scholarly journals Effect of organic loading on phosphorus forms transformation and microbial community in continuous-flow A2/O process

2021 ◽  
Author(s):  
Yajing Li ◽  
Yaping Wu ◽  
Shaopo Wang ◽  
Liyuan Jia
Keyword(s):  
Continuous Flow ◽  
Phosphorus Content ◽  
Inorganic Phosphorus ◽  
Organic Load ◽  
Organic Loading ◽  
Phosphorus Forms ◽  
Abundant Genus ◽  
The Impact ◽  
Extracellular Polymer ◽  
Phosphorus Storage

Abstract A continuous-flow Anaerobic/Anoxic/Oxic (A2/O) system was operated at different organic concentrations to systematically investigate the effect on the nutrient removal, secretion characteristics of extracellular polymer, phosphorus forms transformation and changes in functional flora in this system. The results showed that high organic loading was more conducive to promote the secretion of extracellular polymeric substance (EPS), the increase of polysaccharide content was more obvious compared with protein, the impact of organic loading on the components of loosely-bound EPS (LB-EPS) was higher than that of tight-bound EPS (TB-EPS). Phosphorus in sludge floc mainly existed in the form of inorganic phosphorus (IP), and IP mainly existed in the form of apatite inorganic phosphorus (AP). High organic load showed higher phosphorus storage in EPS, and the phosphorus content in EPS was positively correlated with the content of EPS. Non-apatite phosphorus (NAIP) content played an important role in the extracellular dephosphorization. The abundance of Nitrosomonas and Nitrospira responsible for nitrification decreased with the increase of organic loading. The group of denitrifiers was large, and Azospira was the most abundant genus among them. Dechloromonas, Acinetobacter, Povalibacter, Chryseolinea and Pirellula were the functional genera closely associated with phosphorus removal.

scholarly journals Forms of Nitrogen and Phosphorus in Suspended Solids: A Case Study of Lihu Lake, China

2020 ◽  
Vol 12 (12) ◽  
pp. 5026 ◽  
Author(s):  
Jialu Li ◽  
Qiting Zuo
Keyword(s):  
Water Quality ◽  
Suspended Solids ◽  
Inorganic Phosphorus ◽  
Nitrogen And Phosphorus ◽  
Lake Ecosystems ◽  
Phosphorus Forms ◽  
Sequential Extraction Method ◽  
Main Component ◽  
The Impact

Suspended solids are an important part of lake ecosystems, and their nitrogen and phosphorus contents have a significant effect on water quality. However, information on nitrogen and phosphorus forms in suspended solids remains limited. Therefore, a case study was conducted in Lihu Lake (China), a lake with characteristically high amounts of suspended solids. Nitrogen and phosphorus speciation in suspended solids was analyzed through a sequential extraction method. We also evaluated the sources of various forms of nitrogen and phosphorus and their different effects on eutrophication. The total nitrogen (TN) content was 758.9–3098.1 mg/kg. Moreover, the proportions of various N forms in the suspended solids of the study areas were ranked as follows: Hydrolyzable nitrogen (HN) > residual nitrogen (RN) > exchangeable nitrogen (EN). Total phosphorus (TP) ranged from 294.8 to 1066.4 mg/kg, and 58.6% of this TP was inorganic phosphorus (IP). In turn, calcium (Ca)-bound inorganic phosphorus (Ca-Pi) was the main component of IP. The correlation between various nitrogen and phosphorus forms showed that there were different sources of suspended nitrogen and phosphorus throughout Lihu Lake. Correlation analysis of water quality indices and comparative analysis with surface sediments showed that in Lihu Lake, the dissolved nitrogen and phosphorus contents in water were influenced by sediment through diffusion, while particle phosphorus content in water was influenced by suspended solids through adsorption; however, due to the higher phosphorus contents in suspended solids, we should pay more attention to the impact of suspended solids.

scholarly journals Impact of Chronic Tetracycline Exposure on Human Intestinal Microbiota in a Continuous Flow Bioreactor Model

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 886
Author(s):  
Youngbeom Ahn ◽  
Ji Young Jung ◽  
Ohgew Kweon ◽  
Brian T. Veach ◽  
Sangeeta Khare ◽  
...  
Keyword(s):  
Molecular Analysis ◽  
Intestinal Microbiota ◽  
Continuous Flow ◽  
Antimicrobial Drug ◽  
Bioreactor Culture ◽  
Analysis Techniques ◽  
Human Intestinal Microbiota ◽  
Traditional Cultures ◽  
The Impact

