STUDY THEME 7: Quality Assessment (Water Quality Parameters \& Fitness of Use) 12. A BODs test was conducted using wastewater with a strong BOD as seed in a standard BODs test where the values of initial DO and the DO at day 5 were 8.6 and 2.6mg/L, respectively. A volume of 2.8mL was used in the BOD test on the seed wastewater. In the test on the target wastewater - a treated wastewater from the secondary clarifiers - the test was seeded with 0.15mL of the seed wastewater above. The test was conducted on 45mL of sample. The initial DO reading in the test on the actual sample was 7.8mg/L and final DO reading was 3.8mg/L. Assuming no significant oxygen demand by dilution water used to fill up the bottles, (a) Determine the rough BOD s value of the effluent from the secondary clarifiers (sample) based on the above information. (12pts) (b) If a blank of nutrient rich dilution water only has initial and final DO values of 8.8 and 7.8mg/L, respectively, adjust the BOD5 value obtained in (a) above to correct for the oxygen demand of the dilution water. (8pts) (c) If degradation rate coefficient kdc is equal to 0.23d1 (base 10), determine the approximate CBOD u(LoC) of the secondary clarifier effluent. (4 pts ) (d) Further analysis of the effluent sample shows that the actual measured BOD values at 8,10,12, 14,16 and 18 days are as shown in the Table (below). Using this information and the parameters Loc and kdc from ' c ' above, determine the nitrogenous degradation rate coefficient (ki,N) and ultimate nitrogenous oxygen demand (L0N) of the system. (18 pts ) (e) Using the information in ' c ' and ' d ', i. Determine the computed NBOD value at day 16. (6pts) ii. Determine the computed total BOD value at day 16 and report the error between the measured and the computed value. (4pts)