41 Questions
What is the process known as when harmful disease-producing bacteria in water are killed to make it safe for drinking?
Disinfection
Which law describes the reduction in microorganisms when exposed to a disinfectant over time?
Chick's Law
What does excess lime treatment do to water in terms of its pH value?
Raises the pH
Why is boiling water not considered a practical method for disinfection?
It cannot remove future contaminations
Which method of disinfection involves the breaking down of ozone into normal oxygen and nascent oxygen?
Ozone treatment
What does a first-order reaction mean in disinfection kinetics?
The rate of the reaction remains constant
What is the total available head at the treatment plant?
Difference in water surface elevations in the influent of first treatment unit and that in the effluent of last treatment unit
Which of the following is NOT considered a basic principle when preparing the hydraulic profile through the plant?
Preparing hydraulic profiles for only one main path of flow through the plant
What does the head loss through the treatment plant consist of?
Sum of head losses in the treatment units and connecting piping
Which of the following is included in the head losses through the treatment unit?
Head losses through the unit
What does the total loss through the connecting pipings, channels, and appurtenances consist of?
Sum of head loss due to contraction and enlargement, friction, and bends
Why might pumping be needed in a treatment plant?
To maintain a constant flow rate by gravity
What is the germicidal action of chlorine explained by according to the Enzymatic hypothesis?
Chlorine kills the enzymes essential for the metabolic processes of living organisms
How is chlorine usually added to the water supply?
By forming a gas, Cl2(g)
What does the dissociation of hypochlorous acid (HOCl) form?
Hypochlorite ion (OCl-)
What are the free chlorine compounds that compose the free chlorine residual?
Hypochlorous acid and hypochlorite ion (OCl-)
What is formed when excess free chlorine is added beyond the 1:1 initial molar ratio in the breakpoint reaction?
Monochloramine is removed
What are chloramines mainly composed of in drinking water systems?
Monochloramine (NH2Cl)
What is the relationship between chloramine species and chlorine dose illustrated by?
Molar ratios between chlorine and nitrogen
What contributes to an increase in chlorine demand as explained in the text?
Reactions with reduced iron at corrosion sites
What does the treatment plant layout refer to?
Arrangement of treatment units at a treatment plant site
Which principle is important to consider for site development according to the text?
Utilizing existing site topography for gravity flow
What is the main purpose of a water distribution system?
To deliver water to consumers with appropriate quality, quantity, and pressure
Which of the following is NOT a requirement of a good distribution system?
Distribution pipes should be directly connected to sewer lines
Where are distribution pipes typically laid for water distribution networks?
Below road pavements
Which of the following is a key layout requirement for a distribution system to minimize leakage?
Having a water-tight system
What guides the layout of distribution pipes in a distribution network?
The layout of roads above which the pipes are generally laid
Why should all distribution pipes preferably be laid away from or above sewer lines?
To improve water quality in the distribution system
What method is used to calculate the head losses and corrected flows in a distribution network as described in the text?
Hardy Cross Method
In the Hardy Cross method, what is assumed to be constant for different formulas mentioned in the text?
Value of x
How are the corrected flows in the pipes adjusted in the Hardy Cross method as described in the text?
By adjusting assumed flows
In the context of the text, what is the purpose of analyzing closed loops ABCD and CDEF using Hardy Cross method?
To compute head losses and corrected flows
What is the role of the law of continuity in the process of assuming flows in each pipe according to the text?
To conserve mass flow rate
What parameter is used to compute the head losses in the pipes within the closed loop system as explained in the text?
$\frac{L}{470 \times d^{4.87}}$
What is the main function of distribution reservoirs?
To absorb hourly variations in demand
Where should distribution reservoirs ideally be located?
Close to the center of demand
What is the purpose of balancing storage in a distribution reservoir?
To equalize fluctuating demand against constant supply
Which principle must be satisfied in any pipe network according to the text?
Applying the law of continuity
What is the main purpose of the Hardy-Cross method in pipe network analysis?
To assume a distribution of flow that satisfies continuity at each junction
How is the correction 'd' computed in the Hardy-Cross method for pipe network analysis?
$d = Q - Q_a$
What does 'SK.Q^x = - SKx.Q^(x-1)d' represent in the Hardy-Cross method equation?
'SK.Q^x' represents head loss in a pipe loop
Test your knowledge on the process of disinfection and sterilization, specifically focusing on Chick's Law. Learn about the first-order reaction involved in reducing microorganisms when exposed to disinfectants.
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