Migration of microorganisms between nitrification-denitrification flocs, anammox biofilms and blank carriers during mainstream anammox start-up.

To solve the shortage of inoculum, the feasibility of establishing simultaneous partial nitrification, anammox, and denitrification (SNAD) reactor through inoculating nitrification-denitrification sludge, anammox biofilm and blank carriers was investigated. Advanced nitrogen removal efficiency of 91.2 ± 3.6 % was achieved. Bacteria related to nitrogen removal and fermentation were enriched in anammox biofilm, blank carriers and flocs, and the abundance of dominant anaerobic ammonia oxidizing bacteria (AnAOB), Candidatus Brocadia, reached 3.4 %, 0.5 % and 0.3 %, respectively. Candidatus Competibacter and Calorithrix became the dominant denitrifying bacteria (DNB) and fermentative bacteria (FB), respectively. The SNAD system was successfully established, and new mature biofilms formed in blank carriers, which could provide inoculum for other anammox processes. Partial nitrification, partial denitrification and aerobic_chemoheterotrophy were existed and facilitated AnAOB enrichment. Microbial correlation networks revealed the cooperation between DNB, FB and AnAOB that promoted nitrogen removal. Overall, the SNAD process was started up through inoculating more accessible inoculum.

Increasing biomass concentration facilitates simultaneous nitrogen removal and sludge reduction under low C/N conditions.

To overcome the issues of limited carbon source and high sludge production in partial denitrification/anammox (PD/A) process, the effects of mixed liquor suspended solids (MLSS) and carbon/nitrogen ratio (C/N) on PD/A were investigated through parallel experiments. Nitrogen removal efficiencies decreased significantly when C/N was reduced (1.5 â†’ 0.75). When MLSS was doubled, the nitrogen removal efficiencies in the two parallel reactors increased from 75.3 %, 72.9 % to 86.9 %, 89.7 %, respectively, and sludge yields decreased obviously. Combining with in-situ test, it was speculated when MLSS increased, fermentation was enhanced, providing substrate for partial denitrification. Thauera, involved in partial denitrification, decreased obviously with reduced C/N, but increased from 9.93 % to 38.16 % when MLSS doubled, which could promote the PD/A process. Terrimonas and Ignavibacterium (fermentative bacteria) increased from 1.26 %, 5.22 % to 6.62 %, 6.30 %, respectively. These results proved that increasing MLSS under low C/N ratios promoted fermentation in PD/A system, facilitating efficient nitrogen removal and sludge reduction.

Synergy between Nitrogen Removal and Fermentation Bacteria Ensured Efficient Nitrogen Removal of a Mainstream Anammox System at Low Temperatures.

Simultaneous partial nitrification, anammox, denitrification, and fermentation (SNADF) is a novel process achieving simultaneous advanced sludge reduction and nitrogen removal. The influence of low temperatures on the SNADF reactor was explored to facilitate the application of mainstream anammox. When temperature decreased from 32 to 16 °C, efficient nitrogen removal was achieved, with a nitrogen removal efficiency of 81.9-94.9%. Microbial community structure analysis indicated that the abundance of Candidatus Brocadia (dominant anaerobic ammonia oxidizing bacteria (AnAOB) in the system) increased from 0.03% to 0.18%. The abundances of Nitrospira and Nitrosomonas increased from 1.6% and 0.16% to 2.5% and 1.63%, respectively, resulting in an increase in the ammonia-oxidizing bacteria (AOB) to nitrite-oxidizing bacteria (NOB) abundance ratio from 0.1 to 0.64. This ensured sufficient nitrite for AnAOB, promoting nitrogen removal. In addition, Candidatus Competibacter, which plays a role in partial denitrification, was the dominant denitrification bacteria (DNB) and provided more nitrite for AnAOB, facilitating AnAOB enrichment. Based on the findings from microbial correlation network analysis, Nitrosomonas (AOB), Thauera, and Haliangium (DNB), and A4b and Saprospiraceae (fermentation bacteria), were center nodes in the networks and therefore essential for the stability of the SNADF system. Moreover, fermentation bacteria, DNB, and AOB had close connections in substrate cooperation and resistance to adverse environments; therefore, they also played important roles in maintaining stable nitrogen removal at low temperatures. This study provided new suggestions for mainstream anammox application.

