The effect of low sludge age on wastewater fractionation (SS, SI)

2003 ◽  
Vol 47 (11) ◽  
pp. 203-209 ◽  
Author(s):  
S. Haider ◽  
K. Svardal ◽  
P.A. Vanrolleghem ◽  
H. Kroiss
Keyword(s):  
Activated Sludge ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
The Other ◽  
Second Stage ◽  
Lower Maximum ◽  
The Difference ◽  
Selection Of ◽  
Activated Sludge Systems ◽  
Raw Wastewater

In lab-scale experiments at the 2-stage activated sludge pilot plant of Vienna's central WWTP it is shown that the wastewater soluble COD concentration, which is inert to a sludge with SRT < 1 d (SIA) is about double compared to the SI concentration in sludge with SRT > 10 d (SIB). Unexpectedly the ratio of SIA/SIB is independent of the sludge age between SRTs of 0.4 and 1.0 days. The difference between the two SI fractions is soluble COD that is readily biodegradable by the sludge with SRT > 10 d. However, it is degraded at a lower maximum growth rate. These results comply with earlier results gained with different methods and at different WWTPs. It is hypothesised that very low sludge ages result in a selection of fast growing bacteria, which can utilise only part of the SS in the raw wastewater. The other part of SS therefore remains in the wastewater and can thus be utilised for enhanced denitrification in the second stage. It is still unknown beyond which sludge age the soluble inert COD SIA starts to decrease, finally reaching the value SIB for low loaded systems (SRT > 5 days). From this point on SI and SS are assumed only to depend on the wastewater composition and not on the sludge age. The assumption of the Activated Sludge Model No.1 that the biodegradable fractions can be modelled as a single substrate and by a single removal kinetic (one Monod term) appears not to be applicable for low sludge ages. Some suggestions for mathematical modelling, design and operation of 2-stage activated sludge systems are given.

Biodegradation of EDTA in Pulp and Paper Mill Effluents by Activated Sludge

1999 ◽  
Vol 40 (11-12) ◽  
pp. 259-265 ◽  
Author(s):  
C. G. van Ginkel ◽  
H. Kester ◽  
C. A. Stroo ◽  
A. M. van Haperen
Keyword(s):  
Activated Sludge ◽  
Iminodiacetic Acid ◽  
Maximum Growth ◽  
Paper Mill ◽  
Maximum Growth Rate ◽  
Pulp And Paper Mill ◽  
Paper Mill Effluents ◽  
Alkaline Conditions ◽  
Neutral Conditions ◽  
Activated Sludge Systems

Activated sludge systems operated under alkaline conditions remove EDTA. To improve EDTA removal a better understanding of EDTA biodegradation and its intermediates as well as knowledge of kinetic parameters are a prerequisite. Activated sludge appeared to degrade EDTA via ethylenediaminetriacetate (ED3A). The sludge was able to split ED3A into readily biodegradable iminodiacetic acid and iminoacetaldehydeacetate. The maximum growth rate of EDTA-grown sludge was approximately 0.15 days−1. The Km for EDTA and maximum oxidation rate of EDTA-grown sludge were 10 mg/L and 135 mg O2 g−1 SS day−1. Specially cultivated activated sludge degraded EDTA under neutral conditions and was capable of degrading the FeEDTA complex at a low rate. Bioaugmentation of EDTA-grown sludge enabled EDTA removal in a treatment system under neutral conditions.

Interpretation of Experimental Data with Regard to the Activated Sludge Model No.1 and Calibration of the Model for Municipal Wastewater Treatment Plants

1992 ◽  
Vol 25 (6) ◽  
pp. 167-183 ◽  
Author(s):  
H. Siegrist ◽  
M. Tschui
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Municipal Wastewater Treatment ◽  
Activated Sludge Model

The wastewater of the municipal treatment plants Zürich-Werdhölzli (350000 population equivalents), Zürich-Glatt (110000), and Wattwil (20000) have been characterized with regard to the activated sludge model Nr.1 of the IAWPRC task group. Zürich-Glatt and Wattwil are partly nitrifying treatment plants and Zürich-Werdhölzli is fully nitrifying. The mixing characteristics of the aeration tanks at Werdhölzli and Glatt were determined with sodium bromide as a tracer. The experimental data were used to calibrate hydrolysis, heterotrophic growth and nitrification. Problems arising by calibrating hydrolysis of the paniculate material and by measuring oxygen consumption of heterotrophic and nitrifying microorganisms are discussed. For hydrolysis the experimental data indicate first-order kinetics. For nitrification a maximum growth rate of 0.40±0.07 d−1, corresponding to an observed growth rate of 0.26±0.04 d−1 was calculated at 10°C. The half velocity constant found for 12 and 20°C was 2 mg NH4-N/l. The calibrated model was verified with experimental dam of me Zürich-Werdhölzli treatment plant during ammonia shock load.

