MIDTERM 1

Question 1

what are the two sources of water?

Answer 1

fresh and salt

Question 2

what is one of the main byproducts of desalination?

Answer 2

salt

Question 3

what are some factors affecting water use?

Answer 3

population (rapid urbanization)
geographic location
agricultural intensification
type of the community (residential vs industrial vs commercial)
even more i dont wanna type

Question 4

how can be calculate water demand?

Answer 4

future demands
local government by-laws and design guidelines, where applicable
historic demand

Question 5

what are the 4 items that water sampling programs want to obtain?

Answer 5

information on the characteristic of potential and existing water sources
routine operating data on overall plant performance
data that can be used to document the performance of a given treatment operation or process
data needed to report regulatory compliance

Question 6

in the context of water sampling programs, what are the 4 items that they must uphold to?

Answer 6

representative
reproducible
defensible
useful

Question 7

what are the three components of water sampling?

Answer 7

sample collection
preservation and analysis of samples
statistical considerations

Question 8

true for false, some contaminants of water, other than dissolved gases, contribute to the solids load?

Answer 8

false (all contaminants)

Question 9

how does the design of water treatment facilities depend of the type of solids present?

Answer 9

for water - TDS content to assess suitability of water source for public, industrial, agriculture uses

Question 10

how does the design of wastewater treatment facilities depend on the type of solids present?

Answer 10

for wastewater - to determine the most suitable type of treatment and its reuse potential

Question 11

what is the size range of colloids? what is the implication of the presence of colloids in the treatment of drinking water?

Answer 11

size range from 10^-6 to 10^-3

want to remove colloids as contaminants can stick to colloids and they also do not settle due to surface effects (friction, interaction w/ other particles)

Question 12

what is tubidity?

Answer 12

a measure of light-transmitting properties of water

Question 13

what are the main causes of turbidity in water?

Answer 13

colloidal and residual matter

Question 14

does turbidity cause health impacts?

Answer 14

no

Question 15

what is the process of coagulation and flocculation? and what does it do to water?

Answer 15

use of an agent that sticks to colloids and makes them larger and can settle out or get caught in a filter

Question 16

what are the major inorganic constituent cations?

Answer 16

calcium, magnesium, sodium, potassium

Question 17

what are the major inorganic constituent anions?

Answer 17

carbonate, bicarbonate, sulphate, chloride, nitrate

Question 18

what is alkalinity?

Answer 18

a measure of water’s capacity to neutralize acids

Question 19

what are the major forms of alkalinity (anions)

Answer 19

bicarbonate, carbonate, hydroxide

Question 20

how is hardness caused?

Answer 20

hardness is caused by multivalent (polyvalent) cations (calcium and magnesium)

Question 21

what are some problems of hardness?

Answer 21

precipitate soap (reducing its cleaning action)
sealing problems in hot water pipes, boilers, kettles

Question 22

what is total hardness?

Answer 22

a term used to describe the combination of calcium and magnesium hardness

Question 23

why are hardness values usually represented in terms of mg/L of CaCO3?

Answer 23

its the most common cause of scaling

Question 24

what is another word for carbonate hardness? Why is it called this?

Answer 24

temporary hardness, (easily removed by heating)

Question 25

what is another world for non-carbonate hardness? why is it called this?

Answer 25

permanent hardness (NOT easily removed by heating)

Question 26

what are the major sources of TOC (raw water)

Answer 26

natural organic material (NOM)
synthetic organic compounds (SOC)

Question 27

what is the origin of NOM?

Answer 27

originates from degradation and end produce of
- plants and animal material
- microorganisms

Question 28

What is a DBP and how is it formed?

Answer 28

DBP or disinfection byproducts are a produce of the disinfectant (Cl, CO2) reacting with NOM

Question 29

what are the factors that that DBP formation is dependent on?

Answer 29

pH, temperature, NOM concentration, chlorine concentration, residence time etc.

Question 30

what are some processes to remove NOM in water treatment processes?

Answer 30

coagulation
filtration
dissolved air floatation
adsorption, oxidation, ion exchange

Question 31

what is BOD?

Answer 31

(biochemical oxygen demand), if oxidation of organic compound is carried out by micro-organisms using organic matter as food source, the amount of O2 consumed is known as BOD

Question 32

for a BOD test, when would you need to seed bacteria?

Answer 32

for any sample without sufficient bacterial population (pulp mill process water

Question 33

what is the chemical oxygen demand (COD)

Answer 33

measures the oxygen equivalent of the organic matter in the presence of acid and heat. The amount of dichromate at the end of the test is measured

Question 34

what is TOC?

Answer 34

for small amounts of organics
instrumental test using infrared analyzer
sample evaporated and oxidized to CO2
analyzer measures CO2 concentration