Login
Register
E-alert
2022 Vol. 40, No. 5
Display Method:
2022, 40(5): 1-8.
doi: 10.13205/j.hjgc.202205001
Abstract:
The high concentration of chloride ions prevalent in refractory industrial wastewater affects the performance of advanced oxidation and generates harmful organochlorine by-products. In this study, phenol was selected as the target pollutant and the generation of adsorbable organic halogens(AOX) during its oxidation by two typical advanced oxidation processes, namely UV/PDS and UV/H2O2, were investigated in the presence of Cl-. The results showed that UV/PDS was more effective than UV/H2O2 in the degradation and mineralization of phenol under experimental conditions in the presence of 1000 mg/L and 10000 mg/L Cl-. However, the AOX concentration formed during UV/PDS oxidation was about 10 times higher than that in UV/H2O2. The UV/H2O2 process tended to form more AOX under strongly acidic conditions(pH=3), while the AOX generation in the UV/PDS process was not significantly affected by the initial pH. Simulations of the steady-state concentrations of the four chlorine radicals revealed that the chlorine radical concentration increased for 1~2 orders of magnitude, when Cl- increased from 1000 mg/L to 10000 mg/L. The concentration in the UV/PDS system was significantly higher than that in UV/H2O2, which may be an important reason for the significant difference in AOX observed in the two advanced oxidation processes under different conditions. Similarly, the UV/PDS generated more AOX when treating actual wastewater, and the effect of organic structure and composition in wastewater on AOX generation was stronger than the effect of TOC concentration in wastewater.
The high concentration of chloride ions prevalent in refractory industrial wastewater affects the performance of advanced oxidation and generates harmful organochlorine by-products. In this study, phenol was selected as the target pollutant and the generation of adsorbable organic halogens(AOX) during its oxidation by two typical advanced oxidation processes, namely UV/PDS and UV/H2O2, were investigated in the presence of Cl-. The results showed that UV/PDS was more effective than UV/H2O2 in the degradation and mineralization of phenol under experimental conditions in the presence of 1000 mg/L and 10000 mg/L Cl-. However, the AOX concentration formed during UV/PDS oxidation was about 10 times higher than that in UV/H2O2. The UV/H2O2 process tended to form more AOX under strongly acidic conditions(pH=3), while the AOX generation in the UV/PDS process was not significantly affected by the initial pH. Simulations of the steady-state concentrations of the four chlorine radicals revealed that the chlorine radical concentration increased for 1~2 orders of magnitude, when Cl- increased from 1000 mg/L to 10000 mg/L. The concentration in the UV/PDS system was significantly higher than that in UV/H2O2, which may be an important reason for the significant difference in AOX observed in the two advanced oxidation processes under different conditions. Similarly, the UV/PDS generated more AOX when treating actual wastewater, and the effect of organic structure and composition in wastewater on AOX generation was stronger than the effect of TOC concentration in wastewater.
2022, 40(5): 9-17,94.
doi: 10.13205/j.hjgc.202205002
Abstract:
To explore the potential of Chlorella vulgaris(C. vulgaris) in fixing CO2, purifying wastewater and producing protein simultaneously, the effects of different ammonium concentrations(30 mg/L, 60 mg/L, 90 mg/L NH4Cl) and CO2 concentrations(0.038% and 10%) on the growth, CO2 fixation, nutrients removal and protein production of C. vulgaris were studied. The combination of Logistic function and the modified Monod function was also used to describe the relationship between C. vulgaris specific growth rate and concentration of ammonium(NH+4-N) and phosphate(PO3-4-P), respectively.Resultsshowed that the biomass of 10% CO2 group(380.16~499.52 mg/L) was 3.54~8.30 times that of 0.038% CO2 group(44.73~120.00 mg/L). Meanwhile, the consumption rates of ammonium and phosphate in the 10% CO2 group were significantly higher than those in the 0.038% CO2 group. Correlation analysis showed that specific growth rate, carbon fixation rate, protein were all positively correlated with C. vulgaris biomass(R2>0.86, P<0.05). With 10% CO2 and 60 mg/L NH4Cl, the maximum values of specific growth rate, carbon fixation rate, and protein were 0.21 d-1, 42.62 mg/(L·d), and 228.43 mg/L, respectively. In addition, the fitting results indicated that the combination of Logistic function and the modified Monod function could well describe C. vulgaris growth(correlation coefficient R2 is 0.39~0.96), and nutrients were more easily utilized by C. vulgaris at 10% CO2. This experiment could provide a theoretical reference for fixing CO2, purifying wastewater and producing protein simultaneously by microalgae.
To explore the potential of Chlorella vulgaris(C. vulgaris) in fixing CO2, purifying wastewater and producing protein simultaneously, the effects of different ammonium concentrations(30 mg/L, 60 mg/L, 90 mg/L NH4Cl) and CO2 concentrations(0.038% and 10%) on the growth, CO2 fixation, nutrients removal and protein production of C. vulgaris were studied. The combination of Logistic function and the modified Monod function was also used to describe the relationship between C. vulgaris specific growth rate and concentration of ammonium(NH+4-N) and phosphate(PO3-4-P), respectively.Resultsshowed that the biomass of 10% CO2 group(380.16~499.52 mg/L) was 3.54~8.30 times that of 0.038% CO2 group(44.73~120.00 mg/L). Meanwhile, the consumption rates of ammonium and phosphate in the 10% CO2 group were significantly higher than those in the 0.038% CO2 group. Correlation analysis showed that specific growth rate, carbon fixation rate, protein were all positively correlated with C. vulgaris biomass(R2>0.86, P<0.05). With 10% CO2 and 60 mg/L NH4Cl, the maximum values of specific growth rate, carbon fixation rate, and protein were 0.21 d-1, 42.62 mg/(L·d), and 228.43 mg/L, respectively. In addition, the fitting results indicated that the combination of Logistic function and the modified Monod function could well describe C. vulgaris growth(correlation coefficient R2 is 0.39~0.96), and nutrients were more easily utilized by C. vulgaris at 10% CO2. This experiment could provide a theoretical reference for fixing CO2, purifying wastewater and producing protein simultaneously by microalgae.
2022, 40(5): 18-24,30.
doi: 10.13205/j.hjgc.202205003
Abstract:
In order to convert biomass into high-quality liquid fuel, penicillin residue was selected as catalytic pyrolysis material and pyrolysis experiments were carried out at temperatures of 400℃, 500℃, 600℃ and 700℃. To maximize the yield of biomass oil, the optimal pyrolysis temperature was explored. On this basis, CoO/HZSM-5 and NiO/HZSM-5 were selected as catalysts for catalytic pyrolysis of penicillin residue to explore their catalytic effect on the quality improvement of bio-oil. The results showed that the yield of biomass oil obtained by pyrolysis of penicillin residue at 500℃ reached the peak without catalyst. At the same temperature, the yield of biomass oil decreased when catalyst CoO/HZSM-5 and NiO/HZSM-5 were added, but the content of hydrocarbons in the bio-oil increased by 8.66 and 7.41 percentage points, reaching 25.34% and 24.09%, respectively; the contents of oxygen-containing substances including alcohols, esters, and aldehydes decreased by 9.68 and 12.49 percentage points, respectively, to 31.74% and 30.34%; the contents of nitrogen-containing heterocyclic substances decreased by 5.96 and 12.49 percentage points, respectively, to 32.51% and 35.07%. The catalytic pyrolysis of three amino acids and the intermediate product DKP was studied to further explain the catalytic pyrolysis mechanism of penicillin residue.For the purpose of maximizing the rate, the optimal pyrolysis temperature was also explored.
In order to convert biomass into high-quality liquid fuel, penicillin residue was selected as catalytic pyrolysis material and pyrolysis experiments were carried out at temperatures of 400℃, 500℃, 600℃ and 700℃. To maximize the yield of biomass oil, the optimal pyrolysis temperature was explored. On this basis, CoO/HZSM-5 and NiO/HZSM-5 were selected as catalysts for catalytic pyrolysis of penicillin residue to explore their catalytic effect on the quality improvement of bio-oil. The results showed that the yield of biomass oil obtained by pyrolysis of penicillin residue at 500℃ reached the peak without catalyst. At the same temperature, the yield of biomass oil decreased when catalyst CoO/HZSM-5 and NiO/HZSM-5 were added, but the content of hydrocarbons in the bio-oil increased by 8.66 and 7.41 percentage points, reaching 25.34% and 24.09%, respectively; the contents of oxygen-containing substances including alcohols, esters, and aldehydes decreased by 9.68 and 12.49 percentage points, respectively, to 31.74% and 30.34%; the contents of nitrogen-containing heterocyclic substances decreased by 5.96 and 12.49 percentage points, respectively, to 32.51% and 35.07%. The catalytic pyrolysis of three amino acids and the intermediate product DKP was studied to further explain the catalytic pyrolysis mechanism of penicillin residue.For the purpose of maximizing the rate, the optimal pyrolysis temperature was also explored.
2022, 40(5): 25-30.
doi: 10.13205/j.hjgc.202205004
Abstract:
Fe3O4-RGO nanocomposite catalyst was prepared by coprecipitation method and then investigated in Fenton-like process when treating landfill leachate. The effect of reaction time, initial pH value, catalyst mass concentration and H2O2 dosage on COD removal rate of landfill leachate were studied. The results indicated that when the initial pH value was 3, catalyst mass concentration was 1 mg/L and H2O2 dosage was 0.08 mmol/L, the removal rate of COD removal rate reached a maximum of 64.7% after 90 minutes reaction. The comparison of organic components showed that the macromolecular organic matter in the landfill leachate was well degraded after Fenton-like treatment. The Fe3O4-RGO nanocomposite catalyst had good repeatability, and the COD removal rate of landfill leachate was only reduced by 2.3% after 5 times usage.
