We are observing the stalked ciliates in SBR sludge in pilot SBR plant since from a month. The concentration is increasing and we can see them with eyes. We observed them under microscopy; they are active and eating microbes (probably). The SRT of the plant is 10 days and HRT is 13 hrs. The plant is performing well and SVI is about 90-100 ml/gm. We are curious about the quantity of ciliates, might impact on plant performance.
Any research data/ experience about higher life forms in SBR sludge can be helpful for further interpretations.
It indicates a healthy biomass!
Flagelates and swimming ciliates are normally present at a short sludge but at a sludge age greater than 10 days expect crawling and stalked ciliates. They may help reduce turbidity by feeding on free bacteria. Expect a reduction in ciliates at a higher sludge age and an appearance of rotifers.
Protozoa in Biological Sewage Treatment Processes ii. Protozoa as Indicators in the Activated Sludge Process, Curds et al, (1970) Water Research.
Sandip, the role of protists feeding on bacteria in treatment processes has been well documented, this is the earliest paper I know of:
Butterfield, C.T., W.C. Purdy, and E.J. Theriault. 1931. Experimental studies of natural purification in polluted waters IV. The influence of the plankton on the biochemical oxidation of organic matter. Public Health Reports 46:393-426.
but there are other more recent ones, search for the authors Curds, Madoni, and
this .pdf might also help: http://www.formatex.info/microbiology2/972-979.pdf
Hello Sandip,
Members of this group of protozoa have stalks with which they attach to floc particles or other surfaces. These stalks render the organism sessile for the most part. With their rings of cilia surrounding their opening, stalked ciliates are very efficient feeders. In the presence of low dissolved oxygen they can contract their stalks, and/or swim to a location of higher dissolved oxygen. Ciliates of this group may have singular stalks or colonial stalks, depending upon species. They are found in the environment when bacterial floc or population is mature, D.O. is high, and overall bacterial concentration is high. They serve as good indicators of a stable wastewater environment, and generally healthy sludge. Example: Vorticella, Tokophyra, Epistylis sp.
(Source:InterBio Inc. Woodlands, TX 77381,United States).
hello!
I agree with former answers - stalked ciliates are normally found in starting phases of ASWWTPs, in concentrations ranging from 10E4 to 10E5 / liter.
But they are also well adapted under transient conditions, i.e. sludge losses, hydraulic transient overload or intermittent low recirculating flow. For instance, they may be encountered in concentrations over 10E6 / liter as soon as one day after a recirculating pump breakdown.
Furthermore, stalked ciliates genera differ strongly along with other parameters like effluent origin or aeration pattern, so it would be a valuable information to identify the genera (refer to the old Curds identification key, more recently traduced in italian by Madoni, or to the excellent "how to know the protozoa" by Jahn and Bovee).
For more details refer to following papers and especially the last one (I strongly apologize for these papers are very old and written in french...):
DRAKIDÈS C., 1977. Étude d'une biocénose en conditions limitantes. Cas de l'adaptation d'une boue activée à un effluent industriel (monopropylène- glycol en présence de Ca Cl2). La Technique de l'Eau et de l'Assainissement, 365, 21-32.
DRAKIDÈS C., 1978. L'observation microscopique des boues activées appliquée à la surveillance des installations d'épuration: technique d'étude et interprétation. Techniques et Sciences Municipales, 2 - 78, 85-98.
DRAKIDÈS C., 1980. La microfaune des boues activées. Étude d'une méthode d'observation et application au suivi d'un pilote en phase de démarrage. Water Research, 14, 1199-1207.
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