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2022 Vol. 40, No. 3
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2022, 40(3): 1-6,153.
doi: 10.13205/j.hjgc.202203001
Abstract:
Membrane technologies have been applied in Chinese water sector for decades, playing a significant role in eliminating water pollution and alleviating water scarcity. This paper surveyed the full-scale applications of membrane technologies for municipal wastewater treatment and reclamation in China, and emphatically analyzed the development characteristics of membrane bioreactor. The techno-economic features of membrane bioreactor showed advantages to conventional activated sludge process regarding pollutant removal and cost-benefit analysis. Moreover, this review summarized the joint-forces from environment, policy and market which had been driving membrane technologies' application in water sector, and presented the perspectives on efficient and effective materials, advanced technologies, intelligent operation and low-carbon systems in China, in effort to peak carbon dioxide emissions before 2030 and achieve carbon neutrality before 2060.
Membrane technologies have been applied in Chinese water sector for decades, playing a significant role in eliminating water pollution and alleviating water scarcity. This paper surveyed the full-scale applications of membrane technologies for municipal wastewater treatment and reclamation in China, and emphatically analyzed the development characteristics of membrane bioreactor. The techno-economic features of membrane bioreactor showed advantages to conventional activated sludge process regarding pollutant removal and cost-benefit analysis. Moreover, this review summarized the joint-forces from environment, policy and market which had been driving membrane technologies' application in water sector, and presented the perspectives on efficient and effective materials, advanced technologies, intelligent operation and low-carbon systems in China, in effort to peak carbon dioxide emissions before 2030 and achieve carbon neutrality before 2060.
2022, 40(3): 7-12.
doi: 10.13205/j.hjgc.202203002
Abstract:
A novel phosphorus recovery process combining membrane filtration and electrochemical struvite precipitation was proposed to treat phosphorus-containing wastewater. The effects of membrane flux, current density, initial phosphorus concentration and polarity reversal time on phosphorus removal and recovery were investigated. The results showed that the average phosphorus removal efficiency was 92.0% at an initial phosphorus concentration of 5 mmol/L, a membrane flux of 22.1 L/(m2·h) and a current density of 20 A/m2, and struvite was the dominant composition of the recovered products. In the flow-through operation mode, different initial phosphorus concentrations had no significant effect on phosphorus removal. When the system was operated in continuous flow mode, the phosphones removal rate was maintained at 90% by 6 min polarity reversal every 4 h operation.
A novel phosphorus recovery process combining membrane filtration and electrochemical struvite precipitation was proposed to treat phosphorus-containing wastewater. The effects of membrane flux, current density, initial phosphorus concentration and polarity reversal time on phosphorus removal and recovery were investigated. The results showed that the average phosphorus removal efficiency was 92.0% at an initial phosphorus concentration of 5 mmol/L, a membrane flux of 22.1 L/(m2·h) and a current density of 20 A/m2, and struvite was the dominant composition of the recovered products. In the flow-through operation mode, different initial phosphorus concentrations had no significant effect on phosphorus removal. When the system was operated in continuous flow mode, the phosphones removal rate was maintained at 90% by 6 min polarity reversal every 4 h operation.
2022, 40(3): 13-17,31.
doi: 10.13205/j.hjgc.202203003
Abstract:
Nowadays, the retrofit of ultra-low emission has been finished in most coal-fired power plants, and are in process in iron and steel plants in China. The concentration of filterable particulate matters (FPM) has been greatly reduced and condensable particulate matters (CPM) have aroused more attention. The fraction of organic matter in CPM emitted from coal-fired power plants (CFPPs) and iron and steel plants remained controversial, which was important to understand the formation mechanism and to promote the emission control of CPM. We collected CPM samples by in-direct dilution method in eight CFPPs and three iron and steel plants (including two sintering and one coke making plants), and specific compositions and fraction of organic matter in CPM were analyzed. The results showed that the concentration of organic compositions from CFPPs was 0.082 mg/m3(0~0.331 mg/m3) and 0.060 mg/m3(0~0.254 mg/m3) at the inlet of flue gas desulfurization and stack, accounting for 4.95% and 10.1% of total CPM content, respectively. For iron and steel plants, the concentration and proportion of organic matter were higher in comparison with those from CFPPs, which were 1.9 mg/m3(0.408~3.98 mg/m3) and 0.382 mg/m3(0.149~0.572 mg/m3) at the inlet of flue gas desulfurization and stack, accounting for 22.2% and 11.1% of total CPM content respectively. Major compositions of organic matter in CPM from CFPPs were esters, whereas alkanes and alkanoic acids were the major composition in CPM from iron and steel plants. In a word, the fractions of organic matter at two kinds of stationary sources were relatively low, more attention should be paid on controlling its inorganic gas precursors.
Nowadays, the retrofit of ultra-low emission has been finished in most coal-fired power plants, and are in process in iron and steel plants in China. The concentration of filterable particulate matters (FPM) has been greatly reduced and condensable particulate matters (CPM) have aroused more attention. The fraction of organic matter in CPM emitted from coal-fired power plants (CFPPs) and iron and steel plants remained controversial, which was important to understand the formation mechanism and to promote the emission control of CPM. We collected CPM samples by in-direct dilution method in eight CFPPs and three iron and steel plants (including two sintering and one coke making plants), and specific compositions and fraction of organic matter in CPM were analyzed. The results showed that the concentration of organic compositions from CFPPs was 0.082 mg/m3(0~0.331 mg/m3) and 0.060 mg/m3(0~0.254 mg/m3) at the inlet of flue gas desulfurization and stack, accounting for 4.95% and 10.1% of total CPM content, respectively. For iron and steel plants, the concentration and proportion of organic matter were higher in comparison with those from CFPPs, which were 1.9 mg/m3(0.408~3.98 mg/m3) and 0.382 mg/m3(0.149~0.572 mg/m3) at the inlet of flue gas desulfurization and stack, accounting for 22.2% and 11.1% of total CPM content respectively. Major compositions of organic matter in CPM from CFPPs were esters, whereas alkanes and alkanoic acids were the major composition in CPM from iron and steel plants. In a word, the fractions of organic matter at two kinds of stationary sources were relatively low, more attention should be paid on controlling its inorganic gas precursors.
2022, 40(3): 18-23.
doi: 10.13205/j.hjgc.202203004
Abstract:
The late-stage waste infiltration fluid from the solid waste landfill in Jiangmen was treated by a combined process of Fe/C micro electrolysis-Fenton oxidation, to reduce COD, turbidity value and the concentration of heavy metal ions in the leachate. Results showed that under the condition of pH between 4 and 5, dosage of iron-carbon composite of 30~40 g/L, aeration volume of 40~60 L/min, the hydraulic retention time (HRT) of 1 hour, the removal rate of Ni2+, Cr(Ⅵ) and Pb2+ in waste leachate was 96%,97% and 96% respectively, the removal rate of the leachate turbidity and COD was 92.41% and 62.33% respectively, the turbidity decreased from 40.73 NTU to 3.09 NTU, and the COD decreased from 579.2 mg/L to 218.16 mg/L. In further Fenton oxidation treatment, research results showed that under the condition of Fe2+concentration of 0.007 mol/L, oxidation time of 90 min, n(H2O2):n(Fe2+)=1.2:1, the removal rate of the COD and turbidity was 67.50% and 53.20% respectively, the value of turbidity was 1.47 NTU, the value of COD was 69.49 mg/L, reaching the Rank Ⅱ limiting value of China's National Standard of Sewage discharge (GB18918-2002).
The late-stage waste infiltration fluid from the solid waste landfill in Jiangmen was treated by a combined process of Fe/C micro electrolysis-Fenton oxidation, to reduce COD, turbidity value and the concentration of heavy metal ions in the leachate. Results showed that under the condition of pH between 4 and 5, dosage of iron-carbon composite of 30~40 g/L, aeration volume of 40~60 L/min, the hydraulic retention time (HRT) of 1 hour, the removal rate of Ni2+, Cr(Ⅵ) and Pb2+ in waste leachate was 96%,97% and 96% respectively, the removal rate of the leachate turbidity and COD was 92.41% and 62.33% respectively, the turbidity decreased from 40.73 NTU to 3.09 NTU, and the COD decreased from 579.2 mg/L to 218.16 mg/L. In further Fenton oxidation treatment, research results showed that under the condition of Fe2+concentration of 0.007 mol/L, oxidation time of 90 min, n(H2O2):n(Fe2+)=1.2:1, the removal rate of the COD and turbidity was 67.50% and 53.20% respectively, the value of turbidity was 1.47 NTU, the value of COD was 69.49 mg/L, reaching the Rank Ⅱ limiting value of China's National Standard of Sewage discharge (GB18918-2002).
