Fluid flow and mixing phenomenon have a significant impact on coagulation and flocculation processes. Particles dissipating the turbulent kinetic energy increase the efficiency of collision, grow in size and incorpora...Fluid flow and mixing phenomenon have a significant impact on coagulation and flocculation processes. Particles dissipating the turbulent kinetic energy increase the efficiency of collision, grow in size and incorporate phosphate from the wastewater Only certain flocks can be separated depending on their stability, size, density, etc.. According to the literature the velocity gradient of the flow （G-value） is the main design parameter of the flocculators, but there is a need to take into account at least the flocks age, too. In this paper, it presents a novel approach to determine the efficiency of flocculators using local mean age theory, residence time distribution and dimensional analysis. Calculations were performed for two constructions of cascade reactors---one with small baffles and one without these; hydraulical performance and the achievable conversion were compared. As a result, the flocculator with small baffles proved to be more efficient than the traditional construction.展开更多
Adsorptive recovery of valuable components from industrial wastewater is highly desirable for avoiding resource wastage but remains a challenge.Herein,we develop an efficient continuous adsorption process for recoveri...Adsorptive recovery of valuable components from industrial wastewater is highly desirable for avoiding resource wastage but remains a challenge.Herein,we develop an efficient continuous adsorption process for recovering aromatic compounds in wastewater from styrene monomer and propylene oxide coproduction(SMPO)plant.Based on our insight into the potential of bio-based porous materials for adsorption application,starch-graft-polystyrene(SPS)and aryl-modifiedβ-cyclodextrin(ACD)were prepared,and novel hypercrosslinked porous polymers combined SPS with ACD(HSPS-ACDs)were synthesized through external crosslinking approach.In a binary-component system,the best-performing one HSPS-ACD(H)with high ACD content and large specific surface area possessed superior capacities for the representative aromatic compounds,acetophenone(AP,2.81 mmol·g^(-1))and 1-phenylethanol(1-PE,1.35 mmol·g^(-1))compared with the previously reported materials.Further,the adsorption properties of aromatic compounds on HSPS-ACD(H)were investigated in batch mode.For practical application,continuous adsorption experiments were conducted in a HSPS-ACD(H)-packed fixed bed,where the target aromatic components in wastewater were effectively retained and further released by elution.Besides showing the reversible adsorption and efficient enrichment effect,the HSPS-ACD(H)-packed fixed bed also maintained great stability in multiple cycles.Moreover,quantum chemical calculations were performed to elucidate the potential mechanism of adsorption of AP and 1-PE onto HSPS-ACD(H).展开更多
This paper reports an approach to estimate the sludge density in a physicochemical treatment of municipal wastewater, experiments considered 4 coagulants (aluminum sulfate SAl, iron sulfate SFe, aluminum polychloride ...This paper reports an approach to estimate the sludge density in a physicochemical treatment of municipal wastewater, experiments considered 4 coagulants (aluminum sulfate SAl, iron sulfate SFe, aluminum polychloride PAX, iron polychloride PIX), and 2 flocculant products (cationic CP and anionic AP polymers). Experimental approach is based on running a set of jar tests at different coagulant concentrations. After the stirring and resting times took place, pH and conductivity were registered finding that SAl and SFe either with or without polymers are the coagulants producing the higher pH drop. Conductivity measures also establish two kind of data since higher conductivity (about 2000 ) was observed for SAl, and PIX, PIX + CP, PIX + AP;otherwise a conductivity about 1300 was observed for SAl + PC, SFe and PAX alone and with CP or AP. Settleable solids (SST) determined with an Imhoff cone were similar for sulfates and polychlorides, but dry sludge (DS) clearly set up two groups the one with higher sludge content corresponds to sulfates group. The quotient of DS divided by the SST provided an estimation of the apparent sludge density, in this way it was observed that higher densities were obtained for sludge from sulfates at lower coagulant concentrations;also sludge from SFe was heavier than the one from SAl. Otherwise, polychlorides produced a lighter sludge in respect to the one obtained with sulfates, and between them the PIX coagulant provided a heavier sludge than the PAX coagulant.展开更多
The influence of the degree of wastewater coagulation-flocculation and supercritical water oxidation (SCWO) methodsisconsidered. The regularities of changes in the composition of the purity of the reagents used and th...The influence of the degree of wastewater coagulation-flocculation and supercritical water oxidation (SCWO) methodsisconsidered. The regularities of changes in the composition of the purity of the reagents used and the parameters of SCWO are established. Based on the results of chromatographic analysis of the effluent after washing the mass rape, it is found that the achievement of the required parameters is achieved by treatment with a combination of coagulation-flocculation method and supercritical water oxidation (SCWO). The necessity of combining techniques is insufficient oxidation in SCWO lignin conducted at T = 400oC and P = 25 MPa, T = 500oC and P = 30 MPa. Effluent treatment of process of styrene and propylene oxide“Nizhnekamskneftekhim”conducted by the SCWO, using an oxidant (H2O2), and without an oxidant showed the possibility of cleaning without the use of an oxidizing agent in the process parameters T = 500oC, P = 30 MPa.展开更多
