Question | Answer |
Name three issues with source water from the Lindsay DWTP. | Flashy, high colour, turbidity not as big of a problem (easier to remove) |
What does TWA or time-weighted average limit mean? | The time-weighted average airborne concentration of a biological or chemical agent to which a worker may be exposed in a work day or work week. |
Winter has the biggest fluctuations in what two parameters? | Hardness, and alkalinity. |
Incoming through the 2 - 24" intake pipes, pH is normally at what level? | 7.8 - 8 |
Incoming through the 2 - 24" intake pipes, turbidity is normally at what level? | 2.0 - 2.5; can spike to 12 ntu's |
After Actiflo, turbidity is normally what value? | 0.1 ntu |
After filtration and actiflo, turbidity ranges from? | 0.024 - 0.039; must be under 0.3 for 90% of the time based on running average. |
When leaving the plant, the optimal pH range is? | 7.25 - 7.3 |
How much water is treated per day? | 8,000 m3 (can increase if demand is needed (i.e fire; one prior to 2009 tours brought demand up to 12,000m3/day)). |
When the intake becomes blocked by a build up of frazil ice, what method clears it off? | Hydroburst as often as needed. |
Why are low lift pumps elevated about a foot or so? | To avoid taking in sludge off river bottom |
How often is the Lindsay generator tested? | Every other week |
What is the purpose of the generator? | Helps ensure required pressure is never lower than 15psi for >15mins. |
How long does the take from intake to distribution? | 10mins for ActiFlo, 1 hour including filtration, ~6 hours from intake to distribution. |
Chlorine residual: flucations of >5 deg over a weekend can result in too high/too low chlorine residual, this is because? | Need larger containment area than volume of tank holding chemicals (110-115%) |
How many train systems are in operation? | 2 Train system |
How many pumps are on chemical feeds, and distribution? | 2 for chemical feeds, and 3 for distribution. |
What two coagulants are used? | PACl (winter) or Alum |
What does Alum need for pH adjustment (6.5-6.8)? | CO2 and caustic soda (aka sodium hydroxide) |
What is needed in PACl? | caustic soda only needed, and only in very small doses. |
What is GAC? | Granulated activated carbon (filters) |
How often are GAC replaced and what does it help with? | Every 3 years, helps with taste & odour |
When is ZM control used and what is associated with it? | May-Oct only, use chlorination (need 0.5ppm). Due to THM issue; must neutralize it again with sodium bisulphate |
What does SCADA stand for? | Supervisory Control and Data Acquisition |
Guideline for Cl2 maximum? | 4mg/L |
In distribution system: what is the free chlorine residual and the total chlorine residual? | Free chlorine residual: 0.05, total chlorine residual: 0.25. |
Where is waste water sent? | To the sewage treatment plant (coagulant helps their treatment) |
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