The anaerobic-anoxic oxidation ditch(A^(2)/O OD)process is popularly used to eliminate nutrients from domestic wastewater.In order to identify the existence of denitrifying phosphorus removing bacteria(DPB),evaluate t...The anaerobic-anoxic oxidation ditch(A^(2)/O OD)process is popularly used to eliminate nutrients from domestic wastewater.In order to identify the existence of denitrifying phosphorus removing bacteria(DPB),evaluate the contribution of DPB to biological nutrient removal,and enhance the denitrifying phosphorus removal in the A^(2)/O OD process,a pilot-scale A^(2)/O OD plant(375 L)was conducted.At the same time batch tests using sequence batch reactors(12 L and 4 L)were operated to reveal the significance of anoxic phosphorus removal.The results indicated that:The average removal efficiency of COD,NH^(+)_(4),PO^(3–)_(4),and TN were 88.2%,92.6%,87.8%,and 73.1%,respectively,when the steady state of the pilotscale A^(2)/O OD plant was reached during 31–73 d,demonstrating a good denitrifying phosphorus removal performance.Phosphorus uptake took place in the anoxic zone by poly-phosphorus accumulating organisms NO^(-)_(2) could be used as electron receptors in denitrifying phosphorus removal,and the phosphorus uptake rate with NO^(-)_(2) as the electron receptor was higher than that with NO^(–)_(3) when the initial concentration of either NO^(-)_(2) or NO^(–)_(3) was 40 mg/L.展开更多
The effects of mesogen-jacketed liquid crystalline polymer poly(dipropyl vinylterephthalate)(PDPVT) on the mechanical and thermal properties of diglycidyl ether of bisphenol-A(DGEBA) epoxy resin were investigated by i...The effects of mesogen-jacketed liquid crystalline polymer poly(dipropyl vinylterephthalate)(PDPVT) on the mechanical and thermal properties of diglycidyl ether of bisphenol-A(DGEBA) epoxy resin were investigated by impact test, tensile test and thermogravimetric analysis(TGA). The mechanism underlying the enhancement of mechanical properties of epoxy resin was studied using 1D wide-angle X-ray diffraction(WAXD) and scanning electron microscope(SEM). It was found that the mechanical properties of 1 wt%–5 wt% PDPVT/DGEBA composites were significantly improved compared to neat epoxy resin. Especially, the epoxy resin with 3 wt% PDPVT had the greatest increase in mechanical properties, with the impact strength, tensile strength and elongation while breaking increased by 87%, 59% and 174%, respectively. The increased mechanical strength was due to the fact that PDPVT maintained liquid crystalline phase in cured PDPVT/DGEBA composites, which would blunt the crack tip and prevent crack propagation. Moreover, PDPVT had slight effect on the thermal stability properties of epoxy resin.展开更多
基金This work was supported by the National Natural Science Foundation of China—the Abroad Young Scholar Foundation(Grant No.50628808)the National Key Technologies Research and Development Program of China during the 11th Five-year Plan Period(Grant No.2006BAC19B02).
文摘The anaerobic-anoxic oxidation ditch(A^(2)/O OD)process is popularly used to eliminate nutrients from domestic wastewater.In order to identify the existence of denitrifying phosphorus removing bacteria(DPB),evaluate the contribution of DPB to biological nutrient removal,and enhance the denitrifying phosphorus removal in the A^(2)/O OD process,a pilot-scale A^(2)/O OD plant(375 L)was conducted.At the same time batch tests using sequence batch reactors(12 L and 4 L)were operated to reveal the significance of anoxic phosphorus removal.The results indicated that:The average removal efficiency of COD,NH^(+)_(4),PO^(3–)_(4),and TN were 88.2%,92.6%,87.8%,and 73.1%,respectively,when the steady state of the pilotscale A^(2)/O OD plant was reached during 31–73 d,demonstrating a good denitrifying phosphorus removal performance.Phosphorus uptake took place in the anoxic zone by poly-phosphorus accumulating organisms NO^(-)_(2) could be used as electron receptors in denitrifying phosphorus removal,and the phosphorus uptake rate with NO^(-)_(2) as the electron receptor was higher than that with NO^(–)_(3) when the initial concentration of either NO^(-)_(2) or NO^(–)_(3) was 40 mg/L.
基金financially supported by the National Natural Science Foundation of China(51343008)
文摘The effects of mesogen-jacketed liquid crystalline polymer poly(dipropyl vinylterephthalate)(PDPVT) on the mechanical and thermal properties of diglycidyl ether of bisphenol-A(DGEBA) epoxy resin were investigated by impact test, tensile test and thermogravimetric analysis(TGA). The mechanism underlying the enhancement of mechanical properties of epoxy resin was studied using 1D wide-angle X-ray diffraction(WAXD) and scanning electron microscope(SEM). It was found that the mechanical properties of 1 wt%–5 wt% PDPVT/DGEBA composites were significantly improved compared to neat epoxy resin. Especially, the epoxy resin with 3 wt% PDPVT had the greatest increase in mechanical properties, with the impact strength, tensile strength and elongation while breaking increased by 87%, 59% and 174%, respectively. The increased mechanical strength was due to the fact that PDPVT maintained liquid crystalline phase in cured PDPVT/DGEBA composites, which would blunt the crack tip and prevent crack propagation. Moreover, PDPVT had slight effect on the thermal stability properties of epoxy resin.
