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2024 Vol. 42, No. 6
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2024, 42(6): 1-8.
doi: 10.13205/j.hjgc.202406001
Abstract:
The floating motion characteristics of oil droplets are one of the important components in the study of migration and transformation characteristics of petroleum-based pollutants in water bodies. In this paper, the upward motion of a single oil droplet in a stationary water body was studied, and the trajectories, instantaneous velocities, shapes, and terminal velocities of oil droplets of different particle sizes were obtained, then the relationships between particle size and deformation degree, instantaneous velocity and trajectory, terminal velocity UT and particle size d, drag coefficient CD and Reynolds number Re were analyzed. It was found that the shape of oil droplets in the water body was mainly spherical and ellipsoidal, the deformation increased with the increase of particle size, but the overall deformation degree was low; the trajectory of oil droplets gradually changed from linear to S-shaped with increasing particle size, while the amplitude of horizontal oscillation gradually increased, but the effect of horizontal oscillation of oil droplets on the droplet vertical velocity can be negligible; the UT gradually increased to the peak with the increase of oil droplet size, and after passing the peak, the UT decreased slightly and then tended to be stable; the CD-Re relationship tended to gradually decrease, stabilize and then rapidly increase. Meanwhile, based on the experimental data and combined with Stokes’ law, a set of CD-Re relations for silicone oil droplets at Re<2000 was obtained.
The floating motion characteristics of oil droplets are one of the important components in the study of migration and transformation characteristics of petroleum-based pollutants in water bodies. In this paper, the upward motion of a single oil droplet in a stationary water body was studied, and the trajectories, instantaneous velocities, shapes, and terminal velocities of oil droplets of different particle sizes were obtained, then the relationships between particle size and deformation degree, instantaneous velocity and trajectory, terminal velocity UT and particle size d, drag coefficient CD and Reynolds number Re were analyzed. It was found that the shape of oil droplets in the water body was mainly spherical and ellipsoidal, the deformation increased with the increase of particle size, but the overall deformation degree was low; the trajectory of oil droplets gradually changed from linear to S-shaped with increasing particle size, while the amplitude of horizontal oscillation gradually increased, but the effect of horizontal oscillation of oil droplets on the droplet vertical velocity can be negligible; the UT gradually increased to the peak with the increase of oil droplet size, and after passing the peak, the UT decreased slightly and then tended to be stable; the CD-Re relationship tended to gradually decrease, stabilize and then rapidly increase. Meanwhile, based on the experimental data and combined with Stokes’ law, a set of CD-Re relations for silicone oil droplets at Re<2000 was obtained.
2024, 42(6): 9-16.
doi: 10.13205/j.hjgc.202406002
Abstract:
In this paper, the sulfur autotrophic denitrification (SAD) process start-up was accomplished in an SBR reactor using sodium thiosulfate as an electron donor, and a gradual increase in substrate loading. The rapid start-up and stable operation of the sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation (SAD/A) autotrophic denitrification system was developed by inoculating Anammox sludge with a combined pH and NO-3-N/NH+4-N regulation strategy. The results showed that in 30 days, the denitrification sludge had been domesticated into SAD sludge. After 90 days, the SBR reactor had been successfully enriched with SAD sludge, and more than 85% of NO-3-N had been removed from the system. The SAD/A system was successfully started after 14 days of operation with an optimal inoculation ratio of 3∶1 for both two species of sludge. After 30 days, the NO-3-N removal rate of the system could reach 85% and the NH+4-N removal rate could reach 80%. The coupled system’s best denitrification efficiency was achieved at a pH of 8 and a NO-3-N/NH+4-N ratio of 1.8, and it operated steadily. High-throughput sequencing results showed that the overall species diversity and richness in the SAD/A system was increased after coupling, and the dominant microbial genera were Candidatus Brocadia and Thiobacillus, with similar relative abundances, indicating a good coupling effect of SAD/A.
In this paper, the sulfur autotrophic denitrification (SAD) process start-up was accomplished in an SBR reactor using sodium thiosulfate as an electron donor, and a gradual increase in substrate loading. The rapid start-up and stable operation of the sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation (SAD/A) autotrophic denitrification system was developed by inoculating Anammox sludge with a combined pH and NO-3-N/NH+4-N regulation strategy. The results showed that in 30 days, the denitrification sludge had been domesticated into SAD sludge. After 90 days, the SBR reactor had been successfully enriched with SAD sludge, and more than 85% of NO-3-N had been removed from the system. The SAD/A system was successfully started after 14 days of operation with an optimal inoculation ratio of 3∶1 for both two species of sludge. After 30 days, the NO-3-N removal rate of the system could reach 85% and the NH+4-N removal rate could reach 80%. The coupled system’s best denitrification efficiency was achieved at a pH of 8 and a NO-3-N/NH+4-N ratio of 1.8, and it operated steadily. High-throughput sequencing results showed that the overall species diversity and richness in the SAD/A system was increased after coupling, and the dominant microbial genera were Candidatus Brocadia and Thiobacillus, with similar relative abundances, indicating a good coupling effect of SAD/A.
2024, 42(6): 17-24.
doi: 10.13205/j.hjgc.202406003
Abstract:
The complex organic composition of desulfurization wastewater in coal-fired power plants greatly affected the high efficiency and low-consumption operation of zero-emission systems, and there was a certain risk of biological toxicity. The organic components and biological toxicity in the desulfurization wastewater treatment process of a coal-fired power plant were analyzed by field test and simulation experiments in this study. The results showed that the two-stage clarification method and the high-efficiency flocculant method could not effectively remove the organic matter in the desulfurization wastewater, but could reduce the humic acid substances in the wastewater. The reflux of nanofiltration concentrate reduced the proportion of tryptophan and tyrosine protein in the effluent of the regulating tank to 30%, but greatly increased the proportion of humic acid substances to 60%. The molecular weights of the pollutants in the desulfurization wastewater were mainly around 2084 Da and 612 Da, and the molecular weight of the pollutants in the nanofiltration concentrate was slightly smaller than that of the pretreated effluent, which may cause membrane fouling by adsorption and plugging pores. The two-stage clarification method and high-efficiency flocculant method could all remarkably reduce the biological toxicity of the effluent of the regulating tank, and the luminescence inhibition rate of luminescent bacteria decreased from 46.23% to 12.45% and 2.57%, respectively. The nanofiltration concentrate enriched a large number of biological toxic substances such as humic acid, and the luminescence inhibition rate increased to 49.05%. The lower molecular weight of the organic matter in the desulfurization wastewater resulted in higher risk of nanofiltration membrane fouling, and the enrichment of humic acid increased the biological toxicity of nanofiltration concentrate.
