[Correlation between the phenotypic domains of the UPOINT system and sexual dysfunction in men with chronic prostatitis/chronic pelvic pain syndrome].

OBJECTIVE: To investigate the correlation of the six phenotypic domains of the UPOINT (urinary, psychosocial, organ-specific, infection, neurologic/systemic, and tenderness) system with premature ejaculation (PE) and ED in male patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). METHODS: We collected the clinical data on 453 cases of CP/CPPS from December 2016 to December 2017, including the general information, CP symptoms, sexual life history, intravaginal ejaculatory latency time (IELT), NIH-CPSI, and IIEF-5 scores. We classified the patients according to the UPOINT system. RESULTS: The CP/CPPS patients were aged 32.75 ± 6.85 years, of whom 45.03% (204/453) were diagnosed with ED and 43.27% (196/453) with PE. The positive rates of the six phenotypic domains of the UPOINT system were 68.78% (U), 60.21% (P), 77.45% (O), 20.34% (I), 46.83% (N), and 65.12% (T), respectively. Multivariate logistic regression analysis showed psychosocial (P) abnormality to be an independent risk factor for PE (OR = 4.55, 95% CI: 2.75－8.06, P < 0.05) and ED (OR = 3.35, 95% CI: 2.02－6.25, P < 0.05). CONCLUSIONS: The psychosocial (P) factor in the UPOINT system plays an important role in the pathogenesis of PE and ED in patients with CP/CPPS.

Nutrient release, recovery and removal from waste sludge of a biological nutrient removal system.

The uncontrolled release of nutrients from waste sludge results in nitrogen and phosphorus overloading in wastewater treatment plants when supernatant is returned to the inlet. A controlled release, recovery and removal of nutrient from the waste sludge of a Biological Nutrient Removal system (BNR) are investigated. Results showed that the supernatant was of high mineral salt, high electrical conductivity and poor biodegradability, in addition to high nitrogen and phosphorus concentrations after the waste sludge was hydrolysed through sodium dodecyl sulphate addition. Subsequently, over 91.8% of phosphorus and 10.5% of nitrogen in the supernatants were extracted by the crystallization method under the conditions of 9.5 pH and 400 rpm. The precipitate was mainly struvite according to X-ray diffraction and morphological examination. A multistage anoxic-oxic Moving Bed Biofilm Reactor (MBBR) was then adopted to remove the residual carbon, nitrogen and phosphorus in the supernatant. The MBBR exhibited good performance in simultaneously removing carbon, nitrogen and phosphorus under a short aeration time, which accounted for 31.25% of a cycle. Fluorescence in situ hybridization analysis demonstrated that nitrifiers presented mainly in floc, although higher extracellular polymeric substance content, especially DNA, appeared in the biofilm. Thus, a combination of hydrolysis and precipitation, followed by the MBBR, can complete the nutrient release from the waste sludge of a BNR system, recovers nutrients from the hydrolysed liquor and removes nutrients from leftovers effectively.

Peripheral platelet count is a diagnostic marker for predicting the risk of rapid ejaculation: findings from a pilot study in rats.

Parameters of peripheral blood cell have been shown as the potential predictors of erectile dysfunction (ED). To investigate the clinical significance of hematological parameters for predicting the risk of rapid ejaculation, we established a rat copulatory model on the basis of ejaculation distribution theory. Blood samples from different ejaculatory groups were collected for peripheral blood cell counts and serum serotonin (5-HT) tests. Meanwhile, the relationship between hematological parameters and ejaculatory behaviors was assessed. Final analysis included 11 rapid ejaculators, 10 normal ejaculators, and 10 sluggish ejaculators whose complete data were available. The platelet (PLT) count in rapid ejaculators was significantly lower than that in normal and sluggish ejaculators, whereas the platelet distribution width (PDW) and mean platelet volume (MPV) were significantly greater in rapid ejaculators. Multivariate logistic regression analysis and receiver operating characteristic (ROC) curve analysis showed that the PLT was an independent protective factor for rapid ejaculation. Meanwhile, rapid ejaculators were found to have the lowest serum 5-HT compared to normal and sluggish ejaculators (P < 0.001). Furthermore, there was a positive correlation between the PLT and serum 5-HT (r = 0.662, P < 0.001), indicating that the PLT could indirectly reflect the serum 5-HT concentration. In addition, we assessed the association between the PLT and ejaculatory parameters. There was a negative correlation between ejaculation frequency (EF) and the PLT (r = -0.595, P < 0.001), whereas there was a positive correlation between ejaculation latency (EL) and the PLT (r = 0.740, P < 0.001). This study indicated that the PLT might be a useful and convenient diagnostic marker for predicting the risk of rapid ejaculation.

