Consider the single stage trickling filter plant from the solution in Example 9.1. The use of...

   

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Consider the single stage trickling filter plant from the solution in Example 9.1. The use of a single stage filter produced a plant efficiency of about 75%. To increase plant efficiency, the engineer decides to add an identical second stage filter in series to the first one. The wastewater flow rate is 2000 m/d with a BOD, concentra- tion of 400 mg/L. Primary clarification removes 30% of the BOD5. The filters are each 12 m in diameter and 1.5 m in depth. The direct recirculation ratio for each stage is 2.0. Wastewater temperature is 5°C a 20°C. Calculate the second stage hydraulic loading rate, organic loading rates, effluent BOD, concentration, and overall plant effi- ciency. Comment on the advantages/disadvantages of using single stage versus two stage trickling filters. #4 (#a) EXAMPLE 9.1 A wastewater treatment plant uses a single stage rock-media trick- ling fiter for secondary treatment, as illustrated in Figure 9.5(a). The wastewater fow rate is 2000 m/d with a BOD, concentration of 400 mg L. Primary clarifcation removes 30% of the BOD,. The flter is 12 m in diameter and 1.5 m in depth. Direct recirculation pump operates at 2.78 m min to the flter. Wastewater temperature is 20°C. Calculate the hydraulic loading rate, organic loading rate, effuent BOD, concen- tration, and overall plant effciency. Consider the single stage trickling filter plant from the solution in Example 9.1. The use of a single stage filter produced a plant efficiency of about 75%. To increase plant efficiency, the engineer decides to add an identical second stage filter in series to the first one. The wastewater flow rate is 2000 m/d with a BOD, concentra- tion of 400 mg/L. Primary clarification removes 30% of the BOD5. The filters are each 12 m in diameter and 1.5 m in depth. The direct recirculation ratio for each stage is 2.0. Wastewater temperature is 5°C a 20°C. Calculate the second stage hydraulic loading rate, organic loading rates, effluent BOD, concentration, and overall plant effi- ciency. Comment on the advantages/disadvantages of using single stage versus two stage trickling filters. #4 (#a) EXAMPLE 9.1 A wastewater treatment plant uses a single stage rock-media trick- ling fiter for secondary treatment, as illustrated in Figure 9.5(a). The wastewater fow rate is 2000 m/d with a BOD, concentration of 400 mg L. Primary clarifcation removes 30% of the BOD,. The flter is 12 m in diameter and 1.5 m in depth. Direct recirculation pump operates at 2.78 m min to the flter. Wastewater temperature is 20°C. Calculate the hydraulic loading rate, organic loading rate, effuent BOD, concen- tration, and overall plant effciency.