scholarly journals Conditions Favoring Proliferation of Glycogen Accumulating Organisms for Excess Biological Carbon Removal in Treating Nutrient Deficient Wastewater

2017 ◽  
Vol 61 (3) ◽  
pp. 149 ◽  
Author(s):  
Andrea Jobbágy ◽  
Bernadett Kiss ◽  
Vince Bakos
Keyword(s):  
Activated Sludge ◽  
Continuous Flow ◽  
The Other ◽  
N Availability ◽  
Filamentous Bacteria ◽  
Severe Deficiency ◽  
And Performance ◽  
Experimental Stage ◽  
Activated Sludge Systems ◽  
P Sources

Impact of marginal availability and severe deficiency of nitrogen on the growth of glycogen accumulating organisms (GAOs) and performance of anaerobic/aerobic activated sludge systems treating nutrient deficient wastewater was investigated at marginal availability and severe deficiency of phosphorus. Two continuous-flow lab-scale systems were operated simultaneously fed by model winery wastewater, one with marginal availability and the other one at severe deficiency of nitrogen. In the second experimental stage, marginal availability of P was converted into severe deficiency by interrupting external dosing.Common practice of dosing N- and P-sources to marginal availability caused enhanced proliferation of filamentous bacteria leading to poor biomass settling and instable operation. At marginal N-availability accumulation of GAOs started when conditions became deficient for phosphorus. In severe lack of nitrogen GAOs overgrew filaments, and outcompeted phosphorous accumulating organisms (PAOs) initially present in the seed. Stable and good performance could be maintained even after withdrawal of phosphorous dosing.

Development of LPE process for fabrication of coated conductors

2000 ◽  
Vol 659 ◽  
Author(s):  
Teruo Izumi ◽  
Natsuro Hobara ◽  
Toru Izumi ◽  
Katsuya Hasegawa ◽  
Masahiko Kai ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Recent Progress ◽  
High Growth ◽  
High Growth Rate ◽  
Coated Conductors ◽  
The Other ◽  
Lower Growth ◽  
The Difference ◽  
Lower Growth Temperature ◽  
Selection Of

ABSTRACTRecent Progress of development for coated conductors by the LPE technique was reviewed. Double layered LPE films were applied to the growth on metal substrates. In both cases of MgO- and NiO- buffers, the constructions were succeeded to grow on Hastelloy and Ni tapes, respectively. In the case of the MgO-buffer, the problem, which is the melting back of the 1st LPE layer during dipping for the growth of the 2nd LPE layer, was found. The problem was solved by means of the selection of the materials for each LPE layer to introduce the difference in the growth temperature for the 1st and the 2nd layers. The lower growth temperature for the 1st LPE layer than that for 2nd one is effective to avoid the problem. On the other hand, the double layered LPE films on Ni tapes revealed Tc of 85K. Concerning the long tape processing, the high growth rate of 1≈ was confirmed even without rotation using the long tape apparatus.

Hearing Results in the Second Stage of Open Mastoidectomy: A Comparison of the Different Techniques

2000 ◽  
Vol 122 (5) ◽  
pp. 748-751 ◽  
Author(s):  
Fernando Cristóbal ◽  
Rafael Gómez-Ullate ◽  
Isabel Cristóbal ◽  
Alfredo Arcocha ◽  
Ramón Arroyo
Keyword(s):  
Point Of View ◽  
Open Cavity ◽  
The Other ◽  
Hearing Results ◽  
Hearing Gain ◽  
Second Stage ◽  
Restoration Techniques ◽  
Ossicular Replacement ◽  
The Difference ◽  
Replacement Prosthesis

OBJECTIVE: The goal of this study was to compare the hearing results obtained through different hearing-restoration techniques in open-cavity mastoidectomy. METHODS AND MATERIAL: A total of 116 ears operated on during the second stage of open mastoidectomy were studied. The hearing gain was registered as the difference between preoperative and 1-year postoperative conversational frequency means (500, 1000, 2000 Hz). High-pitched frequencies (4000 Hz) were used equally. Two groups of studies were carried out: in one study the stapes was intact, and in the other the stapes arch was absent. The columella techniques we examined, from a hearing point of view, are total and partial ossicular replacement prostheses, ossiculoplasty, cartilage with or without perichondrium, and the myringostapediopexy. RESULTS AND CONCLUSIONS: In the group of patients in whom the stapes was intact, the differences in high-pitched frequencies found between the different techniques were negligible, but the differences were quite significant in conversational frequencies, where the partial ossicular replacement prosthesis turned out to be the technique with the worst results. In ears in which only the footplate was present, the total ossicular replacement prosthesis gave better results than any other technique, both in conversational frequencies and in 4000-Hz frequency.

