Continuous Activated Sludge (CAS)

Simply pumping air into a tank of wastewater and hoping for the best is a proven recipe for failure. Beyond the basin itself, you need a deep understanding of microbiology, process control, and hydraulic engineering to design a robust, long-term solution.

Our activated sludge is, of course, the vital ingredient in our advanced Continuous Activated Sludge (CAS) technology. Within the aerated basins, a complex ecosystem of microorganisms, ranging from bacteria to protozoa and metazoa, forms biological flocs. This "activated sludge" is kept in constant, gentle suspension by diffused aeration systems. Thanks to this controlled mixing, the pollutants in the wastewater are brought into direct contact with the microbial floc, where they are consumed and assimilated.

In a fixed-film treatment system, the biomass is attached to a surface and remains in the reactor. In our CAS process, the active sludge must be continuously separated from the treated water in a secondary clarifier before being returned to the treatment basin. This Return Activated Sludge (RAS) is the heart of the continuous process, reseeding the system with a healthy, acclimated microbial population. It is very important to design the clarifier properly not just for effective solids settling but also to ensure a high-quality final effluent. There are several benefits to a suspended growth system. Among them are exceptional treatment efficiency, process flexibility, and a proven track record as the gold standard in wastewater treatment.

The core of the process is the biofilm carriers, which are made from polyethylene with a density sligthy below of water. Several different types of carriers have been developed in order to optimize their function in different applications.

Flexible Solution

Our processes based on the CAS technology are feasible for both industrial and municipal wastewater and are used for:

• Organic (BOD) removal

• Nitrification

• Denitrification

• Biological phosphorus removal

The incredible flexibility of our CAS processes makes them an ideal solution for new plants or for the upgrade and expansion of existing facilities.

Moving Bed Biofilm Reactor (MBBR)

Just to add some plastics, moulded into a peculiar shape, to a wastewater basin and see what you get is a safe way to failure. Besides the carriers you need knowledge of microbiology, hydraulics and engineering to design a long-term solution.

Our carriers are of course a vital ingredi-ent in AnoxKaldnes™ MBBR technology. On their protected surfaces different microorganisms ranging from bacteria to ciliates and rotifers are established in a biofilm. These carriers are kept in motion either by the blast air injection in aerobic systems or by stirrers in anoxic or anaerobic systems. By this motion impurities in the water is transported to the biofilm and are reduced by it.

In a suspended sludge based treatment system the sludge has to continuously be separated from the treated water and returned to the treatment basin. In an AnoxKaldnes™ MBBR, the carriers and the active biofilm are detained in the treatment tank by sieves over the outlet, which allow the treated water to pass to downstream units for further processing. It is very important to design the sieves properly not just for the retention of the carriers but also for hydraulic issues. There are several benefits with a suspended biofilm system. Some of them are increased dura-bility towards toxicity and variable loading, simple operation and a treatment system insensitive of bulking sludge.

The core of the process is the biofilm carriers, which are made from polyethylene with a density sligthy below of water. Several different types of carriers have been developed in order to optimize their function in different applications.

Flexible Solution

Our processes based on the AnoxKaldnes™ MBBR technology is feasible for both industrial and munici-pal wastewater and is used for:

• organic removal

• nitrification

• denitrification

• detoxification

The flexibility of our MBBR processes makes them an ideal solution for new plants or upgrade and expansion of older ones.