2022, 40(3): 24-31.
doi: 10.13205/j.hjgc.202203005
Abstract:
In order to explore the effect of nano-zero-valent iron agglomeration and oxidation reaction on the stabilization effect and potential toxicity of arsenic (As) in soil, nano-zero-valent iron and its possible phase-transition products, including micro-zero-valent iron, nano-Fe2O3, micro-Fe2O3 and nano-Fe3O4 were selected, and the effect of phase transition of nano-zero-valent iron on the stabilization effect and potential toxicity of As-contaminated soils were studied. The results showed that:1) in comparison, nano-zero-valent iron had the best efficiency for As stabilization in the soil, and the water-soluble As content decreased from 2.20 mg/kg to 0.11 mg/kg, the stabilization efficiency was 94.90% when its addition amount was 5%. At the same time, the environmental analysis of As decreased from the medium risk to no risk level; 2) based on results of leaching experiments, it was found that the agglomeration of nano-zero valent iron to micro-zero-valent iron had no significant on the stabilization efficiency of As (P>0.05); 3) the phytotoxicity experiments indicated that the aggregation and oxidation products of nano-zero-valent iron could inhibit the growth of roots and affect the relative root length of rapeseed seeds, however, it had no inhibitory effect on relative seed germination rate and seed germination index; 4) according to morphological analysis, phytotoxicity and environmental risk analysis, we found that micro-Fe2O3 and nano-Fe3O4 had low efficiency for As stabilization in soils, certain environmental risks remained after stabilization treatment. Therefore, in the actual remediation process, the environmental risk of As induced by the phase transition of nano-zero-valent iron needs attention.
In order to explore the effect of nano-zero-valent iron agglomeration and oxidation reaction on the stabilization effect and potential toxicity of arsenic (As) in soil, nano-zero-valent iron and its possible phase-transition products, including micro-zero-valent iron, nano-Fe2O3, micro-Fe2O3 and nano-Fe3O4 were selected, and the effect of phase transition of nano-zero-valent iron on the stabilization effect and potential toxicity of As-contaminated soils were studied. The results showed that:1) in comparison, nano-zero-valent iron had the best efficiency for As stabilization in the soil, and the water-soluble As content decreased from 2.20 mg/kg to 0.11 mg/kg, the stabilization efficiency was 94.90% when its addition amount was 5%. At the same time, the environmental analysis of As decreased from the medium risk to no risk level; 2) based on results of leaching experiments, it was found that the agglomeration of nano-zero valent iron to micro-zero-valent iron had no significant on the stabilization efficiency of As (P>0.05); 3) the phytotoxicity experiments indicated that the aggregation and oxidation products of nano-zero-valent iron could inhibit the growth of roots and affect the relative root length of rapeseed seeds, however, it had no inhibitory effect on relative seed germination rate and seed germination index; 4) according to morphological analysis, phytotoxicity and environmental risk analysis, we found that micro-Fe2O3 and nano-Fe3O4 had low efficiency for As stabilization in soils, certain environmental risks remained after stabilization treatment. Therefore, in the actual remediation process, the environmental risk of As induced by the phase transition of nano-zero-valent iron needs attention.
2022, 40(3): 32-37,138.
doi: 10.13205/j.hjgc.202203006
Abstract:
As the effluent discharge index of sewage treatment plant tends to be more strict, deep denitrification and dephosphorization of tail water gradually becomes an indispensable process. In this study, pyrite was used as the main filler of biofilter to conduct simultaneous denitrification and dephosphorization treatment of wastewater with low concentration of NO3--N and PO43--P, and to investigate the pollutant conversion characteristics and functional microbial changes during the start-up process. The results showed that the simultaneous denitrification and dephosphorization of the biofilter could be realized after 30-day operation, and its maximum total nitrogen removal rate reached 70 g/(m3·d). HRT could be controlled within 6 h to avoid mass production of NO2--N. HRT had little effect on gradual removal of phosphorus from the biofilter and the effluent total phosphorus concentration reduced to 0.2~0.4 mg/L. SEM-EDX and phosphorus morphology analysis showed that phosphorus was mainly removed in the form of iron and phosphorus compounds. Analysis of functional microbial community showed that Thiobacillus (27.6%), Sulfurimonas (11.8%), Thiohalobacter (10.9%) were the main functional microorganisms in the process of autotrophic denitrification. This system was a promising way to remove NO3--N and PO43--P simultaneously from wastewater lack of organic carbon sources.
As the effluent discharge index of sewage treatment plant tends to be more strict, deep denitrification and dephosphorization of tail water gradually becomes an indispensable process. In this study, pyrite was used as the main filler of biofilter to conduct simultaneous denitrification and dephosphorization treatment of wastewater with low concentration of NO3--N and PO43--P, and to investigate the pollutant conversion characteristics and functional microbial changes during the start-up process. The results showed that the simultaneous denitrification and dephosphorization of the biofilter could be realized after 30-day operation, and its maximum total nitrogen removal rate reached 70 g/(m3·d). HRT could be controlled within 6 h to avoid mass production of NO2--N. HRT had little effect on gradual removal of phosphorus from the biofilter and the effluent total phosphorus concentration reduced to 0.2~0.4 mg/L. SEM-EDX and phosphorus morphology analysis showed that phosphorus was mainly removed in the form of iron and phosphorus compounds. Analysis of functional microbial community showed that Thiobacillus (27.6%), Sulfurimonas (11.8%), Thiohalobacter (10.9%) were the main functional microorganisms in the process of autotrophic denitrification. This system was a promising way to remove NO3--N and PO43--P simultaneously from wastewater lack of organic carbon sources.
2022, 40(3): 38-44,73.
doi: 10.13205/j.hjgc.202203007
Abstract:
The moso bamboo based Fe-Co/C composite was prepared by hydrothermal impregnation with the bamboo as the carrier and iron-cobalt composite salt solution as the precursor, and characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Infrared spectroscopy (FT-IR) and specific surface area analyzer (BET). The adsorption process of Fe-Co/C composites for atrazine was investigated by batch experiments. The Fe-Co/C composite exhibited good performance for atrazine removal in water. The equilibrium adsorption capacity of the Fe-Co/C composite was 21.89 mg/g at pH of 7.0, initial concentration of 10 mg/L, dosage of the Fe-Co/C composite of 0.4 g/L and temperature of 25℃. The adsorption process of atrazine on the Fe-Co/C composite could be simulated by the pseudo-second-order model and Langmuir isotherm model. The thermodynamic results showed that the adsorption of atrazine on Fe-Co/C magnetic composite was an endothermic process. The thermodynamic analysis illustrated an endothermic and spontaneous process of atrazine removal using the Fe-Co/C composite. Infrared spectra revealed that hydrogen bonding was one of the major adsorption forces for atrazine on Fe-Co/C composite, and pore effect and л-л conjugate interaction may also promote the adsorption of atrazine on composites.
The moso bamboo based Fe-Co/C composite was prepared by hydrothermal impregnation with the bamboo as the carrier and iron-cobalt composite salt solution as the precursor, and characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Infrared spectroscopy (FT-IR) and specific surface area analyzer (BET). The adsorption process of Fe-Co/C composites for atrazine was investigated by batch experiments. The Fe-Co/C composite exhibited good performance for atrazine removal in water. The equilibrium adsorption capacity of the Fe-Co/C composite was 21.89 mg/g at pH of 7.0, initial concentration of 10 mg/L, dosage of the Fe-Co/C composite of 0.4 g/L and temperature of 25℃. The adsorption process of atrazine on the Fe-Co/C composite could be simulated by the pseudo-second-order model and Langmuir isotherm model. The thermodynamic results showed that the adsorption of atrazine on Fe-Co/C magnetic composite was an endothermic process. The thermodynamic analysis illustrated an endothermic and spontaneous process of atrazine removal using the Fe-Co/C composite. Infrared spectra revealed that hydrogen bonding was one of the major adsorption forces for atrazine on Fe-Co/C composite, and pore effect and л-л conjugate interaction may also promote the adsorption of atrazine on composites.
2022, 40(3): 45-50,88.
doi: 10.13205/j.hjgc.202203008
Abstract:
Unstable Cr fractions existed in sludge seriously threatens environmental safety and human health. Conditions including the blend ratio of sludge and Ca(H2PO4)2, final temperature, heating rate, and retention time, were optimized using an orthogonal experiment. And its effects on residue characteristic and Cr stability were further investigated. Results indicated that pyrolysis could lead to the decomposition of functional groups in sludge, such as CH2, aliphatic nitro-NO2, and bisulfate. In co-pyrolysis with Ca(H2PO4)2, phosphorous functional group was generated in co-pyrolysis residue. Ca(H2PO4)2 was decomposed and Ca(PO3)2 was formed. Meanwhile, Cr in sludge could be transformed into a crystalline compound of Cr2 (SO4)3 during co-pyrolysis. When the condition was blend ratio of 15%, final temperature of 650℃, heating rate of 15℃/min, and retention time of 90 min, the proportion of F4 fraction was the highest. In addition, the leaching concentration of Cr met the IV standard stipulated by the groundwater quality standard (GB/T 14848-2017), indicating that Cr in sludge could be more stable in co-pyrolysis with Ca(H2PO4)2.
