Studies of Procedures for Recovery of Viruses from Activated Sludge

1986 ◽  
Vol 18 (10) ◽  
pp. 149-156 ◽  
Author(s):  
Etsuko Shimohara ◽  
Minoru Nashida ◽  
Mitsumi Kaneko
Keyword(s):  
Activated Sludge ◽  
Recovery Efficiency ◽  
Average Recovery ◽  
Extract Solution ◽  
Beef Extract ◽  
The Media ◽  
Virus Recovery

Several elution media were examined to evaluate their suitability for recovering seeded poliovirus 1 from return activated sludge. Although there were no distinct differences of virus recovery efficiency among the media tested, 3% beef extract solution at pH 9 seemed to be the most practical eluent for the recovery of the viruses adsorbed from the sludge with an average recovery efficiency of 21%, with a range of 6.1 to 34%. The organic flocculation procedure using beef extract was applied to concentrate the eluted viruses. Its effect depended on the type of eluate, and viruses were not always concentrated well.

Round robin investigation of glass wool method for poliovirus recovery from drinking water and sea water

1997 ◽  
Vol 35 (11-12) ◽  
pp. 445-449 ◽  
Author(s):  
Ph. Vilaginès ◽  
B. Sarrette ◽  
H. Champsaur ◽  
B. Hugues ◽  
S. Dubrou ◽  
...  
Keyword(s):  
Sea Water ◽  
Glass Wool ◽  
Recovery Efficiency ◽  
Average Recovery ◽  
Drinking Waters ◽  
Water Microbiology ◽  
The Mean ◽  
Standard Deviations ◽  
Virus Recovery ◽  
Iso 5725

This study was initiated by the AFNOR water microbiology working group to evaluate the performance of the glass wool method for virus recovery. Its reliability was tested with drinking and sea water by respectively nine and thirteen laboratories. In both trials, six were actively involved in water virology research, one was designated as a central laboratory, the others had no experience in virological practices. Analysis of reproducibility and repeatability according to NF-ISO 5725-2 were realized. For drinking waters (24 assays), the average recovery efficiency was 72%, mean standard deviations: repeatability 12.4%; reproducibility 33.6%; inter-laboratories 21%. For sea waters (39 assays), the average recovery efficiency was 75% and the mean standard deviations 6.9%, 17.9% and 11% respectively.

Evaluation of hybrid processes for nitrification by comparing MBBR/AS and IFAS configurations

2007 ◽  
Vol 55 (8-9) ◽  
pp. 43-49 ◽  
Author(s):  
E. Germain ◽  
L. Bancroft ◽  
A. Dawson ◽  
C. Hinrichs ◽  
L. Fricker ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Biofilm Reactor ◽  
Nitrite Accumulation ◽  
Removal Rates ◽  
Solids Retention ◽  
Different Temperatures ◽  
Suspended Biomass ◽  
The Media ◽  
Population Counts ◽  
Ammonia Oxidising Bacteria

An integrated fixed-film activated sludge (IFAS) pilot plant and a moving bed biofilm reactor coupled with an activated sludge process (MBBR/AS) were operated under different temperatures, carbon loadings and solids retention times (SRTs). These two types of hybrid systems were compared, focusing on the nitrification capacity and the nitrifiers population of the media and suspended biomass alongside other process performances such as carbonaceous and total nitrogen (TN) removal rates. At high temperatures and loadings rates, both processes were fully nitrifying and achieved similarly high carbonaceous removal rates. However, under these conditions, the IFAS configuration performed better in terms of TN removal. Lower temperatures and carbon loadings led to lower carbonaceous removal rates for the MBBR/AS configuration, whereas the IFAS configuration was not affected. However, the nitrification capacity of the IFAS process decreased significantly under these conditions and the MBBR/AS process was more robust in terms of nitrification. Ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB) population counts accurately reflected the changes in nitrification capacity. However, significantly less NOBs than AOBs were observed, without noticeable nitrite accumulation, suggesting that the characterisation method used was not as sensitive for NOBs and/or that the NOBs had a higher activity than the AOBs.

Comparison of Three Methods for the Concentration of Poliovirus from Moroccan Shellfish

1994 ◽  
Vol 57 (11) ◽  
pp. 996-1000 ◽  
Author(s):  
NOURREDINE BOUCHRITI ◽  
SAGAR M. GOYAL ◽  
ABDELHAK El MARRAKCHI ◽  
MOHAMMED JELLAL
Keyword(s):  
Mytilus Edulis ◽  
Crassostrea Gigas ◽  
Acid Precipitation ◽  
Precipitation Method ◽  
Ruditapes Decussatus ◽  
Beef Extract ◽  
Dry Milk ◽  
Virus Recovery