Bulk Polymerization of Thermoplastic Shape Memory Epoxy Polymer for Recycling Applications.

Conventional epoxy polymers are thermo-set and difficult to recycle and reuse. In this study, a series of linear thermoplastic epoxy polymers (EPx) with shape memory properties were prepared by using a bifunctional monoamine diglycolamine (DGA) as a curing agent and an equivalent amount of bifunctional rigid epoxy resin (E-51) and bifunctional flexible epoxy resin (polypropylenglycol diglycidyl ether, PPGDGE) in a bulk polymerization reaction. The results showed that these samples can fully react under the curing process of, 60 °C/2 h, followed by 80 °C/2 h, followed by 120 °C/2 h. The introduction of different contents of PPGDGE can adjust the Tg of the material to adapt to different environmental requirements, and can significantly increase the fracture strain of the material and improve its micro-phase separation structure. Thus, Rf of the material is close to 100%, and Rr is increased from 87.98% to 97.76%. Importantly, this linear chain structure allows the material to be easily recycled and reprocessed by dissolving or melting, and also means the material shows potential for 3D printing or other thermoplastic remolding.

A novel simultaneous partial nitrification, anammox, denitrification and fermentation process: Enhancing nitrogen removal and sludge reduction in a single reactor.

This study verified the feasibility of simultaneous partial nitrification, anammox, denitrification and fermentation process under intermittent aeration in a single reactor, and explored the impact of dissolved oxygen (DO) on the synergy between fermentation and nitrogen removal. An advanced nitrogen removal efficiency of 92.8 % and a low observed sludge yield of 0.0268-0.1474 kgMLSS/kgCOD were achieved. In-situ test showed that nitrate and ammonium decreased synchronously in the absence of organic matter, indicating the possibility of simultaneous partial denitrification, anammox and fermentation. Additionally, the abundance of functional genes for acetate production was 66,894 hits, while the key genes relevant to methanogenesis were only 348 hits, which suggested that fermentation might stop at the acid-producing stage and promote partial denitrification-anammox reaction, achieving simultaneous sludge reduction and advanced nitrogen removal performance. When DO increased from 0.1-0.3 to 0.4-0.6 mg/L, the nitrogen removal efficiency was increased (63.9 %→92.8 %) while sludge reduction was negatively affected.

Achieving advanced nitrogen removal and excess sludge treatment via single nitritation/anammox-fermentation combined system.

The feasibility of treating wastewater and excess sludge via simultaneous nitritation, anammox, denitrification and fermentation (SNADF) was investigated in three parallel sequencing batch reactors (SBRs). SBR2 and SBR3 received exogenous nitrification-denitrification sludge and thermal hydrolysis sludge, respectively. Nitrogen removal efficiencies of 92.8 ± 5.9%, 94.6 ± 4.1%, 93.4 ± 4.8% were achieved in SBR1, SBR2, and SBR3, respectively (influent ammonium: 56.0-74.0 mg N/L), with low observed sludge yield of 0.02-0.15, -0.06-0.11, -0.17-0.05 kg mixed liquor suspended solids (MLSS)/kg chemical oxygen demand (COD). Anammox bacterial abundances increased from 3.6 × 109 ± 2.8 × 108 to 8.1 × 109 ± 2.3 × 108, 1.5 × 1010 ± 1.1 × 108, and 1.4 × 1010 ± 2.9 × 108 copies/L in SBR1-SBR3, respectively. The abundances of Nitrosomonas, genes (amo, hao) for partial nitrification, and narGHI genes (nitrate â†’ nitrite) in dominant partial denitrifying bacteria (Candidatus Competibacter) were higher in SBR2 and SBR3 than that in SBR1. These results suggested that adding excess sludge promoted sludge reduction, nitrite production and anammox bacterial enrichment. The SNADF system could treat excess sludge, meanwhile, achieve advanced nitrogen removal.

Enhancing nitrite production rate made anammox bacteria have a competitive advantage over nitrite oxidizing bacteria in mainstream anammox system.