Unstable Cr fractions existed in sludge seriously threatens environmental safety and human health. Conditions including the blend ratio of sludge and Ca(H2PO4)2, final temperature, heating rate, and retention time, were optimized using an orthogonal experiment. And its effects on residue characteristic and Cr stability were further investigated. Results indicated that pyrolysis could lead to the decomposition of functional groups in sludge, such as CH2, aliphatic nitro-NO2, and bisulfate. In co-pyrolysis with Ca(H2PO4)2, phosphorous functional group was generated in co-pyrolysis residue. Ca(H2PO4)2 was decomposed and Ca(PO3)2 was formed. Meanwhile, Cr in sludge could be transformed into a crystalline compound of Cr2 (SO4)3 during co-pyrolysis. When the condition was blend ratio of 15%, final temperature of 650℃, heating rate of 15℃/min, and retention time of 90 min, the proportion of F4 fraction was the highest. In addition, the leaching concentration of Cr met the IV standard stipulated by the groundwater quality standard (GB/T 14848-2017), indicating that Cr in sludge could be more stable in co-pyrolysis with Ca(H2PO4)2.
2022, 40(3): 51-58.
doi: 10.13205/j.hjgc.202203009
Abstract:
A series of Cu-ZSM-5 catalysts with different Cu loadings (1%, 2%, 5% and 10%) were synthesized by equal volume impregnation method, and the effect of Cu loading on n-butylamine catalytic oxidation was investigated. The crystal structure and physicochemical properties of the catalysts were characterized by XRD, N2 adsorption desorption, EPR, H2-TPR and NH3-TPD, and the structure-activity relationship was studied. The catalyst with Cu loading of 10% had the highest catalytic activity, and the complete conversion of n-butylamine was achieved at 300℃. The catalyst with 5% Cu loading had the best N2 selectivity, and the N2 selectivity at low temperature was significantly higher than that of the other catalysts. The characterization results showed that the redox performance of the catalyst mainly affected the n-butylamine conversion, the different Cu loading affected the redox performance of the catalyst materials, and the catalyst with higher Cu loading had excellent redox performance. The high N2 selectivity could be attributed to the isolated Cu2+ species and the weak acid sites of the catalyst, which was conducive to the adsorption activation and deep oxidation of n-butylamine to form N2.
A series of Cu-ZSM-5 catalysts with different Cu loadings (1%, 2%, 5% and 10%) were synthesized by equal volume impregnation method, and the effect of Cu loading on n-butylamine catalytic oxidation was investigated. The crystal structure and physicochemical properties of the catalysts were characterized by XRD, N2 adsorption desorption, EPR, H2-TPR and NH3-TPD, and the structure-activity relationship was studied. The catalyst with Cu loading of 10% had the highest catalytic activity, and the complete conversion of n-butylamine was achieved at 300℃. The catalyst with 5% Cu loading had the best N2 selectivity, and the N2 selectivity at low temperature was significantly higher than that of the other catalysts. The characterization results showed that the redox performance of the catalyst mainly affected the n-butylamine conversion, the different Cu loading affected the redox performance of the catalyst materials, and the catalyst with higher Cu loading had excellent redox performance. The high N2 selectivity could be attributed to the isolated Cu2+ species and the weak acid sites of the catalyst, which was conducive to the adsorption activation and deep oxidation of n-butylamine to form N2.
2022, 40(3): 59-65.
doi: 10.13205/j.hjgc.202203010
Abstract:
From the view of solid combustion, the influence of fuel proportioning and particle size on the temperature of combustion layer and sintering atmosphere were studied by sintering pot experiment. The results showed that as the proportion of pulverized coal in the fuel increased from 0 to 100%, the sintering speed and utilization coefficient increased to 4.32 mm/min and 0.13 t/(m2·h), respectively. The sinter drum strength first increased and then decreased, and the drum index reached the peak value of 58.4%, when the pulverized coal ratio was 25%. The NOx concentration in the flue gas was increased by 28.34 mg/m3, and the CO content was increased by 0.72%. CO promoted the reduction reaction of NO and inhibited the formation of NOx. Under full coal condition, with the percentage of fuel with particle size less than 1 mm reduced from 50% to 10%, NOx in flue gas decreased by 51.33 mg/m3; increasing the fuel particle size could reduce the concentration of NOx emission in flue gas. While the sintering time was prolonged, the total NOx emission was increased. The research results could provide theoretical guidance and reference for sintering fuel selection and the reduction of flue gas emission.
From the view of solid combustion, the influence of fuel proportioning and particle size on the temperature of combustion layer and sintering atmosphere were studied by sintering pot experiment. The results showed that as the proportion of pulverized coal in the fuel increased from 0 to 100%, the sintering speed and utilization coefficient increased to 4.32 mm/min and 0.13 t/(m2·h), respectively. The sinter drum strength first increased and then decreased, and the drum index reached the peak value of 58.4%, when the pulverized coal ratio was 25%. The NOx concentration in the flue gas was increased by 28.34 mg/m3, and the CO content was increased by 0.72%. CO promoted the reduction reaction of NO and inhibited the formation of NOx. Under full coal condition, with the percentage of fuel with particle size less than 1 mm reduced from 50% to 10%, NOx in flue gas decreased by 51.33 mg/m3; increasing the fuel particle size could reduce the concentration of NOx emission in flue gas. While the sintering time was prolonged, the total NOx emission was increased. The research results could provide theoretical guidance and reference for sintering fuel selection and the reduction of flue gas emission.
2022, 40(3): 66-73.
doi: 10.13205/j.hjgc.202203011
Abstract:
The characteristics of the microbial community structure in the sewage treatment plants in the high altitude (Tibet) and low altitude (Wuxi) areas were analyzed and compared by using the high throughput gene sequencing. The results showed that the Simpson index (0.993~0.994) and Shannon index (8.388~8.668) of each sample from high altitude area was higher than that of the low altitude area, but the actual processing efficiency was lower than that of the low altitude area. The highest abundance of bacteria in sludge of high altitude were Haliangium and Ferruginibacter, ranged from 6.5% to 10.3% and from 5.6% to 6.4%, which were associated with the removal of COD. However, the highest abundance of bacteria in the sample of low altitude area was Hyphomicrobium, and the abundance was between 7.8% and 11.4%, which was associated with the function of wastewater treatment denitrification. In low altitude area sample, Candidatus accumulibacter(with the function of phosphorus removal) was detected with an abundance of 1.3%, but not detected in high altitude area sample, replaced by the Tetrasphaera (the abundance range was between 1.2% and 1.6%) and Flavobacterium (the abundance range was between 0.57% and 0.7%). The principal component analysis (PCA) results on environmental conditions showed that the highest correlation with the distribution of bacterial species in high altitude area was the concentration of total nitrogen (TN), followed by the concentration of total phosphorus (TP), ammonia nitrogen (NH4+-N) and dissolved oxygen (DO). In high altitude area, the effects of COD and BOD5 on microbial colony distribution were significantly lower than these in low altitude area.
The characteristics of the microbial community structure in the sewage treatment plants in the high altitude (Tibet) and low altitude (Wuxi) areas were analyzed and compared by using the high throughput gene sequencing. The results showed that the Simpson index (0.993~0.994) and Shannon index (8.388~8.668) of each sample from high altitude area was higher than that of the low altitude area, but the actual processing efficiency was lower than that of the low altitude area. The highest abundance of bacteria in sludge of high altitude were Haliangium and Ferruginibacter, ranged from 6.5% to 10.3% and from 5.6% to 6.4%, which were associated with the removal of COD. However, the highest abundance of bacteria in the sample of low altitude area was Hyphomicrobium, and the abundance was between 7.8% and 11.4%, which was associated with the function of wastewater treatment denitrification. In low altitude area sample, Candidatus accumulibacter(with the function of phosphorus removal) was detected with an abundance of 1.3%, but not detected in high altitude area sample, replaced by the Tetrasphaera (the abundance range was between 1.2% and 1.6%) and Flavobacterium (the abundance range was between 0.57% and 0.7%). The principal component analysis (PCA) results on environmental conditions showed that the highest correlation with the distribution of bacterial species in high altitude area was the concentration of total nitrogen (TN), followed by the concentration of total phosphorus (TP), ammonia nitrogen (NH4+-N) and dissolved oxygen (DO). In high altitude area, the effects of COD and BOD5 on microbial colony distribution were significantly lower than these in low altitude area.