Fe3O4-RGO nanocomposite catalyst was prepared by coprecipitation method and then investigated in Fenton-like process when treating landfill leachate. The effect of reaction time, initial pH value, catalyst mass concentration and H2O2 dosage on COD removal rate of landfill leachate were studied. The results indicated that when the initial pH value was 3, catalyst mass concentration was 1 mg/L and H2O2 dosage was 0.08 mmol/L, the removal rate of COD removal rate reached a maximum of 64.7% after 90 minutes reaction. The comparison of organic components showed that the macromolecular organic matter in the landfill leachate was well degraded after Fenton-like treatment. The Fe3O4-RGO nanocomposite catalyst had good repeatability, and the COD removal rate of landfill leachate was only reduced by 2.3% after 5 times usage.
2022, 40(5): 31-36.
doi: 10.13205/j.hjgc.202205005
Abstract:
High-salinity phosphate-containing wastewater has the characteristics of high salt content, complex pollutant composition and is difficult to be treated by the biological method. The supernatant will contain some PO3-4-P after struvite production by adding excessive inducers and diluents such as Na2HPO4 and NH4HCO3 to seawater. A chemical precipitation method was applied for excessive phosphate removal. In our experiment, poly-aluminium chloride(PAC), FeCl3, Ca(OH)2 and polyacrylamide(PAM) were selected as experimental chemical reagents. The effect of reaction time, the additive amount of a single chemical reagent and a combination of chemical reagents on the phosphate removal effect were studied. Finally, two strategies were selected, which could make the phosphate content in the effluent meet the emission standard. Strategy 1:adding Ca(OH)2 with a molar ratio of Ca:P of 4.5 made the PO3-4-P content decrease to 0.2 mg/L. Strategy 2:adding Ca(OH)2 with a molar ratio of Ca:P of 4.0, PAC with a molar ratio of Al:P of 0.5, and PAM with a concentration of 0.5 g/L made PO3-4-P content decrease to 0.4 mg/L. Strategy 1 was easy to operate while strategy 2 was helpful for solid-liquid separation. Both of them can be used for the treatment of high-salinity phosphate-containing wastewater. The results provide a practical idea for the treatment of high-salinity phosphate-containing wastewater in the future.
High-salinity phosphate-containing wastewater has the characteristics of high salt content, complex pollutant composition and is difficult to be treated by the biological method. The supernatant will contain some PO3-4-P after struvite production by adding excessive inducers and diluents such as Na2HPO4 and NH4HCO3 to seawater. A chemical precipitation method was applied for excessive phosphate removal. In our experiment, poly-aluminium chloride(PAC), FeCl3, Ca(OH)2 and polyacrylamide(PAM) were selected as experimental chemical reagents. The effect of reaction time, the additive amount of a single chemical reagent and a combination of chemical reagents on the phosphate removal effect were studied. Finally, two strategies were selected, which could make the phosphate content in the effluent meet the emission standard. Strategy 1:adding Ca(OH)2 with a molar ratio of Ca:P of 4.5 made the PO3-4-P content decrease to 0.2 mg/L. Strategy 2:adding Ca(OH)2 with a molar ratio of Ca:P of 4.0, PAC with a molar ratio of Al:P of 0.5, and PAM with a concentration of 0.5 g/L made PO3-4-P content decrease to 0.4 mg/L. Strategy 1 was easy to operate while strategy 2 was helpful for solid-liquid separation. Both of them can be used for the treatment of high-salinity phosphate-containing wastewater. The results provide a practical idea for the treatment of high-salinity phosphate-containing wastewater in the future.
2022, 40(5): 37-43.
doi: 10.13205/j.hjgc.202205006
Abstract:
This study investigated the biological degradation behavior of 6 typical pharmaceutical micropollutants in wastewater by a moving bed biofilm reactor(MBBR). The tertiary treatment of the residual target micropollutants from the MBBR effluents by UVC-activated H2O2, HSO-5 and S2O2-8 processes were further investigated under a continuous-flow mode. The results showed that the MBBR process was capable of efficiently degrading N,N-diethyl-meta-toluamide, gemfibrozil and ibuprofen(e.g., their mean degradation rates achieved 835.5, 889.2, 653.3 μg/(L·d), respectively); which however was inefficient in degrading carbamazepine, crotamiton and trimethoprim. The presence of the target pharmaceuticals exhibited negligible impacts on the organic carbon source removal and ammonium nitrification in the MBBR. The high-throughput sequencing results indicated that the majority of microbial communities in the MBBR were classified to the phylum Proteobacteria(65.6%), Planctomycetes(14.8%), Bacteroidetes(7.4%) and Chloroflexi(4.2%); and the major genera included Hyphomicrobium(31.6%), Methylotenera(10.7%), SMIA02(9.6%) and OLB12(4.9%). UVC-activated H2O2, HSO-5 and S2O2-8 processes could efficiently degrade the residual pharmaceutical micropollutants from the MBBR effluent, 92.7%~99.4% degradation efficiencies of the target pharmaceuticals were obtained by using 1.0 mmol/L of oxidants under the given conditions. In comparison with UVC/H2O2 process, UVC/S2O2-8 and UVC/HSO-5 processes exhibited higher selectivity toward the degradation of the target pharmaceutical micropollutants.
This study investigated the biological degradation behavior of 6 typical pharmaceutical micropollutants in wastewater by a moving bed biofilm reactor(MBBR). The tertiary treatment of the residual target micropollutants from the MBBR effluents by UVC-activated H2O2, HSO-5 and S2O2-8 processes were further investigated under a continuous-flow mode. The results showed that the MBBR process was capable of efficiently degrading N,N-diethyl-meta-toluamide, gemfibrozil and ibuprofen(e.g., their mean degradation rates achieved 835.5, 889.2, 653.3 μg/(L·d), respectively); which however was inefficient in degrading carbamazepine, crotamiton and trimethoprim. The presence of the target pharmaceuticals exhibited negligible impacts on the organic carbon source removal and ammonium nitrification in the MBBR. The high-throughput sequencing results indicated that the majority of microbial communities in the MBBR were classified to the phylum Proteobacteria(65.6%), Planctomycetes(14.8%), Bacteroidetes(7.4%) and Chloroflexi(4.2%); and the major genera included Hyphomicrobium(31.6%), Methylotenera(10.7%), SMIA02(9.6%) and OLB12(4.9%). UVC-activated H2O2, HSO-5 and S2O2-8 processes could efficiently degrade the residual pharmaceutical micropollutants from the MBBR effluent, 92.7%~99.4% degradation efficiencies of the target pharmaceuticals were obtained by using 1.0 mmol/L of oxidants under the given conditions. In comparison with UVC/H2O2 process, UVC/S2O2-8 and UVC/HSO-5 processes exhibited higher selectivity toward the degradation of the target pharmaceutical micropollutants.
2022, 40(5): 44-52.
doi: 10.13205/j.hjgc.202205007
Abstract:
To enhance the adsorption performance of the raw diatomite for organic pollutants in water, the modified diatomite(CD300) was simply synthesized, using glucose as a carbon source, by low-temperature pyrolysis of glucose-immersed diatomite. CD300 was characterized by SEM, EDX, FTIR, XRD, and Zeta potential, respectively. The adsorption kinetics, adsorption isotherms and adsorption thermodynamics of tetracycline(TC) as target pollutant were studied. It was observed that the modified adsorbents pyrolyzed at 300℃ performed better than other adsorbents for the TC adsorption, 110.6% higher than that of the raw diatomite. The characterization revealed that the carbonization products were successfully deposited on the surface of diatomite, and the morphology and structure of the raw diatomite were not significantly changed by carbonization modification. Based on correlation coefficient R2, Elovich kinetic model was better to fit the experiment results(R2>0.941), indicating that the adsorption on CD300 was mainly chemisorption. Intra-particle diffusion model showed that the adsorption process was controlled by liquid film diffusion and internal diffusion, and the internal diffusion phase was the main rate control step. The adsorption isotherm analysis showed that the Freundlich model fitted the experimental data better(R2>0.966), indicating that the adsorption was multi-layer adsorption. The thermodynamic parameters, ΔG0<0, ΔH0>0 and ΔS0>0, indicated that the adsorption process was spontaneous, endothermic and the increase of disorder degree. The influence experiments of initial solution pH and ionic strength proved that there might be a strong outer-sphere association between TC molecules and CD300, and electrostatic interaction was a dominant role in adsorption process. In addition, the favorable regeneration performance of CD300 indicated that it could be used as an efficient adsorbent for organic pollutants adsorption removal.