Effect of high salinity on yeast activated sludge reactor operation

2016 ◽  
Vol 74 (9) ◽  
pp. 2124-2134 ◽  
Author(s):  
Matthew Dubois Frigon ◽  
Dongfang Liu
Keyword(s):  
Growth Rate ◽  
Activated Sludge ◽  
High Salinity ◽  
Yeast Species ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Reactor Operation ◽  
Activated Sludge Reactor ◽  
Kinetics Of ◽  
Salinity Wastewater

Yeast activated sludge was developed and operated at salinities of 0, 15, 30, 45, and 60 g/l NaCl. The kinetics of the various sludges degrading a wastewater with glycerol as the carbon source were determined. Inhibition due to salinity was analyzed and it was found that the limiting concentration of NaCl is 120 g/l. Salinity affects the maximum growth rate of the sludge. Reactors were exposed to shock salinity changes. Salt shocks affected maximum growth rate of the reactors but treatment was still effective. The effect of pH adjustment was investigated and it was determined that hourly adjustments of pH led to the most effective treatment outcomes. Finally, DNA of the reactors was investigated. Although Scheffersomyces spartinae (Debaryomycetaceae family) was clearly more suited to the high salinity environment than other yeast species, even at high salinity the number of species was diverse. This suggests the potential to use a number of yeast species for high salinity wastewater treatment.

Hearing results in the second stage of open mastoidectomy: A comparison of the different techniques

2000 ◽  
Vol 122 (5) ◽  
pp. 748-751
Author(s):  
Fernando CristÔBal ◽  
Rafael Gômez-Ullate ◽  
Isabel CristÔBal ◽  
Alfredo Arcocha ◽  
Ramon ArrÔO
Keyword(s):  
Point Of View ◽  
Open Cavity ◽  
The Other ◽  
Hearing Results ◽  
Hearing Gain ◽  
Second Stage ◽  
Restoration Techniques ◽  
Ossicular Replacement ◽  
The Difference ◽  
Replacement Prosthesis

OBJECTIVE: The goal of this study was to compare the hearing results obtained through different hearing-restoration techniques in open-cavity mastoidectomy. METHODS AND MATERIAL: A total of 116 ears operated on during the second stage of open mastoidectomy were studied. The hearing gain was registered as the difference between preoperative and 1-year postoperative conversational frequency means (500, 1000, 2000 Hz). High-pitched frequencies (4000 Hz) were used equally. Two groups of studies were carried out: in one study the stapes was intact, and in the other the stapes arch was absent. The columella techniques we examined, from a hearing point of view, are total and partial ossicular replacement prostheses, ossiculoplasty, cartilage with or without perichondrium, and the myringostapediopexy. RESULTS AND CONCLUSIONS: In the group of patients in whom the stapes was intact, the differences in high-pitched frequencies found between the different techniques were negligible, but the differences were quite significant in conversational frequencies, where the partial ossicular replacement prosthesis turned out to be the technique with the worst results. In ears in which only the footplate was present, the total ossicular replacement prosthesis gave better results than any other technique, both in conversational frequencies and in 4000-Hz frequency.

The effects of added dietary lipid on the body composition of rams and wethers

1975 ◽  
Vol 84 (2) ◽  
pp. 201-208 ◽  
Author(s):  
M. A. Price
Keyword(s):  
Body Composition ◽  
Fat Body ◽  
Maximum Growth ◽  
Dietary Lipid ◽  
Maximum Growth Rate ◽  
The Body ◽  
Lower Percentage ◽  
Factorial Trial ◽  
Lower Maximum ◽  
Free Body

