PERFORMANCE OF A FIXED FILM BIOLOGICAL REACTOR

Abstract

Fixed-film biological reactors are multi-phase processes in which organic matter is absorbed and subsequently oxidized by an attached microbial film. Trickling filter is one of the fixed-film biological reactors which is studied in this dissertation. A review of literature revealed that the development of rational design procedure applicable for a range of organic concentrations could only be accomplished if the mechanism of substrte removal was completely understood. The performance of a fixed-film biological reactor depends upon various parameters such as hydraulic loading, influent substrate concentration, properties of bio-film, filter media characteristics, recirculation and temperature. The present study is aimed to evaluate the effect of variables such as hydraulic flow rate, organic loading, depth and recirculation controlling the performance of trickling filter. Experimental work is carried out in a laboratOry scale trickling filter of 6 cm diameter and 166 cm depth , packed with quartz inert solids packing media of 1.25 cm average size. The experiments are carried out with wastewater prepared in the laboratory by dissolving known. amount of molasses with tap water.. The study observed that filter efficiency decreases from 40 % to 31.2 % with increase of flow from 0.006 m3 /h to 0.01.8 m3/h.The percentage COD removal decreases from 40 to 28 % with increase of influent COD from 250 to 750 mg/1 but rate of .removal increases in both the cases described above. And the efficiency increases from 40% .to 48.8% with increase of recycling ratio from 0 to 0.5. The saturation constant K is experimentally obtained to be 583.3 at 0.006 m /h flow rate.