To enhance the adsorption performance of the raw diatomite for organic pollutants in water, the modified diatomite(CD300) was simply synthesized, using glucose as a carbon source, by low-temperature pyrolysis of glucose-immersed diatomite. CD300 was characterized by SEM, EDX, FTIR, XRD, and Zeta potential, respectively. The adsorption kinetics, adsorption isotherms and adsorption thermodynamics of tetracycline(TC) as target pollutant were studied. It was observed that the modified adsorbents pyrolyzed at 300℃ performed better than other adsorbents for the TC adsorption, 110.6% higher than that of the raw diatomite. The characterization revealed that the carbonization products were successfully deposited on the surface of diatomite, and the morphology and structure of the raw diatomite were not significantly changed by carbonization modification. Based on correlation coefficient R2, Elovich kinetic model was better to fit the experiment results(R2>0.941), indicating that the adsorption on CD300 was mainly chemisorption. Intra-particle diffusion model showed that the adsorption process was controlled by liquid film diffusion and internal diffusion, and the internal diffusion phase was the main rate control step. The adsorption isotherm analysis showed that the Freundlich model fitted the experimental data better(R2>0.966), indicating that the adsorption was multi-layer adsorption. The thermodynamic parameters, ΔG0<0, ΔH0>0 and ΔS0>0, indicated that the adsorption process was spontaneous, endothermic and the increase of disorder degree. The influence experiments of initial solution pH and ionic strength proved that there might be a strong outer-sphere association between TC molecules and CD300, and electrostatic interaction was a dominant role in adsorption process. In addition, the favorable regeneration performance of CD300 indicated that it could be used as an efficient adsorbent for organic pollutants adsorption removal.
2022, 40(5): 53-58,66.
doi: 10.13205/j.hjgc.202205008
Abstract:
A chlortetracycline-degrading strain was isolated from the activated sludge of a chlortetracycline pharmaceutical factory in Zhumadian in Henan. Based on the analysis of its 16S rDNA gene sequence, the isolated strain named JMS-B01 was identified as a member of the genus Bacillus. To improve the chlortetracycline degradation rate, the degradation conditions were optimized. Firstly, three factors playing important roles in the chlortetracycline degradation rate were selected based on the orthogonal test. Then box-Behnken experimental design and response surface method were used to analyze the optimal degradation conditions. The fitting curve had a good correlation with the measured values. The optimal conditions were as follows:temperature of 34.0℃, chlortetracycline concentration of 102.5 mg/L, inoculation amount of 2%(V/V). Under the optimal conditions mentioned above, the chlortetracycline degradation rate reached 96.50%. Temperature was one of the most important factors affecting the chlortetracycline degradation rate of strain JMS-B01.
A chlortetracycline-degrading strain was isolated from the activated sludge of a chlortetracycline pharmaceutical factory in Zhumadian in Henan. Based on the analysis of its 16S rDNA gene sequence, the isolated strain named JMS-B01 was identified as a member of the genus Bacillus. To improve the chlortetracycline degradation rate, the degradation conditions were optimized. Firstly, three factors playing important roles in the chlortetracycline degradation rate were selected based on the orthogonal test. Then box-Behnken experimental design and response surface method were used to analyze the optimal degradation conditions. The fitting curve had a good correlation with the measured values. The optimal conditions were as follows:temperature of 34.0℃, chlortetracycline concentration of 102.5 mg/L, inoculation amount of 2%(V/V). Under the optimal conditions mentioned above, the chlortetracycline degradation rate reached 96.50%. Temperature was one of the most important factors affecting the chlortetracycline degradation rate of strain JMS-B01.
2022, 40(5): 59-66.
doi: 10.13205/j.hjgc.202205009
Abstract:
The removal efficiency of antibiotic pollutants such as sulfamethoxazole(SMX), ciprofloxacin(CIP) and methoxyphenidine(TMP) were studied using magnetic nano-gel beads(Fe3O4@PVA-SA-PAC) composite, and the influences of pH, dosage, initial concentration of pollutants and adsorption time on the adsorption process were analyzed. The result showed that pH=3 was the optimal condition. The adsorption capacity increased with the increase of initial concentration and decreased with the increase of dosage. The adsorption of these three antibiotics by Fe3O4@PVA-SA-PAC showed the coexistence of physical and chemical adsorption, also homogeneous monolayer adsorption and heterogeneous multi-molecular layer adsorption. The adsorption of SMX and CIP was more consistent with the pseudo-first-order kinetic model, while TMP was more consistent with the pseudo-second-order kinetic model. At 308 K, both the Langmuir equation and Freundlich equation reached a high fitting degree(0.938 ≤ R2 ≤ 0.998). By now, the maximum adsorption capacity of SMX, TMP and CIP were 47.188 mg/g, 59.649 mg/g and 96.468 mg/g, respectively. Competitive adsorption experiments showed that the composite gel beads could simultaneously adsorb a variety of target antibiotic pollutants, indicating a good application prospect of adsorption.
The removal efficiency of antibiotic pollutants such as sulfamethoxazole(SMX), ciprofloxacin(CIP) and methoxyphenidine(TMP) were studied using magnetic nano-gel beads(Fe3O4@PVA-SA-PAC) composite, and the influences of pH, dosage, initial concentration of pollutants and adsorption time on the adsorption process were analyzed. The result showed that pH=3 was the optimal condition. The adsorption capacity increased with the increase of initial concentration and decreased with the increase of dosage. The adsorption of these three antibiotics by Fe3O4@PVA-SA-PAC showed the coexistence of physical and chemical adsorption, also homogeneous monolayer adsorption and heterogeneous multi-molecular layer adsorption. The adsorption of SMX and CIP was more consistent with the pseudo-first-order kinetic model, while TMP was more consistent with the pseudo-second-order kinetic model. At 308 K, both the Langmuir equation and Freundlich equation reached a high fitting degree(0.938 ≤ R2 ≤ 0.998). By now, the maximum adsorption capacity of SMX, TMP and CIP were 47.188 mg/g, 59.649 mg/g and 96.468 mg/g, respectively. Competitive adsorption experiments showed that the composite gel beads could simultaneously adsorb a variety of target antibiotic pollutants, indicating a good application prospect of adsorption.
2022, 40(5): 67-74.
doi: 10.13205/j.hjgc.202205010
Abstract:
In this paper, the montmorillonite was saturated with five metal cations by the impregnation method to obtain iron-based montmorillonite(Fe-MT), copper-based montmorillonite(Cu-MT), potassium-based montmorillonite(K-MT), sodium-based montmorillonite(Na-MT), and calcium-based montmorillonite(Ca-MT). The adsorption behavior, main influencing factors, and adsorption mechanism of propranolol on these montmorillonites saturated with five interlayer metal cations were studied. The results showed that the five metal cations saturated montmorillonite had high adsorption capacity for propranolol, in the sequence of Fe-MT>Cu-MT>K-MT>Na-MT>Ca-MT. The increase of adsorption capacity at pH of 3~9 was due to the weakening of the competitiveness of adsorption sites of H+ and propranolol on montmorillonite saturated with metal cations. The decrease of adsorption capacity at pH of 9~11 resulted from propranolol mainly existed in molecular state and the decrease of electrostatic attraction. The presence of K+, Na+, and Ca2+ could inhibit the absorption of propranolol. The addition of humic acid could promote the adsorption of propranolol, but its effect decreased with the increase of humic acid concentration, and even adsorption inhibition occured. Langmuir isothermal adsorption model and the pseudo-second-order kinetic equation could better describe the adsorption process of propranolol. This study was expected to provide a theoretical basis for a comprehensive understanding of the migration and transformation of propranolol in soil environment.
In this paper, the montmorillonite was saturated with five metal cations by the impregnation method to obtain iron-based montmorillonite(Fe-MT), copper-based montmorillonite(Cu-MT), potassium-based montmorillonite(K-MT), sodium-based montmorillonite(Na-MT), and calcium-based montmorillonite(Ca-MT). The adsorption behavior, main influencing factors, and adsorption mechanism of propranolol on these montmorillonites saturated with five interlayer metal cations were studied. The results showed that the five metal cations saturated montmorillonite had high adsorption capacity for propranolol, in the sequence of Fe-MT>Cu-MT>K-MT>Na-MT>Ca-MT. The increase of adsorption capacity at pH of 3~9 was due to the weakening of the competitiveness of adsorption sites of H+ and propranolol on montmorillonite saturated with metal cations. The decrease of adsorption capacity at pH of 9~11 resulted from propranolol mainly existed in molecular state and the decrease of electrostatic attraction. The presence of K+, Na+, and Ca2+ could inhibit the absorption of propranolol. The addition of humic acid could promote the adsorption of propranolol, but its effect decreased with the increase of humic acid concentration, and even adsorption inhibition occured. Langmuir isothermal adsorption model and the pseudo-second-order kinetic equation could better describe the adsorption process of propranolol. This study was expected to provide a theoretical basis for a comprehensive understanding of the migration and transformation of propranolol in soil environment.
2022, 40(5): 75-81.
doi: 10.13205/j.hjgc.202205011
Abstract:
The degradation of lignin is an effective way to improve the biogas fermentation efficiency of lignocellulosic materials, such as straw. For anaerobic microorganisms, lignin is difficult to use, however, recent studies indicated that lignin can be decomposed and utilized by microorganisms through aromatic compounds such as benzoate and phenol. The effect of bioaugmentation with a benzoate-degrading bacterium Sporotomaculum syntrophicum strain FB on the anaerobic corn stalk fermentation was evaluated by batch experiments. The results showed that when the inoculation ratio of S. syntrophicum was 5%, 10%, and 20%, the methane yields were 252.2, 244.9, 234.8 mL/g TS respectively, increased by 20.5%, 17.0%, 12.2% comparing with the control. TS removal rates increased by 2.9%, 3.1%, and 3.4%, respectively. The removal rates of cellulose, hemicellulose and lignin increased by 12%~13%, 3%~5% and 38%~46%, respectively, with the addition of 5%~20% S. syntrophicum. The further experiment verified that the addition of S. syntrophicum could improve the methane yields of methyl cellulose, xylan, and alkali lignin(models for cellulose, hemicelluloses, and lignin, respectively) by 15.7%, 11.4%, 7.8%.