Nitrite oxidizing bacteria (NOB) is easy to accumulate in the mainstream anammox process, leading to the decrease of anammox bacterial abundance and deterioration of nitrogen removal. In this study, anammox bacteria was gradually enriched by increasing nitrite production rate under intermittent aeration despite high NOB abundance. With the DO increased from 0.4 to 0.6 mg/L, Nitrosomonas increased from 0.14% to 0.22%, providing more nitrite for anammox bacteria and promoting its enrichment (grew by 77.4%). Adding extra nitrite of 7.14 mg N/(L·h) during the aeration phase to reactor could further increase anammox bacterial abundance by 117.6%, which was higher than the control reactor (40.2%). In contrast, NOB abundance decreased from 1.4 × 1010 to 1.2 × 1010 copies/L. The results suggested that anammox bacteria had a competitive advantage for nitrite over NOB with increasing nitrite production rate. In addition, Thauera and Dechloromonas, which were responsible for reducing nitrate to nitrite, provided additional substrates for anammox bacteria. Overall, this research provides a new idea for mainstream anammox applications. PRACTITIONER POINTS: Inhibiting NOB might be no longer necessary and difficult for mainstream anammox. Anammox bacteria competed for more nitrite with NOB when nitrite production rate increased. Increasing DO from 0.4 to 0.6 mg/L facilitated anammox bacterial growth and nitrogen removal.

Start-up of mainstream anammox process through inoculating nitrification sludge and anammox biofilm: Shift in nitrogen transformation and microorganisms.

The feasibility of starting up mainstream single-stage partial nitrification-anammox (SPNA) system by inoculating nitrification sludge and anammox biofilm was investigated. The SPNA system treating low-strength synthetic wastewater was rapidly started up with TN removal efficiency of 88.5 ± 1.8% and effluent nitrate concentration of 7.2 ± 1.2 mg/L. Both the abundance and maximum activity of nitrite oxidizing bacteria (NOB) in flocs decreased obviously. Interestingly, the abundance of anaerobic ammonium oxidizing bacteria (AnAOB) in flocs increased from 0.213% to 0.346% despite the sludge retention time (SRT) of flocs decreased to 60 days, the AnAOB in biofilm was 0.434%. That meant AnAOB gradually enriched in flocs and accounted for a fairly high proportion. The inhibition of NOB, partial denitrification and increased aerobic_chemoheterotrophy function in flocs might be the main reasons for AnAOB enrichment. The possibility of simultaneous fermentation, partial denitrification and anammox reaction was predicted in biofilm, further improving the stability of the system.

Effect of Docetaxel Combined with Cisplatin Preoperative Neoadjuvant Chemotherapy for Stage III NSCLC.

The aim of this study was to investigate the effect of docetaxel plus cisplatin preoperative neoadjuvant chemotherapy in stage III non-small cell lung cancer (NSCLC). It was an analytical study carried out from May 2013 to May 2017. Eightytwo patients with stage III NSCLC were divided into Group A and B according to a random number table (n=41). Group A received neoadjuvant chemotherapy with docetaxel plus cisplatin before surgery. Group B underwent surgical treatment after preoperative examination. Compared with group B,operation time of group A was shorter (p<0.001); intraoperative blood loss of group A was lower (p<0.001); surgical resection rate and 1-year survival rate in group A were higher (p=0.013, 0.023). This suggested that preoperative neoadjuvant chemotherapy with docetaxel plus cisplatin may improve surgical resection rate, shorten operation time, reduce intraoperative blood loss, and prolong survival of patients.

Multi-vehicle detection with identity awareness using cascade Adaboost and Adaptive Kalman filter for driver assistant system.

Vision-based vehicle detection is an important issue for advanced driver assistance systems. In this paper, we presented an improved multi-vehicle detection and tracking method using cascade Adaboost and Adaptive Kalman filter(AKF) with target identity awareness. A cascade Adaboost classifier using Haar-like features was built for vehicle detection, followed by a more comprehensive verification process which could refine the vehicle hypothesis in terms of both location and dimension. In vehicle tracking, each vehicle was tracked with independent identity by an Adaptive Kalman filter in collaboration with a data association approach. The AKF adaptively adjusted the measurement and process noise covariance through on-line stochastic modelling to compensate the dynamics changes. The data association correctly assigned different detections with tracks using global nearest neighbour(GNN) algorithm while considering the local validation. During tracking, a temporal context based track management was proposed to decide whether to initiate, maintain or terminate the tracks of different objects, thus suppressing the sparse false alarms and compensating the temporary detection failures. Finally, the proposed method was tested on various challenging real roads, and the experimental results showed that the vehicle detection performance was greatly improved with higher accuracy and robustness.