2022, 40(3): 74-80.
doi: 10.13205/j.hjgc.202203012
Abstract:
Chao Lake is a storage site for the diversion project from the Yangtze River to the Huai River, it is of great significance to optimize the selection of water diversion schemes starting from the whole basin. The paper based on nearly 10 years measured data of hydrology, water quality and meteorology in Chao Lake area with the usage of two-dimensional unsteady water environment model to simulate the combination of external influencing factors. Uncertainty analysis, K-mediods clustering analysis, and SRRC sensitivity analysis were performed on the simulation results to obtain the external influencing factors' qualitative and quantitative weights. The weights of the external influencing factors of ammonia nitrogen and total phosphorus in the Baishitian River Estuary were ranked as diversion water quality (56%)>diversion flow (26%)>wind speed (18%), diversion water quality (57%)>wind speed (29%)>diversion flow (14%); the weights of ammonia nitrogen and total phosphorus in the Hangbu River Estuary were ranked as wind speed (71%)>diversion flow (16%)>Diversion water quality (13%), and wind speed (73%)>diversion water quality (18%)>diversion flow (9%), respectively. Based on the weights of external factors, the over-standard rate algorithm was improved. The over-standard rate of water diversion at Baishitian River Estuary (11.6%) was much lower than that of Hangbu River Estuary (28.4%), and the Baishitian River Estuary was selected as the best diversion scheme. That provided a certain reference value for the comparison and selection of water diversion schemes for large shallow lakes.
Chao Lake is a storage site for the diversion project from the Yangtze River to the Huai River, it is of great significance to optimize the selection of water diversion schemes starting from the whole basin. The paper based on nearly 10 years measured data of hydrology, water quality and meteorology in Chao Lake area with the usage of two-dimensional unsteady water environment model to simulate the combination of external influencing factors. Uncertainty analysis, K-mediods clustering analysis, and SRRC sensitivity analysis were performed on the simulation results to obtain the external influencing factors' qualitative and quantitative weights. The weights of the external influencing factors of ammonia nitrogen and total phosphorus in the Baishitian River Estuary were ranked as diversion water quality (56%)>diversion flow (26%)>wind speed (18%), diversion water quality (57%)>wind speed (29%)>diversion flow (14%); the weights of ammonia nitrogen and total phosphorus in the Hangbu River Estuary were ranked as wind speed (71%)>diversion flow (16%)>Diversion water quality (13%), and wind speed (73%)>diversion water quality (18%)>diversion flow (9%), respectively. Based on the weights of external factors, the over-standard rate algorithm was improved. The over-standard rate of water diversion at Baishitian River Estuary (11.6%) was much lower than that of Hangbu River Estuary (28.4%), and the Baishitian River Estuary was selected as the best diversion scheme. That provided a certain reference value for the comparison and selection of water diversion schemes for large shallow lakes.
2022, 40(3): 81-88.
doi: 10.13205/j.hjgc.202203013
Abstract:
Based on the A2/O process of a sewage plant in Shenzhen and its on-line monitoring data of influent and effluent, the A2/O simulation model was established and corrected by using GPS-X. The reliability of the model was demonstrated. Two impact simulation schemes, continuous impact simulation and random impact simulation, were proposed to simulate two ways of low B/C sewage impact on A2/O process due to the increase of proportion of dissolved inert component (frsi) in total COD. Simulation results showed that TN, TP and COD concentration of effluent exceeded the standard in turn when A2/O was impacted by low B/C sewage, and adding carbon source could reduce the exceeding rate of TN and TP. Reducing the dissolved oxygen concentration in aerobic tank could save carbon source dosage and the minimum exceeding rate of TN and TP was less than COD. When taking the over-standard rate of COD of 5% during the simulation time as the threshold, A2/O process could withstand the continuous impact of sewage with frsi=0.133 and B/C=0.332 for 31 days, or the random impact of sewage with frsi=0.136 and B/C=0.330 for 25 days, sewage with frsi=0.143 and B/C=0.328 for 20 days, sewage with frsi=0.151 and B/C=0.324 for 15 days, sewage with frsi=0.161 and B/C=0.319 for 10 days, and sewage with frsi=0.189 and B/C=0.308 for 5 days, namely.
Based on the A2/O process of a sewage plant in Shenzhen and its on-line monitoring data of influent and effluent, the A2/O simulation model was established and corrected by using GPS-X. The reliability of the model was demonstrated. Two impact simulation schemes, continuous impact simulation and random impact simulation, were proposed to simulate two ways of low B/C sewage impact on A2/O process due to the increase of proportion of dissolved inert component (frsi) in total COD. Simulation results showed that TN, TP and COD concentration of effluent exceeded the standard in turn when A2/O was impacted by low B/C sewage, and adding carbon source could reduce the exceeding rate of TN and TP. Reducing the dissolved oxygen concentration in aerobic tank could save carbon source dosage and the minimum exceeding rate of TN and TP was less than COD. When taking the over-standard rate of COD of 5% during the simulation time as the threshold, A2/O process could withstand the continuous impact of sewage with frsi=0.133 and B/C=0.332 for 31 days, or the random impact of sewage with frsi=0.136 and B/C=0.330 for 25 days, sewage with frsi=0.143 and B/C=0.328 for 20 days, sewage with frsi=0.151 and B/C=0.324 for 15 days, sewage with frsi=0.161 and B/C=0.319 for 10 days, and sewage with frsi=0.189 and B/C=0.308 for 5 days, namely.
2022, 40(3): 89-93,131.
doi: 10.13205/j.hjgc.202203014
Abstract:
Incineration is the mainstream technology of municipal solid waste treatment. Fly ash, as the main pollutant of waste incineration, has become a key link in waste incineration pollution control. In this study, we collected fly ash samples from waste incineration power plants in Lhasa, and analyzed the heavy metals content and leaching toxicity characteristics, and adopted improved potential risk assessment method and health risk assessment method to evaluate the risk of heavy metals in fly ash. The results showed that the heavy metals content of fly ash in Lhasa was relatively high, and the leaching concentration of Pb obviously exceeded the maximum allowable value of the leaching solution in the Identification Standard for Hazardous Wastes (GB 5085.2-2007). Pollution evaluation results showed that Pb in fly ash had heavy risk of pollution to the environment. The health risk assessment results showed that the carcinogenic risk of heavy metals in fly ash to humans was within an acceptable range, but its non-carcinogenic risk value was higher than the non-carcinogenic risk value recommended by the U.S. Environmental Protection Agency (EPA), indicating had a higher non-carcinogenic risk on human body. Among them, the non-carcinogenic risk values of Pb for adults and children were 3.8975 and 9.7458 respectively, which was the main contributor to the non-carcinogenic risk.
Incineration is the mainstream technology of municipal solid waste treatment. Fly ash, as the main pollutant of waste incineration, has become a key link in waste incineration pollution control. In this study, we collected fly ash samples from waste incineration power plants in Lhasa, and analyzed the heavy metals content and leaching toxicity characteristics, and adopted improved potential risk assessment method and health risk assessment method to evaluate the risk of heavy metals in fly ash. The results showed that the heavy metals content of fly ash in Lhasa was relatively high, and the leaching concentration of Pb obviously exceeded the maximum allowable value of the leaching solution in the Identification Standard for Hazardous Wastes (GB 5085.2-2007). Pollution evaluation results showed that Pb in fly ash had heavy risk of pollution to the environment. The health risk assessment results showed that the carcinogenic risk of heavy metals in fly ash to humans was within an acceptable range, but its non-carcinogenic risk value was higher than the non-carcinogenic risk value recommended by the U.S. Environmental Protection Agency (EPA), indicating had a higher non-carcinogenic risk on human body. Among them, the non-carcinogenic risk values of Pb for adults and children were 3.8975 and 9.7458 respectively, which was the main contributor to the non-carcinogenic risk.