The degradation of lignin is an effective way to improve the biogas fermentation efficiency of lignocellulosic materials, such as straw. For anaerobic microorganisms, lignin is difficult to use, however, recent studies indicated that lignin can be decomposed and utilized by microorganisms through aromatic compounds such as benzoate and phenol. The effect of bioaugmentation with a benzoate-degrading bacterium Sporotomaculum syntrophicum strain FB on the anaerobic corn stalk fermentation was evaluated by batch experiments. The results showed that when the inoculation ratio of S. syntrophicum was 5%, 10%, and 20%, the methane yields were 252.2, 244.9, 234.8 mL/g TS respectively, increased by 20.5%, 17.0%, 12.2% comparing with the control. TS removal rates increased by 2.9%, 3.1%, and 3.4%, respectively. The removal rates of cellulose, hemicellulose and lignin increased by 12%~13%, 3%~5% and 38%~46%, respectively, with the addition of 5%~20% S. syntrophicum. The further experiment verified that the addition of S. syntrophicum could improve the methane yields of methyl cellulose, xylan, and alkali lignin(models for cellulose, hemicelluloses, and lignin, respectively) by 15.7%, 11.4%, 7.8%.
2022, 40(5): 82-87.
doi: 10.13205/j.hjgc.202205012
Abstract:
Dehydration and successive anaerobic digestion are widely used for the reduction and resource utilization of the excess sludge from municipal wastewater treatment plants. Cationic polyacrylamide(cPAM) is a commonly used flocculant in the dehydration process, and its influence on the performance of subsequent anaerobic digestion is still not well understood. This study found that cPAM with medium and high molecular weight could inhibit the solubilization and hydrolysis of organic matter, and the efficiency of the subsequent acidogenesis and methanogenesis during anaerobic digestion. In addition, the inhibition effect of medium molecular weight cPAM was stronger. Compared with the control, the maximum yields of soluble protein, polysaccharide, and short-chain fatty acids(SCFAs) decreased by 22.3%, 28.4% and 38.6%, respectively, for the digestion of sludge after the addition of medium molecular weight cPAM; while they declined by 7.4%, 19.4% and 25.9% respectively for high molecular weight cPAM. The 30-day cumulative methane production for sludge digestion with medium and high molecular weight cPAM were(40.4±1.4) mL CH4/g VSS and(49.8±1.3) mL CH4/g VSS, respectively, which were 33.7% and 18.3% lower than that of the control. The results suggested that the effect of cPAM, including the amount and molecular weight of cPAM, on the performance of subsequent anaerobic digestion should be integrated into consideration in the process of excess sludge dewatering to achieve the best overall benefit.
Dehydration and successive anaerobic digestion are widely used for the reduction and resource utilization of the excess sludge from municipal wastewater treatment plants. Cationic polyacrylamide(cPAM) is a commonly used flocculant in the dehydration process, and its influence on the performance of subsequent anaerobic digestion is still not well understood. This study found that cPAM with medium and high molecular weight could inhibit the solubilization and hydrolysis of organic matter, and the efficiency of the subsequent acidogenesis and methanogenesis during anaerobic digestion. In addition, the inhibition effect of medium molecular weight cPAM was stronger. Compared with the control, the maximum yields of soluble protein, polysaccharide, and short-chain fatty acids(SCFAs) decreased by 22.3%, 28.4% and 38.6%, respectively, for the digestion of sludge after the addition of medium molecular weight cPAM; while they declined by 7.4%, 19.4% and 25.9% respectively for high molecular weight cPAM. The 30-day cumulative methane production for sludge digestion with medium and high molecular weight cPAM were(40.4±1.4) mL CH4/g VSS and(49.8±1.3) mL CH4/g VSS, respectively, which were 33.7% and 18.3% lower than that of the control. The results suggested that the effect of cPAM, including the amount and molecular weight of cPAM, on the performance of subsequent anaerobic digestion should be integrated into consideration in the process of excess sludge dewatering to achieve the best overall benefit.
2022, 40(5): 88-94.
doi: 10.13205/j.hjgc.202205013
Abstract:
The effects of alkali treatment pH on the dissolution of organic matter, the types and configuration of amino acids produced by proteolysis and methane production by anaerobic digestion of waste activated sludge were studied. Two kinetic models were used to fit the methanogenesis process, and Spearman analysis was used to investigate the correlation between intermediate amino acids and methane production. The results showed that, when alkali treatment pH was 11, the cumulative methane production was 1.4 times higher than that of the control group. The modified Gompertz model had a good fitting effect on the methanogenesis process, the fitting coefficient was above 0.989, and the error range was within 3.9%. Alkali treatment could increase the content and types of amino acids by proteolysis. The dissolved amino acids have L-type and D-type, with the highest content of L-and D-Cys. The content of L-type was higher than its corresponding D-type(except Thr), in which the racemization degree(D/(D+L)) of Thr was the highest(54.0%), followed by Cys(45.5%) and Ala(44.0%). Among amino acids, D-Leu, D-Asp, L-Thr and L-Cys had a strong correlation with methane production, and their Spearman coefficients were 0.894, 0.9, 0.9 and 0.9(P<0.05), respectively. This study provides a theoretical basis for the follow-up study on the effects of amino acids and their configurations on anaerobic digestion and as well as a new idea for the regulation of anaerobic digestion.
The effects of alkali treatment pH on the dissolution of organic matter, the types and configuration of amino acids produced by proteolysis and methane production by anaerobic digestion of waste activated sludge were studied. Two kinetic models were used to fit the methanogenesis process, and Spearman analysis was used to investigate the correlation between intermediate amino acids and methane production. The results showed that, when alkali treatment pH was 11, the cumulative methane production was 1.4 times higher than that of the control group. The modified Gompertz model had a good fitting effect on the methanogenesis process, the fitting coefficient was above 0.989, and the error range was within 3.9%. Alkali treatment could increase the content and types of amino acids by proteolysis. The dissolved amino acids have L-type and D-type, with the highest content of L-and D-Cys. The content of L-type was higher than its corresponding D-type(except Thr), in which the racemization degree(D/(D+L)) of Thr was the highest(54.0%), followed by Cys(45.5%) and Ala(44.0%). Among amino acids, D-Leu, D-Asp, L-Thr and L-Cys had a strong correlation with methane production, and their Spearman coefficients were 0.894, 0.9, 0.9 and 0.9(P<0.05), respectively. This study provides a theoretical basis for the follow-up study on the effects of amino acids and their configurations on anaerobic digestion and as well as a new idea for the regulation of anaerobic digestion.
2022, 40(5): 95-102,108.
doi: 10.13205/j.hjgc.202205014
Abstract:
Taking the largest estuary in China as an example, regular monitoring was carried out at four major cross-sections, including Xuliujing, Qidonggang, Nangang and Beigang in Yangtze Estuary from 2004 to 2018. Water quality parameters such as permanganate index, ammonia nitrogen(NH3-N) and total phosphorus(TP) were measured in water samples. A comprehensive analysis of the water quality at the cross-sections was conducted via the comprehensive water quality identification index(WQII) method; dissolved oxygen(DO) was selected as the response variable to establish stepwise regression equations and seasonal autoregressive integrated moving average model(SARIMA) for each cross-section, and predictions were made from October to December 2018 to test the accuracy of the models and compare the applicability of the two models at each cross-section. The results showed that:1) based on the monthly data from 2004 to 2018, the average DO concentration at the representative cross-sections of the main sea-entry channels of the Yangtze Estuary was 8.73 mg/L; spatially, the DO concentration in the Yangtze Estuary showed a pattern that Xuliujing was the highest and the northern branch was higher than the southern branch. 2) based on the comprehensive water quality marker index, the sections, water quality was in the order of Qidonggang(3.110)>Xuliujing(3.120)>Beigang(3.220)>Nangang(3.420);3) when predicting DO, the SARIMA model was more accurate than the stepwise regression equation in predicting DO at the Xuliujing, Qidonggang and Beigang section, while the stepwise regression equation performed better at the Nangang section.
Taking the largest estuary in China as an example, regular monitoring was carried out at four major cross-sections, including Xuliujing, Qidonggang, Nangang and Beigang in Yangtze Estuary from 2004 to 2018. Water quality parameters such as permanganate index, ammonia nitrogen(NH3-N) and total phosphorus(TP) were measured in water samples. A comprehensive analysis of the water quality at the cross-sections was conducted via the comprehensive water quality identification index(WQII) method; dissolved oxygen(DO) was selected as the response variable to establish stepwise regression equations and seasonal autoregressive integrated moving average model(SARIMA) for each cross-section, and predictions were made from October to December 2018 to test the accuracy of the models and compare the applicability of the two models at each cross-section. The results showed that:1) based on the monthly data from 2004 to 2018, the average DO concentration at the representative cross-sections of the main sea-entry channels of the Yangtze Estuary was 8.73 mg/L; spatially, the DO concentration in the Yangtze Estuary showed a pattern that Xuliujing was the highest and the northern branch was higher than the southern branch. 2) based on the comprehensive water quality marker index, the sections, water quality was in the order of Qidonggang(3.110)>Xuliujing(3.120)>Beigang(3.220)>Nangang(3.420);3) when predicting DO, the SARIMA model was more accurate than the stepwise regression equation in predicting DO at the Xuliujing, Qidonggang and Beigang section, while the stepwise regression equation performed better at the Nangang section.
