Dual media filters
Dual filters are more efficient than the normal sand media filters in attracting large number of particles present in water. This happens because of the many filter layers with different levels of pores. Another difference noted when compared with the sand media filters is that dual media filters last longer.
Both chemical and physical absorption process are used here. The four crucial stages in media filtration are straining, sedimentation, interception, and diffusion. The last stage is inertial compaction. Application of dual media filters is a good solution for contaminated water. It is excellent for the removal of turbidity, organic matter, and many other impurities. However, dissolved solids are partially removed by this process.