water.
Biofilter has successfully been used as a trickling filter for the
domestic wastewater treatment. It can be used with and without other
biological treatment processes depending on the characteristics of
the influent, and the effluent quality requirement (Fig. 8). The rock,
slag or plastic materials are used as the trickling biofilter media.
The application options of trickling biofilter vary with the treatment objectives, the media type, and the nature of the other treatment units in the process train. It can be used for roughing, carbon
oxidation, combined carbon oxidation and nitrification with different arrangements of two or more biofilters units. The advantages
of using bio-trickling filter over the conventional activated sludge
process are (i) less operational cost, (ii) less area requirement, (iii)
well stabilized sludge (no sludge bulking or floating problem).
In advanced wastewater treatment, biofilter can be used along
with conventional physico-chemical processes such as coagulationflocculation, filtration and sedimentation (Fig. 9). The conventional
filter and the biofilter units can be combined together depending
on the suspended solid concentration. Since the main purpose of
the biofilter is to remove the dissolved organics, the suspended particles are removed in conventional filter before subjecting the wastewater to the biofiltration system.
The biofilter has similarly been assessed by many researchers as
an essential part of surface water treatment for potable to reduce
the microbial growth in the distribution pipe lines, corrosion potential and the disinfection by-products [Bouwer and Crowe, 1988;
Carlson and Amy, 1998]. Normally, GAC biofilter is recommended
to use in the surface water treatment, as in GAC biofilter the organics are removed by both adsorption and biodegradation mechanism