(Solved):     ) BOD value for food processing industry wastewater is estimated to be 11,000 mg/ ...

 

 

) BOD value for food processing industry wastewater is estimated to be 11,000 mg/L. Two trials for a valid BOD test were conducted at 20°C. Raw sample, with initial DO of 2.1 mg/L was used for the first trial. Diluted sample by using Table 1.0 was used for the second trial. The initial DO for diluted sample was 5.1 mg/L. The final DO obtained for first and second trials was 0.1 mg/L and 2.55 mg/L respectively. (i) (ii) (iii) (iv) JILL Based on the data obtained, discuss the validity of the BOD test. Calculate the exact 5-day BOD at 20°C. Calculate the BOD3 at 30°C, if the K20 is 0.12 per day. Assume COD value for the food processing wastewater and justify your answer. Volume of sample (mL) 0.02 0.05 0.10 0.20 0.50 1.00 2.00 5.00 10.00 20.00 50.00 100.00 300.00 TABLE 1.0 Range of BOD value (mg/L) 30,000-105,000 12,000-42,000 6,000-21,000 3,000-10,500 1,200-4,200 600-2,100 300-1,050 120-420 60-210 30-105 12-42 6-21 0-7 (b) A COD test was carried out on sample X and Sample Y. Table 1.0 summarized the information of the test: Table 1.0 COD Test Results Volume of sample Sample dilution Normality of Fe²+ standard solution Titration volume of Fe²+ standard solution for sample Titration volume of Fe²+ standard solution for blank Sample X 20 mL 10 times 0.25 N 14.55 mL 25.35 mL Sample Y 20 mL 50 times 0.1 N 25.35 mL 48.40 mL Determine the actual volume of undiluted sample X and Sample Y used in each flask. Calculate the COD values of sample X and Sample Y.