2022, 40(3): 94-101,228.
doi: 10.13205/j.hjgc.202203015
Abstract:
Based on the study of the spatial distribution and genetic research of chlorinated hydrocarbon pollutants in the quaternary of marine and continental interdeposition in Tianjin, this paper selected a pollution site, a pesticide raw material purification workshop with a production history of 19 years, and investigated the spatial distribution of chlorinated hydrocarbon pollution and the cause of pollution in site soil through geological survey, monitoring sampling, and test analysis. Results showed that:the over-standard chlorinated hydrocarbons in the site include chloroform, 1,1-dichloroethane, 1,2-dichloroethane, carbon tetrachloride and vinyl chloride; the pollution spread around the core area consisted of the workshop in the west and middle of the site, the chemical warehouse in the north, the office in the east, and the area between the workshop in the middle and the warehouse in the east; the pollutant content first increased to the peak with the increase of depth on the whole, and then decreased significantly with the increase of depth. The peak content mainly accumulated in the middle and bottom of silty clay ④2 layer of continental layer and the upper part of silty clay ⑥1 layer or silty soil ⑥3 layer of marine layer. It showed that silty clay layer ④2 and silty clay layer ⑥1 effectively blocked the pollution migration to a certain extent, which was related to the characteristics of high clay and silt content, low sand content and poor permeability.
Based on the study of the spatial distribution and genetic research of chlorinated hydrocarbon pollutants in the quaternary of marine and continental interdeposition in Tianjin, this paper selected a pollution site, a pesticide raw material purification workshop with a production history of 19 years, and investigated the spatial distribution of chlorinated hydrocarbon pollution and the cause of pollution in site soil through geological survey, monitoring sampling, and test analysis. Results showed that:the over-standard chlorinated hydrocarbons in the site include chloroform, 1,1-dichloroethane, 1,2-dichloroethane, carbon tetrachloride and vinyl chloride; the pollution spread around the core area consisted of the workshop in the west and middle of the site, the chemical warehouse in the north, the office in the east, and the area between the workshop in the middle and the warehouse in the east; the pollutant content first increased to the peak with the increase of depth on the whole, and then decreased significantly with the increase of depth. The peak content mainly accumulated in the middle and bottom of silty clay ④2 layer of continental layer and the upper part of silty clay ⑥1 layer or silty soil ⑥3 layer of marine layer. It showed that silty clay layer ④2 and silty clay layer ⑥1 effectively blocked the pollution migration to a certain extent, which was related to the characteristics of high clay and silt content, low sand content and poor permeability.
2022, 40(3): 102-110,165.
doi: 10.13205/j.hjgc.202203016
Abstract:
The concentration of 10 heavy metal elements (Cu, Ni, Cd, As, Pb, Hg, Be, Sb, Co, V) in the soil of a withdrawal farmland in suburb of Nanjing were analyzed and evaluated by comparing with the soil background values and risk screening values (the screening values of agricultural land and construction land). The main conclusions were as follows:1) the maximum content of the 10 heavy metals all exceed the background values. The maximum content of Cu, Cd, As, Pb and Hg exceeded the screening value of farmland. The maximum content of As and Co exceeded the screening value of construction land. The variation coefficient of Cd content was the largest and Hg was the second. 2) For the distribution characteristics of the concentration, the frequency of highest content of Hg, Cd, Pb in upper layer was higher than that in the lower layer, but As, and V was on the opposite. The content of Hg decreased from layer A to layer D in both maximum and median values, while content of Cd showed a U-shape. 3) Single factor index showed that Cu, Cd, As, Pb and Hg were heavily polluted with higher pollution degree than other heavy metals. Nemerov composite pollution index showed that more than 70% of the samples in each layer were in light pollution level, compared with the background values, more than 90% of the samples in each layer were in safe level compared with screening value of NY, and 100% of the samples in each layer were in safe level compared with JSH1. 4) As and Sb (0.810) had the highest correlation with each other, while Hg had weak correlation with other heavy metals. Combined with correlation analysis and principal component analysis, heavy metals mainly came from three sources:natural soil forming process, strong man-made sources of agricultural cultivation and weak man-made sources, like atmospheric deposition in suburban areas. The concentrations of Cu, Ni, Cd, As, Pb, Sb in soil were mainly affected by natural soil forming process firstly and then man-made sources, but Co and V were not affected by man-made sources. Hg and Be were greatly affected by man-made sources besides natural soil forming.
The concentration of 10 heavy metal elements (Cu, Ni, Cd, As, Pb, Hg, Be, Sb, Co, V) in the soil of a withdrawal farmland in suburb of Nanjing were analyzed and evaluated by comparing with the soil background values and risk screening values (the screening values of agricultural land and construction land). The main conclusions were as follows:1) the maximum content of the 10 heavy metals all exceed the background values. The maximum content of Cu, Cd, As, Pb and Hg exceeded the screening value of farmland. The maximum content of As and Co exceeded the screening value of construction land. The variation coefficient of Cd content was the largest and Hg was the second. 2) For the distribution characteristics of the concentration, the frequency of highest content of Hg, Cd, Pb in upper layer was higher than that in the lower layer, but As, and V was on the opposite. The content of Hg decreased from layer A to layer D in both maximum and median values, while content of Cd showed a U-shape. 3) Single factor index showed that Cu, Cd, As, Pb and Hg were heavily polluted with higher pollution degree than other heavy metals. Nemerov composite pollution index showed that more than 70% of the samples in each layer were in light pollution level, compared with the background values, more than 90% of the samples in each layer were in safe level compared with screening value of NY, and 100% of the samples in each layer were in safe level compared with JSH1. 4) As and Sb (0.810) had the highest correlation with each other, while Hg had weak correlation with other heavy metals. Combined with correlation analysis and principal component analysis, heavy metals mainly came from three sources:natural soil forming process, strong man-made sources of agricultural cultivation and weak man-made sources, like atmospheric deposition in suburban areas. The concentrations of Cu, Ni, Cd, As, Pb, Sb in soil were mainly affected by natural soil forming process firstly and then man-made sources, but Co and V were not affected by man-made sources. Hg and Be were greatly affected by man-made sources besides natural soil forming.
2022, 40(3): 111-117,193.
doi: 10.13205/j.hjgc.202203017
Abstract:
In March 2017, 93 dustfall samples were collected in the main urban area of Qingdao, with the purpose of understanding the spatial distribution and source of water-soluble ions in the atmospheric dustfall in Qingdao. The contents of water-soluble ions were determined, including NO3-, Ca2+, SO42-, Cl-, Na+, K+, Mg2+, NH4+, and their spatial distribution and source were analyzed. NO3-, Ca2+ and SO42- were the main ions for dust reduction in Qingdao, accounting for 82% of the total mass concentration of water-soluble ions. There were differences in the spatial distribution of ions, and the areas with higher ion concentration were mainly concentrated in the Southwest of Shinan District and Shinbei District, and northeast of Laoshan District, which were mainly affected by human emission. The mass concentration ratio of NO3-/SO42- in the four urban areas was higher than 1, indicating that mobile pollution sources were the main source. Correlation analysis and PCA-MLR analysis showed that the traffic source was the main source of water-soluble ions in dust in Qingdao, followed by soil dust and sea salt.
In March 2017, 93 dustfall samples were collected in the main urban area of Qingdao, with the purpose of understanding the spatial distribution and source of water-soluble ions in the atmospheric dustfall in Qingdao. The contents of water-soluble ions were determined, including NO3-, Ca2+, SO42-, Cl-, Na+, K+, Mg2+, NH4+, and their spatial distribution and source were analyzed. NO3-, Ca2+ and SO42- were the main ions for dust reduction in Qingdao, accounting for 82% of the total mass concentration of water-soluble ions. There were differences in the spatial distribution of ions, and the areas with higher ion concentration were mainly concentrated in the Southwest of Shinan District and Shinbei District, and northeast of Laoshan District, which were mainly affected by human emission. The mass concentration ratio of NO3-/SO42- in the four urban areas was higher than 1, indicating that mobile pollution sources were the main source. Correlation analysis and PCA-MLR analysis showed that the traffic source was the main source of water-soluble ions in dust in Qingdao, followed by soil dust and sea salt.
2022, 40(3): 118-125.
doi: 10.13205/j.hjgc.202203018
Abstract:
The chemical forms of arsenic (As) in soil environment were sophisticated, and there was a defect in the treatment of different forms of As with conventional solidification and stabilization materials. We integrated the surface adsorption of biochar (BC), pore filling, electrostatic attraction, complexation and co-precipitation oxidation-reduction of ferric manganese binary oxides (FMBO), then a new functional material BCFM was prepared and stabilized with Portland cement. The effect of key parameters on treatment effect was discussed by response surface method. The results showed that when the ratio of BCFM to Portland cement was 9.88% and 8.80%, and the curing time was 20.53 days, the minimum leaching concentration of As was 0.055 mg/L, the exchangeable state proportion was reduced from 4% to 0.5%, the residual state proportion was increased from 77% to 87%, and the unconfined compressive strength exceeded 50 kPa. It was speculated that the curing and stabilization mechanism of BCFM was the combination of Fe-O(H)-As coprecipitation, Mn-O(H)-As oxidation and BC function. The results of this study provide a new technical scheme for long-term curing and stabilization of As.
