[Role of Borate and Phosphate Buffers in the Degradation of Organic Compounds in a PMS/Co2+ System: Influencing Factors and Mechanisms].

Peroxymonosulfate(PMS)-based advanced oxidation processes were widely used for the degradation of organic pollutants. Electron-rich azo dye Acid Orange 7(AO7) was selected as the target organic matter in this work. The differences, influencing factors, efficiency, and mechanisms of a PMS/Co2+ homogeneous system in the degradation of organic pollutants with two different buffers of boric acid(Lewis acid) and phosphoric acid(Bronstede acid) were investigated. The k value of AO7 degradation in the PMS/Co2+ homogeneous system with phosphate buffer was greater than that with borate buffer, but the degradation percentage during the first 10 seconds of the reaction was lower in the former case. These differences were affected by buffer concentration, the PMS and Co2+ dosages, and pH. In the phosphate buffer, ·OH or SO4-· contributed to organic degradation in the PMS/Co2+ system, while in the borate buffer, the nonradical pathway(1O2) made a critical contribution to the removal of organics. This study provides a reference for the application of different types of buffers in the homogeneous catalysis of PMS.

Effects of sodium-glucose cotransporter 2 inhibitors on cardiovascular outcomes in elderly patients with comorbid coronary heart disease and diabetes mellitus.

OBJECTIVE: To investigate the effects of sodium-glucose cotransporter 2 inhibitors (SGLT2i) on cardiovascular outcomes in elderly Chinese patients with comorbid coronary heart disease (CHD) and type 2 diabetes mellitus (T2DM). METHODS: A retrospective cohort study was conducted on 501 elderly inpatients (≥ 60 years) with comorbid CHD/T2DM in Department of Cardiovascular Medicine and Endocrinology, Chinese PLA General Hospital from January 2018 to December 2019. These patients were divided into two groups according to the administration of SGLT2i. All the demographic characteristics and clinical data were collected. Cardiovascular outcomes, including all-cause mortality, major adverse cardiovascular events (MACE), and hospitalization for heart failure (HHF), were followed up. RESULTS: In the cohort, there were 167 patients in the SGLT2i group and 334 patients in the control group. In the efficacy analyses, the incidence of MACE was lower in the SGLT2i group than in the control group: 3.6% vs. 9.3% (P = 0.022). A lower risk of MACE was observed in the SGLT2i group [hazard ratio (HR) = 0.40, 95% CI: 0.17-0.95]. There was no significant difference in the incidence of all-cause mortality or HHF between the two groups. No significant difference of HR was observed for all-cause mortality (HR = 0.41, 95% CI: 0.12-1.41) or HHF (HR = 0.58, 95% CI: 0.12-2.81). CONCLUSIONS: SGLT2i treatment exhibited benefits for elderly patients with comorbid CHD/T2DM with a lower risk for MACE.

[Nitrogen Removal Performance and Nitrogen/Carbon Balance of Oligotrophic Aerobic Denitrifiers].

Due to the problems of low nitrogen removal efficiency and unclear electron transfer during biological denitrification treatment of an oligotrophic drinking water reservoir, the nitrogen removal characteristics, environmental adaptability, and electron transfer during denitrification were systematically studied using the aerobic denitrifier Acinetobacter junii ZMF5, which has efficient nitrogen removal ability. The results showed that:① Strain ZMF5 exhibited efficient heterotrophic nitrification and aerobic denitrification ability, with an ammonia removal rate of 0.211 mg·(L·h)-1 and a nitrate removal rate of 0.236 mg·(L·h)-1, and the nitrification intermediates were not accumulated during the treatment process. ② According to analysis of the nitrogen removal efficiency and growth kinetics of strain ZMF5, the strain can effectively utilize different types of carbon source, and show efficient nitrogen removal efficiency under the conditions of low C/N, low pH, and low temperature. ③ Analysis of nitrogen balance showed that carboxylate compound, compared with carbohydrate, could promote the process of aerobic denitrification and change the nitrogen removal pathway of strain ZMF5, i.e., 38.81% of nitrogen was transformed into gas, higher than the 29.81% for assimilation. ④ Analysis of carbon balance indicated that most carbon sources were used as electron donors in the denitrification process, but fewer electrons were used for nitrate reduction, and with respect to different carbon sources, electron transfer to the nitrate respiratory chain was regulated by different reduction potentials, electron donor abundance, and molecular weight. Acinetobacter junii ZMF5 could be used to control nitrogen pollution in drinking water reservoirs.

