Fixed-Bed Biofilm Activated Sludge
The FBAS is Called Fixed-Bed Biofilm Activated Sludge. The FBAS process is essentially an activated sludge-attached growth process where the plant roots provide the area for the biofilm to develop and grow. The aeration system is divided into a series of biological reactors where fixed biofilm is maintained in every stage of the process. As the influent travels through the cascade, the available nutrient quantity is consumed and as a result, the composition of the ecosystem fixed in the biofilm changes from reactor to reactor, gradually adapting itself to the decreasing nutrient concentration. In each cascade stage, a specially adapted ecosystem will form, thus maximizing the decomposition of contaminants. As reported, some plants with such technologies have been set up in different countries including Hungary, China, France, etc in the last 10 years. However, it will be useful to demonstrate this project under Indian conditions.
Fixed-Bed Biofilm Activated Sludge Advantages :
1. The process requires much lesser land area than conventional activated sludge.
2. The process is odorless and hence the plants can be easily built in an urban area with no negative impact on the value of adjoining areas.
3. It can operate at a much lesser loading rate during the initial days of setting up the plant in new habitations. Due to small area requirements, this technology can offer decentralized solutions and recycling water in local areas.
4. The technology allows for design flexibility and can be adapted for nutrient removal such as P and N, which are today the major concern of pollution in rivers.
Fixed Bed Activated Sludge Disadvantages :
1. In colder climates where the temperature drops to subnormal, the plants have to be protected with a greenhouse otherwise the biota may freeze up.
2. The technology requires more Qualified operators than other technologies.
3. Yet to be validated on reasonable number and sizes of STPs in India.