The effluent from the pulping of E. urophylla by alkali sodium sulfite chemi mechanical process(AS-CMP) was characterized for its biodegradability by photosynthetic bacteria (PSB). Chemical coagulation post treat...The effluent from the pulping of E. urophylla by alkali sodium sulfite chemi mechanical process(AS-CMP) was characterized for its biodegradability by photosynthetic bacteria (PSB). Chemical coagulation post treatment of biotreated wastewater was also studied. One month continuous treatment in the laboratory indicated that the COD Cr , BOD 5 and SS removals in biotreatment stages reached 56%, 83% and 89% respectively, and the CH 2Cl 2 extractives decreased from 10.7 mg/L to 7.7 mg/L. In chemical coagulation post treatment stage, the effects of process conditions, such as coagulant dosage, pH value and the coordinated coagulation flocculation treatment of three kinds of coagulants on coagulation effectiveness were discussed. The optimum operating conditions were given.展开更多
In our previous studies,several papermaking sludge-based flocculants(PSBFs)were synthesized from wood pulp papermaking sludge.The structure-activity relationships of the PSBFs have been investigated in simulated dye w...In our previous studies,several papermaking sludge-based flocculants(PSBFs)were synthesized from wood pulp papermaking sludge.The structure-activity relationships of the PSBFs have been investigated in simulated dye wastewater treatment,but their efficiencies in practical printing and dyeing wastewater(PPDW)treatment are unknown.Herein,an PSBF was prepared,and its performance is discussed in comparison to polyaluminium chloride(PAC)and polyacrylamide(PAM)in PPDW treatment.The PSBF was used in three ways:as an independent flocculant,as a PAC aid,or used to treat the effluent of the PAC system.The results indicated that adding PSBF alone produced similar color and chemical oxygen demand(COD_(Cr))removals as the PAC system alone,but PSBF performed better than PAC when the pH of PPDW was higher than 7.0.Adding PSBF as a PAC aid improved the color,COD_(Cr)and turbidity removals,but the elimination efficiencies were slightly lower than those of the PAC+PAM system.However,when PSBF was used as a flocculant to treat the effluent of the PAC system(PAC→PSBF),the effluent qualities were enhanced.Compared with the PAC system,the color and COD_(Cr)removals of PAC→PSBF system increased by 16.21%and 13.26%,respectively.The excitation and emission matrix fluorescence results indicated that PSBF removed tryptophan-like pollutants more efficiently than PAC.Considering the pH requirements of the subsequent bioreactor treatment in practice,the PAC→PSBF system were also investigated at the PPDW pH level of 7.0.Its maximum removal efficiencies of color,COD_(Cr)and turbidity were 90.17%,32.60%and 82.50%,respectively.展开更多
The use of new food grade polysaccharides (mucilage) obtained from Hibiscus esculentus and Trigonella foenum graceum,commonly called Okra and Fenugreek,respectively,as flocculants was described.These polysaccharides w...The use of new food grade polysaccharides (mucilage) obtained from Hibiscus esculentus and Trigonella foenum graceum,commonly called Okra and Fenugreek,respectively,as flocculants was described.These polysaccharides were used for removal of solids (suspended solids (SS) and total dissolved solids (TDS)) and dyes from real textile effluents and aqueous solutions of different class of synthetic dyes.Influences of varying polysaccharide concentration,contact time and pH on removal of pollutant from the textile...展开更多
To screen multifunctional bacteria for water treatment,a chemical oxygen demand( COD)degradation and flocculation strain S2 A15 was obtained from the offshore sewage outfall at Weihai International Beach. Based on the...To screen multifunctional bacteria for water treatment,a chemical oxygen demand( COD)degradation and flocculation strain S2 A15 was obtained from the offshore sewage outfall at Weihai International Beach. Based on the phylogenetic characteristics,a novel strain was identified as a Planococcus species. Strain S2 A15 was determined to have the ability of flocculation and COD degradation. A series of experiments showed that the strain S2 A15 could be used for the treatment of four types of wastewater,including domestic wastewater( 400 mg/L and 800 mg/L) and high salt domestic wastewater( 400 mg/L and 800 mg/L). Among them,the best effect was exerted by the strain that reduced by 76.9% in domestic wastewater with 400 mg/L COD. The flocculation ratio reached 60.19%. The optimal treatment conditions are also discussed. We confirmed that the strain S2 A15 had salt tolerance and low temperature resistance. The best growth of S2 A15 at salt concentration of 6% and further confirmed that the strain could degrade COD at a low temperature.展开更多
文摘Fluid flow and mixing phenomenon have a significant impact on coagulation and flocculation processes. Particles dissipating the turbulent kinetic energy increase the efficiency of collision, grow in size and incorporate phosphate from the wastewater Only certain flocks can be separated depending on their stability, size, density, etc.. According to the literature the velocity gradient of the flow （G-value） is the main design parameter of the flocculators, but there is a need to take into account at least the flocks age, too. In this paper, it presents a novel approach to determine the efficiency of flocculators using local mean age theory, residence time distribution and dimensional analysis. Calculations were performed for two constructions of cascade reactors---one with small baffles and one without these; hydraulical performance and the achievable conversion were compared. As a result, the flocculator with small baffles proved to be more efficient than the traditional construction.