2022, 40(5): 103-108.
doi: 10.13205/j.hjgc.202205015
Abstract:
In this study, fruit and vegetable wastes and garden wastes were treated with anaerobic hydrolysis technology, and the effect of pH on acid production was also discussed. At temperature of 45℃, pH=6, the volatile fatty acid(VFA) concentration of the fermentation liquor in the reactor reached the maximum value of 12.94 g/L on the 11 th day, which was 3.37 times the VFA concentration under the unregulated pH condition, and the time needed to reach the VFA maximum value was reduced by 20%, greatly improving the acid production efficiency. Regulation of pH could also promote the conversion of soluble COD(SCOD) into VFAs. The maximum VFA/SCOD value was achieved on the 11 th day under the condition of pH 6, was 48.73%, which was beneficial to subsequent utilization as a carbon source. By further analyzing the VFA component and ammonia nitrogen concentration in the fermentation liquor with different pH, the condition of pH=6 could change the fermentation type from ethanol type fermentation to butyric acid type fermentation, which was also beneficial to protein decomposition.
In this study, fruit and vegetable wastes and garden wastes were treated with anaerobic hydrolysis technology, and the effect of pH on acid production was also discussed. At temperature of 45℃, pH=6, the volatile fatty acid(VFA) concentration of the fermentation liquor in the reactor reached the maximum value of 12.94 g/L on the 11 th day, which was 3.37 times the VFA concentration under the unregulated pH condition, and the time needed to reach the VFA maximum value was reduced by 20%, greatly improving the acid production efficiency. Regulation of pH could also promote the conversion of soluble COD(SCOD) into VFAs. The maximum VFA/SCOD value was achieved on the 11 th day under the condition of pH 6, was 48.73%, which was beneficial to subsequent utilization as a carbon source. By further analyzing the VFA component and ammonia nitrogen concentration in the fermentation liquor with different pH, the condition of pH=6 could change the fermentation type from ethanol type fermentation to butyric acid type fermentation, which was also beneficial to protein decomposition.
2022, 40(5): 109-116.
doi: 10.13205/j.hjgc.202205016
Abstract:
To apply Leersia Hexandra Swartz to remediate Ni and Cr complex contaminated soil, root box experiments were used to investigate the changes in the rhizosphere environmental characteristics of Leersia Hexandra Swartz under Ni and Cr composite contamination. The results showed that:the pH of the rhizosphere soil of Leersia Hexandra Swartz was significantly lower(P<0.01) than that of the non-rhizosphere soil and the substrate soil under different concentrations of Ni and Cr; athe urease, acid phosphatase, and acid convertase activities of the inter-rhizosphere soil were significantly higher(P<0.05) than that of the non-rhizosphere soil and the substrate soil. As the concentration of Ni and Cr treatment increased, the pH and soil enzyme activity of Leersia Hexandra Swartz showed different degrees of decrease, and the plant height, biomass, and enrichment coefficient of Leersia Hexandra Swartz were also inhibited. In the correlation analysis, plant height and biomass of Leersia hexandra Swartz showed a significant positive correlation(P<0.01) with soil pH and soil enzyme activity, and soil pH showed the same significant positive correlation(P<0.01) with soil enzyme activity. High-throughput sequencing results showed that the three groups of bacteria with the highest relative abundance in the rhizosphere soil of Leersia Hexandra Swartz were Proteobacteria, Firmicutes and Bacteroidetes; the three genera with the highest relative abundance were Alicyclobacillus, Bordetella and Mucilaginibacter; Hydrotalea may have a facilitating effect on the growth and enrichment capacity of Leersia Hexandra Swartz. The results showed that Leersia Hexandra Swartz could tolerate higher levels of Ni and Cr contamination and that metal-resistant bacteria may be present in its inter-roots, making it a potential plant that can be used for remediation of Ni and Cr complex contaminated soils.
To apply Leersia Hexandra Swartz to remediate Ni and Cr complex contaminated soil, root box experiments were used to investigate the changes in the rhizosphere environmental characteristics of Leersia Hexandra Swartz under Ni and Cr composite contamination. The results showed that:the pH of the rhizosphere soil of Leersia Hexandra Swartz was significantly lower(P<0.01) than that of the non-rhizosphere soil and the substrate soil under different concentrations of Ni and Cr; athe urease, acid phosphatase, and acid convertase activities of the inter-rhizosphere soil were significantly higher(P<0.05) than that of the non-rhizosphere soil and the substrate soil. As the concentration of Ni and Cr treatment increased, the pH and soil enzyme activity of Leersia Hexandra Swartz showed different degrees of decrease, and the plant height, biomass, and enrichment coefficient of Leersia Hexandra Swartz were also inhibited. In the correlation analysis, plant height and biomass of Leersia hexandra Swartz showed a significant positive correlation(P<0.01) with soil pH and soil enzyme activity, and soil pH showed the same significant positive correlation(P<0.01) with soil enzyme activity. High-throughput sequencing results showed that the three groups of bacteria with the highest relative abundance in the rhizosphere soil of Leersia Hexandra Swartz were Proteobacteria, Firmicutes and Bacteroidetes; the three genera with the highest relative abundance were Alicyclobacillus, Bordetella and Mucilaginibacter; Hydrotalea may have a facilitating effect on the growth and enrichment capacity of Leersia Hexandra Swartz. The results showed that Leersia Hexandra Swartz could tolerate higher levels of Ni and Cr contamination and that metal-resistant bacteria may be present in its inter-roots, making it a potential plant that can be used for remediation of Ni and Cr complex contaminated soils.
2022, 40(5): 117-122.
doi: 10.13205/j.hjgc.202205017
Abstract:
Taking the Beijing section of Yongding River as the research object, water quality and water eco-environment status were investigated and the dynamic indexes were monitored to select the candidate indicators. The evaluation indexes were screened by principal component analysis method, and the weight of each index was estimated by the entropy method so as to construct the river eutrophication evaluation index system. And fuzzy mathematics was used to calculate and determine the nutrient level in the Beijing section of Yongding River. The results showed that eutrophication was common in Beijing Section, but the problem was not serious. Two assessment methods, namely, comprehensive trophic level index(TLI) and eutrophication index(EI) were adopted to carry out the comparison, which verified the reliability of the proposed method. This method had the advantages of more flexible index selection and more objective evaluation results, and could be used as an important method and means for water eutrophication evaluation in Beijing section of Yongding River.
Taking the Beijing section of Yongding River as the research object, water quality and water eco-environment status were investigated and the dynamic indexes were monitored to select the candidate indicators. The evaluation indexes were screened by principal component analysis method, and the weight of each index was estimated by the entropy method so as to construct the river eutrophication evaluation index system. And fuzzy mathematics was used to calculate and determine the nutrient level in the Beijing section of Yongding River. The results showed that eutrophication was common in Beijing Section, but the problem was not serious. Two assessment methods, namely, comprehensive trophic level index(TLI) and eutrophication index(EI) were adopted to carry out the comparison, which verified the reliability of the proposed method. This method had the advantages of more flexible index selection and more objective evaluation results, and could be used as an important method and means for water eutrophication evaluation in Beijing section of Yongding River.
2022, 40(5): 141-145,165.
doi: 10.13205/j.hjgc.202205020
Abstract:
As the main energy consumer in wastewater treatment plants(WWTPs), aeration system has a high potential for energy saving. In this study, an air distribution and control system was introduced into Zhangcunhe WWTP, Qingdao. The efficiency of this system was tested, and its effects on the effluent quality and energy consumption were investigated. The results showed that the dissolved oxygen(DO) concentration in the aeration tank could be maintained within ±0.3 mg/L of the setpoint for longer than two-thirds of the running time. By applying the accurate aeration control, the average concentration of effluent chemical oxygen demand(COD) decreased from 19.6 mg/L to 16.7 mg/L, while those of ammonium and total nitrogen(TN) decreased from 0.37 mg/L to 0.28 mg/L, and from 8.48 mg/L to 7.36 mg/L, respectively. The proportion of days with effluent TN<10 mg/L increased from 79% to 100%, indicating a more stable effluent quality. Besides, the power consumption of the aeration system was reduced by 24.8% while the sodium acetate dosing decreased by 15.1%. Therefore, accurate aeration control is an effective approach to reduce the energy and chemical consumption of WWTPs.
As the main energy consumer in wastewater treatment plants(WWTPs), aeration system has a high potential for energy saving. In this study, an air distribution and control system was introduced into Zhangcunhe WWTP, Qingdao. The efficiency of this system was tested, and its effects on the effluent quality and energy consumption were investigated. The results showed that the dissolved oxygen(DO) concentration in the aeration tank could be maintained within ±0.3 mg/L of the setpoint for longer than two-thirds of the running time. By applying the accurate aeration control, the average concentration of effluent chemical oxygen demand(COD) decreased from 19.6 mg/L to 16.7 mg/L, while those of ammonium and total nitrogen(TN) decreased from 0.37 mg/L to 0.28 mg/L, and from 8.48 mg/L to 7.36 mg/L, respectively. The proportion of days with effluent TN<10 mg/L increased from 79% to 100%, indicating a more stable effluent quality. Besides, the power consumption of the aeration system was reduced by 24.8% while the sodium acetate dosing decreased by 15.1%. Therefore, accurate aeration control is an effective approach to reduce the energy and chemical consumption of WWTPs.
