The FAST® Process


FAST (Fixed Activated Sludge Treatment) was developed under our research grant to the University of Kansas. It is a submerged fixed film aerobic sewage treatment process.

That is:

1. Fixed media are submerged beneath the surface of the water in the media tank.
2. A microbial film grows on the surfaces of this fixed media.
3. Oxygen is provided by an aeration blower.
4. The microbial film uses the incoming organic matter in the sewage as food.
5. One byproduct of this biological oxidation is carbon dioxide which is vented to atmosphere.
6. Another byproduct is a fine residual sludge of partially oxidized organic material that settles into a storage compartment at the bottom of the tank.
7. The effluent is clear odorless water with high oxygen content.
8. For marine and offshore applications, this effluent is disinfected and then discharged to the surrounding waters.

Advantages Inherent in the Process

1. The water in the media tank is clear and does not require any clarifier, filter or membrane to meet discharge requirements. This eliminates most of the problems associated with other sewage treatment processes.

2. FAST reacts to changes in loading in one-half the time of conventional biological processes. That is, it will start up twice as fast and adjust to changes in loading twice as fast so that performance is consistent without human intervention.

3. Many biological systems have problems with light loading. The only effect on FAST is that excellent effluent quality gets even better.

4. The biota (the critters that eat the sewage) is much more complex than that in suspended growth processes. FAST supports not only bacteria but segmented sludgeworms, insect larvae and other higher ordered organisms that predate on the lower forms of life, an extra stage of digestion.

The result is a much lower sludge accumulation rate than other units. Also, the sludge is heavier and more concentrated than that obtained from any suspended growth system, including membrane bioreactors (MBR’s).

So, when it comes to sludge, less is produced by weight, it is more concentrated and the rate of accumulation is about as low as you can get in the real world.

5. There are no moving parts in contact with sewage and no adjustments. Clogging is virtually impossible and proper operation does not depend upon the skill of the operator.

6. In the July 2011 official testing for MEPC.159(55) and without filters or membranes of any kind, a standard FAST Model L-3XM produced:

     (a) BOD5 = 4.1 mg/l versus 25 required.

     (b) TSS = 5.8 mg/l versus 35 required.

     (c) COD = 30 mg/l versus 125 required.

     (d) Coliform = 4 versus 100 required.

State of the Art

In 2016, USCG and Transport Canada certified all standard and custom FAST units under MEPC.227(64) using peracetic acid (PAA) for disinfection, this in addition to previous certifications with chlorination and dechlorination. PAA is environmentally friendly and has no harmful byproducts.


The only maintenance required is:

1. Inspect and clean the blower inlet air filter from time to time.
2. Replenish chemicals used for disinfection as required.
3. Pump out the tanks at sea every one to three months or process the sludge with a MarineFAST® Biosolids Management System.

There is no other maintenance.

Flushing Medium

FAST can handle any combination of seawater, freshwater, blackwater, graywater, ground food waste, conventional toilets and vacuum toilets without adjustment.

Performance Based on Experience and Knowhow

The advantages and reliability of FAST sewage treatment systems are inherent in the FAST process. It is a winner where consistently good performance is required, where loading and operating conditions vary and where trained operators are not available.

These applications include but are not limited to commercial marine and offshore. The advantages and reliability of the FAST process also makes it ideal for many land applications.

Every claim made for the FAST process is supported by more than 70,000 installations worldwide and over 40 years of research, development and real world operating history.