Aerobic exercise improves ejaculatory behaviors and complements dapoxetine treatment by upregulating the BDNF-5-HT duo: a pilot study in rats.

Accumulating evidence has revealed many clues that regular aerobic exercise benefits brain health and behaviors. The aims of this study were to explore the effect of aerobic exercise on ejaculatory behaviors, as well as to make a preliminary assessment of aerobic exercise as a complementary strategy to dapoxetine treatment in rapid ejaculators. Copulatory tests of rats and a treadmill training protocol were performed in this study. In total, 12 rapid ejaculators were selected on the basis of ejaculation distribution theory and randomly assigned to 4 groups: control (Ctrol) group, aerobic exercise (Ex) group, dapoxetine (Dapo) group, and Ex+Dapo group. We evaluated the changes in ejaculatory parameters in the 4 groups. Variations in biological markers, including serum corticosterone, serotonin (5-HT), and brain-derived neurotrophic factor (BDNF) of the raphe nucleus, were determined by enzyme-linked immunosorbent assay (ELISA). The primary finding of our study was that both aerobic exercise and acute dapoxetine could enhance ejaculation control and prolong ejaculation latency in rapid ejaculator rats. The ejaculation delay effect of aerobic exercise was nearly equivalent to that of acute dapoxetine. In addition, both aerobic exercise and dapoxetine treatment could lead to increased expression of BDNF and 5-HT in the raphe nucleus of rapid ejaculators. Moreover, the two interventions, when applied together, may further upregulate the expression of BDNF-5-HT duo in a complementary manner. This study highlights the positive effects of aerobic exercise on ejaculation control. Regular aerobic exercise might be a promising complementary treatment to dapoxetine in rats.

[Characteristics of Partial Denitrification in Biofilm System].

As an intermediate form of microbial denitrification, nitrite serves as a key substrate for anaerobic ammonium oxidation (ANAMMOX). This study investigated the partial dentification (PD) characteristics and the coupling feasibility of PD+ANAMMOX in the biofilm system, using a moving bed biofilm reactor which was operated for 120 days. After 40 days of operation with a C/N ratio of 3.0 and filling fraction of 20%, the nitrate-to-nitrite transformation ratio (NTR) reached (69.38±3.53)%, and enzymatic assays indicated that the activities of nitrate reductase (NAR) had increased from 0.03 to 0.45 µmol·(min·mg)-1 while the activities of nitrite reductase (NIR) had decreased from 0.18 to 0.02 µmol·(min·mg)-1. Illumina high-throughput sequencing analysis revealed that the proportion of genus of Thauera bacteria to total microorganism increased from 0.3% (d1) to 37.27% (d64). Finally, the effluent had a total nitrogen (TN) concentration of (6.41±1.50) mg·L-1, indicating a total nitrogen removal ratio of (88.16±2.71)% and confirming the feasibility of PD+ANAMMOX in the biofilm system.

Maternal nicotine exposure impairs brown adipose tissue via AMPK-SIRT1-PGC-1α signals in male offspring.

AIMS: Maternal nicotine exposure during pregnancy and lactation is associated with obesity in offspring. Brown adipose tissue (BAT) is correlated with energy metabolism and obesity. In this study, we explored the mechanism of maternal nicotine exposure on BAT changes in male offspring. MAIN METHODS: Pregnant rats were randomly assigned to nicotine (1.0 mg/kg twice per day, subcutaneous administration) or control groups. In vitro, C3H10T1/2 cells were induced to differentiate into mature brown adipocytes, and 0-50 µM nicotine was given to C3H10T1/2 cells during the differentiation process. KEY FINDINGS: Nicotine-exposed males had white-like adipocytes and abnormal mitochondria structure in iBAT at 26 weeks. The expression of mitochondrial genes, UCP1 and AMPK-SIRT1-PGC-1α pathway were downregulated in the nicotine group at 26 weeks rather than 4 weeks. In vitro, 50 µM nicotine decreased the expression of mitochondrial genes, UCP1 and AMPK-SIRT1-PGC-1α pathway in brown adipocytes. SIGNIFICANCE: Maternal nicotine exposure showed the "programming" effect on the decreased brown-like phenotype in BAT of adult male offspring via downregulating AMPK-SIRT1-PGC-1α pathway. This impairment of BAT may be a potential mechanism of nicotine-induced obesity in male offspring.

[Treatment of Medium Ammonium Wastewater by Single-stage Partial Nitritation-ANAMMOX SMBBR].

A SMBBR was established to treat medium ammonium under room temperature. Results showed that TN load can reach 0.16 kg·(m3·d)-1, and the average TN removal efficiency was (51.58±6.80)% in the SMBBR with an influent ammonia concentration of 100 mg·L-1 and DO of 0.4-0.7 mg·L-1. AOB, ANAMMOX, and NOB activity reached (2253.21±502.10) mg·(m2·d)-1, (4847.46±332.89) mg·(m2·d)-1, and (1455.17±473.83) mg·(m2·d)-1, and ANAMMOX and AOB bacteria were found to develop a good collaborative relationship. Quantitative PCR results showed that the relative abundance of ANAMMOX, AOB and NOB were 11.57%, 1.01% and 0.94%, respectively. The stable operation of single stage partial nitritation-ANAMMOX process provide an alternative technology for medium ammonia wastewater.

[Adaptability of Nitrifying Biofilm Systems to Low Temperature: MBBR and IFAS].

The long-term effects of a decreasing temperature on the nitrification performance, biofilm characteristics, and nitrifier community in a moving-bed biofilm reactor (MBBR) and integrated fixed-film activated sludge (IFAS) system were investigated at various temperatures (20, 15, and 10℃) to explore the adaptability of nitrifying biofilm systems to low temperatures. During the experiment, the extracellular polymeric substances (EPS) in the biofilms increased with decreasing temperature, which resulted in an increased biofilm mass and thickness. As there was only a biofilm phase in the MBBR to remove ammonia, the part of the carriers in the MBBR at 10℃ became plugged, which partially led to a deterioration in the effluent water quality. This indicated that the IFAS system was more adaptable to low temperatures than was the MBBR. Meanwhile, the results for the nitrifier activities showed that, although the nitrification contribution rate of the suspended phase in the IFAS system always dominated during the experiment, that of the fixed phase with regards to the ammonia uptake rate (AUR) gradually increased from 30.72% at 20℃ to 39.85% at 10℃. This indicated that the biofilm played an enhanced role in nitrification in the IFAS system. Moreover, the qPCR results revealed that the nitrifier copies of the number of biofilms increased slightly with decreased temperature, and coincided with an increase in biomass, which partially compensated for the decreased nitrification activity. These findings provide a theoretical basis for the application of the biofilm systems to wastewater treatment.

Insight into the fenton-induced degradation process of extracellular polymeric substances (EPS) extracted from activated sludge.

