SBR technology is one of the most advance system of Activated Sludge process. The Cyclic Activated Sludge Process is operated in a batch reactor mode, which eliminates all the inefficiencies of the continuous processes; A batch reactor is a perfect reactor, which ensures 100% treatment. The complete process takes place in a single reactor, within which all biological treatment steps take place sequentially. A basic cycle comprises:
• Fill-Aeration (F/A)
• Settlement (S)
• Decanting (D)
These phases in a sequence constitute a cycle, which is then repeated hence it can be called Sequential Batch Reactor/ Cyclic Activated Sludge Process.
The concept behind the moving bed bioreactor is to provide continuously operating bio film reactor, which is non-cloggable, does not require back-washing and has no pressure drop. This is achieved by making the bio film grow on smaller carrier elements made of PP and have lower SG than water. Upward moving air bubbles colloid with carrier elements and keep it into constant rotary movement. Collision of air bubbles also causes in split into number of bubbles and finally results into more mass transfer area and more contact time.
The system uses specially designed Bio media, which provides a large surface area per unit weight for biological growth. The bio media is made of plastic material, which has a very high long life. The media is shaped like cylinders with internal fins so as to provide a large surface area in the given volume. The media provides up to 500 sq-m effective area for growth of the bio film per cub-m of volume.
Sewage shall be treated in aeration system by providing suitable size/capacity of diffuse aeration. Suitably selected, optimum type of bio-mass will be added into aerobic tank to start sludge mass growth. BOD/COD get digested in this process and forms sludge mass. A part of BOD also get converted into carbon dioxide. And mixing of bulk is also provided by selecting suitable type of diffusers. However, diffuser performs duel function (i.e. transfer of atmospheric oxygen and mixing of aerated mass). Continuous growth of sludge mass concentration up to 6000 to 8000 ppm is required and excess sludge is subjected to rejection. Hence this mixture of solid and liquid further passes to MBR tank. Most of the biomass gets separated through filtration. A high microorganism population is maintained within the Aeration chamber by recycling part of the separated sludge from Membrane Bioreactor Tank (MBR Tank).
Clear water comes out of membrane as permeate is further chlorinated. It will be suitable for final disposal and recycling for horticulture, cooling tower, flushing and misc uses. Excess Sludge from MBR is subjected to be dried in sludge drawing beds. The dried cake from the sludge drawing beds shall be used as manure.