.52 μg/m3, respectively. This research method realized the rapid effect evaluation under the given air pollution source adjustment plan, and gave the optimal emission reduction plan.
2022, 40(4): 209-216.
doi: 10.13205/j.hjgc.202204030
Abstract:
According to the public opinions on air quality during the period of 2015—2019, big data mining and analysis techniques were used to identify the factors influencing the public’s risk perception, establish a risk perception indicator system, and investigate the temporal and spatial characteristics regarding risk perception level. The results showed that: 1) The primary factor affecting public risk perception was the worry of individual health impact, followed by the impact of environmental quality change. 2) The level of risk perception had significant temporal and spatial differences. It fluctuated and raised in the defined time period. From a spatial perspective, the level of risk perception was high in the north and low in the south, while high in the east and low in the west. 3) The risk perception level in Henan Province and Sichuan Province was the highest in the defined time period, and the risk perception had apparently spatial spillover effect.
According to the public opinions on air quality during the period of 2015—2019, big data mining and analysis techniques were used to identify the factors influencing the public’s risk perception, establish a risk perception indicator system, and investigate the temporal and spatial characteristics regarding risk perception level. The results showed that: 1) The primary factor affecting public risk perception was the worry of individual health impact, followed by the impact of environmental quality change. 2) The level of risk perception had significant temporal and spatial differences. It fluctuated and raised in the defined time period. From a spatial perspective, the level of risk perception was high in the north and low in the south, while high in the east and low in the west. 3) The risk perception level in Henan Province and Sichuan Province was the highest in the defined time period, and the risk perception had apparently spatial spillover effect.
2022, 40(4): 217-223.
doi: 10.13205/j.hjgc.202204031
Abstract:
In this study, an abandoned machinery plant in Southwestern China was taken as the research object. The pollution characteristics and sources were mainly analyzed by combining the principal component analysis method and the Kriging interpolation method, and Monte Carlo simulation in the health risk assessment was introduced for uncertainty analysis. The result showed that Ni, Pb, As and Co were concentrated distributed, and V was evenly distributed. The main sources of pollution were man-made sources of industrial activities in the factory, natural sources of soil parent material, and atmospheric deposition from surrounding industrial activities. The main hazards factors of non-carcinogenic risks were As and Co, and the main carcinogen factor was As. The principal exposure pathway for adults was skin contact, but for children it was oral ingestion. The probability of the non-carcinogenic risk exceeded the threshold for adults and childrenwas 11.60% and 60.88%, and those for carcinogenic risk exceeded the threshold was 4.36% and 2.31%. The most sensitive parameters for adults and children were skin adhesion coefficient and body weight. The significance of the research was to provide guidance and technical support for risk management or remediation of soil in heavy metal contaminated sites.
In this study, an abandoned machinery plant in Southwestern China was taken as the research object. The pollution characteristics and sources were mainly analyzed by combining the principal component analysis method and the Kriging interpolation method, and Monte Carlo simulation in the health risk assessment was introduced for uncertainty analysis. The result showed that Ni, Pb, As and Co were concentrated distributed, and V was evenly distributed. The main sources of pollution were man-made sources of industrial activities in the factory, natural sources of soil parent material, and atmospheric deposition from surrounding industrial activities. The main hazards factors of non-carcinogenic risks were As and Co, and the main carcinogen factor was As. The principal exposure pathway for adults was skin contact, but for children it was oral ingestion. The probability of the non-carcinogenic risk exceeded the threshold for adults and childrenwas 11.60% and 60.88%, and those for carcinogenic risk exceeded the threshold was 4.36% and 2.31%. The most sensitive parameters for adults and children were skin adhesion coefficient and body weight. The significance of the research was to provide guidance and technical support for risk management or remediation of soil in heavy metal contaminated sites.
2022, 40(4): 224-234,243.
doi: 10.13205/j.hjgc.202204032
Abstract:
There are currently a large number of contaminated sites with complex geological conditions in China. Conventional technologies like soil vapor extraction are inefficient in remediating these sites quickly and effectively. Electrical resistance heating (ERH) technology is less affected by soil heterogeneity, and it has a large processing depth and a fast heating speed. It could quickly and effectively remove volatile organic compounds from the unsaturated and saturated zone in soil with complex geological conditions. However, the application of ERH in China begins relatively late, and there are few application cases. To support the further research and application of ERH, this paper first introduces the remediation mechanism of ERH (including promoting the evacuation of pollutants and increasing the degradation rate of pollutants) and how factors such as soil conductivity, electric field strength, groundwater flow and soil heterogeneity affect the efficiency of ERH remediation. The coupling of ERH with other in-situ remediation technologies were reviewed as well. It also describes how to deploy electrode wells and equipment during an ERH process implemented on site. Finally, related soil remediation cases using ERH technologies are discussed, and the future direction of ERH research is pointed out.