[Start-up and Operation of Biofilter Coupled Nitrification and CANON for the Removal of Iron, Manganese and Ammonia Nitrogen].

A pilot-scale bio-filter coupled nitrification and CANON was started up to remove iron, manganese and ammonia nitrogen from groundwater in a plant, and the main removal route of ammonia nitrogen was analyzed. The experiment showed that the bio-filter could be started up successfully and achieved stable operation after 164 days of culture development. The value of △NH4+-N/△NO3--N was 1.49, and the oxidation and removal of Fe(Ⅱ), Mn(Ⅱ), and NH4+-N were (9.87±1.17), (2.25±0.06), and (1.51±0.06) mg·L-1, respectively. The calculation based on the quantitative relationship between nitrogen conservation and dissolved oxygen (DO) measurement indicated that the contribution of CANON to NH4+-N removal was 33.48%-38.87%, and the average ratio of ammonia nitrogen removal amount to DO was 1:3.79-1:3.94. The removal ratio of ammonia nitrogen was lower with lower temperature.

[Effect of Intermediate-Setting Aeration on the CANON Granular Sludge Process in the AUSB Reactor].

The impact of different aeration positions on startup and operation of the continuous flow CANON granular sludge process was considered by inoculating flocculent ANAMMOX activated sludge at room temperature (25±1)℃ in two sets of AUSB reactors. The aeration unit of R1 was installed 0.3 m above the base, while the aeration unit of R2 was set at the bottom. R1 and R2 successfully developed the granule CANON process on the 43rd d and 56th d, respectively. The mean particle diameter of R1 granular sludge increased to 214.79 µm, and the eigenvalue (△NO3--N/△TN) was maintained at 0.128; whereas, the granular sludge size of R2 rose to 205.27 µm with an eigenvalue maintained at 0.129. The nitrogen loading rate (NLR) was gradually increased in the low ammonia-nitrogen (90 mg·L-1) wastewater within R1 and R2. This was more beneficial in R1, resulting in the persistent growth of CANON granular sludge and the enhancement of the systematic nitrogen removal rate (NRR). The average particle diameter of R1 rose to 507.46 µm in 88 d, while NRR reached up to 0.277 kg·(m3·d)-1. R2 granule sludge particle size was 467.72 µm after 108 d of cultivation, and achieved a 0.243 kg·(m3·d)-1NRR, which was 87.73% of that in R1. During the course of steady operation, the specific anoxic/aerobic mode of R1 effectively suppressed NOB microbial activity, the eigenvalue remained around 0.127±0.003, and the NRR of R1 was maintained at about (0.262±0.019) kg·(m3·d)-1. However, NOB was propagated observably in the continuously aerobic R2, whose eigenvalue rose to 0.136±0.004, while NRR was merely (0.231±0.015) kg·(m3·d)-1 after 125 d of long-term operation. During the whole experiment period, the intermediate-setting aerated AUSB accelerated the formation of CANON granular sludge evolving from flocculent ANAMMOX sludge, and better nitrogen removal performance and operational stability were achieved.

[Effect of Organic Carbon Source on Start-up and Operation of the CANON Granular Sludge Process].

The effect of organic carbon on the start-up and operation of the CANON granular sludge process was investigated in two SBR reactors with different strategies:gradually increased organic carbon concentration (R1) and without organic carbon (R2). The results showed that adding 50 mg·L-1 organic carbon accelerated the start-up of the CANON granular sludge process. R1 and R2 were started up in 23 d and 32 d, respectively. Moreover, the appropriate organic carbon enhanced the activity of AOB, AnAOB, and denitrification, increasing the ammonia removal rates and total nitrogen (TN) removal rates. The maximum ammonia removal rates and total nitrogen removal rates of R1 were 92% and 88%, respectively. The maximum ammonia removal rates and total nitrogen removal rates of R2 were 89% and 80%, respectively. Further tests showed that excessive organic carbon concentration decreased the activity of AOB and AnAOB and reduced the removal efficiency of ammonia and total nitrogen. Adding organic carbon promoted denitrification activity and increased nitrogen removal efficiency.

[Arsenic(â ¤) Removal by Granular Adsorbents Made from Backwashing Residuals from Biofilters for Iron and Manganese Removal].

Granular adsorbents for arsenic removal (GA) made from the backwashing residuals from iron and manganese removal biofilters for groundwater were characterized and examined as an arsenate sorbent. The GA were characterized by SEM-EDS microscopy, X-ray diffraction (XRD), and BET surface area measurement. The results showed that the GA had rough surfaces, developed pores, and were mainly amorphous, with small fractions of crystalline quartz and hematite. The surface area of the GA, which consists of many mesopores, was 43.8 m2·g-1. The kinetic studies revealed that arsenate adsorption on the GA was described by a pseudo-second-order kinetic equation, and the Freundlich isotherm equation fit the arsenate adsorption well (R2=0.994). The maximum adsorption capacity calculated by the Langmuir isotherm equation for As(Ⅴ) was 5.05 mg·g-1. Further studies showed that the GA operated well for As(Ⅴ) removal over a broad range in pH from 1.1 to 9.5. The coexistence of HCO3- and SO42- had no great influence on arsenic adsorption, while the H2PO4- and SiO32- showed negative effects. The GA can be regenerated well, and 82% of the original adsorption capacity was maintained after three regeneration cycles.

[Removal of High Concentration of Iron, Manganese and Ammonia Nitrogen from Low Temperature Groundwater Using Single Bio-filter].

A pilot-scale bio-filter was constructed for the removal of high concentrations of iron (TFe 9.0-12.0 mg·L-1, Fe(Ⅱ) 6.5-8.0 mg·L-1), manganese (1.9-2.1 mg·L-1), and ammonia nitrogen (1.4-1.7 mg·L-1) simultaneously from low temperature (5-6℃) groundwater in a plant. The results showed that iron was removed at the beginning of the bio-filter start-up, and manganese and ammonia nitrogen were removed on day 72 and day 75, respectively. The start-up period was influenced by the culture temperature and the raw water quality. For higher filtration rates, the removal of manganese was lower. When the filtration rate was more than 1.0 m·h-1, the maximum removal of manganese was about 3.0 mg·L-1. Manganese was the limiting factor for the increase of filtration rate, and the maximum filtration rate of the single bio-filter was 4.5 m·h-1. When the filtration rate was less than 6.0 m·h-1, the removal of ammonia nitrogen was about 1.5 mg·L-1, which was not affected by the filtration rate. Dissolved oxygen (DO) deficiency led to failure with the removal of more ammonia nitrogen. The required thickness of the bio-filter required for purification increased as the concentration of manganese and ammonia nitrogen increased when DO was sufficient. The removed iron, manganese, and ammonia nitrogen move to the depth of the filter layer, and there will be "manganese dissolution" when the filtration rate is increased. Iron and ammonia nitrogen in the filter layer can be oxidized and removed simultaneously. Manganese is oxidized and removed after the iron and ammonia nitrogen. The effective oxidation and removal section of manganese, iron, and ammonia nitrogen are obviously graded.

Plasma Homocysteine is a Predictive Factor for Arterial Stiffness: A Community-Based 4.8-Year Prospective Study.

The authors investigated whether plasma total homocysteine (tHcy) is a predictive factor for arterial stiffness (carotid-femoral pulse wave velocity [cf-PWV] and carotid-radial PWV) in 1447 patients from a 4.8-year prospective study in Beijing, People's Republic of China. Baseline tHcy showed a significant relationship with follow-up cf-PWV (ß=0.817, P=.015) in a multivariable linear regression analysis. A stepwise logistic regression model showed that baseline levels of tHcy were significantly associated with follow-up cf-PWV in the adjusted models. Furthermore, the baseline tHcy levels showed a significant association with increases in cf-PWV. There was no association between the change in tHcy and increase in PWV. The present study clearly demonstrated an association between tHcy levels and arterial stiffness, indicating that tHcy is an independent predictive factor for arterial stiffness in a community-based population.