The completely autotrophic nitrogen-removal over nitrite (CANON) process has merits in energy saving and consumption reducing, thus being considered as an attractive alternative over the common denitrification technology. In this study, the effects of three common heavy metals (Cu2+, Zn2+ and Mn2+) in wastewater to the CANON process were evaluated comprehensively. A central composite design with response surface methodology was utilized to investigate the joint effect of these three metal ions on the nitrogen removal performance of CANON process. In accordance with the determined optimal dosage in batch tests, four bioreactors were established with different amounts of heavy metal dosage in long-term operation, which determined the optimal concentrations for Cu2+, Zn2+ and Mn2+ to be 0.25, 0.81 and 1.00 mg/L, respectively. However, the optimal dosing level determined in batch tests showed no promotion during long-term experiment. This indicated that the actual concentration of heavy metals in bioreactors during long-term operation could be higher than expectation, leading to the difference between short-term tests and long-term experiment. The distribution of metal ions revealed that Mn2+ was mainly absorbed in anammox bacteria cells while Cu2+ and Zn2+ were mostly identified inside AOB cells. Moreover, the addition of heavy metals consistently showed positive effects for the relative abundance of AOB, while only a low level of dosage could promote the abundance of anammox bacteria. Furthermore, a mathematical model was established to simulate the CANON system considering the impacts of heavy metals, which was calibrated and validated using independent dataset in this study.

One‐stage partial nitritation/anammox (PN/A) has been proposed as a sustainable method for removing nitrogen from various wastewater. However, the activities of ammonium‐oxidizing bacteria (AOB) and anammox bacteria are often inhibited by the exposure to salinity, thereby hindering their wide application in treating industrial wastewater with high salinity. This study reports that the addition of glycine betaine (GB), which is a compatible solute, could alleviate the inhibitory effects of salinity on both AOB and anammox, thereby improving nitrogen removal performance in a one‐stage PN/A system. Short‐term tests showed that with an addition of GB higher than 1 mM, the activity of AOB and anammox under salinity of 30 g/L could be increased by at least 45% and 51%, respectively. The half‐inhibitory concentration of AOB and anammox rose with increasing GB concentration, with 1 mM GB being the optimal cost‐effective dosage. Long‐term experiments also demonstrated that 1 mM GB addition could enhance nitrogen removal performance and shorten recovery time by 42.9% under a salinity stress of 30 g/L. Collectively, GB addition was found to be a feasible and effective strategy to the counteract adverse effects of salinity on PN/A process.

Partial nitritation-Anammox (PN/A) process has been recognized as a sustainable process for biological nitrogen removal. Although various antibiotics have been ubiquitously detected in influent of wastewater treatment plants, little is known whether functional microorganisms in the PN/A process are capable of biodegrading antibiotics. This study aimed to investigate simultaneous nitrogen and antibiotic removal in a lab-scale one-stage PN/A system treating synthetic wastewater containing a widely-used antibiotic, sulfadiazine (SDZ). Results showed that maximum total nitrogen (TN) removal efficiency of 86.1% and SDZ removal efficiency of 95.1% could be achieved when treating 5 mg/L SDZ under DO conditions of 0.5–0.6 mg/L. Compared to anammox bacteria, ammonia-oxidizing bacteria (AOB) made a major contribution to SDZ degradation through their cometabolic pathway. A strong correlation between amoA gene and SDZ removal efficiency was found (p < 0.01). In addition, the degradation products of SDZ did not exhibit any inhibitory effects on Escherichia coli. The findings suggest that it is promising to apply the PN/A process to simultaneously remove antibiotics and nitrogen from contaminated wastewater.

Channel is important for the wireless communication system. The channel in high-speed railway is rapid time-variation and non-stationary. This papers discusses the channel characteristic in open space scenario, and defines 4 patterns. Furthermore a channel pattern recognition algorithm is proposed using k-nearest neighbor method. Simulation results show that the proposed method performs well with high accuracy and robust.