Although EPS in microbial aggregates are importance in successful implementation of biological wastewater treatment systems, they also exhibit detrimental role on certain circumstance, such as excess sludge dewatering. Extensive efforts have been put into the disruption of EPS for improving the dewaterability of excess sludge and Fenton's reagent treatment has been demonstrated to be a very promising sludge conditioning method for EPS destruction. However, the information regarding detailed degradation process of EPS during Fenton's reagent treatment is limited. In this study, EPS were extracted from activated sludge and treated with different concentrations of Fenton's reagent. The physicochemical characteristic changes of EPS under different treatment were investigated in terms of components, EEM, molecular weight (MW), UV-Vis and FTIR. The results showed that EPS were prone to be disintegrated, but hard to be fully mineralized. Humic substances in EPS were more resistant to Fenton's reagent than other components. Low MW components of EPS were preferentially degraded prior to the disruption of high MW components. Besides, the disintegration of EPS into lower MW ones was accompanied by the formation of higher MW compounds caused by the bridge interaction of Fe ions. The cleavage of protein's backbone in EPS was mainly through destruction of amide II (N-H and C-N) in -CO-NH-. Fenton's reagent treatment also led to a significant increase of oxygen-containing functional groups in EPS molecules. This paper may pave a path to deeply understand the mechanisms of dewatering improvements of excess sludge by Fenton's conditioning.

Age Differences in the Relationship between Secondhand Smoke Exposure and Risk of Metabolic Syndrome: A Meta-Analysis.

Secondhand smoke (SHS), a common environmental exposure factor, has become a serious public health problem. Metabolic syndrome is another worldwide clinical challenge. Our study tried to determine the age differences in the relationship between SHS and the risk of metabolic syndrome. Studies were searched in PubMed and Web of Science from 11 November to 30 November 2018. Eighteen studies were finally included based on inclusion and exclusion criteria. The relationship between SHS and the risk indicators of metabolic syndrome was analyzed. The weighted mean difference (WMD) of fasting plasma glucose (FPG), insulin, body mass index (BMI), and waist circumference (WC), and the standard mean difference (SMD) of total cholesterol, triglycerides, and low- and high-density lipoprotein-cholesterol (LDL-C, HDL-C) were calculated in a meta-analysis. SHS was positively associated with the level of insulin and WC. According to the subgroup analysis based on age difference, SHS was positively associated with FPG in the upper age group, and positively associated with LDL-C and negatively associated with HDL-C in the lower age group. BMI showed a more obvious positive correlation in the adults group than in the children and the teenagers group. In conclusion, the association of metabolic syndrome with SHS varies with age. When exposed to SHS, older people may be more susceptible to glucose metabolic disorder, but younger people may be more susceptible to lipid metabolic disorder.

Validity of premature ejaculation diagnostic tool and its association with International Index of Erectile Function-15 in Chinese men with evidence-based-defined premature ejaculation.

The premature ejaculation diagnostic tool (PEDT) is a brief diagnostic measure to assess premature ejaculation (PE). However, there is insufficient evidence regarding its validity in the new evidence-based-defined PE. This study was performed to evaluate the validity of PEDT and its association with IIEF-15 in different types of evidence-based-defined PE. From June 2015 to January 2016, a total of 260 men complaining of PE and defined as lifelong PE (LPE)/acquired PE (APE) according to the evidence-based definition from Andrology Clinic of the First Affiliated Hospital of Anhui Medical University, along with 104 male healthy controls without PE from a medical examination center, were enrolled in this study. All individuals completed questionnaires including demographics, medical and sexual history, as well as PEDT and IIEF-15. After statistical analysis, it was found that men with PE reported higher PEDT scores (14.28 ± 3.05) and lower IIEF-15 (41.26 ± 8.20) than men without PE (PEDT: 5.32 ± 3.42, IIEF-15: 52.66 ± 6.86, P < 0.001 for both). It was suggested that a score of ≥9 indicated PE in both LPE and APE by sensitivity and specificity analyses (sensitivity: 0.875, 0.913; specificity: 0.865, 0.865, respectively). In addition, IIEF-15 were higher in men with LPE (42.64 ± 8.11) than APE (39.43 ± 7.84, P < 0.001). After adjusting for age, IIEF-15 was negatively related to PEDT in men with LPE (adjust r = -0.225, P < 0.001) and APE (adjust r = -0.378, P < 0.001). In this study, we concluded that PEDT was valid in the diagnosis of evidenced-based-defined PE. Furthermore, IIEF-15 was negatively related to PEDT in men with different types of PE.

