The effects of feed strength, hydraulic residence time （HRT）, and operational temperatures on soluble microbial product （SMP） production were investigated, to gain insights into the production mechanism. A carrier...The effects of feed strength, hydraulic residence time （HRT）, and operational temperatures on soluble microbial product （SMP） production were investigated, to gain insights into the production mechanism. A carrier anaerobic baffled reactor （CABR） treating dilute wastewater was operated under a wide range of operational conditions, namely, feed strengths of 300-600 mg/L, HRTs of 9- 18 h, and temperatures of 10-28℃. Generally, SMP production increased with increasing feed strength and decreasing temperature. At high temperature （28℃）, SMP production increased with decreasing HRT. As the temperature was decreased to 18 and 10℃, the SMP production was at its peak for 12 h HRT. Therefore, temperature could be an important determinant of SMP production along with HRT. A higher SMP to soluble chemical oxygen demand （SCOD） ratio was found at high temperature and long HRT because of complete volatile fatty acid degradation. SMP accounted for 50%-75% of the SCOD in the last chamber of the CABR. As a secondary metabolite, some SMP could be consumed at lower feed strength.展开更多
Objective To examine the effect of hydraulic residence time （HRT） on the performance and stability, to treat dilute wastewater at different operational temperatures in a carrier anaerobic baffled reactor （CABR）, a...Objective To examine the effect of hydraulic residence time （HRT） on the performance and stability, to treat dilute wastewater at different operational temperatures in a carrier anaerobic baffled reactor （CABR）, and hence to gain a deeper insight into microbial responses to hydraulic shocks on the base of the relationships among macroscopic performance, catabolic intermediate, and microcosmic alternation. Methods COD, VFAs, and microbial activity were detected with constant feed strength （300 mg/L） at different HRTs （9-18 h） and temperatures （10℃-28℃） in a CABR. Results The removal efficiencies declined with the decreases of HRTs and temperatures. However, the COD removal load was still higher at short HRT than at long HRT. Devastating reactor performance happened at temperature of 10℃ and at HRT of 9 h. HRTs had effect on the VFAs in the reactor slightly both at high and low temperatures, but the reasons differed from each other. Microbial activity was sensitive to indicate changes of environmental and operational parameters in the reactor. Conclusion The CABR offers to certain extent an application to treat dilute wastewater under a hydraulic-shock at temperatures from 10℃to 28℃.展开更多
The recovery of nickel ions and pure water production from dilute nickel-containing solution was achieved simultaneously only within one process by using electrodeionization(EDI)system.With a 55 mg·L-1 nickel ion...The recovery of nickel ions and pure water production from dilute nickel-containing solution was achieved simultaneously only within one process by using electrodeionization(EDI)system.With a 55 mg·L-1 nickel ions feed solution,the outlet concentration of dilute product was below 0.05 mg·L-1,therefore the nickel rejection was higher than 99.9%,and the dilute product resistivity was in the range of 2.02—2.59 MΩ·cm while the concentration of nickel ions in the concentrate stream could reach as high as 1263 mg·L-1.The feasibility of the EDI operation for the recovery of heavy metal ions together with pure water production from dilute industrial heavy metal wastewater was demonstrated in this study,cleaner production and closed circuit circulation can be realized in some industries such as electroplating.展开更多
In this study,the characteristics and kinetics of substrate degradation in anaerobic baffled reactor(ABR) were investigated by using glucose as dilute organic wastewater.Operation conditions,such as hydraulic residenc...In this study,the characteristics and kinetics of substrate degradation in anaerobic baffled reactor(ABR) were investigated by using glucose as dilute organic wastewater.Operation conditions,such as hydraulic residence time(HRT),sludge concentration and temperature were proved to have effects on the treatment efficiency of ABR through the analysis on the kinetics of substrate degradation.Declining growth rate constant K2 was obtained in a small experimental ABR using glucose as influent,based on the experimental results at different temperatures.According to the analysis of Arrhenius relationship,temperature did not affect K2 greatly.This is one of the reasons why comparatively good treatment efficiency may still be achieved at a lower temperature.In the experiment,activation energy(1.92 ×104 J·mol-1) was also obtained from the Arrhenius equation.展开更多
A type of port with a movable cover is designed to increase initial dilution and prevent sea water and sediments from intruding into outfall systems.Horizontal radial jets pro- duced by this type of port in a current ...A type of port with a movable cover is designed to increase initial dilution and prevent sea water and sediments from intruding into outfall systems.Horizontal radial jets pro- duced by this type of port in a current are investigated experimentally and theoretically.The analysis based on Reynolds'equations and self-similarity hypothesis shows that the maximum ve- locity of radial jets decays with r^(-1.5).The relationships between the width,thickness,average di- lution of a submerged wastefield along flow,and the parameters of the port,jet and ambient are established quantitatively and verified by experiments.It is demonstrated that the dilution of horizontal radial jets is much higher than that of vertical round jets and the surface boil point of the former is much more distant than that of the latter.展开更多
文摘The effects of feed strength, hydraulic residence time （HRT）, and operational temperatures on soluble microbial product （SMP） production were investigated, to gain insights into the production mechanism. A carrier anaerobic baffled reactor （CABR） treating dilute wastewater was operated under a wide range of operational conditions, namely, feed strengths of 300-600 mg/L, HRTs of 9- 18 h, and temperatures of 10-28℃. Generally, SMP production increased with increasing feed strength and decreasing temperature. At high temperature （28℃）, SMP production increased with decreasing HRT. As the temperature was decreased to 18 and 10℃, the SMP production was at its peak for 12 h HRT. Therefore, temperature could be an important determinant of SMP production along with HRT. A higher SMP to soluble chemical oxygen demand （SCOD） ratio was found at high temperature and long HRT because of complete volatile fatty acid degradation. SMP accounted for 50%-75% of the SCOD in the last chamber of the CABR. As a secondary metabolite, some SMP could be consumed at lower feed strength.