Three methods were evaluated for the concentration of poliovirus from artificially contaminated oysters (Crassostrea gigas), mussels (Mytilus edulis) and carpet-shell clams (Ruditapes decussatus) grown in Morocco. The methods tested were: an adsorption-elution-precipitation method, a beef extract elution acid-precipitation method, and a non-fat dry milk elution acid-precipitation method. For all shellfish species tested, the adsorption-elution-precipitation method yielded the lowest average virus recovery (27%), whereas the two elution-precipitation methods yielded average virus recoveries of 42% each. The beef extract elution acid-precipitation method yielded the highest virus recovery with clams (53%), whereas non-fat dry milk elution acid-precipitation was advantageous for mussels providing average virus recovery of 47%. For oysters, none of the tested methods gave satisfactory virus recovery. These results point towards the need for the development of better method(s) for the concentration of viruses from Moroccan oysters, while for mussels and clams, the elution-acid precipitation methods may be satisfactory.

Full-scale evaluation of an integrated fixed-film activated sludge (IFAS) process for enhanced nitrogen removal

1996 ◽  
Vol 33 (12) ◽  
pp. 155-162 ◽  
Author(s):  
Clifford W. Randall ◽  
Dipankar Sen
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Plug Flow ◽  
Treatment Plant ◽  
Nitrification Rate ◽  
A Value ◽  
Fixed Film ◽  
Control Section ◽  
The Media ◽  
Retrofit Design

One of the two trains of the 37,000 m3/d Annapolis, Maryland step aeration activated sludge treatment plant was modified for single-sludge anoxic-aerobic operation, and then fixed-film media were integrated into the aerobic zone to enhance nitrification. Rope-like Ringlace media was selected for integration, and 30,000 meters were installed in a volume of 475 m3 for a pilot demonstration. The purpose of the integrated fixed-film media was to upgrade the short hydraulic retention time (HRT) basin (6 hrs nominal) for efficient, year-round nitrogen removal without construction to increase basin volume. An engineering study had concluded that upgrading the facility for year round complete nitrification, without nitrogen removal, would cost US$24 million. The modified train was operated for 12 months, six in the plug-flow MLE configuration, and six in a step-feed configuration. The integrated Ringlace media increased the nitrification rate per unit volume to 225% of that observed in the control section, attaining a value of 1.75 kg/d NH3-N per linear meter at 15°C. The media also increased denitrification in the aerobic media section to the extent that between 30 and 88% of the nitrates formed in the section were denitrified within it, permitting a potential 25% or more reduction in the volume of the anoxic zone. An IFAS retrofit design was developed which incorporated step-feed operation, and reduced the projected construction cost to US$9.2 million.

Modified Procedure for Extraction of Poliovirus from Naturally-Infected Oysters Using Cat-Floc and Beef Extract

1980 ◽  
Vol 43 (2) ◽  
pp. 91-94 ◽  
Author(s):  
EDWARD F. LANDRY ◽  
JAMES M. VAUGHN ◽  
THOMAS J. VICALE
Keyword(s):  
Crassostrea Gigas ◽  
Extraction Procedure ◽  
Acid Precipitation ◽  
Poliovirus Type ◽  
Extraction Procedures ◽  
Precipitation Technique ◽  
Beef Extract ◽  
Virus Recovery

Methods for recovery of poliovirus type 1 (LSc2ab) from naturally-infected oysters (Crassostrea gigas) were examined. Extraction procedures analyzed included glycine-saline and polyelectrolyte (Cat-Floc) methods followed by concentration using modifications of an acid precipitation technique, Direct viral assay of shellfish homogenates, when compared to virus recovery following extraction, indicated that substantially fewer viruses were detected in initial homogenates. These data appeared to support the contention that input values based on homogenate assay were inappropriate in determining recovery efficiencies with naturally-infected shellfish. Since absolute efficiencies could not be determined, relative efficiencies using samples from pooled homogenates were used to determine the recovery efficiencies of various extraction procedures. Cat-Floc extraction followed by a beef extract-modified acid precipitation technique resulted in higher virus recoveries than a glycine-saline extraction procedure.

Evaluation of fluorogenic TSC agar for recovering Clostridium perfringens in groundwater samples

2001 ◽  
Vol 43 (12) ◽  
pp. 201-204 ◽  
Author(s):  
M. Araujo ◽  
R. A. Sueiro ◽  
M. J. Gómez ◽  
M. J. Garrido
Keyword(s):  
Water Pollution ◽  
Clostridium Perfringens ◽  
Membrane Filtration ◽  
The Other ◽  
Human Consumption ◽  
Recovery Efficiency ◽  
Groundwater Samples ◽  
Pollution Indicator ◽  
The Media ◽  
Filtration Technique

