The Microthrix parvicella Puzzle

1994 ◽  
Vol 29 (7) ◽  
pp. 271-279 ◽  
Author(s):  
Dick H. Eikelboom
Keyword(s):  
The Netherlands ◽  
Activated Sludge ◽  
Population Size ◽  
Nutrient Removal ◽  
Ecological Niche ◽  
Control Strategies ◽  
Maximum Size ◽  
Activated Sludge Process ◽  
Filamentous Bacteria ◽  
Microthrix Parvicella

Nowadays the excessive growth of many filamentous bacteria in activated sludge plants can be controlled by the application of so-called selectors. In the Netherlands, about 80 selectors have been constructed at full scale plants so far. However, selectors are frequently not very effective for controlling bulking if M. parvicella is dominating the sludge population. As M. parvicella has also been frequently observed in nutrient removal plants, the development of control strategies for this bacterium has become very urgent. From the substantial information on the occurrence of and attempts to control M. parvicella collected during the last decade, several main conclusions can be drawn.The development of M. parvicella in Dutch treatment plants shows a very distinctive seasonal rhythm, the population reaching its maximum size in early spring.Foaming in Dutch treatment plants is usually caused by M. parvicella.M. parvicella and Actinomycetes spp. seem to compete for the same ecological niche in treatment plants.By comparing the population size of M. parvicella as a function of various modifications in the activated sludge process, it is concluded that this bacterium grows better in so-called carrousel systems than in other extended aeration plants.M. parvicella causes severe bulking in carrousels fed with presettled sewage.The impact/usefulness of selectors for controlling M. parvicella seems to decrease as the overall sludge load of the plant increases. This information is presented to start a discussion about possibilities to solve the M. parvicella puzzle.

scholarly journals Molecular analyses of pure cultures of filamentous bacteria isolated from activated sludge

2005 ◽  
Author(s):  
◽  
Dashika Naidoo
Keyword(s):  
Activated Sludge ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Control Strategies ◽  
In Situ Hybridisation ◽  
Process Efficiency ◽  
Nucleotide Sequencing ◽  
Activated Sludge Process ◽  
Filamentous Bacteria ◽  
Morphological Variations ◽  
Pure Cultures

The activated sludge process is the mostl used biological treatment process. Engineers and microbiologists are constantly seeking ways to improve process efficiency, which can be attributed to the increasing demand for fresh water supplies and proper environmental management. Since the inception of the activated sludge process, bulking and foaming have been major problems affecting its efficiency. Filamentous bacteria have been identified as the primary cause of bulking and foaming. Numerous attempts have been made to resolve this problem. Some of these attempts were effective as interim measures but failed as long term control strategies. The identification of filamentous bacteria and the study of their physiology have been hampered by the unreliability of conventional microbiological techniques. This is largely due to their morphological variations and inconsistent characteristics within different environments. To fully understand their role in promoting bulking and foaming, filamentous bacteria need to be characterized on a molecular level. The aim of this study was, therefore, to identify filamentous bacteria in pure culture with the purpose of validating these findings to the physiological traits of the pure cultures when they were isolated. Fourteen different filamentous cultures were used for this study. The cultures were identified using specific oligonucleotide probes via fluorescent in situ hybridisation and nucleotide sequencing. Prior to sequencing, an agarose gel and a denaturing gradient gel Electrophoresis profile were determined for each isolate. The various techniques were optimised specifically for the filamentous isolates. The isolates were identified as Gordonia amarae, Haliscomenobacter hydrossis, Acinetobacter sp./Type 1863, Type 021N, Thiothrix nivea, Sphaerotilus natans and Nocardioform organisms.

Causes of, and control strategies for, Microthrix parvicella bulking and foaming in nutrient removal activated sludge systems

1998 ◽  
Vol 37 (4-5) ◽  
pp. 9-17 ◽  
Author(s):  
D. Mamais ◽  
A. Andreadakis ◽  
C. Noutsopoulos ◽  
C. Kalergis
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Control Strategies ◽  
Plug Flow ◽  
Pilot Scale ◽  
Long Chain Fatty Acids ◽  
Flow Reactors ◽  
Microthrix Parvicella ◽  
And Control ◽  
Activated Sludge Systems

Bench and pilot scale nutrient removal activated sludge units were used to examine the effect of factors such as temperature, substrate type (easily biodegradable in the form of acetate and slowly biodegradable in the form of oleic acid) on Microthrix parvicella growth. The configurations examined include complete mix with and without selectors (anoxic and anaerobic) and plug flow reactors. The results indicate that low temperatures and substrates in the form of long chain fatty acids favour the growth of M. parvicella. With respect to reactor configuration, a plug flow configuration was shown to be quite effective in controlling the growth of M. parvicella and producing a sludge with good settling characteristics, while the presence of a selector, either anoxic or anaerobic, had no significant effect on the growth of M. parvicella.