基金project supported by the Science and Technology Department of Zhejiang Province (2005C13003).
文摘Objective To examine the effect of hydraulic residence time （HRT） on the performance and stability, to treat dilute wastewater at different operational temperatures in a carrier anaerobic baffled reactor （CABR）, and hence to gain a deeper insight into microbial responses to hydraulic shocks on the base of the relationships among macroscopic performance, catabolic intermediate, and microcosmic alternation. Methods COD, VFAs, and microbial activity were detected with constant feed strength （300 mg/L） at different HRTs （9-18 h） and temperatures （10℃-28℃） in a CABR. Results The removal efficiencies declined with the decreases of HRTs and temperatures. However, the COD removal load was still higher at short HRT than at long HRT. Devastating reactor performance happened at temperature of 10℃ and at HRT of 9 h. HRTs had effect on the VFAs in the reactor slightly both at high and low temperatures, but the reasons differed from each other. Microbial activity was sensitive to indicate changes of environmental and operational parameters in the reactor. Conclusion The CABR offers to certain extent an application to treat dilute wastewater under a hydraulic-shock at temperatures from 10℃to 28℃.
基金supported by National Center for Innovation Research on Circular Economy of Nankai University the Natural Science Foundation of Tianjin (06YFJ MJC04800)
文摘The recovery of nickel ions and pure water production from dilute nickel-containing solution was achieved simultaneously only within one process by using electrodeionization(EDI)system.With a 55 mg·L-1 nickel ions feed solution,the outlet concentration of dilute product was below 0.05 mg·L-1,therefore the nickel rejection was higher than 99.9%,and the dilute product resistivity was in the range of 2.02—2.59 MΩ·cm while the concentration of nickel ions in the concentrate stream could reach as high as 1263 mg·L-1.The feasibility of the EDI operation for the recovery of heavy metal ions together with pure water production from dilute industrial heavy metal wastewater was demonstrated in this study,cleaner production and closed circuit circulation can be realized in some industries such as electroplating.
文摘In this study,the characteristics and kinetics of substrate degradation in anaerobic baffled reactor(ABR) were investigated by using glucose as dilute organic wastewater.Operation conditions,such as hydraulic residence time(HRT),sludge concentration and temperature were proved to have effects on the treatment efficiency of ABR through the analysis on the kinetics of substrate degradation.Declining growth rate constant K2 was obtained in a small experimental ABR using glucose as influent,based on the experimental results at different temperatures.According to the analysis of Arrhenius relationship,temperature did not affect K2 greatly.This is one of the reasons why comparatively good treatment efficiency may still be achieved at a lower temperature.In the experiment,activation energy(1.92 ×104 J·mol-1) was also obtained from the Arrhenius equation.
文摘A type of port with a movable cover is designed to increase initial dilution and prevent sea water and sediments from intruding into outfall systems.Horizontal radial jets pro- duced by this type of port in a current are investigated experimentally and theoretically.The analysis based on Reynolds'equations and self-similarity hypothesis shows that the maximum ve- locity of radial jets decays with r^(-1.5).The relationships between the width,thickness,average di- lution of a submerged wastefield along flow,and the parameters of the port,jet and ambient are established quantitatively and verified by experiments.It is demonstrated that the dilution of horizontal radial jets is much higher than that of vertical round jets and the surface boil point of the former is much more distant than that of the latter.
