What are the 4 categories of impurities in water?
- 1. TDS (Total dissolved solids)
- 2. TSS (Total suspended solids)
- 3. O&G (Oil and Grease)
- 4. DO (Dissolved Organics)
Define potable water
Water that is suitable for drinking
A subsurface zone of trapped water
Name some sources of water
- Surface water: ocean, rivers, lakes
- Land surface water: snow, ice caps, rainfall
- Groundwater: wells, aquifers, water table
What 4 questions should you ask when considering water treatment?
- 1. Where does the water come from?
- 2. What type of water do we have?
- 3. What do we need the water for?
- 4. What are the treatment options?
What separates TDS from TSS?
- TDS has a particle size <0.45um, while TSS is greater
- TSS is organic and inorganic; TDS is just inorganic
Parameters used to define water quality
Temperature, turbidity, dissolved O2, pH, colour, alkalinity, hardness
What are some problems associated with high TDS?
- -Scaling tendency
- -Will corrode
- -Can be toxic
How can you measure TDS?
- -Evaporating the water and weighing the solids left behind
- -Complete ion analysis
What parameters are necessary to predict scaling tendency?
Hardness and alkalinity
The mols of acid required to titrate a water sample to a pH of 4.3
Define retrograde solubility
Solubility goes down as temperature goes up
What's an example of a retrograde soluble compound?
What is temporary hardness?
The sum of the polyvalent cations in water
How is hardness determined?
Through an EDTA titration
What is total hardness?
Temporary + permanent hardness
What is permanent hardness?
Non-bicarbonate hardness (CaCl2, CaCO3, CaSO4)
Why is scale a problem?
- -Can form an impermeable barrier
- -Can increase corrosion (under deposit corrosion)
- -Acts as an insulator
How can you use LSI to determine if a water will scale?
- if LSI = 0, system is at equlibrium (saturated)
- if LSI > 0, supersaturated; scale will form
- if LSI <0, undersaturated; scale will not form
What are 4 ways to prevent scale?
- 1. Manage scale
- 2. Use chemicals to prevent scale formation
- 3. Remove ions before they can precipitate as scale
- 4.Remove water and leave solids behind
What is softening?
Removing the hardness from water
What are some parameters used to control the softening process?
- 1. Adjust the pH
- 2. Adjust ions (hardness and alkalinity)
- 3. Adjust temperature
Alberta Township System
National Topographic System