2022, 40(5): 146-151,158.
doi: 10.13205/j.hjgc.202205021
Abstract:
The treatment performance of the traditional biological phosphorus removal process is vulnerable to the change of influent conditions. To solve this problem, a side-stream activated sludge hydrolysis(SSH) reactor was constructed. The changes in pollutant removal performance and microbial community structure in the SSH reactor and conventional anaerobic/anoxic/aerobic(A2/O) reactor were compared under different influent conditions. The results showed that little change in chemical oxygen demand(COD) removal performance was observed in A2/O and SSH reactors, with COD removal efficiencies of 90%. The increase in influent load and flow rate improved the nitrogen and phosphorus removal performance. The total nitrogen removal efficiency in A2/O and SSH reactors increased from 58% and 72% in Phase Ⅰ, to 67% and 83% in Phase Ⅲ, respectively, whereas the total phosphorus removal efficiency increased from 60% to 80% above. Compared to the A2/O reactor, the change in influent conditions had lower impact on the nitrogen removal performance in the SSH reactor. Under the same influent condition, the nitrogen removal performance in the SSH reactor was more effective, with an average total nitrogen removal efficiency 23% higher than that in the A2/O reactor. The high-throughput sequencing results showed that the SSH reactor had higher microbial community diversity and relative abundances of functional microorganisms for nutrient removal such as Dechloromonas, Accumulibacter, which contributed to its effective and stable reactor performance. The results provided references for the design and practical application of SSH process.
The treatment performance of the traditional biological phosphorus removal process is vulnerable to the change of influent conditions. To solve this problem, a side-stream activated sludge hydrolysis(SSH) reactor was constructed. The changes in pollutant removal performance and microbial community structure in the SSH reactor and conventional anaerobic/anoxic/aerobic(A2/O) reactor were compared under different influent conditions. The results showed that little change in chemical oxygen demand(COD) removal performance was observed in A2/O and SSH reactors, with COD removal efficiencies of 90%. The increase in influent load and flow rate improved the nitrogen and phosphorus removal performance. The total nitrogen removal efficiency in A2/O and SSH reactors increased from 58% and 72% in Phase Ⅰ, to 67% and 83% in Phase Ⅲ, respectively, whereas the total phosphorus removal efficiency increased from 60% to 80% above. Compared to the A2/O reactor, the change in influent conditions had lower impact on the nitrogen removal performance in the SSH reactor. Under the same influent condition, the nitrogen removal performance in the SSH reactor was more effective, with an average total nitrogen removal efficiency 23% higher than that in the A2/O reactor. The high-throughput sequencing results showed that the SSH reactor had higher microbial community diversity and relative abundances of functional microorganisms for nutrient removal such as Dechloromonas, Accumulibacter, which contributed to its effective and stable reactor performance. The results provided references for the design and practical application of SSH process.
2022, 40(5): 152-158.
doi: 10.13205/j.hjgc.202205022
Abstract:
In this study, an electrochemical oxidation system consisting of Ti/RuO2 anode and air diffusion cathode(ADC) was constructed, to oxidative remove methylene blue(MB) in a flow-by reactor. The results showed that the stable concentration of H2O2 produced by ADC reached 45.33 mg/L under the current of 200 mA, with a current efficiency of 65.10%. The ADC-RuO2 system was selective for the oxidation of organic pollutants, since it barely oxidized sodium benzoate but showed a strong decolorizing effect on dyes such as methylene blue. In addition, the oxidizing ability was significantly inhibited in the presence of sodium azide and 2,5 dimethylfuran, suggesting the main active oxidant was singlet oxygen(~1O2). At the residence time of 2 min and 200 mA, the removal efficiency of 0.1 mmol/L MB reached 99% in the system. Furthermore, the energy consumption for reducing the MB concentration by 90% was 0.25 kW·h/m3.
In this study, an electrochemical oxidation system consisting of Ti/RuO2 anode and air diffusion cathode(ADC) was constructed, to oxidative remove methylene blue(MB) in a flow-by reactor. The results showed that the stable concentration of H2O2 produced by ADC reached 45.33 mg/L under the current of 200 mA, with a current efficiency of 65.10%. The ADC-RuO2 system was selective for the oxidation of organic pollutants, since it barely oxidized sodium benzoate but showed a strong decolorizing effect on dyes such as methylene blue. In addition, the oxidizing ability was significantly inhibited in the presence of sodium azide and 2,5 dimethylfuran, suggesting the main active oxidant was singlet oxygen(~1O2). At the residence time of 2 min and 200 mA, the removal efficiency of 0.1 mmol/L MB reached 99% in the system. Furthermore, the energy consumption for reducing the MB concentration by 90% was 0.25 kW·h/m3.
2022, 40(5): 159-165.
doi: 10.13205/j.hjgc.202205023
Abstract:
Oil contaminated soils from the decommissioned well site were with low oil content with an increasing heavy fraction over time. Therefore, bioaugmentation was performed to restore the original properties of the aging contaminated soil. The physicochemical properties and indigenous microbial communities of the contaminated soil from a decommissioned well site were systematically analyzed. Various hydrocarbon degrading strains and bio-emulsifiers were screened to promote a high degradation value. Moreover, the preparation method of immobilized strains was optimized to enhance the environmental resistance. It was found that the oil content of the contaminated soils was up to 14.6 mg/g with 57% of heavy component. There was a lack of heavy oil degrading microorganisms in the soils. Two functional degrading strains with synergistic effects were screened and immobilized to improve the efficiency of hydrocarbon degradation. With the addition of 500 mg/L F-3 bio-emulsifier, the degradation time of meeting the standard was reduced from 120 d to 80 d. Thereafter, a 2700 m2 field test was carried out with the land farming method. After 8 months, the oil content was reduced from 14.6 mg/g to 3.30 mg/g, meeting the requirements of state environmental standards, GB 36600-2018. The screened strains were capable of increasing the degradation rate of the aging oil contaminated soils, where the optimized emulsifier and adding method were in favor of reducing the remediation period.
Oil contaminated soils from the decommissioned well site were with low oil content with an increasing heavy fraction over time. Therefore, bioaugmentation was performed to restore the original properties of the aging contaminated soil. The physicochemical properties and indigenous microbial communities of the contaminated soil from a decommissioned well site were systematically analyzed. Various hydrocarbon degrading strains and bio-emulsifiers were screened to promote a high degradation value. Moreover, the preparation method of immobilized strains was optimized to enhance the environmental resistance. It was found that the oil content of the contaminated soils was up to 14.6 mg/g with 57% of heavy component. There was a lack of heavy oil degrading microorganisms in the soils. Two functional degrading strains with synergistic effects were screened and immobilized to improve the efficiency of hydrocarbon degradation. With the addition of 500 mg/L F-3 bio-emulsifier, the degradation time of meeting the standard was reduced from 120 d to 80 d. Thereafter, a 2700 m2 field test was carried out with the land farming method. After 8 months, the oil content was reduced from 14.6 mg/g to 3.30 mg/g, meeting the requirements of state environmental standards, GB 36600-2018. The screened strains were capable of increasing the degradation rate of the aging oil contaminated soils, where the optimized emulsifier and adding method were in favor of reducing the remediation period.
2022, 40(5): 166-170,177.
doi: 10.13205/j.hjgc.202205024
Abstract:
With the wide application of bag filters in the industry, the treatment of a large number of waste filter bags has become an urgent environmental problem. Through experiments, the method of cleaning and reuse of bag filter materials was explored, and the effects of AMES(α-sulfonyl fatty acid methyl ester sodium) cleaning agent concentration, cleaning time and cleaning temperature on the cleaning effect and service performance of filter materials were studied, which not only realized circular economy but also reduced the operation cost of bag dust removal. The results showed that the optimized running condition was as follows:the cleaning temperature was 40℃, the waste polyphenylene sulfide filter material was put into AMES solution with a mass concentration of 2.5%, the self-designed rolling cleaning machine was used for cleaning for 20 min, and cleaning in ultrasonic cleaning machine was for 10 min. The cleanliness of 95.82%, filtration performance of efficiency for 0.3,0.5,1.0,2.5, 5.0,10.0 μm increased by 81.09%, 86.33%, 94.86%, 98.58%, 99.28%, 99.31%, and air permeability of the filter material of 8.182 m3/(m2·min) were the best, and the cleaning process had no obvious impact on the mechanical properties of the filter material.
With the wide application of bag filters in the industry, the treatment of a large number of waste filter bags has become an urgent environmental problem. Through experiments, the method of cleaning and reuse of bag filter materials was explored, and the effects of AMES(α-sulfonyl fatty acid methyl ester sodium) cleaning agent concentration, cleaning time and cleaning temperature on the cleaning effect and service performance of filter materials were studied, which not only realized circular economy but also reduced the operation cost of bag dust removal. The results showed that the optimized running condition was as follows:the cleaning temperature was 40℃, the waste polyphenylene sulfide filter material was put into AMES solution with a mass concentration of 2.5%, the self-designed rolling cleaning machine was used for cleaning for 20 min, and cleaning in ultrasonic cleaning machine was for 10 min. The cleanliness of 95.82%, filtration performance of efficiency for 0.3,0.5,1.0,2.5, 5.0,10.0 μm increased by 81.09%, 86.33%, 94.86%, 98.58%, 99.28%, 99.31%, and air permeability of the filter material of 8.182 m3/(m2·min) were the best, and the cleaning process had no obvious impact on the mechanical properties of the filter material.
