Anjoo Anna S. J., Sheela A.M
Abstract: The pollution of our water resources is mainly due to the discharge of untreated waste water. Hence the need of the hour is to have an efficient treatment for the waste water. The different stages of treatment are preliminary, primary, secondary, and tertiary or advanced treatment. In secondary treatment, biological treatment is more cost-effective than chemical treatment. Biological treatment of waste water reduces the concentration of pollutant through microbial action and removal of non-settleable organic colloidal solids. The conventional activated sludge process has some disadvantages like high operation cost, requirement of skilled supervision and requirement of more space for the treatment plant. There are various advances and improvements in the reactors to achieve variations in contact time and method of contact, which have resulted in the growth of suspended growth system, attached growth or fixed biofilm systems or combinations thereof. Biofilm processes are proved to be reliable for organic carbon and nutrients removal.In this study, a review of the various biological treatment technologies has been done. Both suspended as well as fixed film processes have been discussed. The various modern technologies include Moving Bed Biofilm Reactor (MBBR), Rotating Biological Contactor (RBC), Integrated Fixed Film Activated Sludge (IFAS), Membrane Bioreactor (MBR), Fluidized Bed Biofilm Reactor (FBBR) and Sequential Batch Reactor (SBR). The merits and demerits have also been ascertained. A comparison of these techniques will surely be helpful to choose the suitable technique.
Keywords: Biological process, Biofilm, Activated Sludge Process, MBBR, RBC, IFAS, MBR, FBBR, SBR