Lecture 6 P1 Flashcards
What does water chemistry focus on?
solutes (dissolved substances)
various chemical reactions and phase transfer processes that alter the concentration of solutes
What determines the rates and types of reactions & phase transfer processes that occur within water?
The unique characteristics of water as a solvent
What are 6 characteristics of water?
density of liquid water is 1g/mL
High surface tension (73 mN/m)
Transparent to visible and UV light (allows light for photosynthesis to penetrate water bodies)
High heat capacity (Temperature stabilization of organisms/geographical regions)
very polar- (ability to hydrate ions -> good solvent of ions and
most important/abundant solvent on earth)
Hydrogen bonding (high melting and boiling points)
What are three reasons water is very important?
Humans contain more than 90% water by mass at birht, drops to 70% as they age
Humans require 2-3 litres of water daily to survive
People can only survive 5-7 days without water
What are the two types of water?
Salt water (water in oceans and seas w high conc of dissolved minerals (97%)
Freshwater (water in ice sheets, ice caps, glaciers, icebergs, ponds, lakes, rivers, streams, and underground aquifers and streams) (3%0
What percent of water can be used by humans?
1% of fresh water
What are 8 beneficial uses of water?
Public supply
Domestic
Irrigation
Livestock
Aquaculture
Industrial
Mining
Thermoelectric Power
What is the dissolution of atmospheric gases critical for?
Dissolved gases, such as O2 (for fish) and CO2 (for photosynthesis) are crucial for living species in water
How much of a gas dissolves in water? How can you calc this?
With Henry’s law
What are the physical characteristics of water? (6)
Total solids, temperature, taste, odor, color, and turbidity measurements
What are the chemical characteristics of water? (7)
Total dissolved solids, total organic carbon, pH, Alkalinity, Hardness, Chemical and Biological Oxygen Demand
What are the biological characteristics of water?
Microbial containment, bacteria viruses for ex
Is temperature essential for environmental studies? Why?
Yes, this is because it controls many ecological processes including chemical reactions
What the temperature of surface water influenced by?
The atmospheric condition
What is the temperature of groundwater controlled by?
the thermal characteristics of bedrock and the depth
What does the temperature interfere with? (7)
the accurate analysis of:
pH
Water Density
Metabolic rates and photosynthesis
Growth of various aquatic plants and microorganisms
Dissolved oxygen and other dissolved gas concentration
Conductivity, solubility, salinity
Oxidation reduction potential
What is apparent color?
This is the color caused by dissolved matters and suspended components (SS: natural causes and/or human activity)
What is true color?
due to dissolved matters only, is the color in the sample after it has been filtered to remove suspended materials such as algae and particulates which cause turbidity
If the water is red and brown, what impurity does this indicate?
iron
if the water is black, what impurity does that indicate?
manganese or organic matter
If the water is yellow or brown, what impurity does that indicate?
dissolved organic/decaying plant matter
If the water is reddish/deep yellow what does that indicate?
algae or dinoflagellates
If the water is green what does that indicate?
water that’s rich in phytoplankton and other algae
If the water is yellow, red, brown, or gray what does that indicate?
soil runoff
What is the environmental significance of colored water?
causes nuisance to drinking water consumption, adversely affects the environment/many industrial processes such as paper and textile manufacturing
What is odor and taste attributed to? (5)
bacterial degradation of algae and algal waste products, iron, manganese, sulfide ions, chlorine
What is the odor in polluted waters?
fecal, fishy, eggy, fleshy, ammoniacal, or greasy
What is the taste in polluted waters?
earthy and musty
What is the odor of Hydrogen Sulfide?
rotten egg
What is the odor and taste of ammonia?
urinal
What is the micro-organism and algae taste?
various unpleasant
What do minerals and salts do for taste?
minerals and salts
What is odor and taste is water causes on people? (4)
Cause poor appetite for food, lowered water consumption, nausea and vomiting, mental disorders
What is turbidity?
A measure of water cloudiness. Caused by suspended materials (um) clays and organics, micro-organisms, and humic acids
When do suspended materials not settle?
Under quiescent conditions
What are turbidimeters (Nephelometers)?
They measure the intensity of light that is scattered by suspended matter and fine dispersion
Environmental significance of turbidity? (4)
Water is aesthetically pleasant, may limit light penetration in aquatic environments, indicator of potential pollution- as pollutants such as dissolved metals and pathogens can attach to suspended particles and enter the water
Clogs gills of fish
What types of solids are in water?
Total dissolved solids (TDS)
Total suspended solids (TSS)
Sum of TDS & TSS is total solids (TS)
Settleable solids- suspended solids that can settle out under quiescent conditions
Volatile solids
fixed solids
What temperature is volatile solids burned off at?
500C
What are fixed solids?
residue after volatile solids are burned
What do total solids refer to?
Material left in a dish after sample is evaporated and dried in oven (103-105 degrees Celsius)
Suspended solids refer to what?
material retained by a standard glass-fiber filter
Dissolved solids refer to what?
material that pass through a standard glass-fiber filter
Volatile solids refer to what?
material lost when dried solids are burnt
How do you determine different types of total solids?
See if (TS) pass through a 0.45 um filter, if yes Total Dissolved Solids (TDS), if no Total Suspended Solids (TSS)
How do you determine total volatile solids (TVS) and total fixed solids (TFS)?
