Obviously, looking under the microscope is the first thing you should do, but you also can use your settleometer to tell what is going on. Run a normal settleometer. Say for example your settling only drops down to 800. Then run a 50/50 dilute sample. 50% water and 50% normal MLSS. In reality, it should settle down to 400 in the same amount of time it if was just too much mlss. If in fact it is due to filamentous bulking, it will probably not settle down to 400 or even close to that number. That will be a quick indicator to look closer under the microscope and see just how many filaments there are and what types are present so you can find a cause and make a process change to make them go away. Remember, chlorine and peroxide can kill filaments, but if you do not make a process change, they will always come back. Change the system, and you select for the right type of bacteria

What is the difference and why is it so important and often overlooked? Internal Filaments are found mostly within the floc structure

Look closer, what appears to be nice floc, in reality is full of holes and spaces. Think of internal filaments as more like forming a sponge. Imagine trying to dewater a sponge. It would not only take quite a bit of pressure, but also polymer. It would hold water and not want to compact either. Internal filaments are just as much of a problem if not more. External filaments can at least be compressed with polymer. It takes more for internal filaments. Do not overlook them. Use your microscope and blow up the sample to 400x or 1000x and take a closer look.

1000x Gram Stain Below is a sample with excessive levels of filaments          

      1000x Neisser Stain

Free floating means the filaments can be found floating in the bulk solution and can cause serious TSS problems.

Here is a short Nocardia form at 100x phase here is a papermill with 1863 free floating

Here is a papermill with a once through lagoon that has problems with short free-floating H. Hydrossis and Thiothrix II.

All of these plants needed to make process changes in order to get rid of the filaments and reduce chances of violating on TSS due to filaments that were free floating.

Zooglea and fungi can cause problems at a plant but are caused by very different situations in a plant and many times are overlooked.

1000x Fungi and zooglea low pH and low nutrients at a pig farm lagoon. This sample on the right is a digestor at a municipal plant. Tons of fiber and fungi. They were turning off the air to try to get more settling during decant and left the air off too long. This can cause serious growth of filaments and fungi.

Below is a perfect example of a plant that had problems and foaming. They do have some industry that discharges to the plant. They were hit with a high loading and had tons of foaming on the plant. They assumed it was filamentous problems.

At 100x bright field it does not look too bad. Zoom in and use some stains. Here is 100 x with Lactophenol cotton blue instant stain. It appears there is quite a bit of amorphous zooglea.

Now with 1000x Neisser and Gram stains, it is quite easy to see there is more zooglea than floc or filaments. Go check your pH and nutrients at the plant. Obviously the high loading from the industry upset the nutrient balance. Many municipalities are not used to having to add nutrients. If you have industry and get a slug of high BOD loading with no N or P present, you can get zoogleal foaming.

Here is a plant with foaming problems and septicity

Here is a plant with Zoogleal bulking and foaming

Here is a plant with foaming and Microthrix parvicella

Here is a plant with septicity problems as well as Grease- Nocardia

You cannot tell by looking at the foam what is really wrong with the plant. Pull a sample, get out your microscope and then look at what is present. The bugs will tell you what is going on and then you can fix it and change the process!

Filamentous Identification and Wastewater Biomass Analyses

Here is why it is so important to worry about solids and how they impact your plant… money, when it comes right down to everything, here are some of the critical cost factors involved with running a wastewater treatment plant,

Electricity is usually the number one cost at a plant. Then solids handling and last polymers used for dewatering. The drier cake solids you can get, the less volume your sludge takes up, the lighter it weighs. If you are paying for solids handling costs based upon volume or weight, it is very critical.

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Filamentous Identification The Easy Way- Training program CD

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Wastewater Biomass Analyses Brochure

The Most Comprehensive Filamentous Bacteria Training Program

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