Lecture 4

Question 1

What is Turbidity?

Answer 1

-Is the measurement of light scattering property of water

Question 2

What are the units of Turbidity?

Answer 2

• (TU)

- (NTU)

Question 3

What are the effects of high temperature waste water?

Answer 3

• Chemical reaction
• Reaction rates
• aquatic life
• Depletion of DO
• ->Increase i biochemical reactions
• ->Oxygen is less soluble in warm water
• Beneficial uses

Question 4

What is electrical conductivity and in a solution?

Answer 4

• The ability to conduct an electrical current

- EC is transported by ions in a solution

Question 5

How is EC used for wastewater treatment?

Answer 5

-EC can be used to test the total dissolved solids

Question 6

What is specific gravity?

Answer 6

-Density per unit Density of the standard

Question 7

What is specific weight?

Answer 7

-Weight per unit Volume

Question 8

What is pH?

Answer 8

-log[H+]

Question 9

What is pOH?

Answer 9

14-pH

Question 10

What is K the equilibrium of water?

Answer 10

[H+][OH-] = Kwater

-1x10-14

Question 11

What is a buffer solution?

Answer 11

-A solution that resists a large amount of pH change when acids or bases are added

Question 12

What is Alkalinity?

Answer 12

-The measure of the capacity of water to neutralize acids

Question 13

What is the equation for Alkalinity?

Answer 13

-Alkalinity (in M) = [HCO3-] + 2[CO3-2] + [OH-] - [H+]

Question 14

What is Alkalinity measured in?

Answer 14

-mg/L of CaCO3

Question 15

What are sources of Nitrogen?

Answer 15

• compounds of plants and animals
• sewage
• run offf

Question 16

What do the element Nitrogen and Phosphate provide for the environment?

Answer 16

-Growth of microorganisms

Question 17

What is BOD?

Answer 17

• Biochemical Oxygen Demand
• A chemical procedure for determining how fast biological organism use oxygen in a body of water.
• It is the measure of the amount of organic compounds in water
• Measure of the dissolved oxygen (DO) used by mirco- organisms

Question 18

What is COD?

Answer 18

• Chemical Oxygen Demand
• independent of the chemical composition in water
• A chemical oxidizing agent is used to oxidize the organics

Question 19

What is pH?

Answer 19

(-) log10 [H+]

Question 20

What is Dissolved Oxygen?

Answer 20

• O2 that diffuses into water by high pressure pushing O2 into water.
• measures the O2 that dissolved in water.

Question 21

Why is Dissolved Oxygen important in wastewater?

Answer 21

-It prevents harmful odors.

Question 22

What month typically will see the lowest levels of DO and Why?

Answer 22

• Summer months

- The increased temperature increases the rate of biochemical reactions in water which cause DO to lower.

Question 23

What is Oxidize?

Answer 23

-To combine chemically with O2

Question 24

What is ThoD?

Answer 24

-The calculated amount of O2 required to oxidize a compound to its final oxidation products

Question 25

How is COD measured?

Answer 25

-The difference between the amount of oxidizing agents at the start of the test and that remaining at the end is the COD

Question 26

What are the typical procedures for measuring BOD in a LAB?

Answer 26

• measurements are done in a 300mL bottle
• bottles contain water to dilute wastewater
• inject with micro-organism

Question 27

What are 2 approaches for BOD calculation?

Answer 27

1. When the BOD of the seeds water/ water dilution is negligible only need DO sample after t amount of days
2. When the BOD dilution is high or seeds DO sample has to be taken initially and after t days

Question 28

What is P in BOD calculation?

Answer 28

• Dilution factor

- fraction of wastewater sample in 300 mL dilution

Question 29

What is f in BOD calculations?

Answer 29

(1 - P)

Question 30

How much higher is COD value from BOD?

Answer 30

-1.25 times higher