[Effects of Cold Acclimation on the Activity of Autotrophic Nitrogen Removal in Granular Sludge and Its Bacterial Population Structure].

Cold acclimation is an effective approach for improving the nitrogen removal performance and operational stability of partial nitritation/ANAMMOX (PN/A) combined processes at low temperatures. To explore the specific effects of cold acclimation on the characteristics of sludge, differentiations in temperature sensitivity, granular morphology, composition of extracellular polymer substance (EPS), and bacterial community structure between PN/A granular sludges cultivated at medium-high temperature (30℃) and acclimated to low temperature (15℃) were investigated in this study. The results of reaction thermodynamics showed that the nitrogen removal performance of the granules acclimated to low temperature (G) was significantly higher than that of those cultivated at medium-high temperature (G) under the low temperature (10-20℃), and the apparent activation energy () of total inorganic nitrogen removal for the former was decreased by 28.

[Performance and Microbial Characteristics of Ammonium-limited and Nitrite-limited ANAMMOX Systems].

The performance and microbial characteristics of ammonium-limited and nitrite-limited ANAMMOX reactors were studied in two continuously stirred tank reactors. The influent TN concentrations were controlled below 50 mg·L. The hydraulic retention time and water temperature were maintained at 2.

[Start-up and Optimization of Denitrifying Phosphorus Removal in ABR-MBR Coupling Process].

The feasibility of the denitrifying phosphorus removal process in the ABR-MBR system with no sludge reflux and high concentration of seeding activated sludge (25 g ·L, in MLSS) in the ABR was investigated. The characteristics of the microbial community in the denitrifying phosphorus removal compartment were also evaluated. The denitrifying phosphorus removal function was achieved by gradually increasing the reflux ratio () from 0% to 200%.

[Characteristics of Organics Transformation and Sludge Morphology in an ABR for Sewage Treatment with Different HRTs].

The characteristics of organics transformation and sludge morphology of in an ABR(anaerobic baffled reactor) for sewage treatment with different HRTs were investigated based on reactor performance, particle size distribution, and scanning electron microscopy (SEM). Results showed that the COD removal rate was stably maintained above 90.0% when the HRT decreased from 15 h to 4 h.

[Realization Process of Nitritation and Changes in Sludge Characteristics in Granular Sludge Reactor for Low Strength Sewage Treatment].

The realization process of nitritation was studied in a CSTR reactor seeding with nitrification granular sludge to treat low ammonia sewage. During the operation period, the physical and chemical properties, the spatial distribution of functional microbes, and the activity of the granular sludge were also investigated to elaborate the main factors for the stability of nitritation. The results showed that nitritation can be successfully achieved and maintained by the cooperative controlling of nitrogen loading rate (NLR) and dissolved oxygen (DO) levels, and the nitrite accumulation rate was over 80%.

[Impact of Hydraulic Retention Time on Performance of Partial Nitrification Granular Sludge in Continuous Stirred-Tank Reactor].

The effects of different hydraulic retention time (HRT) on short-cut nitrification granular sludge were studied in a continuous stirred-tank reactor (CSTR) by maintaining stable influent ammonia nitrogen load. Particle size distribution, extracellular polymeric substances (EPS), and functional bacterial kinetics were analyzed. The morphology of granular sludge, the performance of the CSTR, and the activity of functional microorganisms were investigated.

[Rapid Achievement of Nitrifying Micro-granular Sludge and Its Nitritation Function].

The rapid achievement of nitrifying micro-granular sludge and its nitritation function was studied in a continuously operated internal-loop airlift reactor seeding with floccular sludge. Results showed that the sludge micro-granulation was almost realized within three weeks by gradually reducing the hydraulic retention time from 5 h to 2.5 h.

[Comparison of the Microbial Community Structure in Nitrifying Processes Operating with Different Dissolved Oxygen Concentrations].

High-throughput sequencing was applied to analyze the microbial community structure of nitrifying reactors operated with different dissolved oxygen (DO) levels. Results showed that the nitrifying reactor (R) run with low DO (0.2-0.