The complex organic composition of desulfurization wastewater in coal-fired power plants greatly affected the high efficiency and low-consumption operation of zero-emission systems, and there was a certain risk of biological toxicity. The organic components and biological toxicity in the desulfurization wastewater treatment process of a coal-fired power plant were analyzed by field test and simulation experiments in this study. The results showed that the two-stage clarification method and the high-efficiency flocculant method could not effectively remove the organic matter in the desulfurization wastewater, but could reduce the humic acid substances in the wastewater. The reflux of nanofiltration concentrate reduced the proportion of tryptophan and tyrosine protein in the effluent of the regulating tank to 30%, but greatly increased the proportion of humic acid substances to 60%. The molecular weights of the pollutants in the desulfurization wastewater were mainly around 2084 Da and 612 Da, and the molecular weight of the pollutants in the nanofiltration concentrate was slightly smaller than that of the pretreated effluent, which may cause membrane fouling by adsorption and plugging pores. The two-stage clarification method and high-efficiency flocculant method could all remarkably reduce the biological toxicity of the effluent of the regulating tank, and the luminescence inhibition rate of luminescent bacteria decreased from 46.23% to 12.45% and 2.57%, respectively. The nanofiltration concentrate enriched a large number of biological toxic substances such as humic acid, and the luminescence inhibition rate increased to 49.05%. The lower molecular weight of the organic matter in the desulfurization wastewater resulted in higher risk of nanofiltration membrane fouling, and the enrichment of humic acid increased the biological toxicity of nanofiltration concentrate.
2024, 42(6): 25-34.
doi: 10.13205/j.hjgc.202406004
Abstract:
The removal of antibiotics and heavy metals in the medicine wastewater is a tricky problem, and the metal-organic skeleton hybrid foam MIL-100(Fe)/CMC was used to remove tetracycline (TC) and copper ions (Cu2+). The physicochemical properties of the MOFs hybrid foams were analyzed by X-ray diffraction, scanning electron microscopy, nitrogen adsorption and desorption, as well as thermogravimetric analysis techniques; the influencing factors, stability, and adsorption mechanisms of hybrid foams were analyzed by adsorption experiments. The results showed that MIL-100(Fe)/CMC had porous structure and high thermal stability; MIL-100(Fe)/CMC had-maximum adsorption capacity of 80.40 and 80.04 mg/g for tetracycline (TC) and Cu2+, respectively, in the optimal working condition of 30 mg/L contaminants, 40 mg dosage of MIL-100(Fe)/CMC, 16 hours adsorption time, pH of 6 the ionic strength (NaCl) was negatively correlated with adsorption performance. MIL-100(Fe)/CMC had excellent adsorption and cyclic regeneration performance, and the removal rates of TC and Cu2+ maintained above 70% after six cycles of regeneration. The adsorption of TC and Cu2+ by MIL-100(Fe)/CMC was a self-exothermic process, matching the Langmuir isotherm model and the proposed first-order kinetic model. In conclusion, the metal organic skeleton hybrid foam is proven to have a broad research prospect in the removal of mixed contaminants of antibiotics and heavy metals in the treatment of pharmaceutical wastewater.
The removal of antibiotics and heavy metals in the medicine wastewater is a tricky problem, and the metal-organic skeleton hybrid foam MIL-100(Fe)/CMC was used to remove tetracycline (TC) and copper ions (Cu2+). The physicochemical properties of the MOFs hybrid foams were analyzed by X-ray diffraction, scanning electron microscopy, nitrogen adsorption and desorption, as well as thermogravimetric analysis techniques; the influencing factors, stability, and adsorption mechanisms of hybrid foams were analyzed by adsorption experiments. The results showed that MIL-100(Fe)/CMC had porous structure and high thermal stability; MIL-100(Fe)/CMC had-maximum adsorption capacity of 80.40 and 80.04 mg/g for tetracycline (TC) and Cu2+, respectively, in the optimal working condition of 30 mg/L contaminants, 40 mg dosage of MIL-100(Fe)/CMC, 16 hours adsorption time, pH of 6 the ionic strength (NaCl) was negatively correlated with adsorption performance. MIL-100(Fe)/CMC had excellent adsorption and cyclic regeneration performance, and the removal rates of TC and Cu2+ maintained above 70% after six cycles of regeneration. The adsorption of TC and Cu2+ by MIL-100(Fe)/CMC was a self-exothermic process, matching the Langmuir isotherm model and the proposed first-order kinetic model. In conclusion, the metal organic skeleton hybrid foam is proven to have a broad research prospect in the removal of mixed contaminants of antibiotics and heavy metals in the treatment of pharmaceutical wastewater.
2024, 42(6): 35-42.
doi: 10.13205/j.hjgc.202406005
Abstract:
To explore the seasonal efficiency of non-point source pollution in towns in South China, and deal with the low dissolved oxygen problem in the downstream tidal reach, this study took Huizhou Chating Ecological Regulation Pond (ERP) in Shahe River Basin, a tributary of Dongjiang River, as the monitoring object, and analyzed the migration and transformation process and treatment efficiency of pollutants along the river. The results showed that organic matter and phosphorus in ERP are mainly removed by sedimentation, filtration and retention, while nitrogen is mainly removed by biological nitrification and denitrification. In addition, the concentration of local dissolved oxygen in the pond is high, and the denitrification process is inhibited, resulting in NO-3-N accumulation. On the whole, under the condition of 0.9% wetland/catchment area ratio, the treatment efficiency of the ERP system was stable, and the average reduction rates of COD, NH+4-N, TP and TN were 8.4%, 59.3%, 66.7% and 31.8% and 23.2%, 52.9%, 51.5% and 23.4%, respectively, in drought and rain seasons. Except for the limited removal capacity of TN and NO-3-N, the other water quality indexes in the effluent complies with the Category V standard in the Environmental Quality Standard for Surface Water (GB 3838—2002), and the study can provide technical support for the control of non-point source pollution in surrounding towns.
