Operation of a nitrifying activated sludge airlift (NASA) reactor without biomass carrier

2000 ◽  
Vol 41 (4-5) ◽  
pp. 113-120 ◽  
Author(s):  
J.L. Campos ◽  
R. Mendez ◽  
J.M. Lema
Keyword(s):  
Activated Sludge ◽  
Air Flow ◽  
Small Diameter ◽  
Operation Time ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Total Biomass ◽  
Low Concentrations ◽  
The Mean ◽  
Very High

An ammonia loading rate of 4.1 kg N-NH4+/m3d was fully oxidized to nitrate using a nitrifying airlift without biomass carrier. The developed sludge, with a concentration of 12 gVSS/L and high density (100 gVSS/Lparticle), allowed particles to be retained with small diameter, having very low concentrations of solids in the effluent (5–10 mg VSS/L). The mean diameter of particles containing the majority of total biomass increased from 220 to 360 m during the operation time. The particle size analysis showed that the percentage of flocs with small diameter (1–3 m) is very high but the biomass content of these flocs is negligible with respect to the total biomass value. The oxygen transfer coefficient (KLa) was measured operating at different air flow rates, obtaining similar values during the overall operational period. The use of activated sludge without support gives high nitrifying rates with an easier fluidization and a lowercritical air flow rate than in a biofilm airlift reactor.

Comparison of Activated Sludge Technologies by Particle Size Analysis

2012 ◽  
Vol 223 (7) ◽  
pp. 4319-4331 ◽  
Author(s):  
J. J. Garcia-Mesa ◽  
F. Delgado-Ramos ◽  
M. M. Muñio ◽  
E. Hontoria ◽  
J. M. Poyatos
Keyword(s):  
Particle Size ◽  
Activated Sludge ◽  
Particle Size Analysis ◽  
Size Analysis

Carbon Quality of Four-Year-Old Woodchips in a Denitrification Bed Treating Agricultural Drainage Water

2018 ◽  
Vol 61 (3) ◽  
pp. 995-1000 ◽  
Author(s):  
Ehsan Ghane ◽  
Gary W. Feyereisen ◽  
Carl J. Rosen ◽  
Ulrike W. Tschirner
Keyword(s):  
Particle Size ◽  
Drainage Water ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Agricultural Drainage ◽  
Carbon Quality ◽  
The Mean ◽  
Lignocellulose Index ◽  
Effect Of Age

Abstract. A denitrification bed is a system that can reduce the nitrate concentration in subsurface drainage water. There is a need to investigate the carbon quality of old woodchips to gain a better understanding of the effect of age on woodchip properties. The objectives of this study were to characterize the carbon quality and carbon to nitrogen (C/N) ratio of aged woodchips and to examine the suitability of a denitrification bed for a replicated experiment. To achieve these goals, we excavated four-year-old woodchips along the length of a 106.4 m long denitrification bed near Willmar, Minnesota, and analyzed them for particle size, C/N ratio, and carbon quality. Particle size analysis showed similarities from 12.5 to 106.4 m along the bed. We found a mean C/N ratio ranging from 58.4 ±3.17 to 153.4 ±9.57 (smallest at the inlet). The mean lignocellulose index (LCI, a measure of carbon quality) of the four-year-old woodchips ranged from 0.47 to 0.57 (highest at the inlet). The woodchip particle sizes, C/N ratios, and LCI from 25.9 to 106.4 m along the bed length were similar. In conclusion, the C/N ratio and LCI of the four-year-old woodchips showed effects of decomposition and increased woodchip carbon recalcitrance over time, respectively. Keywords: Denitrifying bioreactor, Tile drainage, Water quality, Woodchip bioreactor.

Particle size analysis and sedimentation properties of activated sludge flocs

1997 ◽  
Vol 36 (4) ◽  
pp. 167-175 ◽  
Author(s):  
Dieter Hilligardt ◽  
Erhard Hoffmann
Keyword(s):  
Particle Size ◽  
Activated Sludge ◽  
Shape Analysis ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Organic Loading ◽  
Sludge Characteristics ◽  
Sludge Flocs ◽  
Factors Influencing ◽  
Differential Sedimentation

Activated sludge is one of the best investigated and understood suspensions. But up to now we still lack the factors influencing the sedimentation velocities concerning the main sludge characteristics/properties to describe the settleability of different sludges. Different in terms of SVI, organic loading, sludge retention time, composition, content of polymers, iron or aluminium, density, porosity and particle size distribution. But for the design of clarifiers most of these parameters are disregarded, of none importance or neglectable. With the help of PSD and particle shape analysis we can improve our knowledge of the settleability of activated sludge flocs. The measurements, done with the CIS show the influence of the differential sedimentation in comparison to the effluent of the secondary clarifiers under different conditions. Calculating the sedimentation velocities, the behaviour of activated and precipitated sludge could be explained and conclusions can be drawn to optimize the solid flux in secondary clarifiers.