[Influence on Desulfurization Efficiency and Interactions of Fe/S and pH During H2S in situ Depression of High Solid Anaerobic Digestion].

To evaluate the influence of Fe/S ratio and pH on sulfide removal efficiency and interactions between Fe/S and pH, anaerobic hydrogen sulfide in situ depression tests and digested sludge liquor sulfide removal tests were carried out by using dewatering sludge from a wastewater treatment plant (WWTP). Results showed that the concentration of hydrogen sulfide in biogas from the thermal pretreatment following anaerobic digestion process could be reduced from 170.4×10-6 to 14.09×10-6 at Fe/S=7.75, which means the biogas desulfurization treatment is not required. Under the condition of pH 7.00-7.50 and Fe/S 1-11, pH is the main influencing factor for sulfide removal. Improving the pH of anaerobic digestion is beneficial in reducing the dosage of Fe(Ⅲ). An Fe/S ratio of 7.0 is the minimum to meet the biogas hydrogen sulfide emission standards during high solid sludge anaerobic digestion. The concentration of hydrogen sulfide was not up to standards if pH was below 7.30.

Composition and functional group characterization of extracellular polymeric substances (EPS) in activated sludge: the impacts of polymerization degree of proteinaceous substrates.

Characteristics of extracellular polymeric substances (EPS) in activated sludge strongly depend on wastewater substrates. Proteinaceous substrates (ProS) present in heterogeneous polymeric form are intrinsic and important parts of wastewater substrates for microorganisms in activated sludge systems. However, correlations between ProS and characteristics of EPS are scarce. This study systematically explored the impacts of monomeric (Mono-), low polymeric (LoP-) and high polymeric (HiP-) ProS on compositions and functional groups of EPS in activated sludge. The results showed that the change of polymerization degree of ProS significantly altered the composition of EPS. Compared to EPSMono-ProS, the proportion of proteins in EPSLoP-ProS and EPSHiP-ProS increased by 12.8% and 27.7%, respectively, while that of polysaccharides decreased by 22.9% and 63.6%, respectively. Moreover, the proportion of humic compounds in EPSLoP-ProS and EPSHiP-ProS were ∼6 and ∼16-fold higher than that in EPSMono-ProS, respectively. The accumulation of humic compounds in EPS increased the unsaturation degree of EPS molecules, and thereby reduced the energy requirement for electrons transition of amide bonds and aromatic groups. Size exclusion chromatography (SEC) analyses detected more molecular clusters in EPSHiP-ProS, indicating more complex composition of EPS in HiP-ProS fed activated sludge. Spectroscopic characterization revealed the dominance of hydrocarbon, protein, polysaccharide and aromatic associated bonds in all three EPS. Nevertheless, with the increase of polymerization degree of ProS, the protein associated bonds (such as CONH, CO, NC, NH) increased, while the polysaccharide associated bonds (such as COC, COH, OCOH) decreased. This paper paves a path to understand the role of ProS in affecting the production and characteristics of EPS in biological wastewater treatment systems.

[Effect of Temperature on PAO Activity and Substrate Competition].

To investigate the effect of temperature on the activity of high-temperature phosphate accumulating organisms (PAOHT) and their competitive ability for the substrate, the sludge from an enhanced biological phosphorus removal (EBPR) reactor stably operated at the high temperature of 30℃ was used. The results showed that PAOHT activity and their competitive ability for the substrate increased with temperature increasing from 15℃ to 30℃. When the temperature was as higher as 30℃, the rates of anaerobic phosphorus release, aerobic phosphorus uptake and acetate uptake of PAOHT were 239.46 mg·(g·h)-1, 79.90 mg·(g·h)-1, 357.47 mg·(g·h)-1, respectively. The corresponding value of ΔP/ΔHAc was 0.628, which was considerably higher than that of PAO reported in literatures. A simplified Arrhenius equation was used to describe the effect of temperature on the rates of anaerobic phosphorus release, aerobic phosphorus uptake and acetate uptake, and the temperature coefficients were 1.08, 1.07 and 1.05, respectively.