To explore the seasonal efficiency of non-point source pollution in towns in South China, and deal with the low dissolved oxygen problem in the downstream tidal reach, this study took Huizhou Chating Ecological Regulation Pond (ERP) in Shahe River Basin, a tributary of Dongjiang River, as the monitoring object, and analyzed the migration and transformation process and treatment efficiency of pollutants along the river. The results showed that organic matter and phosphorus in ERP are mainly removed by sedimentation, filtration and retention, while nitrogen is mainly removed by biological nitrification and denitrification. In addition, the concentration of local dissolved oxygen in the pond is high, and the denitrification process is inhibited, resulting in NO-3-N accumulation. On the whole, under the condition of 0.9% wetland/catchment area ratio, the treatment efficiency of the ERP system was stable, and the average reduction rates of COD, NH+4-N, TP and TN were 8.4%, 59.3%, 66.7% and 31.8% and 23.2%, 52.9%, 51.5% and 23.4%, respectively, in drought and rain seasons. Except for the limited removal capacity of TN and NO-3-N, the other water quality indexes in the effluent complies with the Category V standard in the Environmental Quality Standard for Surface Water (GB 3838—2002), and the study can provide technical support for the control of non-point source pollution in surrounding towns.
2024, 42(6): 43-53.
doi: 10.13205/j.hjgc.202406006
Abstract:
Landfill leachate is a kind of high-concentration organic wastewater that is difficult to treat. Different from conventional wastewater treatment paths, the resource utilization of pollutants is considered to be an important research direction for landfill leachate disposal. Starting from the organic composition of landfill leachate, the research progress of direct recovery of organic matter in landfill leachate by extraction, adsorption, membrane, precipitation, and centrifugation, as well as indirect recovery of organic matter in landfill leachate by anaerobic fermentation, electrochemical, physicochemical and biological conversion is summarized. The necessity and technical feasibility of recycling organic matter from landfill leachate are discussed. The basic applications of recycled products such as VFA, HS, methane, hydrogen, electric energy and PHA are summarized. The engineering application status of organic matter resource technology from landfill leachate is also summarized. In this paper, the feasibility of engineering production of each related technology is analyzed, and the technical barriers of turning to engineering application in the test stage are put forward. Suggestions are put forward from the perspective of economy and technical feasibility. The prospect of resource utilization of landfill leachate is prospected.The feasibility of engineering application of related technologies is also analyzed.
Landfill leachate is a kind of high-concentration organic wastewater that is difficult to treat. Different from conventional wastewater treatment paths, the resource utilization of pollutants is considered to be an important research direction for landfill leachate disposal. Starting from the organic composition of landfill leachate, the research progress of direct recovery of organic matter in landfill leachate by extraction, adsorption, membrane, precipitation, and centrifugation, as well as indirect recovery of organic matter in landfill leachate by anaerobic fermentation, electrochemical, physicochemical and biological conversion is summarized. The necessity and technical feasibility of recycling organic matter from landfill leachate are discussed. The basic applications of recycled products such as VFA, HS, methane, hydrogen, electric energy and PHA are summarized. The engineering application status of organic matter resource technology from landfill leachate is also summarized. In this paper, the feasibility of engineering production of each related technology is analyzed, and the technical barriers of turning to engineering application in the test stage are put forward. Suggestions are put forward from the perspective of economy and technical feasibility. The prospect of resource utilization of landfill leachate is prospected.The feasibility of engineering application of related technologies is also analyzed.
2024, 42(6): 54-62.
doi: 10.13205/j.hjgc.202406007
Abstract:
The transportation and treatment systems of traditional oil fields have large footprint and low efficiency, while the oil-water separation technology of horizontal flow grid tubes is used to transform, exploring energy savings and consumption reduction. The separation law of oil-water-sludge in horizontal grid tubes was studied by combining Fluent software simulation with indoor and field experiments. The numerical simulation results showed that the longer the tube length, the smaller the fluid flow rate, and the better the oil-water separation effect. The inlet oil content increased, and the effluent increased. The oil concentration at the inlet of the six-meter gird tube should be controlled within 0.1%. The results of laboratory and field experiments were basically consistent with the results of numerical simulation, which confirmed the oil-water-sludge separation law explained by numerical simulation. Field experiments have shown that when the inlet flow rate varied between 0.02 m/s to 0.05 m/s, and the inlet oil content varied between 590 mg/L to 2710 mg/L, the effluent oil content was 63 mg/L to 86 mg/L and the suspended solids content was 86 mg/L to 145 mg/L. The grid tube has a stable removal effect on oil and suspended solids, indicating strong resistance to water quality fluctuations. It occupies a small area and has low investment and operating cost.
The transportation and treatment systems of traditional oil fields have large footprint and low efficiency, while the oil-water separation technology of horizontal flow grid tubes is used to transform, exploring energy savings and consumption reduction. The separation law of oil-water-sludge in horizontal grid tubes was studied by combining Fluent software simulation with indoor and field experiments. The numerical simulation results showed that the longer the tube length, the smaller the fluid flow rate, and the better the oil-water separation effect. The inlet oil content increased, and the effluent increased. The oil concentration at the inlet of the six-meter gird tube should be controlled within 0.1%. The results of laboratory and field experiments were basically consistent with the results of numerical simulation, which confirmed the oil-water-sludge separation law explained by numerical simulation. Field experiments have shown that when the inlet flow rate varied between 0.02 m/s to 0.05 m/s, and the inlet oil content varied between 590 mg/L to 2710 mg/L, the effluent oil content was 63 mg/L to 86 mg/L and the suspended solids content was 86 mg/L to 145 mg/L. The grid tube has a stable removal effect on oil and suspended solids, indicating strong resistance to water quality fluctuations. It occupies a small area and has low investment and operating cost.
2024, 42(6): 63-70.
doi: 10.13205/j.hjgc.202406008
Abstract:
This article systematically analyzes the industrial layout, equipment level, progress in ultra-low emission transformation, and current situation of air pollution prevention and control in the steel industry in the Guangxi region. It also analyzes the common difficulties in the process of ultra-low emission transformation. Combining with current environmental protection requirements and the development status of pollution control technology, it proposes strategies and suggestions to accelerate the transformation of the steel industry from long-process steelmaking to short-process steelmaking, by utilizing location advantages and promoting the green and high-quality development and transformation of the steel industry in the region.
This article systematically analyzes the industrial layout, equipment level, progress in ultra-low emission transformation, and current situation of air pollution prevention and control in the steel industry in the Guangxi region. It also analyzes the common difficulties in the process of ultra-low emission transformation. Combining with current environmental protection requirements and the development status of pollution control technology, it proposes strategies and suggestions to accelerate the transformation of the steel industry from long-process steelmaking to short-process steelmaking, by utilizing location advantages and promoting the green and high-quality development and transformation of the steel industry in the region.
2024, 42(6): 71-81.
doi: 10.13205/j.hjgc.202406009
Abstract:
Seasonal variation, source characteristics as well as light extinction contribution of water-soluble inorganic ions (WSIIs) in PM2.5 were explored in the northern suburb of Anyang. Gaseous pollutants, PM2.5 samples, and their chemical components were online monitored from March 2018 to February 2019. The results showed that the annual average concentrations of PM2.5 and WSIIs were (76.68±73.00) μg/m3 and (45.60±34.17) μg/m3, respectively, which showed obvious seasonal variation with the maximum values in winter, and the minimum values in summer. NH+4 most likely existed in the form of (NH4)2SO4, NH4NO3, and NH4Cl in four seasons at the observation sites. The main sources of WSIIs were secondary nitrate, secondary sulfate, dust, and combustion source by using positive matrix factorization (PMF). Furthermore, the revised IMPROVE algorithm was used to estimate the extinction coefficient (best). The results illustrated that the extinction contribution of SNA could reach 67%. Finally, typical pollution episodes were explored in winter in this study. Continuous emission and accumulation of pollutants under unfavorable metrological conditions was the major cause of the PM2.5 pollution events at this site. Meanwhile, a rapid increase of SNA, especially SO2-4, can lead to higher PM2.5 concentrations. Hence, the control of SNA is not only conducive to the reduction of regional PM2.5 concentration, but also to improving atmospheric visibility.
Seasonal variation, source characteristics as well as light extinction contribution of water-soluble inorganic ions (WSIIs) in PM2.5 were explored in the northern suburb of Anyang. Gaseous pollutants, PM2.5 samples, and their chemical components were online monitored from March 2018 to February 2019. The results showed that the annual average concentrations of PM2.5 and WSIIs were (76.68±73.00) μg/m3 and (45.60±34.17) μg/m3, respectively, which showed obvious seasonal variation with the maximum values in winter, and the minimum values in summer. NH+4 most likely existed in the form of (NH4)2SO4, NH4NO3, and NH4Cl in four seasons at the observation sites. The main sources of WSIIs were secondary nitrate, secondary sulfate, dust, and combustion source by using positive matrix factorization (PMF). Furthermore, the revised IMPROVE algorithm was used to estimate the extinction coefficient (best). The results illustrated that the extinction contribution of SNA could reach 67%. Finally, typical pollution episodes were explored in winter in this study. Continuous emission and accumulation of pollutants under unfavorable metrological conditions was the major cause of the PM2.5 pollution events at this site. Meanwhile, a rapid increase of SNA, especially SO2-4, can lead to higher PM2.5 concentrations. Hence, the control of SNA is not only conducive to the reduction of regional PM2.5 concentration, but also to improving atmospheric visibility.
2024, 42(6): 82-93.
doi: 10.13205/j.hjgc.202406010
Abstract:
The narrow active window is one of the key limitations for vanadium-titanium based catalysts in selective catalytic reduction of NOx with NH3 under dielectric barrier discharge. The V2O5/microporous TiO2 catalyst prepared by the hydrothermal method exhibited obvious wide NH3-SCR active window characteristics under the synergistic effect of dielectric barrier discharge. By comparing the catalytic performance of empty tubes, 4V/TiO2, and the vanadium-titanium based catalyst with the microporous carrier at room temperature, as well as the reaction behavior of the catalyst in N2/O2, N2/O2/NH3, N2/O2/NO atmosphere, the catalytic reaction mechanism of the catalyst was analyzed. The sulfur and water resistance of the microporous-carrier catalyst was tested, and the microstructure of the material was analyzed by XRD, SEM, BET, XPS, TGA and FTIR. The results showed that the denitrification efficiency of the 4V/MP-TiO2 catalyst was increased by 33.68% compared to conventional vanadium-titanium catalysts, and it maintained a denitrification efficiency of more than 80% in the range of 243 J/L to 442 J/L. It has good sulfur and water resistance while reducing energy consumption. This is due to the loose overall structure of microporous TiO2, which has a rich pore structure, improving the pore volume of the carrier, as well as the dispersion of the catalyst, and more active adsorption sites for NH3, which is conducive to broadening the active window. At the same time, microporous TiO2 enhances the ability of the catalyst to oxidize NO, which facilitates the rapid SCR reaction when the specific input energy is high.
The narrow active window is one of the key limitations for vanadium-titanium based catalysts in selective catalytic reduction of NOx with NH3 under dielectric barrier discharge. The V2O5/microporous TiO2 catalyst prepared by the hydrothermal method exhibited obvious wide NH3-SCR active window characteristics under the synergistic effect of dielectric barrier discharge. By comparing the catalytic performance of empty tubes, 4V/TiO2, and the vanadium-titanium based catalyst with the microporous carrier at room temperature, as well as the reaction behavior of the catalyst in N2/O2, N2/O2/NH3, N2/O2/NO atmosphere, the catalytic reaction mechanism of the catalyst was analyzed. The sulfur and water resistance of the microporous-carrier catalyst was tested, and the microstructure of the material was analyzed by XRD, SEM, BET, XPS, TGA and FTIR. The results showed that the denitrification efficiency of the 4V/MP-TiO2 catalyst was increased by 33.68% compared to conventional vanadium-titanium catalysts, and it maintained a denitrification efficiency of more than 80% in the range of 243 J/L to 442 J/L. It has good sulfur and water resistance while reducing energy consumption. This is due to the loose overall structure of microporous TiO2, which has a rich pore structure, improving the pore volume of the carrier, as well as the dispersion of the catalyst, and more active adsorption sites for NH3, which is conducive to broadening the active window. At the same time, microporous TiO2 enhances the ability of the catalyst to oxidize NO, which facilitates the rapid SCR reaction when the specific input energy is high.
2024, 42(6): 94-102.
doi: 10.13205/j.hjgc.202406011
Abstract:
In this study, iron ore tailings and coal gangue were used as raw materials to prepare high-strength and lightweight ceramsite by referring to the methods and equipment of iron ore pelletization in ferrous metallurgy. The influence of pelleting parameters on the properties of the pellet, and the influence of roasting parameters on the properties of ceramsite were investigated, and the structure-function relationship among the phase composition, structure, and performance of the ceramsite was explored. The results showed that the composition structure of 45% iron ore tailings and 55% coal gangue was calculated based on Riley’s three-phase diagram, and the green pellet was prepared under the conditions of 60% of particle size below 0.074 mm, 8 min pelletizing duration, and 10.5% moisture. After drying, the dried pellet was roasted at 1175 ℃ for 25 min to prepare ceramsite. The bulk density, apparent density, 1 h water absorption, and cylinder compressive strength was 859 kg/m3, 1705 kg/m3, 8.0%, and 6.7 MPa, which meet the requirements of various indexes of high-strength and light-weight ceramsite. The main phases of the ceramsite are quartz, feldspar, and hematite, which can provide strength for ceramsite. The well-developed pores in the ceramsite are beneficial to reducing bulk density, and apparent density, but the over-developed pores of the outer layer harm the cylinder compression strength.
In this study, iron ore tailings and coal gangue were used as raw materials to prepare high-strength and lightweight ceramsite by referring to the methods and equipment of iron ore pelletization in ferrous metallurgy. The influence of pelleting parameters on the properties of the pellet, and the influence of roasting parameters on the properties of ceramsite were investigated, and the structure-function relationship among the phase composition, structure, and performance of the ceramsite was explored. The results showed that the composition structure of 45% iron ore tailings and 55% coal gangue was calculated based on Riley’s three-phase diagram, and the green pellet was prepared under the conditions of 60% of particle size below 0.074 mm, 8 min pelletizing duration, and 10.5% moisture. After drying, the dried pellet was roasted at 1175 ℃ for 25 min to prepare ceramsite. The bulk density, apparent density, 1 h water absorption, and cylinder compressive strength was 859 kg/m3, 1705 kg/m3, 8.0%, and 6.7 MPa, which meet the requirements of various indexes of high-strength and light-weight ceramsite. The main phases of the ceramsite are quartz, feldspar, and hematite, which can provide strength for ceramsite. The well-developed pores in the ceramsite are beneficial to reducing bulk density, and apparent density, but the over-developed pores of the outer layer harm the cylinder compression strength.
2024, 42(6): 103-110.
doi: 10.13205/j.hjgc.202406012
Abstract:
In recent years, the production of perishable organic waste in kitchens has been increasing. To improve the degradation rate, it is urgent to develop an efficient process for degrading perishable organic waste in the kitchen. In this paper, we screened a bacterial strain that can adapt to perishable organic waste in the kitchen and degrade oil efficiently. Samples were collected from perishable organic waste and oil-contaminated soil, and 16S rDNA sequencing technology was used to construct a strain growth tree, and response surface analysis was used to study the optimal growth conditions of the strain. Through screening and functional verification, a lipid-degrading strain, named as TH1, was obtained and identified as Serratia marcescens. The single-factor experiment and response surface method showed that the lipase activity reached 213.70 U/L under the condition of temperature of 30 ℃, pH=7.54, and salinity of 1%. The results can provide germplasm resources for the subsequent development of composite bacterioides for efficient degradation, mechanism research, and resource utilization of perishable kitchen organic waste.
In recent years, the production of perishable organic waste in kitchens has been increasing. To improve the degradation rate, it is urgent to develop an efficient process for degrading perishable organic waste in the kitchen. In this paper, we screened a bacterial strain that can adapt to perishable organic waste in the kitchen and degrade oil efficiently. Samples were collected from perishable organic waste and oil-contaminated soil, and 16S rDNA sequencing technology was used to construct a strain growth tree, and response surface analysis was used to study the optimal growth conditions of the strain. Through screening and functional verification, a lipid-degrading strain, named as TH1, was obtained and identified as Serratia marcescens. The single-factor experiment and response surface method showed that the lipase activity reached 213.70 U/L under the condition of temperature of 30 ℃, pH=7.54, and salinity of 1%. The results can provide germplasm resources for the subsequent development of composite bacterioides for efficient degradation, mechanism research, and resource utilization of perishable kitchen organic waste.
2024, 42(6): 111-118.
doi: 10.13205/j.hjgc.202406013
Abstract:
As an important component of kitchen waste, oil has an important influence on kitchen waste composting. In this study, 0% (T1), 3% (T2), 6% (T3), and 12% (T4) vegetable oil were added to the kitchen waste for aerobic composting. The amount of oil added was based on the dry weight of the kitchen waste added to the compost. The effects of oils on the humification of kitchen waste aerobic composting were studied by characterizing the changes in physical and chemical properties, humic acid components, and humic acid precursors in the composting process. The results showed that: After 30 days of aerobic composting of the kitchen waste with different concentrations of oil, the compost of different treatment groups reached the requirements of decomposition, and the highest temperature was 70.9 ℃, 64.8 ℃, 65 ℃ and 67.2 ℃, respectively. The high-temperature period of compost reached more than 7 days. The germination rates of seeds were 119.22%, 113.50%, 114.03%, and 120.52%, respectively. In the T2, T3, and T4 treatment groups, oil accumulation occurred at high temperatures, and the highest oil content was 1.66 times, 1.99 times, and 1.76 times the initial oil content. On the 30th day of composting, the HA/FA ratio of the four treatment groups was 0.55, 0.70, 0.80, and 1.30, respectively. The HA/FA ratio was the highest when the oil content was 12%, indicating that the humification degree of compost was the strongest when the oil content was 12%. Adding 12% oil can prolong the high-temperature period of compost and promote the formation of precursors, thus promoting the humification process of compost. The results of redundancy analysis showed that the content of oil was positively correlated with the formation of humic acid precursors and humus components. In conclusion, when the oil content is 12% of the dry weight of food waste, the degradation of oil has the best effect on the humification process of kitchen waste aerobic compost.
As an important component of kitchen waste, oil has an important influence on kitchen waste composting. In this study, 0% (T1), 3% (T2), 6% (T3), and 12% (T4) vegetable oil were added to the kitchen waste for aerobic composting. The amount of oil added was based on the dry weight of the kitchen waste added to the compost. The effects of oils on the humification of kitchen waste aerobic composting were studied by characterizing the changes in physical and chemical properties, humic acid components, and humic acid precursors in the composting process. The results showed that: After 30 days of aerobic composting of the kitchen waste with different concentrations of oil, the compost of different treatment groups reached the requirements of decomposition, and the highest temperature was 70.9 ℃, 64.8 ℃, 65 ℃ and 67.2 ℃, respectively. The high-temperature period of compost reached more than 7 days. The germination rates of seeds were 119.22%, 113.50%, 114.03%, and 120.52%, respectively. In the T2, T3, and T4 treatment groups, oil accumulation occurred at high temperatures, and the highest oil content was 1.66 times, 1.99 times, and 1.76 times the initial oil content. On the 30th day of composting, the HA/FA ratio of the four treatment groups was 0.55, 0.70, 0.80, and 1.30, respectively. The HA/FA ratio was the highest when the oil content was 12%, indicating that the humification degree of compost was the strongest when the oil content was 12%. Adding 12% oil can prolong the high-temperature period of compost and promote the formation of precursors, thus promoting the humification process of compost. The results of redundancy analysis showed that the content of oil was positively correlated with the formation of humic acid precursors and humus components. In conclusion, when the oil content is 12% of the dry weight of food waste, the degradation of oil has the best effect on the humification process of kitchen waste aerobic compost.