The chemical forms of arsenic (As) in soil environment were sophisticated, and there was a defect in the treatment of different forms of As with conventional solidification and stabilization materials. We integrated the surface adsorption of biochar (BC), pore filling, electrostatic attraction, complexation and co-precipitation oxidation-reduction of ferric manganese binary oxides (FMBO), then a new functional material BCFM was prepared and stabilized with Portland cement. The effect of key parameters on treatment effect was discussed by response surface method. The results showed that when the ratio of BCFM to Portland cement was 9.88% and 8.80%, and the curing time was 20.53 days, the minimum leaching concentration of As was 0.055 mg/L, the exchangeable state proportion was reduced from 4% to 0.5%, the residual state proportion was increased from 77% to 87%, and the unconfined compressive strength exceeded 50 kPa. It was speculated that the curing and stabilization mechanism of BCFM was the combination of Fe-O(H)-As coprecipitation, Mn-O(H)-As oxidation and BC function. The results of this study provide a new technical scheme for long-term curing and stabilization of As.
2022, 40(3): 126-131.
doi: 10.13205/j.hjgc.202203019
Abstract:
In this paper, the changes of soil enzyme activity and spinach biomass and their effects on soil physical and chemical properties and crop growth during spinach planting were studied by pot comparative experiment with two types of nutrient soils(nutrient soil A of municipal solid waste after thermal hydrolysis + high temperature aerobic compost and nutrient soil B of municipal solid waste after thermal hydrolysis) produced by different pretreatment processes. The results showed that both nutrient soil A and nutrient soil B could effectively increase the activities of urease, catalase and sucrase in the soil during spinach planting and it had a tendency to increase with the increase of nutrient soil dosage; at the same stage of spinach growth, the soil enzyme activity of nutrient soil A was higher than that of treatment group B and control group, and the highest urease value was 9.10 mg/g, appearing in the treatment group with the ratio of soil to nutrient soil of 5:1 (30 d). The application of the two kinds of nutrient soil could inhibit the activity of neutral phosphatase to some extent. Both nutrient soil A and nutrient soil B could significantly improve the biomass of spinach, especially when nutrient soil A applied with the ratio of soil to nutrient soil of 5:1, and then the fresh weight of spinach in the control group was 64.19 g, 132.32% higher than that in the control group. The application of nutrient soil A and B could affect soil enzyme activity and increase spinach biomass, and the overall effect of nutrient soil A was more obvious. The results of this study can provide theoretical basis and technical reference for effective resource utilization of MSW.
In this paper, the changes of soil enzyme activity and spinach biomass and their effects on soil physical and chemical properties and crop growth during spinach planting were studied by pot comparative experiment with two types of nutrient soils(nutrient soil A of municipal solid waste after thermal hydrolysis + high temperature aerobic compost and nutrient soil B of municipal solid waste after thermal hydrolysis) produced by different pretreatment processes. The results showed that both nutrient soil A and nutrient soil B could effectively increase the activities of urease, catalase and sucrase in the soil during spinach planting and it had a tendency to increase with the increase of nutrient soil dosage; at the same stage of spinach growth, the soil enzyme activity of nutrient soil A was higher than that of treatment group B and control group, and the highest urease value was 9.10 mg/g, appearing in the treatment group with the ratio of soil to nutrient soil of 5:1 (30 d). The application of the two kinds of nutrient soil could inhibit the activity of neutral phosphatase to some extent. Both nutrient soil A and nutrient soil B could significantly improve the biomass of spinach, especially when nutrient soil A applied with the ratio of soil to nutrient soil of 5:1, and then the fresh weight of spinach in the control group was 64.19 g, 132.32% higher than that in the control group. The application of nutrient soil A and B could affect soil enzyme activity and increase spinach biomass, and the overall effect of nutrient soil A was more obvious. The results of this study can provide theoretical basis and technical reference for effective resource utilization of MSW.
2022, 40(3): 132-138.
doi: 10.13205/j.hjgc.202203020
Abstract:
This paper took the food waste as the research object, and conducted the continuous dynamic fermentation experiment to explore the biogas production and microbial distribution of the food waste in the transition zone between medium and high temperature. The results showed that under the same organic load, the biogas yield, methane concentration and key parameters of fermentation broth were significantly better than those of the fermentation system under the medium temperature (38℃) fermentation temperature, with higher biogas yield and more stable fermentation parameters. Through high-throughput microbial sequencing, it was found that there were significant differences in bacterial community structure and richness between 44℃ and 38℃ fermentation system, while there were no significant differences in archaea community structure and richness, which indicated that the main reason why the fermentation temperature of food waste at 44℃ was better than that at 38℃, was that more abundant fermentative bacteria promoted hydrolysis stage and acid production stage. That was conducive to the digestion and utilization of methane microorganism.
This paper took the food waste as the research object, and conducted the continuous dynamic fermentation experiment to explore the biogas production and microbial distribution of the food waste in the transition zone between medium and high temperature. The results showed that under the same organic load, the biogas yield, methane concentration and key parameters of fermentation broth were significantly better than those of the fermentation system under the medium temperature (38℃) fermentation temperature, with higher biogas yield and more stable fermentation parameters. Through high-throughput microbial sequencing, it was found that there were significant differences in bacterial community structure and richness between 44℃ and 38℃ fermentation system, while there were no significant differences in archaea community structure and richness, which indicated that the main reason why the fermentation temperature of food waste at 44℃ was better than that at 38℃, was that more abundant fermentative bacteria promoted hydrolysis stage and acid production stage. That was conducive to the digestion and utilization of methane microorganism.
2022, 40(3): 147-153.
doi: 10.13205/j.hjgc.202203022
Abstract:
The electrochemical characteristics of anode materials for microbial fuel cells (MFC) affect their electrical performance and pollutant reduction capacity. In this experiment, the phosphomolybdic acid/reduced graphene oxide/polypyrrole (PMo12/rGO/PPy) anode was obtained by electrochemical deposition method. Then the morphology and electrochemical characteristics of PMo12/rGO/PPy anode were analyzed. Finally, the electricity generation and reduction performance of PMo12/rGO/PPy anode MFC at different concentrations of perchlorate (ClO4-) were investigated. The results showed that the PMo12/rGO/PPy anode provided a larger specific surface area than the control for the attachment of microorganisms, thus providing more active sites for electron transport. The use of PMo12/rGO/PPy anode resulted in an increase of charge transfer amount by 493%, a decrease of charge transfer impedance by 83.3%, and an increase of exchange current density by 53.4%. At the same time, when the concentration of ClO4- was 420 mg/L, PMo12/rGO/PPy anode MFC had the best power generation performance, and the maximum output voltage reached 148.47 mV.
The electrochemical characteristics of anode materials for microbial fuel cells (MFC) affect their electrical performance and pollutant reduction capacity. In this experiment, the phosphomolybdic acid/reduced graphene oxide/polypyrrole (PMo12/rGO/PPy) anode was obtained by electrochemical deposition method. Then the morphology and electrochemical characteristics of PMo12/rGO/PPy anode were analyzed. Finally, the electricity generation and reduction performance of PMo12/rGO/PPy anode MFC at different concentrations of perchlorate (ClO4-) were investigated. The results showed that the PMo12/rGO/PPy anode provided a larger specific surface area than the control for the attachment of microorganisms, thus providing more active sites for electron transport. The use of PMo12/rGO/PPy anode resulted in an increase of charge transfer amount by 493%, a decrease of charge transfer impedance by 83.3%, and an increase of exchange current density by 53.4%. At the same time, when the concentration of ClO4- was 420 mg/L, PMo12/rGO/PPy anode MFC had the best power generation performance, and the maximum output voltage reached 148.47 mV.
2022, 40(3): 154-158,23.
doi: 10.13205/j.hjgc.202203023
Abstract:
According to the material characteristics of each component in waste lead paste, the raw materials of waste lead paste were rinsed and screened for 154 μm aperture, 77 μm aperture and 54 μm aperture step by step. Afterwards, electrolytic separation experiments were carried out on the materials above each grade of sieve, PbSO4, and metal lead mixture in the lower fiber and the upper fiber were collected respectively. Through scanning electron microscope (SEM) morphology analysis and X-ray diffraction (XRD) detection, the results showed that the diaphragm fiber in waste lead paste could be separated effectively by step rinse screening and electrolytic separation. The main lead compounds in the material above the sieve were PbSO4 and a small amount of Pb, and the main components in the material below the sieve were PbO2 and PbSO4. After 54 μm aperture sieving experiment, the separated diaphragm fibers reached 9.45%(by mass ratio) of the total waste lead paste.
