Denitrification performance and bacterial flora analysis of immobilized denitrification filler in industrial wastewater.

The study aimed at evaluating the nitrogen removal performance of the immobilized denitrification filler, and the influence of shock loading on the high-rate denitrification process. A pilot scale reactor was operated for treatment of aniline production wastewater. The nitrogen removal activity significantly increased in the continuous feed experiments, reaching 5.23 kg N m-3 day-1 on day 31 (30 °C) at Hydraulic Retention Time (HRT) = 10 h. In the impact experiment, the denitrification filler was inhibited by Free Nitrite Acid (FNA) when the shock load flowed 1.5 times into the bioreactor and recovered after the load was restored for 20 h. The high-throughput results demonstrated that the dominant position of the denitrifying bacteria further enhanced in a micro toxic and high-salinity environment, providing a basis for the dominance of the composite denitrifying bacteria and the efficacy of the immobilization technology.

[Research on Denitrification Performance of Enhanced Secondary Effluent by Embedded Denitrification Filler and Pilot Application].

The use of an embedded broad-spectrum high-efficiency denitrification filler to treat secondary effluent from municipal wastewater treatment plants can effectively reduce total nitrogen (TN) concentration of the effluent. This study consists of two parts. The D1 stage studies the adaptability of the secondary effluent based on the embedded denitrification, removal effect of total nitrogen, stable working conditions, and backwashing conditions; In the D2 stage, the change in the nitrogen removal performance of the filler under the condition of a year-long stable operation was studied. The variation in the microbial population before and after the operation of the embedded packing was studied by high-throughput sequencing and real-time quantitative PCR detecting system real-time (qPCR). In this research, the embedded denitrification filler had a water temperature of (24±1)℃, pH:7.1, hydraulic retention time (HRT):1 h, and filling rate:10%. Sodium acetate was added to ensure stable operation for seven days. Under adequate carbon source conditions, the filler can adapt to the quality of secondary effluent water and achieve effluent TN<5mg·L-1. By comparing and studying the effect of different HRT on the removal of filler TN, it is concluded that HRT is 30 min and the filling rate is 10%. After a year of stable operation under 7.2 m3·d-1influent conditions, the TN removal rate can reach 90.42%, and the total nitrogen in the effluent can be stabilized below 5 mg·L-1. In comparison with the backwashing effect, the backwashing strength was 5.2 L·(m2·s)-1, and the cycle is three days long. High-throughput sequencing and real-time quantitative PCR analysis results show that the abundance and copy number of denitrifying functional genus in the filler before and after the operation exhibited significant changes, which indicated that the bacteria could achieve good self-growth under embedding conditions.

[Study on the rotary angle, plain radiographs and CT appearance in unilateral locked facet of cervical spine].

OBJECTIVE: To study the rotary angle and image features, so as to help early diagnosis. METHODS: Four adult cervical spine (C1-T1) specimens were used, including 2 males and 2 females,ranging in age from 28 to 40 years old. X-ray and CT examination were performed before the experiment. C2-C4 and C5-T1 were fixed respectively using self-made clamp. Unilateral locked facet of cervical spine was simulated under the violence of inflection and rotation, in which the muscle contraction was partially simulated, and at last the plain radiographs and CT of unilateral locked facet of cervical spine were analyzed. RESULTS: In unilateral locked facet of cervical spine, the average rotary angle was 19.75 degrees, and average forward shift of vertebral was 3.68 mm. The intervertebral foramina below the injury plane were showed at 0 degrees,10 degrees, 180 degrees,190 degrees; the intervertebral foramina above the injury plane were showed at 150 degrees,160 degrees, 00 degrees, -10 degrees, and the facet was locked or in disorder at the injury plane. The intervertebral foramina at the anterior oblique position was bigger in interlocking side, but it was smaller in the opposite side. CT scan showed rotary spine, the naked facet sign; coronal plane reconstruction showed bilateral asymmetry; sagittal plane reconstruction obviously showed unilateral locked facet. CONCLUSION: X-ray and CT both can independently diagnose unilateral locked facet of cervical spine. CT and three-dimensional reconstruction are more better than X-ray to diagnosing it.