There are currently a large number of contaminated sites with complex geological conditions in China. Conventional technologies like soil vapor extraction are inefficient in remediating these sites quickly and effectively. Electrical resistance heating (ERH) technology is less affected by soil heterogeneity, and it has a large processing depth and a fast heating speed. It could quickly and effectively remove volatile organic compounds from the unsaturated and saturated zone in soil with complex geological conditions. However, the application of ERH in China begins relatively late, and there are few application cases. To support the further research and application of ERH, this paper first introduces the remediation mechanism of ERH (including promoting the evacuation of pollutants and increasing the degradation rate of pollutants) and how factors such as soil conductivity, electric field strength, groundwater flow and soil heterogeneity affect the efficiency of ERH remediation. The coupling of ERH with other in-situ remediation technologies were reviewed as well. It also describes how to deploy electrode wells and equipment during an ERH process implemented on site. Finally, related soil remediation cases using ERH technologies are discussed, and the future direction of ERH research is pointed out.
2022, 40(4): 235-243.
doi: 10.13205/j.hjgc.202204033
Abstract:
Anaerobic ammonia oxidation (Anammox)-based high performance nitrogen removal from municipal wastewater provides the possibility of energy self-sufficient operation for municipal wastewater treatment plants (MWTPs). Firstly, the process and advantages of Anammox nitrogen removal are reviewed in this article. Then the challenges and solutions of the application of Anammox-based autotrophic nitrogen removal technology in MWTPs are analyzed, including nitrite oxidizing bacteria (NOB) inhibition, anaerobic ammonia oxidizing bacteria (AnAOB) enrichment and retention, and the balance control between AnAOB and aerobic ammonia oxidizing bacteria (AOB). Finally, future research directions of the nitrogen removal from municipal wastewater via Anammox were proposed.
Anaerobic ammonia oxidation (Anammox)-based high performance nitrogen removal from municipal wastewater provides the possibility of energy self-sufficient operation for municipal wastewater treatment plants (MWTPs). Firstly, the process and advantages of Anammox nitrogen removal are reviewed in this article. Then the challenges and solutions of the application of Anammox-based autotrophic nitrogen removal technology in MWTPs are analyzed, including nitrite oxidizing bacteria (NOB) inhibition, anaerobic ammonia oxidizing bacteria (AnAOB) enrichment and retention, and the balance control between AnAOB and aerobic ammonia oxidizing bacteria (AOB). Finally, future research directions of the nitrogen removal from municipal wastewater via Anammox were proposed.
2022, 40(4): 244-253.
doi: 10.13205/j.hjgc.202204034
Abstract:
In recent years, the problem of combined pollution of heavy metals in the left contaminated sites in China becomes increasingly prominent. In order to effectively block the migration and diffusion of heavy metals, barrier technology has become the focus of site pollution control at home and abroad. In this study, we systematically analyzed typical application examples of barrier technologies in heavy metal contaminated sites, and then we summarized the current situation of advanced materials and correlated construction methods of barrier technologies, to explore the main problems of different barrier technologies in the process of application. At last, we put forward popular research directions, including combined application of different barrier technologies and engineering decision-making of barrier system application, in the respects of technology, economy and land reuse, so as to provide theoretical and technical references for heavy metal pollution control in complex scenarios.
In recent years, the problem of combined pollution of heavy metals in the left contaminated sites in China becomes increasingly prominent. In order to effectively block the migration and diffusion of heavy metals, barrier technology has become the focus of site pollution control at home and abroad. In this study, we systematically analyzed typical application examples of barrier technologies in heavy metal contaminated sites, and then we summarized the current situation of advanced materials and correlated construction methods of barrier technologies, to explore the main problems of different barrier technologies in the process of application. At last, we put forward popular research directions, including combined application of different barrier technologies and engineering decision-making of barrier system application, in the respects of technology, economy and land reuse, so as to provide theoretical and technical references for heavy metal pollution control in complex scenarios.
2022, 40(4): 254-255.
Abstract:
