Question

WASTE WATER ENGINEERING

CIVIL ENGINEERING 4th SEM

KINDLY SOLVE WITHIN 90MIN AND GET 100% BEST RATINGS

3. (a) Explain working and construction of trickling filter with sketch 3 (a) What is difference between intermittent and continuous settling tank? 2

Answer 1

bioreactors 2314a) Trickling Filters are attached growth in which randomly packed solid media provides the surface area for the growth of biofilm. There are voids between the solid media which enables passage of wastewater and air and ventilation of produced Wastewater influent is applied from the top uniformly using rotating jet arms on the entire plan. 7% Packed media over which the biofiber) grows x-section Nozzeles on the rotating asm through which the wastewater is uniformly distributed Plan NOT hence unlike (Top view) It is a suspended growth system ; those this attached growth system requires less area for good efficiency & removal, the carrier media (which is usually crushed stones slag etc)

wastewater i biomass require high porosity and must have large surface area to volume ratis. As the micro-organisms growth on the carrier media with passing of grows on carrier me dia by BIOFILMS. As it grows, thickness of biofilm increases After a certain thickness; they fall off due to high. weight / get sheared due to the wastewater flow and bacteria are killed due to endogent thick biofilms will not be getting food & Oxygen to them they oxidate and die ). This is called SLOUGHING Biofilm is quickly at places created by Sloughing The efficiency of a Trickling Filter (as given by National Council of Research) empirically is: n auto established - 1+ 0.44 VE no efficiency of Bodo removal in 1st stage w = gs. = Applied Bods to the filter & leg/day V = Volume F = Recirculation factor filter, m3 [f-1 if no recycle

a tanks. then Q3 (6) Intermittent Setting Tank Calso called QUIESCENT tanks) are those which stose water for a cestain period and keep it in complete rest. (Usually 24 hours) In that time; suspended particles are settled at the bottom of the tank. After 24 hours, the water is discharged through the outlet The settled particles are removed after discharge of water this also needs 6-12 hours. period of 30-36 hours will be required between the two successive filling of these fill and draw This requires atleast two tanks (and if additional tank is to provided as stand required). In a continuous flow type settling tank, sewage continuously admitted into the tank and allowed to flow slowly (ie the flow velocity is reduced) in the tanta dubing hobich particles in the suspension settle down and its flows set continuously become tank. The Nelocity of flow of sewage in these tan is reduced by providing sufficient length of travel for sewage in the tank. The flow velocity is adjusted from inlet to outlet of the tank is slightly more than that required for setting of those particles. These are today minimum 3 tanks are منه in such a to move mostly used