Clostridium perfringens is widely recognised as a reliable water pollution indicator. Since several media can be employed for the membrane filtration enumeration of this microorganism, the main aim of this work was to investigate the ability of fluorocult-supplemented TSC-agar (Merck) for recovering Cl. perfringens from public springs used for direct human consumption. Cl. perfringens recovery was also performed on mCP agar (Cultimed) according to Directive 98/83 as well as on TSC-Agar (Merck), TSN-Agar (Merck) and SPS-Agar (BBL) media. Variance analysis of data obtained showed no statistically significant differences in the counts obtained among all media employed in this work. However, the Cl. perfringens recovery efficiencies with TSC and fluorogenic TSC agars were significantly greater (P = < 0.05) than the corresponding values of mCP and TSN media. On the other hand, the identification of typical and atypical colonies isolated from all media demonstrated that fluorogenic TSC agar was the most specific medium for Cl. perfringens recovery in groundwater samples (85.3% of typical colonies and 82.8% of atypical colonies confirmed). In summary, the membrane filtration technique with fluorogenic TSC agar showed the best performance characteristics of all the media tested as judged by their recovery efficiency and specificity in these water samples.

Comparison of Two Methods for the Recovery of Rotavirus from Mussels and Oysters

1991 ◽  
Vol 24 (2) ◽  
pp. 423-426 ◽  
Author(s):  
S. Boher ◽  
C. Beril ◽  
D. Terver ◽  
L. Schwartzbrod
Keyword(s):  
Polyethylene Glycol ◽  
Borate Buffer ◽  
Cover Slip ◽  
Beef Extract ◽  
Second Procedure ◽  
Virus Recovery ◽  
Concentration Methods ◽  
Polyethylene Glycol 6000

Two extraction-concentration methods for recovering rotavirus from mussels and oysters are compared. Molluscs are artificially contaminated by a one hour stay in seawater seeded with rotavirus SA 11. Results show that the first procedure using a glycine-NaCl pH 10 solution and an organic flocculation gives quite similar virus recovery from mussels and oysters, whatever the quantities of rotavirus in seawater are. The second procedure using a borate buffer - 3 % beef extract pH 9 and a double precipitation with Polyethylene glycol 6000 leads in most cases to a more efficient virus recovery, based on immunofluorescent foci counts on cover slip cultures of MA 104.

Modifications of the Tentative Standard Method for Improved Virus Recovery Efficiency

1980 ◽  
Vol 72 (6) ◽  
pp. 350-355 ◽  
Author(s):  
Mark D. Sobsey ◽  
J. Steven Glass ◽  
Robert R. Jacobs ◽  
William A. Rutala
Keyword(s):  
Standard Method ◽  
Recovery Efficiency ◽  
Virus Recovery

Effects of Suspended Solids on Inactivation of Poliovirus by Chlorine

1983 ◽  
Vol 15 (5) ◽  
pp. 137-143 ◽  
Author(s):  
Mitsumi Kaneko ◽  
Hideko Igarashi
Keyword(s):  
Activated Sludge ◽  
Contact Time ◽  
Suspended Solids ◽  
Residual Chlorine ◽  
Protective Effects ◽  
Beef Extract

Attempts were made to indicate the protective effects of the suspended solids for inactivation of polioviruses in water by chlorine. Solids associated viruses, which were prepared by centrifugation after mixing polioviruses with sterilized kaoline or activated sludge and/or by elution with pH 8, 2% beef extract, were inactivated by chlorine. The activated sludge was found to absorb 96% of total poliovirus added, whereas 74% of the viruses added was absorbed to the kaoline. It has become clear that activated sludge which is porous in structure protects the viruses from inactivation by chlorine more effectively than kaoline does. When the concentration of the virus-containing solids was 10 mg/l, initial residual chlorine of 1.0 mg/l was not enough to get more than 3 log10 viral reduction with 30 minutes contact time. The concentration of 1.0 mg/l could affect inactivation of viruses seriously.

Estimation of Biomass Concentration and Population Dynamics in a Captor® Activated Sludge System

1994 ◽  
Vol 29 (7) ◽  
pp. 149-152 ◽  
Author(s):  
M. P. Reddy ◽  
K. R. Pagilla ◽  
P. R. Senthilnathan ◽  
H. W. Johnson ◽  
P. S. Golla
Keyword(s):  
Population Dynamics ◽  
Activated Sludge ◽  
Microbial Population ◽  
Biomass Concentration ◽  
Activated Sludge Process ◽  
Free Swimming ◽  
Activated Sludge System ◽  
Suspended Growth ◽  
Fixed Film ◽  
The Media

A technique was developed to measure the equivalent MLSS in the fixed film Captor® media-activated sludge process. The technique accounts for the wear in the media as well as unequal wear in different media. The microbial population variations encountered during three years of full scale operation of the Captor® process, at the Moundsville WWTP were recorded. It has been found that fixed film media seem to support predominantly rotifers, followed by free swimming ciliates, and single stalk ciliates. In contrast, the suspended growth activated sludge population contained lower level organisms, mostly free swimming ciliates, followed by stalk ciliates, flagellates, and a few rotifers.

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