Assessment of sludge particle removal from wastewater by disc filtration

2012 ◽  
Vol 7 (2) ◽  
Author(s):  
B.-M. Wilén ◽  
Ann Johansen ◽  
Ann Mattsson
Keyword(s):  
Pore Size ◽  
Removal Efficiency ◽  
Total Phosphorus ◽  
Particle Size Analysis ◽  
Effluent Treatment ◽  
Size Analysis ◽  
Particle Removal ◽  
Solids Concentration ◽  
Low Concentrations ◽  
Sludge Particle

To meet stricter effluent discharge limits of total phosphorus, microscreens can be applied for tertiary effluent treatment. The Rya WWTP has recently been upgraded with microscreens in the form of disc filters. Extensive characterisation of the wastewater from different locations in the plant (influent, after primary settling) and secondary settler effluent, was performed to increase the understanding of the potential of removing different components from the wastewater. The wastewater was fractionated by filtration through filter cloths with pore sizes 40, 20, 15, and 10 μm and through finer filters with pore size 1.2, 0.45, 0.2 and 0.1 μm. Particle size analysis (PSA) was used to assess the removal efficiency of the filter cloths. High removal degrees were achieved were particles larger or equal in size to the pore size were strained. Some floc break-up took place leading to an increased number of small particles (1–5 μm) after filtration. The suspended solids concentration could be reduced to 1 mg/l with total phosphorus concentrations of <0.2 mg/l. Some removal of metals could be observed when filtering wastewater with higher concentrations (influent and secondary settler effluent) whereas no effect could be seen for the effluent wastewater, probably due to the low concentrations present. The results from this study indicate a poor removal efficiency of pathogens measured as indicator microorganisms.

scholarly journals The Toxicity of Aluminium Salts to Lecane Inermis Rotifers: Are Chemical and Biological Methods Used to Overcome Activated Sludge Bulking Mutually Exclusive?

2013 ◽  
Vol 39 (3) ◽  
pp. 127-138 ◽  
Author(s):  
Beata Klimek ◽  
Edyta Fiałkowska ◽  
Janusz Fyda ◽  
Wioleta Kocerba-Soroka ◽  
Agnieszka Pajdak-Stós ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Effective Concentration ◽  
Aluminium Chloride ◽  
Aluminium Sulphate ◽  
Sludge Bulking ◽  
Low Concentrations ◽  
Different Temperatures ◽  
The Mean ◽  
Biological Methods ◽  
Rotifer Population

Abstract The aim of this study was to assess the effects of two flocculants that are often used to overcome activated sludge bulking problems - aluminium chloride, AlCl3, and aluminium sulphate, Al2(SO4)3 - on Lecaneinermis (Rotifera, Monogononta) at three different temperatures: 8, 15 and 20°C. The mean EC50 value (effective concentration, mg dm-3) calculated for the 24 h mortality test was 0.012 mg Al3+dm-3. Next, the effects of low concentrations of the Al-salts on the population development from single individuals (parthenogenetic females) were tested in a 21-day experiment. At concentrations as low as EC4.8 and EC0.48, both Al-salts affected rotifer population negatively. However, temperature was the most pronounced factor that modified the toxicity of the Al-salts to the rotifers. On the 12th day of the experiment, there were significant interactions between temperature and the Al-salts, indicating that the chemicals were more toxic to the rotifers at 20°C than at lower temperatures. The weaker rotifers sensitivity to Al-salts (especially to AlCl3) in temperatures below 15°C, when the biggest problems associated with sludge bulking occurs,may means use both rotifers and chemicals reasonable and effective.

PROGESTERONE RECEPTORS IN THE RAT UTERUS: VARIATIONS IN CYTOSOL AND NUCLEI DURING THE OESTROUS CYCLE AND PREGNANCY

1978 ◽  
Vol 76 (1) ◽  
pp. 43-48 ◽  
Author(s):  
M. T. VU HAI ◽  
F. LOGEAT ◽  
E. MILGROM
Keyword(s):  
Binding Sites ◽  
Total Concentration ◽  
Progesterone Receptors ◽  
Mean Value ◽  
Oestrous Cycle ◽  
Small Peak ◽  
Low Concentrations ◽  
The Mean ◽  
High Level ◽  
Very High

SUMMARY The concentration of progesterone receptors in rat uterine cytosol and nuclei was measured during the oestrous cycle and pregnancy. The method used allowed the measurement of the total concentration of binding sites (unbound and hormone-bound). During the oestrous cycle, the concentration of receptors in the cytosol peaked at pro-oestrus, low concentrations were observed at oestrus and metoestrus, and an increase was seen at dioestrus. In the nuclei, maximum concentrations occurred at pro-oestrus and dioestrus. The number of receptors in the cytosol was very low during the first half of pregnancy, but the concentration increased progressively after day 15 to attain a very high level (about 26 000 binding sites/cell) on day 22. In the nuclei, the concentration of receptors was low at the beginning of pregnancy. On day 5 (day of implantation) there was a slight increase, which corresponded to a decrease in the number of cytosolic receptors and a small peak in the level of progesterone in the plasma. Maximum concentrations were attained during a 'plateau' period between days 9 and 15. Thereafter, there was a decrease in the concentration of nuclear receptors and on day 22, the mean value was very low; in some animals, probably on the verge of parturition, no receptors were detectable in the nuclei.

