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Template Assisted Crystallization (TAC) is a a commercial softening alternative. Which of the following description is wrong A. TAC involves the adsorption of cations and anions B. TAC involves the crystallization of hardnessions O C.TAC involves the detachment of nanocrystalls back to the treated water D. TAC has a greater removal efficiency for hardness than RO or ion exchange 1 pts D Question 19 In a soil remediation project, the contaminated water containing mercury was treated by a chemical to convert soluble mercury into insoluble solid. The following results of soluble mercury concentrations (ppm) in the water samples were obtained before and after the treatment. Please use t-test to determine the chemical treatment leads to significant differences or reduction of soluble mercury, assuming p=0.05 Sample site# Before chemical treatment After chemical treatment 1 25 15 2 21 23 3 18 18 60 4 19 12 5 23 8 29 6 16 A Chemical treatment made a significant change B. Chemical treatment did not make a significant change bus O Cunable to compare the difference A set of samples from an abandoned industrial site detected a suspected groundwater contaminant at a mean concentration of 0.045 kg/L with a standard deviation of 0.007 mg/L. How many samples are required to be collected at a confidence level of 95% and power of 90% if the mean background concentration of the contaminant is 0.035 mg/L? O A3 B.4 C.5 D. 6 > Question 15 If we use lime, Ca(OH)2, and soda ash, Na2CO3, to treat this water in question to remove all hardness. How much (mg/Las CaCO3) of Ca(OH)2 will be needed? A. 150 B. 100 C. 112.5 D.225 Which of the following statement about CBOD and NBOD is wrong? O CBOD is carbonaceous biological oxygen demand. This BOD refers to the portion of total BOD usually related to organic carbons as result of biodegradation, NBOD is non-biological oxygen demand. NBOD refers to the portion of total BOD usually related to the conversion of ammonia nitrogen to nitrite or nitrate, CBOD and NBOD evolve at different stages of biodegradation. NBOD is characterized by a post stage of biodegradation, where CBOD occurs throughout the entire biodegradation if any carbonaceous organics are present