2024, 42(6): 119-126.
doi: 10.13205/j.hjgc.202406014
Abstract:
With the continuous promotion of the construction of Zero-Waste City, the demand for decoration waste treatment is increasing day by day. However, there are still shortcomings in the prediction of the amount of decoration waste in relevant office buildings and the research on resource utilization. In this study, the BP neural network was used to study the characteristics and trends of the source of office building decoration waste in 31 provinces and cities (except for Hong Kong, Macao and Taiwan). After the test, the goodness-of-fit of the trained BP neural network was R=0.93693>0.9, and the model accuracy was excellent. According to the prediction results of the BP model, the total amount of office building renovation waste occurring in China will reach 7.856 million tons by 2030, with a growth rate of 36.8% compared with 2020. Using ArcGIS means to characterize the spatial and temporal distribution of office renovation waste emissions in China, the study shows that the national occurrence is mainly in the southeast coastal and Sichuan-Chongqing regions, supplemented by the central and southern regions, and the overall low occurrence in the rest of the regions. Since the waste paper-faced gypsum board accounts for the largest proportion of the waste, up to 58.9%, a study on its resource treatment and disposal was conducted. Through comparison experiments with desulfurization gypsum, it was proved that its mechanical properties was better than that of desulfurization gypsum under high dosing. The optimal amount of gypsum as a retarder and the best mechanical properties of cement samples were determined by comparing different processes. The cement performance was optimal when a 5% waste gypsum board was added. The best flexural strength of the cement samples made by mixing raw materials was 8.9 MPa and the compressive strength was 46.5 MPa.
With the continuous promotion of the construction of Zero-Waste City, the demand for decoration waste treatment is increasing day by day. However, there are still shortcomings in the prediction of the amount of decoration waste in relevant office buildings and the research on resource utilization. In this study, the BP neural network was used to study the characteristics and trends of the source of office building decoration waste in 31 provinces and cities (except for Hong Kong, Macao and Taiwan). After the test, the goodness-of-fit of the trained BP neural network was R=0.93693>0.9, and the model accuracy was excellent. According to the prediction results of the BP model, the total amount of office building renovation waste occurring in China will reach 7.856 million tons by 2030, with a growth rate of 36.8% compared with 2020. Using ArcGIS means to characterize the spatial and temporal distribution of office renovation waste emissions in China, the study shows that the national occurrence is mainly in the southeast coastal and Sichuan-Chongqing regions, supplemented by the central and southern regions, and the overall low occurrence in the rest of the regions. Since the waste paper-faced gypsum board accounts for the largest proportion of the waste, up to 58.9%, a study on its resource treatment and disposal was conducted. Through comparison experiments with desulfurization gypsum, it was proved that its mechanical properties was better than that of desulfurization gypsum under high dosing. The optimal amount of gypsum as a retarder and the best mechanical properties of cement samples were determined by comparing different processes. The cement performance was optimal when a 5% waste gypsum board was added. The best flexural strength of the cement samples made by mixing raw materials was 8.9 MPa and the compressive strength was 46.5 MPa.
MECHANISM OF SOLIDIFICATION OF HEAVY METALS (Zn, Cd) BY LADLE FURNACE SLAG-FLY ASH BASED GEOPOLYMERS
2024, 42(6): 127-135.
doi: 10.13205/j.hjgc.202406015
Abstract:
To improve the pollution of heavy metals and increase the utilization rate of solid waste, this study prepared geopolymers for the solidification of Zn2+, and Cd2+ under alkaline excitation conditions using ladle furnace slag (LFS) and fly ash (FA) as raw materials, and sodium hydroxide and water glass as alkaline activator. The effect of Zn2+ and Cd2+ doping on the strength of the cured body was investigated, and the immobilization effect of the geopolymer on Zn2+ and Cd2+ was evaluated by leaching experiments, and the immobilization mechanism was investigated by combining the characterization methods such as XRD, SEM-EDS, FT-IR, and XPS. The results showed that the LFS-FA-based geopolymer has good compatibility with Zn2+ and Cd2+, the compressive strength of the cured body containing 1.0% Cd2+ for 28 d could reach 40.62 MPa, and the curing rate of Zn2+ and Cd2+ in the hydration leaching experiments was over 99.6%; there was no new phase generated in the cured body after the incorporation of Zn2+ and Cd2+, and no chemical valence change occurred during the curing process. Metal ions can be effectively fixed in ladle furnace slag base polymer, mainly through physical encapsulation, and adsorption, while a small number of heavy metal ions exist in the curing body in the form of Si—O—M and Al—O—M (M=Zn, Cd) through chemical bonding.
To improve the pollution of heavy metals and increase the utilization rate of solid waste, this study prepared geopolymers for the solidification of Zn2+, and Cd2+ under alkaline excitation conditions using ladle furnace slag (LFS) and fly ash (FA) as raw materials, and sodium hydroxide and water glass as alkaline activator. The effect of Zn2+ and Cd2+ doping on the strength of the cured body was investigated, and the immobilization effect of the geopolymer on Zn2+ and Cd2+ was evaluated by leaching experiments, and the immobilization mechanism was investigated by combining the characterization methods such as XRD, SEM-EDS, FT-IR, and XPS. The results showed that the LFS-FA-based geopolymer has good compatibility with Zn2+ and Cd2+, the compressive strength of the cured body containing 1.0% Cd2+ for 28 d could reach 40.62 MPa, and the curing rate of Zn2+ and Cd2+ in the hydration leaching experiments was over 99.6%; there was no new phase generated in the cured body after the incorporation of Zn2+ and Cd2+, and no chemical valence change occurred during the curing process. Metal ions can be effectively fixed in ladle furnace slag base polymer, mainly through physical encapsulation, and adsorption, while a small number of heavy metal ions exist in the curing body in the form of Si—O—M and Al—O—M (M=Zn, Cd) through chemical bonding.