2022, 40(5): 171-177.
doi: 10.13205/j.hjgc.202205025
Abstract:
To better guide the selection of nozzles of air-assisted dust suppression sprayer, five sprayer nozzles with different internal structures were collected to carry out a comparative study on the atomization characteristics, and the selected nozzles were used in the project site to test the dust reduction effect. The results showed that:1) the Spray and Taige nozzles had larger atomization angle, meeting the needs of large area dust reduction, and were suitable for most dust suppression sprayers; 2) under the same water supply pressure, the droplet diameter of the Spray nozzle with an outlet diameter of 0.5 mm was much smaller than that of other nozzles, and its installation in the dust suppression sprayer was beneficial to fine dust capture; 3) the spray nozzle with an outlet diameter of 0.5 mm was installed in the dust suppression sprayer at the project site, to measure the total dust reduction efficiency and respirable dust reduction efficiency, which were higher than 90% and 80% respectively, and the dust reduction effect was good.
To better guide the selection of nozzles of air-assisted dust suppression sprayer, five sprayer nozzles with different internal structures were collected to carry out a comparative study on the atomization characteristics, and the selected nozzles were used in the project site to test the dust reduction effect. The results showed that:1) the Spray and Taige nozzles had larger atomization angle, meeting the needs of large area dust reduction, and were suitable for most dust suppression sprayers; 2) under the same water supply pressure, the droplet diameter of the Spray nozzle with an outlet diameter of 0.5 mm was much smaller than that of other nozzles, and its installation in the dust suppression sprayer was beneficial to fine dust capture; 3) the spray nozzle with an outlet diameter of 0.5 mm was installed in the dust suppression sprayer at the project site, to measure the total dust reduction efficiency and respirable dust reduction efficiency, which were higher than 90% and 80% respectively, and the dust reduction effect was good.
2022, 40(5): 178-183,140.
doi: 10.13205/j.hjgc.202205026
Abstract:
Through the combination of big data preprocessing and object-oriented Petri theory, the mathematical model was applied to the environmental big data preprocessing, and the error analysis between the simulation data and the preprocessed online monitoring data was carried out. Based on OPMSE simulation platform, the error threshold range was set. If it exceeded the threshold range, the internet of things was used for early warning to preprocess the data again. The monitoring data could be output to the calculation and analysis module of the integrated environmental management and control platform for subsequent processing after passing the verification, which realized the real-time verification and early warning of the data collection and analysis process of an integrated environmental management and control platform.
Through the combination of big data preprocessing and object-oriented Petri theory, the mathematical model was applied to the environmental big data preprocessing, and the error analysis between the simulation data and the preprocessed online monitoring data was carried out. Based on OPMSE simulation platform, the error threshold range was set. If it exceeded the threshold range, the internet of things was used for early warning to preprocess the data again. The monitoring data could be output to the calculation and analysis module of the integrated environmental management and control platform for subsequent processing after passing the verification, which realized the real-time verification and early warning of the data collection and analysis process of an integrated environmental management and control platform.
2022, 40(5): 184-192,236.
doi: 10.13205/j.hjgc.202205027
Abstract:
The large-scale construction activities and operation of urban metro consumes huge quantity of resources and energy, which has gradually become a major contribution to the environmental impact of the urban transportation sector. Taking Shenzhen as a case, this paper evaluated the resource and energy consumption intensities of metros' construction stage by using life cycle assessment(LCA) method. The global warming potential(GWP), measured by CO2 equivalent, was chosen as the impact indicator to build a carbon emission calculation model of metro's construction phase. Meanwhile, scenarios-based analysis was adopted to predict the emission reduction potentials. The results showed that the cumulative carbon emission caused by the construction of metro lines and stations in Shenzhen city reached approximately 27.3 million tons of CO2e by 2020, of which 72% from the stations' construction, and 28% from the tunnels construction. Specifically, the carbon emission intensities of shield tunnels and stations were approximately 13000 tons CO2 e/km and 371.2 tons CO2 e/100 m2, respectively. In addition, the carbon emission reduction rate of metros' construction reached 8.5% annually, or an accumulative amount of 5.08 million tons from 2021 to 2035, if green technologies adopted, such as the use of recycled concrete and recycled steel. And that can probably significantly alleviate the carbon emission of metros' construction.
The large-scale construction activities and operation of urban metro consumes huge quantity of resources and energy, which has gradually become a major contribution to the environmental impact of the urban transportation sector. Taking Shenzhen as a case, this paper evaluated the resource and energy consumption intensities of metros' construction stage by using life cycle assessment(LCA) method. The global warming potential(GWP), measured by CO2 equivalent, was chosen as the impact indicator to build a carbon emission calculation model of metro's construction phase. Meanwhile, scenarios-based analysis was adopted to predict the emission reduction potentials. The results showed that the cumulative carbon emission caused by the construction of metro lines and stations in Shenzhen city reached approximately 27.3 million tons of CO2e by 2020, of which 72% from the stations' construction, and 28% from the tunnels construction. Specifically, the carbon emission intensities of shield tunnels and stations were approximately 13000 tons CO2 e/km and 371.2 tons CO2 e/100 m2, respectively. In addition, the carbon emission reduction rate of metros' construction reached 8.5% annually, or an accumulative amount of 5.08 million tons from 2021 to 2035, if green technologies adopted, such as the use of recycled concrete and recycled steel. And that can probably significantly alleviate the carbon emission of metros' construction.
2022, 40(5): 193-196,250.
doi: 10.13205/j.hjgc.202205028
Abstract:
Riparian zone of the clear water gallery(RZCWG) is the most important ecological protective screen for intercepting terrestrial contaminants. Therefore, to evaluate the suitability of RZCWG, it should not only evaluate the results of RZCWG for intercepting exogenous contaminants, but also reflect the technical features of intercepting exogenous contaminants for RZCWG and the comprehensive effect on the environment, society and economics. Based on the analytic hierarchy process, this paper selected 18 evaluation indexes to construct the suitability evaluation system for the riparian zone of project of the clear water gallery and evaluate the suitability of the landward buffer zone pollution interception project of the clear water gallery of Guangming Dayan River. The evaluation results indicated that the evaluated river was in a very suitable state of intercepting exogenous contaminants, in which 62.5% sections were in a very suitable state and 37.5% sections were in a suitable state. The evaluation method for RZCWG based on AHP could integrate the function management of riparian zone, vegetation and ecological reconstruction, land utilization, waterfront planning and design of the project evaluation of RZCWG, and provide support for the implementation of RZCWG projects.
Riparian zone of the clear water gallery(RZCWG) is the most important ecological protective screen for intercepting terrestrial contaminants. Therefore, to evaluate the suitability of RZCWG, it should not only evaluate the results of RZCWG for intercepting exogenous contaminants, but also reflect the technical features of intercepting exogenous contaminants for RZCWG and the comprehensive effect on the environment, society and economics. Based on the analytic hierarchy process, this paper selected 18 evaluation indexes to construct the suitability evaluation system for the riparian zone of project of the clear water gallery and evaluate the suitability of the landward buffer zone pollution interception project of the clear water gallery of Guangming Dayan River. The evaluation results indicated that the evaluated river was in a very suitable state of intercepting exogenous contaminants, in which 62.5% sections were in a very suitable state and 37.5% sections were in a suitable state. The evaluation method for RZCWG based on AHP could integrate the function management of riparian zone, vegetation and ecological reconstruction, land utilization, waterfront planning and design of the project evaluation of RZCWG, and provide support for the implementation of RZCWG projects.
2022, 40(5): 197-204,217.
doi: 10.13205/j.hjgc.202205029
Abstract:
Numerical simulation plays an important role in groundwater in-situ chemical remediation. Based on the physical and chemical reactions occurring in the remediation procedure, the relevant governing equations were analyzed, including soil equilibrium, continuity of fluid phases, and mass transport. Several common pieces of software for groundwater in-situ chemical remediation were introduced and compared. The effect of soil deformation on groundwater flow and mass transport was highlighted and the problems for current numerical simulation were discussed. Further development in numerical simulation of in-situ chemical remediation was proposed, including coupling among soil deformation, groundwater flow and mass transport, injection of remediation agents and resultant soil deformation and failure and change in permeability, as well as the effect of injection on soil mechanical properties.
Numerical simulation plays an important role in groundwater in-situ chemical remediation. Based on the physical and chemical reactions occurring in the remediation procedure, the relevant governing equations were analyzed, including soil equilibrium, continuity of fluid phases, and mass transport. Several common pieces of software for groundwater in-situ chemical remediation were introduced and compared. The effect of soil deformation on groundwater flow and mass transport was highlighted and the problems for current numerical simulation were discussed. Further development in numerical simulation of in-situ chemical remediation was proposed, including coupling among soil deformation, groundwater flow and mass transport, injection of remediation agents and resultant soil deformation and failure and change in permeability, as well as the effect of injection on soil mechanical properties.
RELEASE OF MICROPLASTICS FROM PLASTIC PRODUCTS AND THEIR ENVIRONMENTAL TRANSPORT BEHAVIORS: A REVIEW
2022, 40(5): 205-217.
doi: 10.13205/j.hjgc.202205030
Abstract:
The poor management and disposal of plastic products are the key factors leading to microplastics pollution. Microplastics adsorbs various pollutants in the environment, and easily be ingested and enriched by macroalgae, animals, plants and other organisms, possessing a huge environmental risk. The cities, as the main producer and consumer of plastic products, is an important source of microplastic pollution. Plastic products will be affected by various environmental factors, such as temperature, light, mechanical force, hydraulic scouring, etc., resulting in ageing, cracking, peeling and migrating to the natural environment, endangering humans, animals, plants and so on. It is very critical to understand the release behavior of microplastics from plastic products and their migration mechanism in environmental media, for assessing the risk of urban microplastic pollution. The release behavior of microplastics from household goods, garbage and urban facility were reviewed. The migration mechanisms of microplastics in water, quartz sand and soil media were described, providing references for the prevention, control and purification of microplastics. In the future, the impact of environmental factors on the release and migration of microplastics in the urban plastic facility, and the interaction with pollutants in the urban water environment should be further studied.