Microencapsulation of diglycidyl 1,2-cyclohexanedicarboxylate by in situ polymerization: preparation and characterization

e-Polymers ◽  
2015 ◽  
Vol 15 (6) ◽  
pp. 377-383 ◽  
Author(s):  
Hai-Ping Wang ◽  
Meng-Qiang Li ◽  
Chang Guo ◽  
Si-Qian Hu
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Shell Material ◽  
The Core ◽  
The Mean ◽  
Decomposition Behavior ◽  
Shell Wall Thickness

AbstractMicrocapsules containing a glycidyl ester-type epoxy resin were successfully synthesized by in situ polymerization, with poly(melamine-urea-formaldehyde) as the shell material and diglycidyl 1,2-cyclohexanedicarboxylate (DGCHD) as the core substance. Scanning electron microscopy was performed to investigate the surface morphology and shell wall thickness of the microcapsule. The fabrication, diameters and thermal decomposition behavior of the resultant microcapsules were studied by means of Fourier transform infrared spectroscopy, laser particle size analysis, and thermogravimetric analysis (TGA), respectively. Results indicated that the highest loading of DGCHD in the as-prepared microcapsules was about 89.1 wt.% and that the mean diameter of the capsules was in the range of 50–130 μm, which can be adjusted by changing the feeding mass ratio of the core/shell material and emulsifying rate, respectively. TGA results showed that the microencapsulated DGCHD degraded in two distinguishable stages.

Simple Way for Ag-NPs Preparation based on Starch Macromolecule

2021 ◽  
Vol 18 ◽  
Author(s):  
H.M. Fahmy ◽  
A.A. Ali ◽  
A. Abou-Okeil
Keyword(s):  
Particle Size ◽  
Antibacterial Properties ◽  
Particle Size Analysis ◽  
Molar Ratio ◽  
Size Analysis ◽  
Ag Nps ◽  
Stabilizing Agent ◽  
Oxidized Starch ◽  
Vis Spectroscopy ◽  
The Mean

: Finding a sustainable, inexpensive way for Ag-NPs synthesis is considered as one of the most important requirements for industrial application. Oxidized starch was prepared using sodium periodate. Oxidized starch (DAS) was characterized by measuring aldehyde content and using FTIR spectroscopy. DAS was used as reducing and stabilizing agent for the preparation of Ag nanoparticles (Ag-NPs). Factors that may affect the preparation of Ag-NPs include pH, AgNO3/DAS molar ratio, temperature and time were studied. UV-Vis. spectroscopy and particle size analysis showed that DAS can act as reducing and stabilizing agent for the preparation of Ag-NPs and the mean particle size was 19 nm. The so prepared AgNPs were used as antibacterial agent for cotton fabric using the pad dry cure method. The results of antibacterial test showed that the presence of Ag-NPs enhanced the antibacterial properties of the treated cotton fabrics.

Complexation of Cinnamon Essential Oil by β-Cyclodextrin and its Release Characteristics at High Temperature

2010 ◽  
Vol 146-147 ◽  
pp. 619-622 ◽  
Author(s):  
Xi Hong Li ◽  
Juan Yun ◽  
Ya Ge Xing ◽  
Yao Xiao ◽  
Yao Tang
Keyword(s):  
Size Distribution ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Cinnamon Oil ◽  
Mean Diameter ◽  
Ft Ir ◽  
The Mean ◽  
Cinnamon Essential Oil ◽  
High Instability ◽  
Scanning Electron

The high instability is one of the most important problems for cinnamon oil. The complexation of cinnamon oil by β-cyclodextrin (β-CD) and its controlled release characteristics were investigated in this paper. The composition of microencapsulated cinnamon oil was evaluated using Fourier transform infrared spectroscopy (FT-IR). The size distribution and surface morphology of the resultant microcapsules were also characterized using Beckman Coulter particle size analysis, scanning electron microscopy (SEM), respectively. And the size distribution is narrow and the mean diameter is 20.78 μm. Results demonstrated the rates of cinnamon oil released from microencapsulation were accelerated with the increase of RH.

Sign in / Sign up

Export Citation Format

Share Document