SUMMARYA 2 × 3 factorial trial designed to investigate the effects of castration and three diets on growth and body composition of 30 male Dorset Horn × (Border Leicester × Merino) lambs is described. The three diets were: (a) a standard ration of equal weights of lucerne chaff and pelleted concentrates; (b) a similar ration to (a) plus 7·5% by weight of lipid (peanut oil and tallow); (c) a greater ration of (a) calculated to be isocaloric for digestible energy with diet (b).At the beginning of the trial a group of 40 lambs (20 rams, 20 wethers) were shorn and five rams and five wethers were selected at random and slaughtered to establish initial body composition. The remaining 30 lambs, 15 rams and 15 wethers aged about 22 weeks and having mean weights of 33·0 kg (rams) and 31·2 kg (wethers), were randomly divided within sex into three groups and allocated to the three diets for 92 days. At the end of this period the lambs were again shorn, and then slaughtered and dressed.During the trial, rams gained significantly (P < 0·001) more weight than wethers, and lambs on diet (a) gained significantly (P < 0·01) less weight than those on (b) and (c). Weight gains on the latter two diets were similar. Diet generally had little effect on body composition, although there was a tendency, within sexes, for lambs on diet (b) to have a greater fat content than those on the other diets. Rams had significantly greater carcass weights (P < 0·01), head percentage (P < 0·001) and various m. longissimus dorsi dimensions than wethers, but significantly less fat in all the locations measured, including a lower percentage of chemically extractible fat in the offals and carcasses. Estimations of the energy stored in the wool-free body during the trial indicated that wethers stored significantly more energy in the form of fat than rams (P < 0·001), but that rams stored significantly more non-fat energy than wethers (P < 0·001). It is concluded that a maximum growth rate exists for the non-fat body, and that it is higher in rams than wethers. Thus the addition of dietary lipid (which increases energy intake with comparatively small increases in weight or volume of feed), is more likely to promote fat deposition in wethers, which have a lower maximum capacity for non-fat storage, than in rams.

The roles of microbes in the removal and inactivation of viruses in a biological wastewater treatment system

1996 ◽  
Vol 33 (10-11) ◽  
pp. 243-250 ◽  
Author(s):  
Tae-Dong Kim ◽  
Hajime Unno
Keyword(s):  
Activated Sludge ◽  
The Other ◽  
Virus Concentration ◽  
Activated Sludge Process ◽  
Filter Feeder ◽  
Virus Removal ◽  
First Order ◽  
Second Stage ◽  
Strong Filter ◽  
Model Virus

The objective of this research is to clarify the mechanism for virus removal in an activated sludge process. The roles of microbes, i.e. bacteria, protozoa and metazoa, which form activated sludge were investigated using poliovirus as a model virus. In a bacteria cultures, the virus concentration decreased in the first one hour after which no further decrease was observed. This phenomenon is explained by the interaction of bacterial floc and virus where virus was removed by reversible adsorption. On the other hand, in the mixed culture of bacteria and protozoa, or of bacteria and metazoa, the virus removal process was observed to proceed in two first-order processes. In the first stage, virus was removed from the liquid phase by adsorption onto the floc, whereas in the second stage, virus is removed by predation of the other microbes, i.e. protozoa or metazoa. Moreover, the floc-forming ability and the feeding manner of the microbes strongly affected the virus removal. Especially, a filter feeder microbe was more effective in virus removal than a detritus feeder microbe. Among the microbes used in the experiments, P. erythrophthalma which had a large mouth and a strong filter-feeding ability as well as a high floc-forming ability showed the most efficient virus removal.

scholarly journals Effects of Different Stress Parameters on Growth and on Oleuropein-Degrading Abilities of Lactiplantibacillus plantarum Strains Selected as Tailored Starter Cultures for Naturally Table Olives

2020 ◽  
Vol 8 (10) ◽  
pp. 1607
Author(s):  
Amanda Vaccalluzzo ◽  
Alessandra Pino ◽  
Maria De Angelis ◽  
Joaquín Bautista-Gallego ◽  
Flora Valeria Romeo ◽  
...  
Keyword(s):  
Salt Content ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Starter Cultures ◽  
Stress Factors ◽  
Process Conditions ◽  
Table Olives ◽  
Low Salt ◽  
Beta Glucosidase ◽  
Selection Of

The use of β-glucosidase positive strains, as tailored-starter cultures for table olives fermentation, is a useful biotechnological tool applied to accelerate the debittering process. Nowadays, strains belonging to Lactiplantibacillus plantarum species are selected for their high versatility and tolerance to stress conditions. The present study investigated the effect of different stress factors (pH, temperature and NaCl) on growth and on oleuropein-degrading abilities of selected L. plantarum strains. In addition, the presence of the beta-glucosidase gene was investigated by applying a PCR based approach. Results revealed that, overall, the performances of the tested strains appeared to be robust toward the different stressors. However, the temperature of 16 °C significantly affected the growth performance of the strains both singularly and in combination with other stressing factors since it prolongs the latency phase and reduces the maximum growth rate of strains. Similarly, the oleuropein degradation was mainly affected by the low temperature, especially in presence of low salt content. Despite all strains displayed the ability to reduce the oleuropein content, the beta-glucosidase gene was detected in five out of the nine selected strains, demonstrating that the ability to hydrolyze the oleuropein is not closely related to the presence of beta-glucosidase. Data of the present study suggest that is extremely important to test the technological performances of strains at process conditions in order to achieve a good selection of tailored starter cultures for table olives.

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