2024, 42(6): 136-145.
doi: 10.13205/j.hjgc.202406016
Abstract:
Soil serves as a significant sink for plastic waste and microplastics. Investigating the pollution status and ecological risks of microplastics in agricultural soil can provide fundamental data and theoretical support for the management of soil microplastic pollution. In this study, soil samples were collected from greenhouse vegetable fields in different regions of Wuhan. Microplastics in the soil were quantitatively and qualitatively analyzed using the Nile Red fluorescence staining method and Raman spectroscopy. The results revealed an average abundance of microplastics in the cultivated layer soil of vegetable fields in Wuhan to be (2938.9±1637.5) particles per kilogram of dry weight (n/kg dw), predominantly in the form of fibers and fragments. Polyethylene (PE) and polypropylene (PP) were identified as the main polymer types, exhibiting a significant positive correlation. Microplastics at different depths in the sampling areas showed similarities in morphology and types. The risk assessment using the pollution load index method indicated a risk level of Class I for all sampled regions. However, the risk assessment using the risk index and potential risk index methods revealed higher risks at sampling points where polyvinyl chloride (PVC) was detected, suggesting the need for standardized models in the future to assess the ecological risks of microplastics.
Soil serves as a significant sink for plastic waste and microplastics. Investigating the pollution status and ecological risks of microplastics in agricultural soil can provide fundamental data and theoretical support for the management of soil microplastic pollution. In this study, soil samples were collected from greenhouse vegetable fields in different regions of Wuhan. Microplastics in the soil were quantitatively and qualitatively analyzed using the Nile Red fluorescence staining method and Raman spectroscopy. The results revealed an average abundance of microplastics in the cultivated layer soil of vegetable fields in Wuhan to be (2938.9±1637.5) particles per kilogram of dry weight (n/kg dw), predominantly in the form of fibers and fragments. Polyethylene (PE) and polypropylene (PP) were identified as the main polymer types, exhibiting a significant positive correlation. Microplastics at different depths in the sampling areas showed similarities in morphology and types. The risk assessment using the pollution load index method indicated a risk level of Class I for all sampled regions. However, the risk assessment using the risk index and potential risk index methods revealed higher risks at sampling points where polyvinyl chloride (PVC) was detected, suggesting the need for standardized models in the future to assess the ecological risks of microplastics.
2024, 42(6): 146-152.
doi: 10.13205/j.hjgc.202406017
Abstract:
The efficiency, influencing factors, and mechanism of removing atrazine from soil by ascorbic acid/persulfate were studied. When the concentrations of ascorbic acid and persulfate were 10 and 30 mmol/L, respectively, the degradation ratio of atrazine in soil achieved 92.4% at a pH of 3.0. The co-existing inorganic anions (Cl- and HCO-3) could inhibit the degradation of atrazine. Low concentrations of dissolved organic matter (0 to 2.5 mg/L) could promote the degradation of atrazine, while high concentrations of dissolved organic matter (>5 mg/L) could inhibit the oxidation of atrazine. On the one hand, ascorbic acid could directly activate persulfate to generate sulfate radicals and hydroxyl radicals. On the other hand, ascorbic acid could promote the release of iron ions from the soil and the cycle of Fe2+/Fe3+, which indirectly enhances the activation of persulfate. In addition, ascorbic acid could enhance the desorption of atrazine from the soil and reduce the mass transfer resistance between atrazine and oxidative radicals, which was beneficial for promoting atrazine oxidation. The degradation pathways of atrazine in the ascorbic acid/persulfate system mainly involved dealkylation oxidation, dechlorination, and hydroxylation.
The efficiency, influencing factors, and mechanism of removing atrazine from soil by ascorbic acid/persulfate were studied. When the concentrations of ascorbic acid and persulfate were 10 and 30 mmol/L, respectively, the degradation ratio of atrazine in soil achieved 92.4% at a pH of 3.0. The co-existing inorganic anions (Cl- and HCO-3) could inhibit the degradation of atrazine. Low concentrations of dissolved organic matter (0 to 2.5 mg/L) could promote the degradation of atrazine, while high concentrations of dissolved organic matter (>5 mg/L) could inhibit the oxidation of atrazine. On the one hand, ascorbic acid could directly activate persulfate to generate sulfate radicals and hydroxyl radicals. On the other hand, ascorbic acid could promote the release of iron ions from the soil and the cycle of Fe2+/Fe3+, which indirectly enhances the activation of persulfate. In addition, ascorbic acid could enhance the desorption of atrazine from the soil and reduce the mass transfer resistance between atrazine and oxidative radicals, which was beneficial for promoting atrazine oxidation. The degradation pathways of atrazine in the ascorbic acid/persulfate system mainly involved dealkylation oxidation, dechlorination, and hydroxylation.
2024, 42(6): 153-159.
doi: 10.13205/j.hjgc.202406018
Abstract:
The intelligent management of wastewater treatment plants (WWTPs) requires high-quality and rich data support. However, in the current management mode of WWTPs, issues such as excessive aeration, excessive dosing, and monitoring have led to deficiencies in the quantity and quality of operation and maintenance data. The performance of various data-driven models supported by such defective data is not sufficient. How to improve the quality and quantity of data is crucial for the research and application of various artificial intelligence models. This study proposed a wastewater treatment data enhancement method based on generative adversarial networks (WP-GAN) to address the data defects, and validated the proposed method using a classic wastewater treatment artificial neural network model (W-ANN). The dataset used in the study was from a large urban WWTP with an anaerobic-anoxic-aerobic (A2O) process. The measured data was amplified 5-fold through data enhancement treatment, and the W-ANN model was trained with pre- and post-enhancement data samples. It was found that the performance of the W-ANN model was significantly improved: the fitting degree increased from 20% to 65%, and the maximum simulation accuracy increased from 67.85% to 75.55%. The method proposed in this study is a universal data enhancement method to address data deficiencies, which can provide better data support for various data-driven models for the intelligent management of WWTPs.
The intelligent management of wastewater treatment plants (WWTPs) requires high-quality and rich data support. However, in the current management mode of WWTPs, issues such as excessive aeration, excessive dosing, and monitoring have led to deficiencies in the quantity and quality of operation and maintenance data. The performance of various data-driven models supported by such defective data is not sufficient. How to improve the quality and quantity of data is crucial for the research and application of various artificial intelligence models. This study proposed a wastewater treatment data enhancement method based on generative adversarial networks (WP-GAN) to address the data defects, and validated the proposed method using a classic wastewater treatment artificial neural network model (W-ANN). The dataset used in the study was from a large urban WWTP with an anaerobic-anoxic-aerobic (A2O) process. The measured data was amplified 5-fold through data enhancement treatment, and the W-ANN model was trained with pre- and post-enhancement data samples. It was found that the performance of the W-ANN model was significantly improved: the fitting degree increased from 20% to 65%, and the maximum simulation accuracy increased from 67.85% to 75.55%. The method proposed in this study is a universal data enhancement method to address data deficiencies, which can provide better data support for various data-driven models for the intelligent management of WWTPs.