The susceptibility of the completely autotrophic nitrogen removal over nitrite (CANON) process to high salinity limits its widespread application. The addition of glycine betaine (GB), a type of compatible solutes that could resist osmotic stress, could be an effective strategy to enhance the salt tolerance ability of aerobic and anaerobic ammonium oxidizing bacteria (AOB and anammox bacteria) involved in the CANON process. This study aims to make use of mathematical modeling to systematically investigate the effects of salt and GB addition on the activities of AOB and anammox bacteria and the treatment performance of the CANON process. To this end, a series of dedicated batch tests and long-term experiments for the CANON process with salt and GB additions were conducted and the data was used to calibrate and validate the model established to consider the relationships between salt and GB concentrations and bacterial growth in the CANON process. The calibrated/validated CANON process model was then applied to simulate the long-term impacts of GB addition concentration and sludge retention time (SRT) on the CANON process. The results showed that 1 mM GB addition and a SRT of 50 days would be sufficient to protect AOB and anammox bacteria under the high salinity (30 g/L NaCl) conditions studied and therefore reduce the time needed to recover the treatment performance of the CANON process from exposure to salt inhibition by 35%-40%. (C) 2020 Elsevier Ltd. All rights reserved.

A single-stage anaerobic ammonium oxidation (ANAMMOX) process with an integrated biofilm–activated sludge system was carried out in a laboratory-scale flow-through reactor (volume = 57.6 L) to treat pharmaceutical wastewater containing chlortetracycline. Partial nitrification was successfully achieved after 48 days of treatment with a nitrite accumulation of 70%. The activity of ammonia oxidizing bacteria (AOB) decreased when the chemical oxygen demand (COD) concentration of the influent was 3000 mg/L. When switching to the single-stage ANAMMOX operation, (T = 32–34 °C, DO = 0.4–0.8 mg/L, pH = 8.0–8.5), the total nitrogen (TN) removal loading rate and efficiency were 1.0 kg/m3/d and 75.2%, respectively, when the ammonium concentration of the influent was 287 ± 146 mg/L for 73 days. The findings of this study imply that single-stage ANAMMOX can achieve high nitrogen removal rates and effectively treat pharmaceutical wastewater with high concentrations of COD (1000 mg/L) and ammonium.

Nitrification process has been reported to be capable of degrading various pharmaceuticals due to the cometabolism of ammonia-oxidizing bacteria (AOB). The membrane aerated biofilm reactor (MABR) is an emerging configuration in wastewater treatment with advantages of high nitrification rate and low energy consumption. However, there are very few studies investigating the degradation of antibiotics at environmentally relevant levels in nitrifying MABR systems. In this study, the removal of two widely used antibiotics, cephalexin (CFX) and sulfadiazine (SDZ), was evaluated in two independent MABRs with nitrifying biofilms. The impacts of CFX and SDZ exposure on the nitrification performance and microbial community structure within biofilms were also investigated. The results showed that nitrifying biofilms were very efficient in removing CFX (94.6%) and SDZ (75.4%) with an initial concentration of 100 μg/L when hydraulic retention time (HRT) was 4 h in the reactors. When HRT decreased from 4 h to 3 h, the removal rates of CFX and SDZ increased significantly from 23.4 ± 1.0 μg/(L·h) and 18.7 ± 1.1 μg/(L·h), respectively, to 27.7 ± 1.3 μg/(L·h) (p＜0.01) and 20.8 ± 2.4 μg/(L·h) (p＜0.05), while the removal efficiencies decreased to 86.0% and 61.5%, respectively. Despite the exposure to CFX and SDZ, the nitrification performance was not affected, and microbial community structure within biofilms also remained relatively stable. This study shows that nitrifying MABR process is a promising option for the efficient removal of antibiotics from domestic wastewater.

The widespread popularity of high-speed railways (HSRs) urges a critical demand on high-data-rate railway communication services for both train operation and passenger experience. To satisfy the ever-increasing requirements, future HSR communication systems, such as long-term evolution for railway (LTE-R), fifth generation (5G) on HSR, and 5G for railway (5G-R), and corresponding transmission technologies, e.g., mobile relay, coordinated multipoint, massive multiple-input multiple-output (MIMO), and millimeter-wave (mmWave), have recently attracted much attention. Radio channel modeling is the foundation of design and evaluation of wireless systems and transmission technologies. This paper focuses on a survey of channel modeling for the future HSR communication systems. The significant requirements of future HSR channel models are highlighted, and recent advances in the HSR channel modeling are reviewed. Finally, potential research directions for future HSR channel modeling are outlined.