Studying potential dietary exposure to antimicrobial drug residues via meat and dairy products is essential to ensure human health and consumer safety. When studying how antimicrobial residues in food impact the development of antimicrobial drug resistance and disrupt normal bacteria community structure in the intestine, there are diverse methodological challenges to overcome. In this study, traditional cultures and molecular analysis techniques were used to determine the effects of tetracycline at chronic subinhibitory exposure levels on human intestinal microbiota using an in vitro continuous flow bioreactor. Six bioreactor culture vessels containing human fecal suspensions were maintained at 37 °C for 7 days. After a steady state was achieved, the suspensions were dosed with 0, 0.015, 0.15, 1.5, 15, or 150 µg/mL tetracycline, respectively. Exposure to 150 µg/mL tetracycline resulted in a decrease of total anaerobic bacteria from 1.9 × 107 ± 0.3 × 107 down to 2 × 106 ± 0.8 × 106 CFU/mL. Dose-dependent effects of tetracycline were noted for perturbations of tetB and tetD gene expression and changes in acetate and propionate concentrations. Although no-observed-adverse-effect concentrations differed, depending on the traditional cultures and the molecular analysis techniques used, this in vitro continuous flow bioreactor study contributes to the knowledge base regarding the impact of chronic exposure of tetracycline on human intestinal microbiota.

Wastewater fermentation and nutrient removal in sequencing batch reactors

1998 ◽  
Vol 38 (1) ◽  
pp. 255-264 ◽  
Author(s):  
Germán Cuevas-Rodríguez ◽  
Óscar González-Barceló ◽  
Simón González-Martínez
Keyword(s):  
Activated Sludge ◽  
Volatile Fatty Acids ◽  
Organic Load ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Organic Loading ◽  
Nitrogen And Phosphorus ◽  
Loading Rates ◽  
Average Value ◽  
Experimental Runs

This research project was conducted to analyze the performance of a SBR reactor when being fed with anaerobically fermented wastewater. Important was to determine the capacity of the system to remove nitrogen and phosphorus. Two SBR reactors, each one with a volume of 980 liters, were used: one used as fermenter and the other as activated sludge SBR. Using 8-hour cycles, the reactors were operated and studied during 269 days. The fermenter produced an effluent with an average value of 223±24 mg/l of volatile fatty acids. The activated sludge SBR was tested under 3 organic loading rates of 0.13, 0.25, and 0.35 kgCODtotal/kgTSS·d. For the three tested organic loading rates, PO4-P concentrations under 1.1 mg/l and COD between 37 and 38 mg/l were consistently achieved. Exceptionally high NH4-N influent values were measured during the time of the experimentation with the organic load of 0.25 kgCODtotal/kgTSS·d, not reaching in this case full nitrification. Denitrification was observed during the fill phase in every cycle. SVI values between 40 and 70 were determined during the experimental runs.

MINERALIZATION OF SOIL ORGANIC PHOSPHORUS WITH PARTICULAR REFERENCE TO THE EFFECT OF LIME

1963 ◽  
Vol 43 (1) ◽  
pp. 97-106 ◽  
Author(s):  
R. L. Halstead ◽  
J. M. Lapensee ◽  
K. C. Ivarson
Keyword(s):  
Phosphorus Content ◽  
Organic Phosphorus ◽  
Acid Soils ◽  
Inorganic Phosphorus ◽  
Eastern Canada ◽  
Surface Samples ◽  
Soil Organic Phosphorus ◽  
Repressive Effect ◽  
Partial Sterilization ◽  
Positive Effect

In a laboratory experiment, liming resulted in an average decline of 3.6 per cent in the total organic phosphorus content of incubated surface samples of seven acid soils from eastern Canada. Increases of 2.6 and 5.1 per cent in 1N H2SO4- and 4N HCl-soluble inorganic phosphorus, respectively, and a decrease of 46.4 per cent in NaHCO3-soluble organic phosphorus (pH 8.5) provided further evidence of mineralization of organic phosphorus following liming. There was some evidence, however, that the differences in NaHCO3-soluble organic phosphorus following liming were due only in part to mineralization, since Ca(OH)2 added to a soil just prior to extraction with NaHCO3 had a repressive effect on the solubility of the organic phosphorus compounds.Some mineralization of organic phosphorus occurred when unlimed samples were incubated in the laboratory for 9 months.Marked increases in microbiological activity, as indicated by increased numbers of microorganisms, and increased CO2 and NO3-nitrogen production, were associated with lower values for extractable organic phosphorus following liming. Partial sterilization of samples with toluene lowered biological activity in the unlimed and limed samples. Toluene was found, however, to have a positive effect on release of phosphorus from organic form.