Nitrite oxidizing bacteria (NOB) dominating in nitrifying community in full-scale biological nutrient removal wastewater treatment plants.

Nitrification activities and microbial populations of ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) were investigated in 10 full-scale biological nutrient removal wastewater treatment plants in Xi'an, China. Aerobic batch tests were used to determine the nitrifying activities while fluorescence in situ hybridization was used to quantify the fractions of AOB and NOB in the activated sludge. The results showed that nitrifying bacteria accounted for 1-10% of the total population. Nitrosomonas and Nitrospira were the dominant bacteria for AOB and NOB respectively. Moreover, the average percentage of AOB was 1.27% and that of NOB was 4.02%. The numerical ratios of NOB/AOB varied between 1.72 and 5.87. The average ammonium uptake rate and nitrite uptake rate were 3.25 ± 0.52 mg (NH4+-N)/g(VSS) h and 4.49 ± 0.49 mg (NO2--N)/g(VSS) h, respectively. Correspondingly, the activity of NOB was 1.08-2.00 times higher than that of AOB. Thus, NOB was the dominating bacteria in nitrifying communities. The year-round data of Dianzicun (W6) also expressed a similar trend. Since NOB had higher activities than that of AOB, a large nitrite oxidation pool could be formed, which guaranteed that no nitrite would be accumulated. Therefore, stable nitrification could be achieved. A conceptual model was proposed to describe the population variation of AOB and NOB in a nitrifying community.

[Enrichment of Nitrospira in Activated Sludge and Kinetic Characterization].

Nitrospira was enriched from activated sludge by using fed-batch cultivation, and its related kinetic characterization was studied. The results showed that Nitrospira could be successfully enriched from the activated sludge for a controlled nitrite concentration no higher than 2 mg·L-1. The maximum nitrate oxidation rate was 48.72 mg·(g·h)-1. The fluorescence for the in situ hybridization results showed that Nitrospira accounted for about 75% of the total biomass, while Nitrobacter accounted for only 0.1%. In addition, the kinetic parameters of Nitrospira at 20℃ were also investigated. The results showed that the optimum growth temperature for Nitrospira was 30-35℃. The temperature correction coefficient τN was 1.046. The nitrite half-saturation constant KS and oxygen half-saturation constant KO were (0.32±0.03)mg·L-1 and (1.52±0.09)mg·L-1, respectively. This study on the kinetic characterization of Nitrospira provided a theoretical foundation for the treatment plant design and process optimization.

[Fast Start-up of ANAMMOX and the Spatial Distribution of EPS in ANAMMOX Granules].

An anaerobic sequencing batch reactor(ASBR) inoculated with activated sludge was employed to investigate the start-up of anaerobic ammonium oxidation(ANAMMOX) process and the spatial distribution of extracellular polymeric substances(EPS) in ANAMMOX granules. The results showed that the removal rates of NH4+-N and NO2--N reached more than 99%. The removal rate of total nitrogen(TN) was 89.87%±0.43% and the TN removal load in the ASBR was 1.7 kg·(m3·d)-1. The ratios of nitrite consumption and nitrate production to ammonium consumption were 1.32±0.08 and 0.24±0.03, respectively. Besides, the pH and the effluent nitrate concentration in bulk liquid were considered as two simple indicators for rapid diagnosis of ANAMMOX performance. The proteins(PN) was the main component of EPS in ANAMMOX granular sludge. The PN and polysaccharides(PS) in ANAMMOX granules were (59.61±5.64) mg·g-1 and (12.21±2.04) mg·g-1, respectively, with the ratio of PN/PS reaching approximately 4.88±1.39. ß-D-glucofuranose and dead cells were distributed in the outermost layer of granules, while living cells, PN, lipids, α-glucosamine and α-mannose were distributed throughout the granules and mainly concentrated on the outside of granules. PN and lipids constituted the framework of ANAMMOX granules and ANAMMOX bacteria were embedded among the PN and lipids matrix.

[Comparison of Operating Performance of Partial Nitritation Systems with Two Different Inhibition Strategies].