According to the material characteristics of each component in waste lead paste, the raw materials of waste lead paste were rinsed and screened for 154 μm aperture, 77 μm aperture and 54 μm aperture step by step. Afterwards, electrolytic separation experiments were carried out on the materials above each grade of sieve, PbSO4, and metal lead mixture in the lower fiber and the upper fiber were collected respectively. Through scanning electron microscope (SEM) morphology analysis and X-ray diffraction (XRD) detection, the results showed that the diaphragm fiber in waste lead paste could be separated effectively by step rinse screening and electrolytic separation. The main lead compounds in the material above the sieve were PbSO4 and a small amount of Pb, and the main components in the material below the sieve were PbO2 and PbSO4. After 54 μm aperture sieving experiment, the separated diaphragm fibers reached 9.45%(by mass ratio) of the total waste lead paste.
2022, 40(3): 159-165.
doi: 10.13205/j.hjgc.202203024
Abstract:
A design of automatic garbage sorting bin based on model YOLO v5 was proposed, and applied to public places in non-residential communities (such as railway stations, bus stations, shopping malls, schoolyards, etc.). The trash bin was designed with 4 trash cans, arranged in two rows and two columns, with a rotating shaft in the middle, which drove the temporary storage drawer of garbage above the shaft to rotate. The monocular camera was used to collect video images, the embedded chip, Jetson nano by NVIDIA was used as the host computer's main control chip, and the YOLO v5 deep learning model was used for automatic garbage extraction and identification, and the recognition result information of the host computer was sent to the control board of the lower computer, Arduino, through the serial port. The control board, Arduino, controlled the motor to drive the opening of the temporary storage drawer to rotate to the top of the corresponding trash can, and then controlled the lifting platform to dump the trash and complete the automatic classification of the trash. The test results showed that the garbage identification results were stable and reliable, with an accuracy rate of 97%, thus the automatic garbage classification was realized.
A design of automatic garbage sorting bin based on model YOLO v5 was proposed, and applied to public places in non-residential communities (such as railway stations, bus stations, shopping malls, schoolyards, etc.). The trash bin was designed with 4 trash cans, arranged in two rows and two columns, with a rotating shaft in the middle, which drove the temporary storage drawer of garbage above the shaft to rotate. The monocular camera was used to collect video images, the embedded chip, Jetson nano by NVIDIA was used as the host computer's main control chip, and the YOLO v5 deep learning model was used for automatic garbage extraction and identification, and the recognition result information of the host computer was sent to the control board of the lower computer, Arduino, through the serial port. The control board, Arduino, controlled the motor to drive the opening of the temporary storage drawer to rotate to the top of the corresponding trash can, and then controlled the lifting platform to dump the trash and complete the automatic classification of the trash. The test results showed that the garbage identification results were stable and reliable, with an accuracy rate of 97%, thus the automatic garbage classification was realized.
2022, 40(3): 166-172,211.
doi: 10.13205/j.hjgc.202203025
Abstract:
In this study, the Nansha River Basin in the urban-rural fringe of Beijing was selected, and the inflow concentration of non-point source pollution in the typical area was calculated with traditional export coefficient method and the EcoHat-NPS model method, respectively. The point source and non-point source pollution were separated by using one-dimensional water quality model, and the calculated value of non-point source concentration in each estuary was calculated based on the measured non-point source concentration. The accuracy of the calculation results of the two methods was compared and analyzed. The results showed that:1) there was a plain calculation accuracy in the export coefficient method and a good calculation accuracy in the EcoHat-NPS model simulation method. The average simulation accuracy R2 of the four pollutants (COD, NH3-N, TP, TN) was 0.83, 0.94, 0.94, 0.82, respectively. The simulation effect of NH3-N and TP was better, followed by COD and TN; 2) the inflow COD, NH3-N, TN and TP calculated by export coefficient method was 1110.9, 70.9, 391.8, 5.02 t/a, respectively; while that of the EcoHat-NPS model method was 1403.34, 78, 388.2, 7.3 t/a, respectively; 3) Ecohat-NPS model with the flexible calculation time scale could identify the main non-point source pollution areas, which was more suitable for the estimation of non-point source pollution in Beijing. After the further data refining, it could be extended to the whole city's rivers for the estimation of non-point source pollution in Beijing.
In this study, the Nansha River Basin in the urban-rural fringe of Beijing was selected, and the inflow concentration of non-point source pollution in the typical area was calculated with traditional export coefficient method and the EcoHat-NPS model method, respectively. The point source and non-point source pollution were separated by using one-dimensional water quality model, and the calculated value of non-point source concentration in each estuary was calculated based on the measured non-point source concentration. The accuracy of the calculation results of the two methods was compared and analyzed. The results showed that:1) there was a plain calculation accuracy in the export coefficient method and a good calculation accuracy in the EcoHat-NPS model simulation method. The average simulation accuracy R2 of the four pollutants (COD, NH3-N, TP, TN) was 0.83, 0.94, 0.94, 0.82, respectively. The simulation effect of NH3-N and TP was better, followed by COD and TN; 2) the inflow COD, NH3-N, TN and TP calculated by export coefficient method was 1110.9, 70.9, 391.8, 5.02 t/a, respectively; while that of the EcoHat-NPS model method was 1403.34, 78, 388.2, 7.3 t/a, respectively; 3) Ecohat-NPS model with the flexible calculation time scale could identify the main non-point source pollution areas, which was more suitable for the estimation of non-point source pollution in Beijing. After the further data refining, it could be extended to the whole city's rivers for the estimation of non-point source pollution in Beijing.
2022, 40(3): 173-180,146.
doi: 10.13205/j.hjgc.202203026
Abstract:
In order to assess the impact of mandatory municipal solid waste (MSW) classification on urban MSW integrated management, the implementation process of Shanghai MSW classification was reviewed, and the environmental effects of Shanghai's MSW integrated management under different classification levels were predicted, with the idea of life cycle assessment. Shanghai's MSW classification has gone through four stages, including pilot, promotion, adjustment and compulsory promotion. The guiding idea has changed from Recycling to Reduction, Recycling and Harmless. The effect of reduction gradually emerges from the adjustment stage, and the calorific value of residual waste increases. In the 8 simulated scenarios, when wet waste, recyclable waste and residual waste were mixed into and disposed of, the total environmental impact potential value was the highest, reaching 1.22×10-13 PET2000/t. When the proportion of wet waste, recyclables and residual waste was respectively 30%, 20% and 50% (the maximum treatment capacity of anaerobic digestion, incineration and recycling of MSW in Shanghai accounted for 25%, 60%, 15% of the total treatment capacity), none of the native MSW was directly disposed by landfilling, and the environmental effect could be optimized with 8.13×10-14 PET2000/t. From the perspective of whole-process management of MSW, classified delivery is a prerequisite, and supporting appropriate treatment and disposal facilities can better show its advantages of environmental benefit.
In order to assess the impact of mandatory municipal solid waste (MSW) classification on urban MSW integrated management, the implementation process of Shanghai MSW classification was reviewed, and the environmental effects of Shanghai's MSW integrated management under different classification levels were predicted, with the idea of life cycle assessment. Shanghai's MSW classification has gone through four stages, including pilot, promotion, adjustment and compulsory promotion. The guiding idea has changed from Recycling to Reduction, Recycling and Harmless. The effect of reduction gradually emerges from the adjustment stage, and the calorific value of residual waste increases. In the 8 simulated scenarios, when wet waste, recyclable waste and residual waste were mixed into and disposed of, the total environmental impact potential value was the highest, reaching 1.22×10-13 PET2000/t. When the proportion of wet waste, recyclables and residual waste was respectively 30%, 20% and 50% (the maximum treatment capacity of anaerobic digestion, incineration and recycling of MSW in Shanghai accounted for 25%, 60%, 15% of the total treatment capacity), none of the native MSW was directly disposed by landfilling, and the environmental effect could be optimized with 8.13×10-14 PET2000/t. From the perspective of whole-process management of MSW, classified delivery is a prerequisite, and supporting appropriate treatment and disposal facilities can better show its advantages of environmental benefit.
2022, 40(3): 181-187,202.
doi: 10.13205/j.hjgc.202203027
Abstract:
In recent years, landfill mining is becoming one of the important technologies of landfill ecological management. However, the feasibility of landfill mining has always been a key decision-making factor restricting landfill mining projects. Taking a simple waste dump in Yuecheng District of Shaoxing as the example, based on the landfill construction, operation overview and site survey results, the evaluation index system was selected and established on three dimensions of landfill stabilization degree, environmental risk level and economic effect. And the feasibility evaluation system suitable for urban domestic waste landfill mining was constructed by using analytic hierarchy process and comprehensive evaluation method to provide decision-making basis for landfill mining. Results showed that:the first stage dump was moderately stable, with low environmental risk and low economic performance; the second stage dump was moderately stable, with low environmental risk and high economic performance. Landfill mining of both two stages dumps were feasible, and suitable for landfill ecological treatment.