Abstract 5857: Low Operative Mortality with implantation of a Continuous Flow LVAD and Impact of Concurrent Cardiac Procedures

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Jay D Pal ◽  
Charles T Klodell ◽  
Ranjit John ◽  
Francis Pagani ◽  
Joseph G Rogers ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Continuous Flow ◽  
Operative Mortality ◽  
Negative Impact ◽  
Venous Pressure ◽  
Heartmate Ii ◽  
Cardiac Procedures ◽  
Increased Risk ◽  
The Impact ◽  
Tricuspid Repair

Objective: Our goal was to determine the operative mortality of isolated implantation of the HeartMate II continuous flow LVAD and the impact of additional concurrent cardiac procedures on patient outcomes. Methods: In a multicenter trial, 279 patients at 33 clinical sites underwent implantation of the HeartMate II continuous flow LVAD as a bridge to transplantation from March 2005 to March 2007. HeartMate II implantation (HM II) was the only procedure required in 172 patients while 80 patients required concurrent cardiac procedures in conjunction with LVAD implantation (HM II+CCP). Results: Preoperative characteristics were similar, but central venous pressure (14.5 vs 11.6 mmHg) was greater for patients requiring concurrent cardiac procedures, suggesting worse right heart dysfunction. Mean cardiopulmonary bypass times increased from 97 to 120 minutes when a concurrent cardiac procedure was performed (p<0.001). Length of stay slightly increased from 23 to 26 days (p=0.17). Overall 30- and 180-day mortality was 5.8% and 13.3% for the HM II group, and 11.3% and 20.0% for the HM II+CCP group. Concurrent valvular procedures increased the risk to 8.5% and 19.1%. Patients who underwent an aortic valve replacement with cardioplegic arrest had a 30-day mortality of 25%, higher than for isolated concurrent mitral (0%) or tricuspid repair (3.3%). Other cardiac procedures were associated with a 30-day mortality of 27.8%. Survival at 180 days was 87% for HMII alone and 80% for HMII+CCP. Conclusion: There is a low 5.8% operative mortality for patients requiring uncomplicated HeartMate II implantation, with no apparent increased risk for concurrent PFO closure, mitral or tricuspid repair. However, concurrent aortic valve and other cardiac procedures are associated with a significantly decreased survival. The increased risk of these procedures must be balanced against the negative impact of uncorrected aortic insufficiency during VAD support.

scholarly journals INFLUENCE OF TECHNOGENIC EMISSIONS OF THE AGMZ ON THE ECOLOGICAL TOXICOLOGICAL STATE OF THE AGROECOSYSTEMS OF THE DEBET RIVER BASIN, RA

2020 ◽  
Vol 6 (6(75)) ◽  
pp. 26-30
Author(s):  
S. A. Hunanyan ◽  
T. A. Jhangiryan ◽  
A. L. Mkrtchyan
Keyword(s):  
Heavy Metal ◽  
Vegetation Cover ◽  
Phosphorus Content ◽  
Humus Content ◽  
Chemical Properties ◽  
Contamination Rate ◽  
Agricultural Crops ◽  
Yield Capacity ◽  
The Impact ◽  
Properties Of Soil

Upon the investigations the contamination rate of soil and vegetation cover of the basin at river Debed and the impact of technogenesis on the agro-chemical properties of soil and yield capacity of agricultural crops has been identified. It has been found out that the content of heavy metal forms exceeds that of the control one by the following figures: Cu-in 47,5 and 31,8; Pb-32,9 and 36,1; Mo-35,9 and 23,8; Zn-9,5 and 19,1; Co-5,1 and 5,9; Cd25,5 and 23,1 times. The humus content has decreased in 1,2-2,7 times, that of the total and mobile nitrogen has decreased in 1,1-2,17 and 1,4-2,6 times, phosphorus content in 1,0-1,87 and 1,08-2,74 times, potassium content in 1,0-1,38 and 1,13-2,06 times. The environmental reaction has turned from the neutral and poorly alkaline into poorly acidic and acidic one. The amount of HM in the soil and plants has exceeded the MAC (maximum allowable concentration) and the yield capacity of agricultural crops has fallen down by 7,5-29 %.

Determination of inorganic phosphorus using rhodamine b by the continuous-flow technique

1977 ◽  
Vol 80 (3) ◽  
pp. 431-433 ◽  
Author(s):  
L. Zahradníǒek ◽  
J. Kratochvíla ◽  
A. Garčic
Keyword(s):  
Rhodamine B ◽  
Continuous Flow ◽  
Inorganic Phosphorus
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