RTW Engineering - Filamentous Microorganism Identification

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Filamentous Microorganism Identification

Tetra Tech RTW has extensive experience in identifying microorganisms found in activated sludge. This experience provides Tetra Tech RTW a basis from which to assist its clients with problems related to plant upset, whether bulking or foaming in nature. For example, it is well established that filamentous microorganisms grow in response to the environmental conditions experienced in the activated sludge treatment process. As a result, these microorganisms may be present in excessive numbers, thereby producing conditions of poor settling in clarifiers or foaming in aeration basins. Alternatively, under certain conditions, sludge microorganisms may produce unwanted levels of polysaccharides that may also degrade sludge quality. Therefore, under conditions of plant upset, identification of the associated microorganisms or the presence of excessive polysaccharide can help prescribe solutions to mitigate or to avoid altogether the undesirable condition. In other words, by determining predominant constituents under poor operating conditions, Tetra Tech RTW can suggest a remedial plan to produce a higher quality, more controllable activated sludge.
Tetra Tech RTW utilizes various microscopic observation methods for Filament Identification including:

Wet Mounting
Gram Staining
Neisser Staining
PHB Staining
Sheath Staining
Polysaccharide (India Ink) Staining
Sulfur Oxidation Testing

Sample Preparation and Delivery
Please provide Tetra Tech RTW with approximately 30 milliliters of liquid sample (usually taken from mixed liquor or foam froth in an aeration basin or oxidation ditch). It is important to ensure that the sample is taken from a well-mixed zone near the end of the process (i.e., prior to the feed to the clarifier) and that samples not include material scraped from the sidewalls of the basin. Further, in the case of foam samples, it is important that these samples be removed from a location near the center of the basin, as opposed to near the sidewalls where the foam may have 'aged' since its generation. The 30-ml sample should be placed in a 100-ml plastic screw-top bottle. It is important to ensure that at least 50% of the bottle volume remains as headspace so as to maintain aerobic conditions in the liquid sample during shipping. Securing the closed screw-top cap with electrical tape can provide extra security against sample leakage. Please note that it is unnecessary to send samples in an ice chest.

Please send the sample via overnight delivery to:
Ronald G. Schuyler
Senior Consultant
Tetra Tech RTW Engineering
1576 Sherman Street, Suite 100
Denver, CO 80203-1713

For planning purposes, please notify Ronald G. Schuyler, P.E., B.C.E.E prior to sending samples at Ron.Schuyler@tetratech.com. Any questions related to filamentous microorganism identification can also be directed to Mr. Schuyler either via email or by telephone. The cost for the service is $350 per evaluation, which includes a letter report and photomicrographs.