Two SBRs which were under high ammonia loading[1 kg·(m3·d)-1] and different dual inhibition with feed-batch were employed to study how to control the stability of partial nitritation system. The experimental result showed that the dual inhibition of FNA and DO or FA and DO could implement partial nitrification process at 35℃±1℃ and the ammonia concentration of 1000 mg·L-1. The effluent NO2--N/NH4+-N ratio was about 1, and the effluent NO3--N concentration was close to 0, which was suitable for the appropriate influent for the ANAMMOX. In R1, under the dual inhibition of high FA and low DO concentration, the nitrite oxidizing rate was reduced from 28.16 mg·(g·h)-1 to 0.3 mg·(g·h)-1 (calculated as NO2--N, the same as below). The ammonia oxidizing rate decreased by 43.60%, which was stable at about 20 mg·(g·h)-1 (calculated as NH4+-N, the same as below). In R2,under the dual inhibition of high FNA and low DO concentration, the nitrite oxidizing rate reduced from 12.37 mg·(g·h)-1 to 0.02 mg·(g·h)-1. But the ammonia oxidizing rate remained at a higher level[45 mg·(g·h)-1]. Comparing the nitrification performance of the two SBRs under different control strategies, the dual inhibition of high FNA and low DO concentration had the advantages of short cultivation period, high biological activity and stable operation. It is therefore more suitable for the achievement of the partial nitrification.

[Non-CO2 Greenhouse Gas Release from Different Biological Wastewater Treatment Processes].

Methane (CH4) and nitrous oxide (N2O) are two of the most important non-CO2 greenhouse gases. And municipal sewage treatment plant is an important anthropogenic source of CH4 and N2O. Therefore, it is essential to measure the production and emission of CH4 and N2O during biological wastewater treatment process. The surface emission flux isolation chamber was employed to collect the gas sample from the Xi'an No.3 WWTP (the Orbal oxidation ditch process) and Xi'an NO.4 WWTP (A/A/O process) to determine the contents of methane and nitrous oxide. And the effects of temperature and dissolved oxygen concentration on non-CO2 greenhouse gases emission from Xi'an NO.4 WWTP were discussed. The results showed that methane and nitrous oxide emission factors from No.3 WWTP were 1181 mg CH4 per m3 influent and 36.20 mg N2O per m3 influent, respectively while those from the No.4 WWTP were 209 mg CH4 per m3 influent and 54.64 mg N2O per m3 influent. In addition, the important influencing factors which affected methane and nitrous oxide emission were temperature, aeration strategy, DO, nitrite oxidation rate and specific methanogenic activity.

Is polymeric substrate in influent an indirect impetus for the nitrification process in an activated sludge system?

Different from monomeric substrate, polymeric substrate (PS) needs to undergo slow hydrolysis process before becoming available for consumption by bacteria. Hydrolysis products will be available for the heterotrophs in low concentration, which will reduce competitive advantages of heterotrophs to nitrifiers in mixed culture. Therefore, some links between PS and nitrification process can be expected. In this study, three lab-scale sequencing batch reactors with different PS/total substrate (TS) ratio (0, 0.5 or 1) in influent were performed in parallel to investigate the influence of PS on nitrification process in activated sludge system. The results showed that with the increase of PS/TS ratio, apparent sludge yields decreased, while NO3--N concentration in effluent increased. The change of PS/TS ratio in influent also altered the cycle behaviors of activated sludge. With the increase of PS/TS ratio from 0 to 0.5 and 1, the ammonium and nitrite utilization rate increased ∼2 and 3 times, respectively. The q-PCR results showed that the abundance of nitrifiers in activated sludge for PS/TS ratio of 0.5 and 1 were 0.7-0.8 and 1.4-1.5 orders of magnitude higher than that for PS/TS ratio of 0. However, the abundance of total bacteria decreased about 0.5 orders of magnitude from the former two to the latter. The FISH observation confirmed that the nitrifiers' microcolony became bigger and more robust with the increase of PS/TS ratio. This paper paves a path to understand the role of PS/TS in affecting the nitrification process in biological wastewater treatment systems.