Effect of Recirculation Ratio, Organic Loading and Suspended Solids Loading on the Efficiency of the Trickling FiltersWith Plastic Media

Abstract

In this research, an experimental laboratory plant was constructed in order to evaluate the effect of recirculation ratio, organic loading and suspended solids loading on the removal efficiency of trickling filter with plastic media. The plant consisted of four biological trickling filter which were similar in shape, each with a volume equal to (35 liters). Synthetic wastewater was used to operate the plant. To study the impact of recirculation ratio on the system, three of these plants (first, second and third) were operated on recirculation ratio of (100%, 200% and 300%) respectively, whereas the fourth operated without recirculation. To study the effect of increase organic loading, the study program was divided into nine stages, in the three continuation following stages the organic loading rate was steady then increasing in the three suffix continuation following stages thus until ultimate ninth stage, beginning with (1.5 kg COD/m 3 .day) then (2.1 kg COD/m 3 .day) and up to (2.7 kg COD/m 3 .day). The results of the study revealed that; theremoval efficiency of the biological trickling filter increase when the recirculation operation was exist, and the efficiency increased when increase recirculation ratio, so the average efficiency of first stage removal of organic loading was in the trickling filters (first, second, third and fourth ) (84.5%, 86.3%, 87.5%, 80%) respectively. The results also showed that; increasing organic and suspended solid loading decreases removal efficiency of organic matter, ammonia and phosphate.