[Reactivation Performance of Nitrosation Flocculent Sludge After Long-term Storage]

In order to explore the nitrogen removal performance of nitrosation flocculent sludge subject to long-term storage, nitrosation flocculent sludge which had been stored at 4℃ for ten months was inoculated in a continuous stirred tank reactor (CSTR) to investigate its activity recovery performance. MiSeq high throughput sequencing technology was also employed to analyze the structure of the microbial community before and after reactivation. Results showed that, under DO control of DO 0.4-0.8 mg·L^-1, pH value of about 8 and temperature of (30±1)℃, the sludge could be reactivated in 15 days. Both the removal efficiency of ammonia nitrogen and the accumulation ratio of nitrite nitrogen were higher than 90%. The color of the sludge quickly changed from grey at early inoculation to brown, while the sludge volume index (SVI) quickly decreased and both mixed liquor volatile suspended solids (MLVSS)/mixed liquor suspended solids (MLSS) and extracellular polymer substances (EPS) significantly increased. With the recovery of nitrosation performance, anaerobic and heterotrophic bacteria were washed out, the relative abundance of ammomia-oxidizing bacteria such as Nitrosomonas significantly increased, while the growth of nitrite-oxidizing bacteria such as Nitrospria was selectively inhibited. Nitrosation flocculent sludge could be inoculated after long-term storage to achieve rapid start-up of partial nitrification and allow practical application of partial nitrification processes.

[Feasibility of Sulfur-based Autotrophic Denitrification of Photovoltaic Wastewater Containing High Fluorine]

Effect of different influent F^- concentrations on nitrogen removal efficiency of sulfur-based autotrophic denitrification was researched at room temperature(20-25℃) using domesticated biofilm reactor to explore the feasibility of sulfur-based autotrophic denitrification of photovoltaic wastewater containing high fluorine. The results indicated that when the influent F^- concentration was in the range of 0-700 mg·L^-1, the nitrogen removal efficiency promoted with rising influent F^- concentration. The maximum TN removal rate of 1.0 kg·(m³·d)^-1 was attained with the influent F^- concentration was 700 mg·L^-1. When the influent F^- concentration increased to 700-900 mg·L^-1, the removal rate of TN reached a stable level at 0.81-0.87 kg·(m³·d)^-1 after short-term domestication. When the influent F^- concentration was above 900 mg·L^-1, the removal efficiency of reactor lowered with rising influent F^- concentration. The minimum TN removal rate was 0.4-0.5 kg·(m³·d)^-1. Photovoltaic wastewater was used as the influent of the reactor. After 50 d operation, the reactor gained steady denitrification efficiency. With the influent NO₃^--N concentration of 390-420 mg·L^-1, F^- concentration of 800 mg·L^-1, and HRT of 8.8 h, the maximum TN removal rate of 1.1 kg·(m³·d)^-1 was attained. The effluent TN concentration was 15-25 mg·L^-1, which met the standard of sewage discharge. Costs of treating photovoltaic wastewater by disposing conventional denitrification and sulfur-based autotrophic denitrification were 2.468 Yuan·t^-1 and 2.0728 Yuan·t^-1, respectively. Compared with conventional denitrification, the sulfur-based autotrophic denitrification could save more costs.

[Effect of Element Sulfur Particle Size and Type of the Reactor on Start-up of Sulfur-based Autotrophic Denitrification Reactor]

The effect of element sulfur particle size and type of the reactor on sulfur autotrophic denitrification reactor start-up was researched at room temperature(19-24℃) by using sulfur autotrophic denitrification bio-membrane reactor and anaerobic sludge bed biofilm reactor and inoculating anaerobic sludge. The research indicated that after 65 d operation, the bio-membrane reactor gained steady denitrification efficiency. With an influent NO₃^--N of 150 mg·L^-1, and an HRT of 3.3 h, the removal efficiencies of NO₃^--N and TN were 91% and 77%, and the removal rate of TN was 0.67-0.83 kg·(m³·d)^-1. The increase of volumetric loading rate of NO₃^--N and production of nitrogen gas led to the floating of sludge in the anaerobic sludge bed biofilm reactor. With an influent NO₃^--N of 185 mg·L^-1 and an HRT of 3.3 h, the maximum removal rate of NO₃^--N of 1.1 kg·(m³·d)^-1 was attained in anaerobic sludge bed biofilm reactor. But the increase of effluent NO₃^--N and NO₂^--N lowered the quality of effluent water seriously, and the floating of sludge affected the steady operation of the anaerobic sludge bed biofilm reactor. Sulfur particles with particle size of 0.8 mm and 3.0 mm were used as electron donors for start-up of two batch reactors. The experiment results indicated that the reactor which used sulfur particle size of 0.8 mm attained higher removal efficiency of NO₃^--N and TN, and its effluent accumulated less NO₂^--N compared with the reactor which used particle size of 3.0 mm.

[A review on the treatment of spastic cerebral palsy with selective posterior rhizotomy]

OBJECTIVE

To inquire the indications, contraindications, and operative methods of the treatment of spastic cerebral palsy with selective posterior rhizotomy (SPR), and to improve the therapeutic results and decrease the incidence rate of complications.

METHODS

The documents about SPR were extensively consulted, and the mechanisms, indications, contraindications, operative methods, muscular tension changes and complications after operation were reviewed.

RESULTS

With the methods of SPR, I alpha fibers of afferent nerve were selectively amputated, reflex circle of spinal cord was locked, and the muscular tension was decreased, so myospasm was removed. The results after operation and incidence rate of complications were closely related to the indications. The therapeutic results were better when the percent of spinal nerve rhizotomy was less than 50%.

CONCLUSION

It is a good method for the treatment of spastic cerebral palsy.

[The shunt for portal hypertension in children]

Ten children with portal hypertension were treated with shunt operations. Among them, 9 were extrahepatic and one was intrahepatic lesion. The follow-up for 1-14 years showed: (1) In the 3 patients treated with splenopneumopexy, hemorrhage from the esophageal varices were controlled and portopulmonary shunt was demonstrated by Doppler ultrasound and radionuclide; (2) In the 6 patients treated with mesocaval shunt, 3 were non-recurrent bleeding and 2 died of recurrent bleeding or other disease respectively; (3) In one child with hepatic cirrhosis (11 year old) treated by splenorenal shunt, non-recurrent bleeding occurred. The authors suggest the portopulmonary shunt by splenopneumopexy is safe and effective for the portal hypertension of children.