高速铁路的快速发展使得高速铁路无线信道特性的研究成为热点,但高速铁路信道测量的不易性也使目前的研究工作仍存在不足之处.以北京—天津(京津)城际高速铁路无线信道的具体环境为基础,在平原、车站、城郊3个典型的高速铁路环境中,从两方面深入剖析高速铁路信道的传播特性.一方面,通过莱斯K因子、时延扩展、到达角以及功率角度谱等信道参数,研究高速铁路信道的小尺度衰落特性;另一方面,把以功率相关性为基础的稳态间隔作为特征参数来刻画高速铁路信道的非平稳特性,并基于有限状态的马尔科夫链模型,分析高铁信道多径传播的时变特性.

This paper focuses on the analysis of propagation characteristics for train-ground communication (TGC) systems in tunnel scenarios at both low frequency and millimeter-wave (mmWave) bands, based on ray-tracing (RT) simulation. The material parameters in the RT simulation are calibrated by measurement data collected in realistic tunnel environments. A practical three dimension (3D) tunnel TGC environment considering the existence of train cars is established, which is further divided into three kinds of scenarios, involving the direct coverage, relay coverage, and in-train coverage scenarios. Both large-scale and small-scale propagation characteristics, such as path loss and root mean square delay spread, are analyzed for the three tunnel TGC scenarios. The obtained results can provide useful information for the design of future fifth-generation (5G) tunnel TGC systems.

Fourteen polybrominated diphenyl ether (PBDE) congeners were measured in water, suspended particulate matter (SPM), and sediment samples collected from the entire expanse of the Yellow River in dry and wet seasons. Higher concentrations of PBDEs were found in the middle and lower reaches of the river compared with those in the upper reaches, ascribed to the relatively developed and urbanized cities located in the areas near the middle and lower reaches. The PBDE concentrations in the samples collected during the dry season were lower than those in the samples collected during the wet season because of thaw and rainfall. The dominant congener, with a contribution of 44.6-90.3%, was BDE-209, which originated from the residual of commercial deca-BDE. Three groups of congeners in all the samples showed good correlations with the coefficient ranging from 0.662 to 0.999 (p < 0.01), indicating common sources and similar environmental behaviors. Regression analysis suggested that the local industrial product (IP) and population density (PD) were good indicators of PBDEs in the water and sediment of the Yellow River.

The short- and long-term effects of chlortetracycline (CTC) on the nitritation- anaerobic ammonium oxidation (anammox) process were evaluated. The half maximal inhibitory concentration of CTC in the batch tests of the nitritation-anammox process was 278.91mg/L at an exposure time of 12hr. The long-term effects of CTC on the process were examined in a continuous-flow nitritation-anammox reactor. Within 14days, the nitrogen removal rate significantly decreased from 0.61 to 0.25kgN/m3/day with 60 mg/L CTC in the influent. The performance suppressed by CTC barely recovered, even after CTC was removed from the influent. Furthermore, the inhibition of CTC also reduced the relative abundance of ammonium oxidizing bacteria (AOB) and anaerobic ammonium oxidizing bacteria (AnAOB) in the reactor, resulting in both a decreased amount of and an imbalance between AOB and AnAOB. When fresh anammox sludge was reseeded into the nitritation-anammox reactor, the nitrogen removal rate recovered to 0.09 ± 0.03 kg N/m3/day.

Combined contact oxidation and step-feed A/O process were used to treat caffeine production wastewater.The pilot-plant results showed good effects on caffeine production wastewater treatment.Effluent with residual contents of below 300 mg/L (removal rate above 85％),30 mg/L (removal rate above 90％) for COD and NH~-N respectively were obtained.The process had strong resistance to the load capacity of inflow,and could treat the high salinity and high organic nitrogen wastewater with good economic benefits.

This study provided a deep insight into the impacts of trace elements (Mn2+, Zn2+ and Cu2+) on nitritation-anammox process. For short-term exposure, all the three elements could improve the nitrogen removal rate (NRR) and the optimal concentrations were 2.0 mg/L, 2.0 mg/L and 0.5 mg/L for Mn2+, Zn2+ and Cu2+, respectively. Accordingly, the NRRs were enhanced 54.62%, 45.93% and 44.09%. The long-term experiments were carried out in lab-scale sequencing batch reactors. The surprising results showed that only Mn2+ addition could enhance the long-term nitritation-anammox process, and the NRR increased from 0.35 ± 0.01 kg N/m3/d (control, no extra trace element addition) to 0.49 ± 0.03 kg N/m3/d. Vice versa, the amendment of Zn2+ reduced the NRR to 0.28 ± 0.02 kg N/m3/d, and Cu2+ had no significant effect on the NRR (0.36 ± 0.01 kg N/m3/d). From the analysis of microbial community structure, it was explained by the increasing abundance of anaerobic ammonium oxidizing bacteria (AnAOB) only in Mn2+ treatment, whereas Zn2+ predominantly promoted ammonium oxidizing bacteria (AOB). Additionally, the majority of Mn2+ was identified inside AnAOB cells, and Zn2+ and Cu2+ were mainly located in AOB. Our results indicated the synergistic effects of trace elements on nitritation-anammox, both short-term encouraging activities of AnAOB and long-term altering microbial community structure. This work implies the importance of trace elements addition in nitritation-anammox process.

