Unit 5 Flashcards by Evita Azcona

Why is permeability of the subsurface rock important to the flow of groundwater?

It determines how easy or difficult it is for water to move.

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Why are materials such as sand and gravel considered to be good aquifers for groundwater?

Because of their permeability.

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If a well is drilled into a confined aquifer, why is a pump not normally necessary for the water to
get to the surface?

Because of the natural or artesian pressure that exists in the aquifer.

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Why are unconfined aquifers more vulnerable to contamination from surface activities?

They only have one layer of impermeable material beneath the saturated zone.

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What is the benefit to an AF base buying drinking water from an adjacent city?

The water typically needs little or no additional treatment.

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Even though much of the undesirable material in groundwater is filtered out during the passage
through underground layers of sand, clay, rock, and gravel, what is a major limiting factor in
using groundwater a source of drinking water?

Excessive mineral content.

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Why is groundwater considered to be more advantageous than surface water as a source of
drinking water?

more difficult to contaminate.

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River water may be safe one day, but significantly contaminated the next. Why is this?

Because of the discharge of pollutants into the water.

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Why should the nature of a stream or lake be investigated to ensure its dependability as a water
source?

The availability of surface water may vary widely with each season of the year.

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When are complete studies of a water source for adequacy and dependability necessary?

If the water source must supply a large and constant amount of water.

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Why must the range of alkalinity in water be controlled?

prevent acidic corrosion & the precipitation of salts

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What can cause objectionable taste or odor in drinking water?

The water probably contains chemicals, minerals, and organic matter such as algae.

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Why is it important to have adequate dissolved oxygen levels in drinking water?

Adequate levels are necessary to prevent the drinking water from tasting flat.

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What effect do chemicals and organisms have in polluted water?

They cause the water to exhaust its oxygen.

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Why is it important to regularly test for microbial pathogens in the water distribution system?

To confirm the effectiveness of the water filtration and disinfection practices.

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When might drinking water require additional treatment other than chlorine?

there are chlorine-resistant pathogens.

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How do primary drinking water standards protect PH?

By limiting contaminant levels in drinking water.

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Why is it important to know which regulatory agency has primacy for drinking water criteria at
the base?

tells you the agency that has the primary responsibility for administering drinking water criteria at your installation.

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What base drinking water standard(s) must be complied with for installations outside the
continental United States?

DOD FGS or EGS.

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Water system classification by the EPA generally depends on what two factors?

number of people served
if system serves the same customers year-round

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List four typical areas of concern that a base’s WHPP should address.

(1) Runoff from the flight line
(2) entomology shop
(3) potential surface discharges from any base industrial operations,
(4) golf course maintenance operations.

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What type of water systems do the NPDWRs apply to?

public water systems

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What is a PWS?

A system that has at least 15 service connections, or regularly serves an average of at least 25 individuals
daily at least 60 days a year.

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What is a primacy agency?

The agency of the state or federal government that has primary enforcement responsibility in accordance
with the SDWA.

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What does water treatment consist of?

Adding or removing substances from water in order to produce a desired change in quality.

What is the purpose disinfecting water?

To inactivate microorganisms in the water, thereby preventing them from affecting the human body.

What’s the difference between a primary and secondary water disinfectant?

1- used to achieve a desired disinfection level to inactivate microorganisms 2- provides longer-lasting protection as the water moves through the distribution system to the consumers.

What is one of the main concerns with adding disinfectants to drinking water?

react with natural materials in the water to form byproducts

If a water main had a loss of positive pressure less than 20 psi within the main, what actions are required?

must be disinfected & tested for coliform bacteria

Why is chlorine a preferred method of disinfecting water?

leaves a residual in the water - easily measured - economical

What are the concerns with adding fluoride to drinking water?

- adults bone effects - children teeth stains

After the repair of a water main where the slug chlorination method was used, what steps must follow next?

- water line is flushed - samples are taken for bacteriological analysis.

What is the purpose of having three chlorination methods when installing new water lines?