基金supported by National Natural Science Foundation of China(21868002 and 21961160741)the Natural Science Foundation of Guangxi Province(2018GXNSFAA281206,2020GXNSFGA297001,2020GXNSFAA297044)+2 种基金Dean Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2021Z010)Specific research project of Guangxi for research bases and talents(AD18126005)special funding for‘Guangxi Bagui Scholars’,Guangxi scholarship fund for the middle-aged backbone teachers。
文摘Adsorptive recovery of valuable components from industrial wastewater is highly desirable for avoiding resource wastage but remains a challenge.Herein,we develop an efficient continuous adsorption process for recovering aromatic compounds in wastewater from styrene monomer and propylene oxide coproduction(SMPO)plant.Based on our insight into the potential of bio-based porous materials for adsorption application,starch-graft-polystyrene(SPS)and aryl-modifiedβ-cyclodextrin(ACD)were prepared,and novel hypercrosslinked porous polymers combined SPS with ACD(HSPS-ACDs)were synthesized through external crosslinking approach.In a binary-component system,the best-performing one HSPS-ACD(H)with high ACD content and large specific surface area possessed superior capacities for the representative aromatic compounds,acetophenone(AP,2.81 mmol·g^(-1))and 1-phenylethanol(1-PE,1.35 mmol·g^(-1))compared with the previously reported materials.Further,the adsorption properties of aromatic compounds on HSPS-ACD(H)were investigated in batch mode.For practical application,continuous adsorption experiments were conducted in a HSPS-ACD(H)-packed fixed bed,where the target aromatic components in wastewater were effectively retained and further released by elution.Besides showing the reversible adsorption and efficient enrichment effect,the HSPS-ACD(H)-packed fixed bed also maintained great stability in multiple cycles.Moreover,quantum chemical calculations were performed to elucidate the potential mechanism of adsorption of AP and 1-PE onto HSPS-ACD(H).
文摘This paper reports an approach to estimate the sludge density in a physicochemical treatment of municipal wastewater, experiments considered 4 coagulants (aluminum sulfate SAl, iron sulfate SFe, aluminum polychloride PAX, iron polychloride PIX), and 2 flocculant products (cationic CP and anionic AP polymers). Experimental approach is based on running a set of jar tests at different coagulant concentrations. After the stirring and resting times took place, pH and conductivity were registered finding that SAl and SFe either with or without polymers are the coagulants producing the higher pH drop. Conductivity measures also establish two kind of data since higher conductivity (about 2000 ) was observed for SAl, and PIX, PIX + CP, PIX + AP;otherwise a conductivity about 1300 was observed for SAl + PC, SFe and PAX alone and with CP or AP. Settleable solids (SST) determined with an Imhoff cone were similar for sulfates and polychlorides, but dry sludge (DS) clearly set up two groups the one with higher sludge content corresponds to sulfates group. The quotient of DS divided by the SST provided an estimation of the apparent sludge density, in this way it was observed that higher densities were obtained for sludge from sulfates at lower coagulant concentrations;also sludge from SFe was heavier than the one from SAl. Otherwise, polychlorides produced a lighter sludge in respect to the one obtained with sulfates, and between them the PIX coagulant provided a heavier sludge than the PAX coagulant.