In recent years, landfill mining is becoming one of the important technologies of landfill ecological management. However, the feasibility of landfill mining has always been a key decision-making factor restricting landfill mining projects. Taking a simple waste dump in Yuecheng District of Shaoxing as the example, based on the landfill construction, operation overview and site survey results, the evaluation index system was selected and established on three dimensions of landfill stabilization degree, environmental risk level and economic effect. And the feasibility evaluation system suitable for urban domestic waste landfill mining was constructed by using analytic hierarchy process and comprehensive evaluation method to provide decision-making basis for landfill mining. Results showed that:the first stage dump was moderately stable, with low environmental risk and low economic performance; the second stage dump was moderately stable, with low environmental risk and high economic performance. Landfill mining of both two stages dumps were feasible, and suitable for landfill ecological treatment.
2022, 40(3): 194-202.
doi: 10.13205/j.hjgc.202203029
Abstract:
With the increasing production of municipal solid waste (MSW), the disposal of MSW has been one of the annoying problems in the process of urbanization. Recently, the reutilization of MSW as raw materials for biochar production provides a novel approach for MSW disposal. However, the systematic demonstration of the biochar production from MSW and the potential application is still inefficient. Therefore, the main approaches of biochar production from MSW are mainly introduced, and the influences of MSW types and treatment processes on the biochar yields, as well as the characteristics are also analyzed. Furthermore, the potential application of biochar derived from MSW in landfills treatment (i.e. leachate treatment, landfill cover and permeable reactive barrier materials) and soil improvement (i.e. physical and chemical properties and nutritional environment). The results shows that:1) pyrolysis and hydrothermal carbonization are the common ways for biochar production derived from MSW. The produced biochar possesses large specific surface area and porosity, and the contents of some components such as carbon and calcium are much higher than that of the ordinary biochar, which has strong adsorption capacity for pollutants (i.e. iodine ion, copper ion); 2) the characteristics of MSW and its production process exhibits evident effect on the properties of generated biochar; 3) biochar derived from MSW can be used in landfill remediation and soil improvement to remediate the soil, air and groundwater pollution caused by landfill, and improve the nutrients bioavailability in soil. It can provide some guidance for the biochar production from MSW and its application for environmental remediation.
With the increasing production of municipal solid waste (MSW), the disposal of MSW has been one of the annoying problems in the process of urbanization. Recently, the reutilization of MSW as raw materials for biochar production provides a novel approach for MSW disposal. However, the systematic demonstration of the biochar production from MSW and the potential application is still inefficient. Therefore, the main approaches of biochar production from MSW are mainly introduced, and the influences of MSW types and treatment processes on the biochar yields, as well as the characteristics are also analyzed. Furthermore, the potential application of biochar derived from MSW in landfills treatment (i.e. leachate treatment, landfill cover and permeable reactive barrier materials) and soil improvement (i.e. physical and chemical properties and nutritional environment). The results shows that:1) pyrolysis and hydrothermal carbonization are the common ways for biochar production derived from MSW. The produced biochar possesses large specific surface area and porosity, and the contents of some components such as carbon and calcium are much higher than that of the ordinary biochar, which has strong adsorption capacity for pollutants (i.e. iodine ion, copper ion); 2) the characteristics of MSW and its production process exhibits evident effect on the properties of generated biochar; 3) biochar derived from MSW can be used in landfill remediation and soil improvement to remediate the soil, air and groundwater pollution caused by landfill, and improve the nutrients bioavailability in soil. It can provide some guidance for the biochar production from MSW and its application for environmental remediation.
2022, 40(3): 203-211.
doi: 10.13205/j.hjgc.202203030
Abstract:
Sludge based biochar has been widely studied in environmental pollution remediation, soil improvement and carbon fixation, due to its excellent pore structure, large specific surface area and strong adsorption capacity. Based on the sources and properties of sludge biochar, this paper introduces the mechanism of soil structure improvement and nutrient composition amelioration after applying sludge biochar to soil, and summarizes the preparation process, the characteristics and the effectiveness of sludge biochar on soil. Through the analysis for the quality of sludge biochar as fertilizer, the safety of sludge biochar and its positive effect on soil environment are evaluated. In addition, through the brief classification of the typical problems on soil, it provides reference for the selection of sludge biochar preparation process from the perspective of adaptation of soil improvement requirements and sludge biochar characteristics. Therefore, the application of sludge biochar has important practical significance in promoting the utilization of sludge resources and achieving carbon emission reduction. Finally, key research directions, such as optimizing the preparation process, objectively evaluating the environmental risks of land use, strengthening the modification, and attaching importance to the comprehensive benefit evaluation of sludge biochar, are put forward.
Sludge based biochar has been widely studied in environmental pollution remediation, soil improvement and carbon fixation, due to its excellent pore structure, large specific surface area and strong adsorption capacity. Based on the sources and properties of sludge biochar, this paper introduces the mechanism of soil structure improvement and nutrient composition amelioration after applying sludge biochar to soil, and summarizes the preparation process, the characteristics and the effectiveness of sludge biochar on soil. Through the analysis for the quality of sludge biochar as fertilizer, the safety of sludge biochar and its positive effect on soil environment are evaluated. In addition, through the brief classification of the typical problems on soil, it provides reference for the selection of sludge biochar preparation process from the perspective of adaptation of soil improvement requirements and sludge biochar characteristics. Therefore, the application of sludge biochar has important practical significance in promoting the utilization of sludge resources and achieving carbon emission reduction. Finally, key research directions, such as optimizing the preparation process, objectively evaluating the environmental risks of land use, strengthening the modification, and attaching importance to the comprehensive benefit evaluation of sludge biochar, are put forward.
2022, 40(3): 212-220.
doi: 10.13205/j.hjgc.202203031
Abstract:
As an efficient water and wastewater treatment technology, the combined ozone/ceramic membrane process has achieved rapid development since 2003. To promote the detailed research and extensive use of the prospective process in China, the mechanism of the catalytic ozonation on/in ceramic membrane is discussed and the performance of the hybrid process is also studied. The current knowledge and research status including membrane pollution prevention, pollutant removal and disinfection by-product degradation is summarized. The future development direction is also predicted according to the review. It is expected that the preparation and modification of ceramic membrane materials, the confined nano space effect of membrane pore and the ozone aeration mode will be the key focuses of ozone/ceramic membrane technology in the future.
As an efficient water and wastewater treatment technology, the combined ozone/ceramic membrane process has achieved rapid development since 2003. To promote the detailed research and extensive use of the prospective process in China, the mechanism of the catalytic ozonation on/in ceramic membrane is discussed and the performance of the hybrid process is also studied. The current knowledge and research status including membrane pollution prevention, pollutant removal and disinfection by-product degradation is summarized. The future development direction is also predicted according to the review. It is expected that the preparation and modification of ceramic membrane materials, the confined nano space effect of membrane pore and the ozone aeration mode will be the key focuses of ozone/ceramic membrane technology in the future.
2022, 40(3): 221-228.
doi: 10.13205/j.hjgc.202203032
Abstract:
Microplastics (MPs) are emerging persistent organic pollutants, which are characterized by small particle size, large specific surface area, strong absorbability and refractory to degradation. MPs can interact with other pollutants in the environment, resulting in the generation of the combined pollutants. In recent years, MPs have been found in various environmental medias and living organisms. MPs have received substantial attention, as it could threaten ecosystem balance and human health. In this review, the classification and stability evaluation of MPs are summarized. In addition, the abundance and types of MPs in marine, fresh water, rainwater runoff and wastewater treatment plants are presented. The interaction between MPs and other pollutants, and their synergistic transfer in the environment are discussed. And then the adverse effects of MPs on phytoplankton and human beings are evaluated. The research directions of MPs are also discussed.
Microplastics (MPs) are emerging persistent organic pollutants, which are characterized by small particle size, large specific surface area, strong absorbability and refractory to degradation. MPs can interact with other pollutants in the environment, resulting in the generation of the combined pollutants. In recent years, MPs have been found in various environmental medias and living organisms. MPs have received substantial attention, as it could threaten ecosystem balance and human health. In this review, the classification and stability evaluation of MPs are summarized. In addition, the abundance and types of MPs in marine, fresh water, rainwater runoff and wastewater treatment plants are presented. The interaction between MPs and other pollutants, and their synergistic transfer in the environment are discussed. And then the adverse effects of MPs on phytoplankton and human beings are evaluated. The research directions of MPs are also discussed.
2022, 40(3): 229-230.
Abstract:
