Question Answer
The driving force of the hydrologic cycle is? The sun
All water from surface and subsurface sources originates from? Precipitation
This type of well is close to the ground surface, is under the influence of atmospheric pressure, and is not confined by overlying impervious soils? Shallow well
This type of well is confined by an overlying impervious layer of rock or soil with an accompanying impervious layer below, at the base of the aquifer? Deep well or artesian well
These wells are under hydraulic pressure by the overlying strata and may have static water levels higher than the top of the aquifer, or underside of the overlying impervious strata? Artesian well
Where groundwater flows by gravity along the water bearing strata and seeps from the ground, and the underlying impervious strata guides the groundwater to the surface discharge location? Spring
The primary and secondary objectives of water treatment are to produce water that is? Safe for human consumption; Aesthetically pleasing
The degree of water treatment is dependent on the characteristics of? The raw water source
In water treatment, processes such as screening, aeration, mixing, sedimentation, and filtration are considered as what type of treatment? Physical treatment
In water treatment, processes such as water stabilization (corrosion control), coagulation, flocculation, disinfection, softening, mineral control, and taste and odour control are considered as what type treatment? Chemical treatment
The design of the distribution system and the location of pump houses and storage reservoirs depend on these three various factors? Demand, Topography, and Layout
The volume of water stored in a distribution system depends on these three factors? Maximum day demand; Fire demand; and Emergency storage required
In distribution systems that have large variations in elevation, the distribution layer is divided into? Pressure zones
These are established in a distribution system that has large variations in elevation in order to reduce the static pressure on the lower regions of the system, while maintaining satisfactory pressure in the upper regions of the distribution system? Pressure zones
A lack of pipeline interconnections, or the presence of dead-end lines throughout a distribution system produce these two undesirable effects? Lower flow velocities; Bad tasting water (stagnation)
How can areas throughout a distribution system be supplied with sufficient pressure and a reliable water supply with this layout design concept? Pipeline interconnections
What is a significant source that impacts taste, odour and colour problems in surface water sources? Organic decomposition
What is the best way to treat taste and odour problems (list three examples)? Aeration and oxidation; Carbon filtration; Powdered activated carbon
In which seasons are taste, odour, and colour generally the most problematic (list three)? Fall, Early winter, and Spring
Which natural phenomena is a cause of seasonal problems with taste, odour, and colour? Thermal turnover
The presence of these minerals produce a reddish colored water which leaves unattractive red and black stains on plumbing fixtures? Iron and manganese
Chloroform, bromodichloromethane, dibromochloromethane, and bromoform are categorized as? Trihalomethanes (THMs)
How are THMs formed (be specific)? When free chlorine combines with naturally occurring organic matter
Which chemical and physical characteristics of water, when in high amounts, increase the formation of THMs? pH and temperature
What is the temporal range in which THM formation can occur? Within minutes or days from the first introduction of chlorine
Which chemical can also affect the rate of THM formation? Bromide
The addition of which treatment chemicals can contribute to the formation of THMs? Lime or caustic soda
In order to control taste and odour problems, selection of the depth at which an intake is to be constructed depends on? The amount of decomposing organic matter
What is the ideal intake velocity that is used to reduce the intake or entrapment of suspended particles and small fish? 0.15 m/s (0.5 ft./s)
When surface water source reliability and quality are in question, what is used to mitigate the consequences of an inconsistent water supply? Raw water storage reservoir
These are sometimes constructed to reduce the level of suspended solids and turbidity of raw water, but they can also be used as storage reservoirs? Sedimentation basins
In a raw water reservoir, this is measured from the maximum water surface elevation to the top of the bank? Freeboard
List three types of suspended solids that are removed by filtration? Fine clay, silt, and carryover floc (from sedimentation basins)
List four types of microorganisms that are removed by filtration? Algae, bacteria, viruses, and protozoa
This type of filtration follows coagulation, flocculation, and sedimentation treatment processes? Conventional filtration
With this type of filtration, chemical pre-treatment and conditioning is still usually required? Direct filtration
Filtration efficiency is dependent upon the five following factors? Chemical characteristics of the water; Physical characteristics of suspended matter; Concentration of solids in suspension; Degree of pre-treatment; and Characteristics of filtering material and method of filter operation
The flow rate through the filter is directly proportional to which three factors? Driving force or head of water above the filter; Inverse proportional resistance of filter medium; Solids on the filter
This is the distance measured from the water level above the filter to the underside of the filter bed medium? Total head
Under “no flow” conditions in a filtration unit, the available head in the filter is equal to? The total head
When filtration starts, the filter medium exhibits what? A resistance to flow
With the filtration process, the initial head loss or pressure loss is indicated by? The “start of run”
With the filtration process, head loss increases across the filter and the amount of head available decreases. Why does this occur? Sediment deposition on the filter surface, and sediment penetration of the upper layers of the medium
What develops when the filtering process time extends beyond the capacity of the filter to pass flow? Negative pressure
When the available head in a filtration unit can no longer drive water through the medium, this is called? Resistance to flow
In a filtration unit, this occurs when available head (to drive water through the medium) is equal to the head resistance across the flow? Resistance to flow
When available head is equal to the head resistance across the flow in a filtration unit, it is time to? Backwash the filter
Negative pressures in a filtration unit can cause the development of? Air pockets
What are two problems caused by air pockets in a filtration unit? Reduction in effective filtering area; Increase in filtering flow rate across other parts of the filter
What is a significant consequence of allowing air pockets to develop in a filtration unit? Water quality problems
With this type of filter, the water level or pressure above the medium forces water through the filter? Gravity filter
This type of filter typically consists of single, dual or mixed media filtration units? Gravity filters
A single media gravity filter uses what type of media? Sand
A dual media gravity filter uses which types of media? Sand and a top layer of anthracite
A mixed-media gravity filter uses which types of media, and in what order (top to bottom)? Anthracite (top layer), followed by sand and garnet layers
How can the effective filtering rate of a gravity filter be increased? Using varying filter media and depths
In a gravity filter, what is one way to trap larger particles that would normally clog the lower sand filter bed? Anthracite top layer
This process produces a reversed flow across the filter that is of a sufficient upward velocity that fluidizes the media beds and carries away the captured material? Backwash
This type of filtration is similar to gravity filtration except that the filter medium is enclosed in a pressure vessel? Pressure Filtration
What purpose does pressurizing the water passing through a pressure filter serve? Supplies the needed head across the filter medium
This type of filtration unit is likely used in small municipal applications where water demands are generally lower? Pressure filters
This type of filtration should not normally be used in municipal applications other than for special situations? Pressure filters
This type of filtration unit is not as effective as gravity filtration? Pressure filters
This type of filtration uses a fine mesh screen called a septum that is coated with a slurry of filter media material prior to filtration? Diatomaceous-earth filtration
The procedure of coating the septum with a slurry of diatomite material is called? Precoat
During filtration, why are small quantities of diatomite fed continually to coat the filter septum? So that the filter surface does not become clogged
This type of filtration unit is backwashed when the pressure head across the filter becomes too high? Diatomaceous-earth filtration unit
This type of filtration unit relies on a head of water above the media surface to slowly force water through the medium? Slow sand filters
Unlike gravity filters, this type of filter removes particles by straining, absorption, and biological action? Slow sand filters
Gravity filter filtration rates range between? 1.68-6.74 L/s/m2
Slow sand filtration rates range between? 0.08-1.09 L/s/m2
Where is the majority of filtered material removed in a slow sand filter? The top few centimeters
In a slow sand filtration unit, the biological growth on the top portion of the filter medium helps to remove which two contaminants from water? Bacteria and turbidity
Which characteristic of filter media is used to measure the passage of suspended solids? Finesse
Which characteristic of filter media is observed to prevent high flow resistance? Permeability
Which two characteristics of filter media are used to determine the interaction with chemicals or substances present in the water? Inertness/reactivity
This characteristic of filter media is used to gauge efficiency during backwashing (settling rate)? Grading
Which two characteristics are used to determine the longevity of filter media? Hardness and durability
Which two characteristics are used to determine the quality and safety of filter media? Absence of impurities/insolubility in water
In general, ______ filter media produce better water quality then _____media? Finer/coarse

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