MODELING OF BIOFILTRATION FOR REMOVAL OF HEAVY METALS FROM WASTEWATER

Abstract

Biofilter is fast emerging as an important wastewater treatment facility. This is because it has got many advantages over the conventional treatment facilities concerning design as well as operating conditions, like Design without complex technical devices, compactness, no noise and no odor emissions. Biofilter consists of a packed bed of support media on which the microorganism grows and forms the biofilm which in turns degrades or accumulates the impurities. On reaching the saturation capacity of microorganisms, we have to backwash the biofilter. In this case biofilter is used to treat heavy metals such as cobalt, lead, and manganeSe. In order to study the performance of a biofilter it is essential to understand the complex process occurring in biofilter. With an apropos to the above, the mathematical model appears to have an unmatched concerns for analysis and simulation of process. Thus it is desirable to develop a mathematical model for removing heavy metals from wastewater using biofilter. In the present dissertation work, an unsteady state model for biofilter has been developed which incorporates partial differential equations along with initial conditions as well as Danckwerts boundary conditions. The model equations are solved by using MATLAB PDE (Partial Differential Equations) solvers. The laboratory scale operating data are available in literature, were selected for testing the model predictions and to ascertain the correctness of the proposed model. The concentration profiles of manganese, cobalt, and lead in biofilter with time have been computed and compared with those reputed in the literature. The results are found to be in good agreement. The concentration profiles along the length have also been computed. The simulation calculations are carried out for treatment of three metals cobalt, lead, manganese under operating conditions collected from literature. The concentration profiles of all the three metals along the length of the biofilter with time have been studied. Simulations have been performed to know the best flow rate using bioaccumulation rate (metal accumulated in pg/l.h) as the criteria. In the view of above simulation results it is concluded that proposed model may be used for the analysis of biofilter and optimization of its operation.