Experimental Investigations of Performance of Lateral Flow Sand-Bed Filters for Wastewater Treatment
Abstract
Experimental investigations were done to analyze the effect of temperature, loading rate and filtration length on the filtration efficiency of lateral flow sand-bed filter (LFSF) model. In the present study a lateral sand bed filter model (LFSF) has constructed to simulate river sand bed and the effect of temperature, loading rate and filtration length on the filtration efficiency of the model has been analyzed.LFSF was quite efficient in organicmatter(BOD)removalwithmeanremovalefficiency90.6%andwithmeanincreaseefficiency of 48.9 % in DO. Mean removal efficiency in total coliform removal was 34.9 %. The sand filter model has shown lesser removal in EC, TDS and Salinity (4-6%). pH of wastewater shows it slightly changed from acidic to alkaline due to filtration. Mean pH value of wastewater increased from 6.72 (before filtration) to 7.5 (after filtration). Temperature of sand shows positive effect on BOD removal. As temperature of sand bed increases from 28.4 to 35.80C, BOD removal % increases from 80.3 to 91.5. Loading rate has significant effect on pollutant removal, as loading rate was increased from 0.30 m3/m2/hr (35.8 l/hr) to 0.33 m3/m2/hr (54 l/hr), mean removal efficiencies for BOD, EC, TDS and Salinity reduced from 94.54, 6.10, 6.06 and 6.10 to 86.77, 2.85, 2.92 and 5.88 respectively. As filtration length has increased in the LFSF, BOD removal has alsoincreased.This paper clearly show that the naturally formed river sand-bed at convex side of river which is a waste land can be effectively utilized on the sustainable basis for further treatment of the secondary wastewater in a city like Varanasi, India, situated on the concave bank of theriver Ganga.