- provide flexibility in responding to specific situations to disinfect new water lines while still ensuring an absence of coliforms.

What is a cross-connection in regards to the installation backflow prevention and cross- connection control program?

any temporary or permanent connection between a public water system and any source or system

What is the responsibility of civil engineering and, specifically, the backflow program manager (BPM) for the installation backflow prevention program?

investigate & document all cross-connections on the installation

What are the general procedures for disinfecting existing lines?

(1) Trench treatment. (2) Swabbing pipes and fittings with hypochlorite solution. (3) Flushing and chlorination of the line. (4) Bacteriological sampling.

Why are routine inspections of each cross-connection required?

To identify and eliminate potential risks.

What are BE’s responsibilities in the backflow prevention and cross-connection control program?

assigns hazard classifications to each cross-connection

Why is a water system sanitary survey conducted?

provide safe drinking water

The results of a sanitary survey provide the installation with what type of valuable information?

threats to the water quality and system reliability.

Why is it vital that a finished water storage facility be properly designed, operated, and maintained?

protect water from loss of chlorine residual, bacteria re-growth, contaminant entry

During the onsite visit of a sanitary survey, why is it important to conduct a review of the water supply source?

source of contaminants, pathogens, and particles.

Why does source water dictate the type of treatment processes and facilities used to achieve safe drinking water?

contaminated by harmful microorganisms & require treatment

Explain why BE personnel must refer to both AFMAN 48–138_IP and AFI 48–144 for field water?

AFMAN 48–138_IP - policy to ensure water used by military for drinking, & sanitation is adequate. AFI 48–144 - ensure all other AF surveillance requirements are met

Identify at least four BE-specific roles outlined in AFMAN 48–138_IP to meet PM field water objectives.

(1) Perform drinking water quality surveillance. (2) Support investigations of potential drinking water-related illnesses. (3) Maintain records of drinking water quality surveillance. (4) Ensure laboratories perform analyses using required analytical methods.

Explain the difference between STP standards and LTP standards.

STP standards are water quality standards that must be met to declare a water system potable **DURING ** the first 30 days of field operations LTP standards are water quality standards that must be met AFTER the first 30 days

Explain why LTP standards and MEGs are not the same.

MEGs do not need to be met for water to be considered potable.

Summarize how host nation municipal water source selection should be handled.

must be considered a raw water source until it is approved by PM personnel.

What does a raw water source sanitary survey involve?

examining water source & the surrounding area for existing pollution

How many bottled water samples should be tested by PM personnel?

1 % of the total # of bottles

What is the significance (or vulnerability) of a water system that presents numerous access points?

increased risk for an attack by operatives.

Why are WVA program review checklists an important part of the WVA process?

uniform way to ensure water security

As part of the water vulnerability pre-assessment phase, why is in important to research key documents and historical records?

can provide information concerning threats,

Why are subject matter experts a primary focal point for gathering water vulnerability information?

most knowledgeable individuals with program area of concern

What is the goal of conducting an “eyes on” physical assessment of water assets and access points?

identify vulnerable assets & access points

When are non-AF water mains that transit through areas accessible to the public of special concern?

When the purveyor is relying solely on a fence for security

Why must exterior surfaces of a portable storage reservoir/tank be inspected?

To check for corrosion and structural defects.

Who should use a designated filling station?

Contractors, vendors, and others not affiliated with base.

Why are fire hydrants of particular concern for water vulnerability?

accessibility, large port openings

What is the benefit of public notification of drinking water results?

ensure that consumers will know if there is a problem with their drinking water.

Why and when is a Tier 1 public notice required?

24 hours.

If a water system violates a drinking water standard that does not have a direct impact on human health, how long does the water supplier have to notify the public?

Up to one year.

If a base receives a consumer confidence report from a local water supplier, what is provided to the base population?

Either a copy of the original report or a modified version.

What agencies must be consulted to determine if there are more stringent standards (than the EPA) that must be followed/complied with?