[Start-up and Stable Operation of CANON Coupled with Denitrifying Phosphorus Removal].

A process coupled completely autotrophic nitrogen removal over nitrite (CANON)with denitrifying phosphorus removal in a modified anaerobic baffled reactor (ABR) coupled with a membrane bioreactor (MBR), inoculated with ordinary activated sludge, was proposed for treating artificial wastewater with ammonia 200 mg·L and COD/TN=1. This experiment studied the start-up of the process and its nitrogen and phosphorus removal efficiency by controlling the recycle ratio and increasing it from 50% to 200% step by step, with a temperature of (25±1)℃ and pH of 7.5±0.

[Effect of Sludge Retention Time and pH on the Denitrifying Phosphorus Removal Process].

In this work, the effects of the sludge retention time (SRT, 35, 25, or 15 d) and pH (7.5, 8.0, 8.

[High-rate Nitrogen Removal in a Two-stage Partial Nitritation-ANAMMOX Process Under Mainstream Conditions].

A two-stage partial nitritation (PN)-ANAMMOX process was successfully carried out for low-strength NH-N (50 mg·L) wastewater treatment at ambient/low temperatures. The results show that an average total nitrogen removal rate and removal efficiency above 0.6 kg·(m·d)and 80% could be maintained, respectively, at temperatures between 20℃ and 14℃.

[Start-up and Stable Operation of ABR-MBR Denitrifying Phosphorus Removal Process].

The nitrogen and phosphorus removal characteristics during the start-up and the long-term operational stability of an anaerobic/anoxic (A/A) ABR coupled aerobic MBR system treating low C/N domestic wastewater were investigated. The results showed that the denitrifying phosphorus bacteria (DPBs) were successfully enriched within 46 d by controlling the nitrate recycling ratio (increasing from 150% to 300%), with a temperature of 30℃±2℃, volume loading rate of 0.8 kg·(m·d) and sludge reflux ratio of 80% in the ABR, sludge retention time (SRT) in the denitrifying phosphorus removal functional area of 25 d, and the dissolved oxygen (DO) of 1-2 mg·L in the MBR.

[Research on change process of nitrosation granular sludge in continuous stirred-tank reactor].

In order to investigate the effect of different types of reactors on the nitrosation granular sludge, a continuous stirred-tank reactor (CSTR) was studied, using mature nitrosation granular sludge cultivated in sequencing batch reactor (SBR) as seed sludge. Results indicated that the change of reactor type and influent mode could induce part of granules to lose stability with gradual decrease in sludge settling ability during the initial period of operation. However, the flocs in CSTR achieved fast granulation in the following reactor operation.

[Effects of anaerobic feeding period on nitrifying granular].

Alternating anoxic/oxic conditions have profound effects on both ammonium (AOB) and nitrite (NOB) oxidizing bacteria. In this study the influence of alternating anoxic/oxic condition on nitrifying granules was evaluated in a laboratory-scale column-type sequencing batch reactor (SBR). The anoxic phase was extended from 10 min to 120 min by increasing the anaerobic feeding time.

[Alteration of anterior chamber and angle structure in eyes with primary angle closure after laser peripheral iridotomy].

Objective: To quantitatively evaluate the long-term changes in anterior segment morphology by using ultrasound biomicroscopy (UBM) after laser peripheral iridotomy (LPI) in eyes with primary angle closure (PAC).

Methods: This was a clinical case series study. A total of 54 eyes with PAC of 31 consecutive patients were enrolled.

Laser peripheral iridotomy with and without iridoplasty for primary angle-closure glaucoma: 1-year results of a randomized pilot study.

Purpose: To compare the efficacy and safety of laser peripheral iridotomy with or without laser peripheral iridoplasty in the treatment of eyes with synechial primary angle-closure or primary angle-closure glaucoma.

Design: Randomized, controlled clinical trial.

Methods: Consecutive patients older than 40 years with synechial primary angle-closure or primary angle closure glaucoma were recruited.