S. natans


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Bioaugmentation products for Wastewater applications in Papermills, Refineries, Chemical, Tanneries, Municipalities, Textiles, Steel, Agriculture, Animal feedlot,  Gun Powder plant, Food and Beverage- Dairy Products, Orange Juice factory, Wineries, Cookie factory, Vegetable processing plant, Meat packing, Barbecue Restaurant, Aquaculture, Ornamental Ponds for algae control, CAFO, Nursing homes, Military, Campgrounds, Universities, Regulatory agencies


Lab Services:



Filamentous Identification Lab Service. One reason to identify filaments is to determine the filaments characteristics and then determine the type present.  If the type is found out, a root cause can usually be associated with a particular filament.  If the cause is known, then a correction can be made to alleviate problems. Chlorination is only a quick fix.  Without process changes, filaments will grow back after chlorination.

Wastewater Biomass Analyses and Cooling Tower Analyses also available


Training Materials:



Training is an integral part of any job. Not everyone is at the same level of training. Many people want beginning concepts and basics. Some need technical information or troubleshooting. Some want equipment, technology or process information.

We have developed a full set of Basic training, Advanced training, Filamentous Identification the Easy Way as well as custom training CD's Manuals. We also provide hands-on training classes and soon will have an Online "E-University".




 Sphaerotilus natans


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S. natans filamentous identification



We hope you like the new look of our Filamentous Bacteria Identification Pages

If you would like more information on filaments, you might want to consider purchasing our Filamentous Identification the Easy Way Training materials.

We also have our lab that can perform a Filamentous identification lab analyses of your own MLSS for more information


Sphaerotilus natans

This filament is very common in low D.O. environments. Don't get overly technical.  When trying to determine species, stick to the basics, and focus on the causes and controls of the filaments present. The main point of any filamentous identification is not to get a PhD, but to fix your plant!



Relatively long , non-motile filaments (100-1000 µm). Straight or smoothly curved with tree-like false branching.  The cells are round-ended and rod shaped (1.0-1.8 x 1.5-3.0) and are contained in a clear, tightly fitting sheath.   Note: They can be rectangular when the cells are tightly packed within the sheath.  The cell septa are clear and easily observable with indentations. Filaments radiate outward from the floc surface into the bulk solution and can cause sludge settling interference by inter-floc bridging.  The filament is usually Gram negative and Neisser negative.  There are no sulfur granules. Poly-ß-hydroxybutric acid  (PHB) is frequently observed as dark intracellular granules.  In wastewater that is nutrient deficient, an exocellular slime coat may be present.  Attached growth is usually uncommon, but may occur when at low growth rate.


Similar Organisms:

Type 1701 may be related, but the diameter is much smaller.



This filament is usually found in environments where there is low DO but reasonable F/M ratios.  Can be caused by too long RAS lines or sludge being held too long in the secondary clarifier.



RAS chlorination can be used to get rid of the filaments but process changes should also be made. Cell lyses occurs readily on this type of filament, although the empty sheaths still remain. Sludge wasting is necessary to remove them entirely from the system.   Manipulation of F/M and DO concentration can be used to control the filaments. 



Sphaerotilus natans  ranks 6th in number of predominance.  Typically not found in pulp-mills with activated sludge.


For more information on Filamentous Identification

Type 1701

Type 021N

More photos to come. . .


If you need more information on our Filamentous Identification the Easy Way Training CD or on Internet training on Filamentous bacteria, causes and controls.

How and why on Wastewater Biomass Analyses

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