The effect of gas phase conditions on the performance of anaerobic ammonium oxidation (ANAMMOX) bacteria under short-term preservation was studied. Under the conditions of normal temperature (14±0.5)℃ and low temperature (4±0.5)℃, ANAMMOX bacteria were preserved in the four gas phase conditions (13393mg/m3 NO, 1339mg/m3 NO, nitrogen and air) for 28days and the recovery experiments of ANAMMOX bacteria preserved under normal temperature condition was studied. The results showed that the activities of the ANAMMOX bacteria preserved in 13393mg/m3 NO and nitrogen conditions were higher than that of the bacteria preserved in the air at the corresponding temperature. The retention rates of ANAMMOX bacteria were 23.40%, 86.22%, 61.54% and 46.47%, respectively,under the four kinds of preservation (normal temperature condition), However, Under low temperature conditions, the retention rates were 36.53%, 47.12%, 53.53% and 42.95%, respectively; The results demonstrated that preservation in oxygen-free environment was beneficial to maintain color and settleability of bacteria while biomass decreased and in high concentrations of NO Can reduce the loss of biomass during preservation. The results of the recovery experiments showed that the distribution of each stage during the recovery process was various in different preservation mode. The adaptation period of bacteria preserved in air was 6cycles while in nitrogen was 2 cycles.

Hydrazine is an important intermediate for anaerobic ammonium oxidation (anammox), in which ammonium and nitrite are converted to nitrogen gas. Hydrazine addition is known to improve the nitrogen removal capacity in anammox-based processes. However, the underlying mechanism remains unknown. This study investigated the effects of hydrazine addition on conversion performance for normal anammox substrates (ammonium, nitrite and nitrate) using batch experiments with various combinations of nitrogenous as substrates for the anammox bacteria in the presence or absence of hydrazine. Hydrazine addition improved specific anammox activity (SAA) by 42%, of which 5% was attributed to increased ammonium removal by strengthening anammox, 25% to acceleration of nitrite degradation by the bioreaction where exogenous hydrazine was reacted with nitrite to generate azide, and 12% to reducing nitrate production rate through selective inhibition of nitrite-nitrate oxidoreductase (NXR) activity by generating azide. A model in which hydrazine addition enhances the nitrogen removal capacity in an anammox system was established, which can provide theoretical guidance for engineering applications of anammox with trace hydrazine addition.

介绍了北方某化学合成类制药厂废水处理系统的处理工艺流程、主要构筑物构成及设计参数，通过对该制药厂废水处理系统进行水质调研，分析评价了该废水处理系统的水质指标，系统对COD、T OC、N H3-N、T P的平均去除效率分别为98.8％、99.4％、84.3％、94.3％，出水水质多项指标可达《化学合成类制药工业水污染物排放标准》（GB 21904-2008）。

介绍了内蒙古某抗生素废水处理厂的处理工艺流程、处理单元类型及其详细设计参数,通过对该污水处理厂半年内运行效果的调研,分析评价该污水处理系统的处理效果及出水指标;该水厂工艺流程对COD、TOC、氨氮、总氮、总磷、BOD和急性毒性的平均去除率分别为96.52％、95.83％、50.24％、55.20％、62.05％、98.52％和99.14％,COD、氨氮、总氮、总磷出水水质分别为477、438、556.7和7.69 mg/L,达到排放到城区下水道要求,园区内所有废水汇集到园区污水处理厂进行集中深度处理达标后排放水体.通过对该水厂工艺的介绍和水质分析,为我国抗生素生产企业面临的废水处理工艺类型选择及工程改造升级提供一定参考.