Performances of three R-AN-D-N wastewater treatment plants in the Czech Republic

2004 ◽  
Vol 50 (7) ◽  
pp. 249-255 ◽  
Author(s):  
Z. Bejvl ◽  
P. Matuška ◽  
J. Stara ◽  
P. Chudoba
Keyword(s):  
Wastewater Treatment ◽  
Czech Republic ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Industrial Effluents ◽  
Filamentous Bacteria ◽  
The Czech Republic ◽  
Treated Sewage ◽  
Nutrient Removal Efficiency

The evolution of Czech standards requires higher efficiency of nutrient removal from municipal wastewaters. At the beginning of the last decade of 20th century, a new activated sludge configuration called R-AN-D-N process has been described, successfully tested and now largely used at several wastewater treatment plants (WWTP) in the Czech republic. The main feature of the R-AN-D-N process is the introduction of a regeneration zone in sludge recycle, which enables to increase sludge age in the system without any substantial increase in WWTP volume. Performances of three Czech large WWTP with R-AN-D-N configuration have been monitored and compared within a period of one and a half years. The results confirmed excellent nutrient removal efficiency for wastewaters with different proportion between sewage and industrial effluents. Two of three monitored WWTP received wastewaters from breweries (Budweiser and Pilsner Urquell). The settleability of activated sludge from all three WWTP was correct, with SVI values usually ranging from 50 to 150 ml/g. Monitoring of sludge composition indicated proliferation of several filamentous bacteria, particularly types 0581, 0092 and M. parvicella. No severe bulking events were observed. Finally, the operational costs expressed in CZK (Czech crown: 1CZK = €0.0322) per cubic metre of treated sewage or per capita amounts respectively from 2.24 to 6.52, and from 285 to 342.

Sewage-treatment under substantial load variations in winter tourism areas – a full case study

2004 ◽  
Vol 50 (7) ◽  
pp. 147-155 ◽  
Author(s):  
S. Winkler ◽  
N. Natsché ◽  
T. Gamperer ◽  
M. Dum
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Sewage Treatment ◽  
Activated Sludge Process ◽  
Two Stage ◽  
Winter Tourism ◽  
Load Variations ◽  
Sudden Load

The sewage-load variations in winter tourism areas are characterized by sudden increases - in the ange of a factor two to three - within only a few days at the start and the end of the tourist season, especially at Christmas. The sudden load increases occur during periods of low wastewater temperatures, which is an additional demanding factor with respect to nitrogen removal. A full case study was carried out at WWTP Saalfelden, which is located near one of Austria's largest skiing resorts. The plant is designed for 80,000 PE and built according to the HYBRID®-concept, which is a special two stage activated sludge process for extensive nutrient removal.

FLUORESCENCE MONITORING OF AN ALTERNATING ACTIVATED SLUDGE PROCESS

1994 ◽  
Vol 30 (4) ◽  
pp. 229-238 ◽  
Author(s):  
S. Isaacs ◽  
M. Henze
Keyword(s):  
Oxygen Uptake ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Oxygen Uptake Rate ◽  
Peak Oxygen Uptake ◽  
Activated Sludge Process ◽  
Anaerobic Conditions ◽  
Mode Of Operation ◽  
Operation Cycle ◽  
Abrupt Rise

The fluoresence of a nitrification/denitrification tank in an activated sludge nutrient removal process was monitored over a two month period. The process employs an alternating mode of operation which subjects the sludge to a periodically changing environment (aerobic, anoxic and anaerobic) at the point in the process where the fluoresence is measured. The fluoresence signal decreased slowly during aerated periods and increased slowly during anoxic (denitrifying) periods. An abrupt rise in the fluoresence signal was found to occur upon the transition from anoxic to anaerobic conditions. The minimum fluoresence signal occurring during each operation cycle appeared to define a baseline whose general upward and downward movements correlated well with peak oxygen uptake rate.

Towards understanding the taxonomy of some of the filamentous bacteria causing bulking and foaming in activated sludge plants

1996 ◽  
Vol 34 (5-6) ◽  
pp. 137-144 ◽  
Author(s):  
Linda L. Blackall ◽  
Elizabeth M. Seviour ◽  
Debbie Bradford ◽  
Helen M. Stratton ◽  
Mitchell A. Cunningham ◽  
...  
Keyword(s):  
Activated Sludge ◽  
16S Rdna ◽  
Phylogenetic Relationship ◽  
Pure Culture ◽  
Gram Negative Bacteria ◽  
Filamentous Bacteria ◽  
Gram Negative ◽  
Rdna Sequences ◽  
16S Rdna Sequences ◽  
Microthrix Parvicella

Several filamentous bacteria obtained in pure culture from activated sludge plants were characterised using their 16S rDNA sequences to determine their phylogenetic relationship to other bacteria. “Microthrix parvicella” was shown to be an unusual actinomycete, while the Gram negative bacteria Type 0092, Type 0411 and Type 1863 all belong to the Flexibacter-Cytophaga-Bacteroides phylum, and Type 0803 is a member of the beta subclass of the Proteobacteria. The practical value of obtaining this information is discussed.

Effect of Supplemental Carbon Source on Phosphate Removal in an Alternating Activated Sludge Process

1993 ◽  
Vol 28 (11-12) ◽  
pp. 499-512 ◽  
Author(s):  
S. H. Isaacs ◽  
M. Henze ◽  
H. Søeberg ◽  
M. Kümmel
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Plant ◽  
Phosphate Uptake ◽  
Phosphate Removal ◽  
Activated Sludge Process ◽  
Significant Release

Pilot plant studies indicate that the addition of COD in the form of acetate to an alternating nutrient removal activated sludge process as a means to improve denitrification rates is not detrimental to biological phosphate removal. This is in spite of the fact that the added acetate can cause a significant release of phosphate during the anoxic phases in the aeration tanks. The added COD also appears to result in increased rates of aerobic phosphate uptake, thus improving the phosphate removal ability of the process. These observations are presented and discussed in the paper.

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