2024, 42(6): 160-168.
doi: 10.13205/j.hjgc.202406019
Abstract:
To realize the automation of waste sorting, the research of vision-based automatic detection of recyclable waste is of great importance. To realize the automation of waste sorting, the traditional horizontal frame target detection algorithm loses the directional information of the target during the detection, and the overlap of the positioning frame is serious so that the true length and width of the target cannot be obtained, which is unfavorable to the subsequent sorting. The algorithm is based on the improvement of the RetinaNet network, adding the angle prediction module in the detection head, using the PSC angle encoder to improve the angle return boundary problem, introducing the Balanced L1 loss function to balance the gradient contribution of simple and difficult samples, and replacing the backbone network with the Swin Transformer to enhance the feature extraction capability of the network. The network with angle prediction can locate the garbage more accurately, and the improved network accuracy (mAP) reaches 78.4%, which is 12 percentage points higher than the original algorithm, while the detection effect of PSC is better than other methods compared with other angle encoders.
To realize the automation of waste sorting, the research of vision-based automatic detection of recyclable waste is of great importance. To realize the automation of waste sorting, the traditional horizontal frame target detection algorithm loses the directional information of the target during the detection, and the overlap of the positioning frame is serious so that the true length and width of the target cannot be obtained, which is unfavorable to the subsequent sorting. The algorithm is based on the improvement of the RetinaNet network, adding the angle prediction module in the detection head, using the PSC angle encoder to improve the angle return boundary problem, introducing the Balanced L1 loss function to balance the gradient contribution of simple and difficult samples, and replacing the backbone network with the Swin Transformer to enhance the feature extraction capability of the network. The network with angle prediction can locate the garbage more accurately, and the improved network accuracy (mAP) reaches 78.4%, which is 12 percentage points higher than the original algorithm, while the detection effect of PSC is better than other methods compared with other angle encoders.
2024, 42(6): 169-177.
doi: 10.13205/j.hjgc.202406020
Abstract:
At present, with the rapid development of society and the rapid growth of the urban population, garbage pollution has become increasingly prominent, and garbage classification is imperative. Manual processing has the problems of heavy tasks and low efficiency, and some automated classification methods have low detection accuracy and slow speed. To improve the accuracy of garbage detection in complex scenes, lighten the structure, and make it easier to deploy, an improved YOLO v5s garbage detection model, Lightweight Garbage Detection YOLO (LGD-YOLO) was proposed, which integrated a lightweight convolution module, attention mechanism, and multiple receptive field modules. First, Ghost convolution and Slim Neck module including GSConv were introduced into the network structure to make the model lighter. Secondly, the coordinate attention mechanism was embedded to focus on important information to improve the detection accuracy. Finally, the multi-receptive field module was introduced to improve the multi-scale detection capability of the model and avoid missing detection of small target objects. The data set containing trash garbage images in different environments was tested and verified. The experimental results showed that the parameters and calculation amount of the improved model were 5.77 M and 9.2 GFLOPs, respectively, which were 22.4% and 56.4% less than the original model. The single image detection speed was 26.5 ms, meeting the real-time requirements of garbage detection. In addition, the improved algorithm has good detection accuracy, with mAP0.5 and mAP0.5∶0.95 reaching 96.20% and 77.77%, respectively, which was superior to the current popular target detection algorithm.
At present, with the rapid development of society and the rapid growth of the urban population, garbage pollution has become increasingly prominent, and garbage classification is imperative. Manual processing has the problems of heavy tasks and low efficiency, and some automated classification methods have low detection accuracy and slow speed. To improve the accuracy of garbage detection in complex scenes, lighten the structure, and make it easier to deploy, an improved YOLO v5s garbage detection model, Lightweight Garbage Detection YOLO (LGD-YOLO) was proposed, which integrated a lightweight convolution module, attention mechanism, and multiple receptive field modules. First, Ghost convolution and Slim Neck module including GSConv were introduced into the network structure to make the model lighter. Secondly, the coordinate attention mechanism was embedded to focus on important information to improve the detection accuracy. Finally, the multi-receptive field module was introduced to improve the multi-scale detection capability of the model and avoid missing detection of small target objects. The data set containing trash garbage images in different environments was tested and verified. The experimental results showed that the parameters and calculation amount of the improved model were 5.77 M and 9.2 GFLOPs, respectively, which were 22.4% and 56.4% less than the original model. The single image detection speed was 26.5 ms, meeting the real-time requirements of garbage detection. In addition, the improved algorithm has good detection accuracy, with mAP0.5 and mAP0.5∶0.95 reaching 96.20% and 77.77%, respectively, which was superior to the current popular target detection algorithm.
2024, 42(6): 178-186.
doi: 10.13205/j.hjgc.202406021
Abstract:
The in-production enterprise cannot layout sampling by grid comprehensively, due to the daily production, which leads to difficulties in identifying the spatial distribution of contamination. The article took a Hunan lead processing enterprise as the research object, using the spatial interpolation method of Voxler to supplement the blank area based on the detected results of the sampling points, and then drawing the spatial distribution map of the characteristic contaminants. The application of the Voxler spatial model showed the results as follows: on the one hand, Voxler could visually characterize the distribution of contaminants, and effectively fill in the lack of detailed inspection contents; on the other hand, compared with the traditional 2-D analysis model, it could provide more accurate area result of the contaminated soil. There was lead pollution in the entire factory area, and the area of contaminated soil exceeding the standard was about 340000 m3. The composite pollution of arsenic, cadmium, and lead under the smelting area, acid production area, and raw material storage area, had the volume calculated as about 130000 m3. The precise positioning and the precise measurement can provide design support for the later risk assessment and pollution control of similar enterprises.
The in-production enterprise cannot layout sampling by grid comprehensively, due to the daily production, which leads to difficulties in identifying the spatial distribution of contamination. The article took a Hunan lead processing enterprise as the research object, using the spatial interpolation method of Voxler to supplement the blank area based on the detected results of the sampling points, and then drawing the spatial distribution map of the characteristic contaminants. The application of the Voxler spatial model showed the results as follows: on the one hand, Voxler could visually characterize the distribution of contaminants, and effectively fill in the lack of detailed inspection contents; on the other hand, compared with the traditional 2-D analysis model, it could provide more accurate area result of the contaminated soil. There was lead pollution in the entire factory area, and the area of contaminated soil exceeding the standard was about 340000 m3. The composite pollution of arsenic, cadmium, and lead under the smelting area, acid production area, and raw material storage area, had the volume calculated as about 130000 m3. The precise positioning and the precise measurement can provide design support for the later risk assessment and pollution control of similar enterprises.