Ignite at 500 degrees celsius, then total volatile solids, if it does not ignite at 500 degrees celsius then total fixed solids
What salinity expressed as?
Measure of all the dissolved salts in water
What units is salinity expressed as?
usually expressed in ppm unit by weight
What are the classes of water in terms of salinity?
Fresh water (<1,000 ppm)
Slightly saline water (1,000 - 3,000 ppm)
Moderately saline water (3,000 - 10,000 ppm)
Highly saline water (10,000 - 35,000 ppm)
What is the presence of salt in ocean water?
3.5%
What levels of sodium chloride in blood cause seizures, coma?
> 160 mmol/L
What levels of sodium chloride in blood cause weakness/lethargy?
> 150 mmol/L
What levels of sodium chloride in blood is normal?
125-136 mmol/L
What levels of sodium chloride in blood cause nausea, drowsiness?
<125 mmol/L
What levels of sodium chloride in blood convulsions, coma?
<110 mmol/L
How much sodium, chloride is in seawater?
470 mmol/L, 550 mmol/L
How much sodium, chloride is in human blood?
137-146 mmol/L, 98-109 mmol/L
What is hardness?
The amount of dissolved calcium and magnesium in the water, used to describe water that does not lather well, high scale forming potential
What is origin of hardness?
Most calcium enters the water from CaCO3 in the form of limestone or from mineral deposits of CaSO4
What is the Hardness index?
(Ca2+) + (Mg2+) x MW (CaCO3) x 1000 (mg/L) expressed in milligrams per liter of calcium carbonate equivalents
What hardness of Calgary tap water? (North versus South)
North is hard, South is less hard
Which river supplies water for the bearspaw water treatment plant?
Bow river
Which river supplies water for the Glenmore Water Treatment Plant?
Elbow river
What plant of calgary has water primarily supplied to the north of the city?
The Bearspaw Plant
What plant of calgary has water primarily supplied to the south of the city?
The Glenmore Plant
What is alkalinity?
The buffering capacity of water, the ability of water to resist the decrease in pH by “capturing” H+ by alkaline components
What is alkalinity in terms of the number of moles?
It’s the number of moles H+ required to titrate 1L of a water sample to the endpoint using methyl orange as an indicator (changes color at ph=4, CO2 equivalent point)
For most surface waters total alkalinity?
Total alkalinity = 2(CO3^2-) + (HCO3^-) + (OH^-) - (H+)
What are three aggregate measures of organics in wastewater?
Biochemical Oxygen Demand (BOD)
Chemical Oxygen Demand (COD)
Total Organic Carbon (TOC)
What is dissolved oxygen?
A DO test measures the concentration of oxygen dissolved in a water or wastewater sample
What is the concentration of DO in a water sample significantly influenced by?
Temperature: As water temperature increases DO, DO decreases
Salinity: As water salinity increases, DO decreases
Atmospheric Pressure: As pressure increases, DO also increases (I.e, water holds less oxygen as you increase altitude)
How much O2 dissolves in a certain amount of water? What eqn?
O2= H X Po2 = H x (Px x O2)
What are the factors affecting dissolved oxygen?
Temperature (The solubility of gases in water decreases with increasing temperature)
Degradation of organic matter (CH2O)
What is the biochemical oxygen demand?
The amount of oxygen required by microorganisms to oxidize dissolved organic matter in the water samples.
What is the chemical oxygen demand (COD)?
The amount of oxygen consumed as a result of oxidation (by dichromate, a powerful oxidizing agent), of dissolved organic matter (and other oxidizable components) in the water sample
Explain the differences in COD vs BOD?
- COD Is fast and reliable for wastewater treatment operation & monitoring
- COD can be interpreted in terms of BOD, if reliable correlation factors have been established
- Does not distinguish between biodegradable & non-biodegradable organic matter
What is total organic carbon? What are it’s benefits and side effects?
Is the measurement of the total organic carbon in a wastewater sample by a TOC analyzer
- it’s fast and convenient
- Has on-line monitoring & process control
- Does not differentiate between organics which are biodegradable and which are not
- Have a high capital cost
What is the theoretical Oxygen Demand?
If wastewater contains identifiable organic compounds, thOD required for the oxidation of these organic can be calculated by wirting the eqn describing the oxidation of the organics to carbon dioxide and water and then balancing it.
What are the microbiological characteristics of water?
bacteria
algae
protozoa
fungi&molds
viruses
helminths
What are the two ways diseases are transmitted?
fecal-oral route, or indirect route via contaminated water and food
What type of diseases are caused by viruses?
Hepatitus A
Rotavirus
What types of diseases are caused by bacteria?
Typhoid
Cholera
What type of diseases are caused by protozoa?
Giardiasis
Cryptosporidiosis
What are the difficulties with routine testing of pathogens in water?
Present in low numbers, limited survival time, numerous pathogens to analyze, time and cost prohibitive
What are indicator organisms?
a basic monitoring tool used to determine prescence of pathogens in natural and treated water
What are the ideal characteristics of indicator organisms?
Present when pathogens are present in water, absent in uncontaminated water, present in higher numbers than pathogens in contaminated water, better survival in water than pathogens, easy to analyze