The poor management and disposal of plastic products are the key factors leading to microplastics pollution. Microplastics adsorbs various pollutants in the environment, and easily be ingested and enriched by macroalgae, animals, plants and other organisms, possessing a huge environmental risk. The cities, as the main producer and consumer of plastic products, is an important source of microplastic pollution. Plastic products will be affected by various environmental factors, such as temperature, light, mechanical force, hydraulic scouring, etc., resulting in ageing, cracking, peeling and migrating to the natural environment, endangering humans, animals, plants and so on. It is very critical to understand the release behavior of microplastics from plastic products and their migration mechanism in environmental media, for assessing the risk of urban microplastic pollution. The release behavior of microplastics from household goods, garbage and urban facility were reviewed. The migration mechanisms of microplastics in water, quartz sand and soil media were described, providing references for the prevention, control and purification of microplastics. In the future, the impact of environmental factors on the release and migration of microplastics in the urban plastic facility, and the interaction with pollutants in the urban water environment should be further studied.
2022, 40(5): 218-226.
doi: 10.13205/j.hjgc.202205031
Abstract:
Huge amounts of sludge are produced in wastewater treatment, and the treatment and disposal of sewage sludge had become a rising challenge for the wastewater plant. Anaerobic digestion is a traditional method for sewage sludge treatment, which has some shortages. Recent research showed that thermal-alkaline pretreatment could enhance the anaerobic digestion of sewage sludge. In this study, the research progress of thermal-alkaline pretreatment of sludge was thoroughly reviewed, including the mechanism of thermal-alkaline pretreatment, the impact of thermal-alkaline pretreatment on the sludge properties and anaerobic digestion and the influencing factors. And the feasibility of thermal-alkaline pretreatment for enhancing anaerobic digestion of sewage sludge was discussed through energy consumption analysis. Finally, the enhancement of thermal-alkaline pretreatment on anaerobic digestion and its prospects and problems were also discussed.
Huge amounts of sludge are produced in wastewater treatment, and the treatment and disposal of sewage sludge had become a rising challenge for the wastewater plant. Anaerobic digestion is a traditional method for sewage sludge treatment, which has some shortages. Recent research showed that thermal-alkaline pretreatment could enhance the anaerobic digestion of sewage sludge. In this study, the research progress of thermal-alkaline pretreatment of sludge was thoroughly reviewed, including the mechanism of thermal-alkaline pretreatment, the impact of thermal-alkaline pretreatment on the sludge properties and anaerobic digestion and the influencing factors. And the feasibility of thermal-alkaline pretreatment for enhancing anaerobic digestion of sewage sludge was discussed through energy consumption analysis. Finally, the enhancement of thermal-alkaline pretreatment on anaerobic digestion and its prospects and problems were also discussed.
2022, 40(5): 227-236.
doi: 10.13205/j.hjgc.202205032
Abstract:
The mass production of chloropyridine herbicides and their wide application in agricultural production and daily life causes them to be continuously detected in wastewater, drinking water, and other environments, and possesses potential hazards to the ecological environment and human health. How to effectively remove chloropyridine contaminants becomes a focus in the field of water pollution control. In terms of compound structure, the breaking of the C-Cl bond is critical to the degradation of chloropyridine compounds. This work provides an overview of research advances in the removal of chloropyridine contaminants and challenges. Related strategies including adsorption, advanced oxidation methods, catalytic hydrogenation and coupling technologies, etc., have demonstrated an excellent pollutant detoxification effect. The mechanisms, process parameters, and major challenges of pollutants removal are discussed in detail. The adsorption method faces problems such as difficulty in degrading pollutants, developing new adsorbent materials, and adsorbent regeneration. Advanced oxidation technology has a high pollutant mineralization rate, but its disadvantages are low oxidation efficiency and high operating cost. The catalytic hydrogenation degraded pollutants directionally, but the degradation is still incomplete. Biological treatment technology is economical and effective, but the removal rate of pollutants still needs to be improved. The studies indicate that due to the refractory characteristics of chloropyridine contaminants, it is efficient to remove the pollutants with independent treatment technology. The combination of multiple treatment methods is a feasible strategy for the efficient removal of pollutants. Researches on the transformation technologies and mechanisms of chloropyridine in the environment have important theoretical and practical guiding value for the efficient detoxification and degradation of risk pollutants.
The mass production of chloropyridine herbicides and their wide application in agricultural production and daily life causes them to be continuously detected in wastewater, drinking water, and other environments, and possesses potential hazards to the ecological environment and human health. How to effectively remove chloropyridine contaminants becomes a focus in the field of water pollution control. In terms of compound structure, the breaking of the C-Cl bond is critical to the degradation of chloropyridine compounds. This work provides an overview of research advances in the removal of chloropyridine contaminants and challenges. Related strategies including adsorption, advanced oxidation methods, catalytic hydrogenation and coupling technologies, etc., have demonstrated an excellent pollutant detoxification effect. The mechanisms, process parameters, and major challenges of pollutants removal are discussed in detail. The adsorption method faces problems such as difficulty in degrading pollutants, developing new adsorbent materials, and adsorbent regeneration. Advanced oxidation technology has a high pollutant mineralization rate, but its disadvantages are low oxidation efficiency and high operating cost. The catalytic hydrogenation degraded pollutants directionally, but the degradation is still incomplete. Biological treatment technology is economical and effective, but the removal rate of pollutants still needs to be improved. The studies indicate that due to the refractory characteristics of chloropyridine contaminants, it is efficient to remove the pollutants with independent treatment technology. The combination of multiple treatment methods is a feasible strategy for the efficient removal of pollutants. Researches on the transformation technologies and mechanisms of chloropyridine in the environment have important theoretical and practical guiding value for the efficient detoxification and degradation of risk pollutants.
2022, 40(5): 237-243.
doi: 10.13205/j.hjgc.202205033
Abstract:
Municipal solid waste incineration fly ash is rich in dioxins, heavy metals and soluble salts, and belongs to hazardous waste and needs harmless treatment. But in waste incineration industry in China, laying heavy emphasis on flue gas and ignoring fly ash is a prevalent problem, and becomes a bottleneck of the development of waste incineration at present. This paper reviewes the generation, physicochemical properties and disposal techniques of fly ash incineration. Three mainstream fly ash treatment methods and their technical difficulties in application, including chelating stable coupling landfill, water washing desalting coupling cement kiln co-treatment and thermal treatment were introduced emphatically. This paper can provide technical references for the harmless treatment of waste incineration fly ash.
Municipal solid waste incineration fly ash is rich in dioxins, heavy metals and soluble salts, and belongs to hazardous waste and needs harmless treatment. But in waste incineration industry in China, laying heavy emphasis on flue gas and ignoring fly ash is a prevalent problem, and becomes a bottleneck of the development of waste incineration at present. This paper reviewes the generation, physicochemical properties and disposal techniques of fly ash incineration. Three mainstream fly ash treatment methods and their technical difficulties in application, including chelating stable coupling landfill, water washing desalting coupling cement kiln co-treatment and thermal treatment were introduced emphatically. This paper can provide technical references for the harmless treatment of waste incineration fly ash.
2022, 40(5): 244-250.
doi: 10.13205/j.hjgc.202205034
Abstract:
China is a major producer of steroidal APIs. The fermentation residue produced during the production of steroidal drugs by microbial transformation is a very valuable resource. However, there are still a small amount of toxic steroid residues in the fermentation residue, which is listed as national hazardous waste by the Ministry of Environmental Protection in China. At present, there are still some difficulties in the treatment of steroid drug fermentation residue, which has severely restricted the healthy development of pharmaceutical enterprises. For this reason, many researchers have conducted extensive research on the harmlessness and resource utilization of the residue. This paper starts with the source, pollution property and management requirements of steroid drug fermentation residue, and reviews its current research status and latest progress in the harmless and resource utilization, including pretreatment technologies such as hydrothermal treatment, alkali heat treatment and microwave treatment, resource utilization technologies such as fuel, fertilization and materialization, incineration, etc. The feasibility and operability of different treatment and disposal technologies were comprehensively analyzed, and finally the future research directions in this field were prospected.
China is a major producer of steroidal APIs. The fermentation residue produced during the production of steroidal drugs by microbial transformation is a very valuable resource. However, there are still a small amount of toxic steroid residues in the fermentation residue, which is listed as national hazardous waste by the Ministry of Environmental Protection in China. At present, there are still some difficulties in the treatment of steroid drug fermentation residue, which has severely restricted the healthy development of pharmaceutical enterprises. For this reason, many researchers have conducted extensive research on the harmlessness and resource utilization of the residue. This paper starts with the source, pollution property and management requirements of steroid drug fermentation residue, and reviews its current research status and latest progress in the harmless and resource utilization, including pretreatment technologies such as hydrothermal treatment, alkali heat treatment and microwave treatment, resource utilization technologies such as fuel, fertilization and materialization, incineration, etc. The feasibility and operability of different treatment and disposal technologies were comprehensively analyzed, and finally the future research directions in this field were prospected.