文摘The influence of the degree of wastewater coagulation-flocculation and supercritical water oxidation (SCWO) methodsisconsidered. The regularities of changes in the composition of the purity of the reagents used and the parameters of SCWO are established. Based on the results of chromatographic analysis of the effluent after washing the mass rape, it is found that the achievement of the required parameters is achieved by treatment with a combination of coagulation-flocculation method and supercritical water oxidation (SCWO). The necessity of combining techniques is insufficient oxidation in SCWO lignin conducted at T = 400oC and P = 25 MPa, T = 500oC and P = 30 MPa. Effluent treatment of process of styrene and propylene oxide“Nizhnekamskneftekhim”conducted by the SCWO, using an oxidant (H2O2), and without an oxidant showed the possibility of cleaning without the use of an oxidizing agent in the process parameters T = 500oC, P = 30 MPa.
文摘The effluent from the pulping of E. urophylla by alkali sodium sulfite chemi mechanical process(AS-CMP) was characterized for its biodegradability by photosynthetic bacteria (PSB). Chemical coagulation post treatment of biotreated wastewater was also studied. One month continuous treatment in the laboratory indicated that the COD Cr , BOD 5 and SS removals in biotreatment stages reached 56%, 83% and 89% respectively, and the CH 2Cl 2 extractives decreased from 10.7 mg/L to 7.7 mg/L. In chemical coagulation post treatment stage, the effects of process conditions, such as coagulant dosage, pH value and the coordinated coagulation flocculation treatment of three kinds of coagulants on coagulation effectiveness were discussed. The optimum operating conditions were given.
文摘In our previous studies,several papermaking sludge-based flocculants(PSBFs)were synthesized from wood pulp papermaking sludge.The structure-activity relationships of the PSBFs have been investigated in simulated dye wastewater treatment,but their efficiencies in practical printing and dyeing wastewater(PPDW)treatment are unknown.Herein,an PSBF was prepared,and its performance is discussed in comparison to polyaluminium chloride(PAC)and polyacrylamide(PAM)in PPDW treatment.The PSBF was used in three ways:as an independent flocculant,as a PAC aid,or used to treat the effluent of the PAC system.The results indicated that adding PSBF alone produced similar color and chemical oxygen demand(COD_(Cr))removals as the PAC system alone,but PSBF performed better than PAC when the pH of PPDW was higher than 7.0.Adding PSBF as a PAC aid improved the color,COD_(Cr)and turbidity removals,but the elimination efficiencies were slightly lower than those of the PAC+PAM system.However,when PSBF was used as a flocculant to treat the effluent of the PAC system(PAC→PSBF),the effluent qualities were enhanced.Compared with the PAC system,the color and COD_(Cr)removals of PAC→PSBF system increased by 16.21%and 13.26%,respectively.The excitation and emission matrix fluorescence results indicated that PSBF removed tryptophan-like pollutants more efficiently than PAC.Considering the pH requirements of the subsequent bioreactor treatment in practice,the PAC→PSBF system were also investigated at the PPDW pH level of 7.0.Its maximum removal efficiencies of color,COD_(Cr)and turbidity were 90.17%,32.60%and 82.50%,respectively.
文摘The use of new food grade polysaccharides (mucilage) obtained from Hibiscus esculentus and Trigonella foenum graceum,commonly called Okra and Fenugreek,respectively,as flocculants was described.These polysaccharides were used for removal of solids (suspended solids (SS) and total dissolved solids (TDS)) and dyes from real textile effluents and aqueous solutions of different class of synthetic dyes.Influences of varying polysaccharide concentration,contact time and pH on removal of pollutant from the textile...
基金Sponsored by Foundation for Outstanding Young Scientist in Shandong Province(Grant No.BS2014NY012)China Postdoctoral Science Foundation(Grant No.2015M581456)Weihai Major Science and Technology Projects(Grant No.2015ZD08)
文摘To screen multifunctional bacteria for water treatment,a chemical oxygen demand( COD)degradation and flocculation strain S2 A15 was obtained from the offshore sewage outfall at Weihai International Beach. Based on the phylogenetic characteristics,a novel strain was identified as a Planococcus species. Strain S2 A15 was determined to have the ability of flocculation and COD degradation. A series of experiments showed that the strain S2 A15 could be used for the treatment of four types of wastewater,including domestic wastewater( 400 mg/L and 800 mg/L) and high salt domestic wastewater( 400 mg/L and 800 mg/L). Among them,the best effect was exerted by the strain that reduced by 76.9% in domestic wastewater with 400 mg/L COD. The flocculation ratio reached 60.19%. The optimal treatment conditions are also discussed. We confirmed that the strain S2 A15 had salt tolerance and low temperature resistance. The best growth of S2 A15 at salt concentration of 6% and further confirmed that the strain could degrade COD at a low temperature.