State and local regulators.

What is the importance of a consumer confidence report?

puts the annual drinking water quality report into the hands of customers.

What does the consumer confidence report provide?

A summary of all the water monitoring your BE office conducted at the base over the past year.

When is the consumer confidence report disseminated to the base population?

By July 1st each year.

If an installation does not purchase its water from a local municipality, who is responsible for preparing the annual consumer confidence report?

BE.

If there are microbiological indicators in treated swimming pools or hot tubs, then what does this indicate?

Possible insufficient water exchange, disinfection, and/or maintenance.

When is a pre-season swimming pool inspection done and why?

30 days prior to the pool opening.

On what four factors does water quality depends?

- efficiency of disinfection - sanitary conditions - #bathers in the pool at any one time - total # bathers per day

Why are disease transmission hazards greatest among swimmers in fresh water swimming pools?

Because swimmers tend to ingest more water in swimming pools than swimmers in brackish estuarine water and salt water.

Describe the water quality parameters BE team members ensure are met during pre-season spa/hot tub inspections.

Measuring pH, temperature, and the disinfectant residual level.

Explain the reason why you don’t normally collect bacteriological samples from a spa/hot tub.

Because conditions change so rapidly research indicates the need to collect a sample only if an illness occurs.

Cite the reason why natural bathing areas present significantly more pathogenic organism risks.

Natural bathing area water is not chemically treated.

Cite the other agencies BE works with to jointly establish safety and warning guidelines for bathing area hazards?

FSS, PH, and ground safety.

How are SP and VP described in terms of energy?

SP is potential energy. VP is kinetic energy.

What is the purpose of the air mover?

To create the pressure needed to begin and maintain airflow.

Why do we measure TP?

In conjunction with SP, it indirectly gives VP.

What is the vena contracta?

Squeezing the air stream caused by air trying to rush into the confines of the duct from many directions, thus producing turbulence losses.

What are the principal causes of dynamic loss in a ventilation system other than in the hood?

Bend in the duct & changes in duct size

What are the principal causes of friction losses?

Rough duct material, high air velocity, small duct diameter, and long ducts.

At what points in a system would you expect the strongest negative SP and the strongest positive SP?

Strongest negative SP: at the fan inlet. Strongest positive SP: at the fan outlet.

When should you use a density factor in ventilation work?

When air stream temperatures are 30 F

Describe capture velocity.

The speed of the air at a point in front of the hood that is required to pull contaminants into the hood.

The velocity of air across the plane of an inlet or outlet to the system describes which type of velocity?

Face velocity.

What are the two parameters at a given point in ventilation systems that are needed to calculate the Q?

Area and velocity.

What is important to remember when calculating the Q from your measurements?

Calculate using the area in square feet at the point where you measured the velocity.

Under what conditions is a slight positive pressure desirable?

When adjoining rooms are not occupied.

Why can supply alone be used for dilution ventilation far more effectively than exhaust alone?

Supply gives more directional air flow for proper mixing with contaminants.

What three circumstances would result in a high K factor?

Inefficient ventilation (poor mixing), higher contaminant toxicities, and non-uniform evolution of contaminant.

Explain why ventilation for dilution to a LEL or even 25 percent of a LEL would not protect the health of an exposed person.

The LELs for chemicals far exceed the OELs and often the IDLH levels.

What is a saturation concentration?

The maximum concentration of a chemical vapor that air can hold at a certain temperature.

What are the benefits of the lower air volumes handled by local exhaust systems?

efficient & economical

How does inadequate makeup air directly affect the performance of a local exhaust system?

causes a negative pressure

If a new local exhaust system was to be installed in a machine shop, what provision could you recommend that would ensure the system was always used properly?

Interlock the local exhaust system with machinery so that they must be used together.

What are the two major advantages to local exhaust enclosures?

best contaminant control with the lowest air volumes.

What are the two types of key parameters for local exhaust systems?

Duct velocity and required Q.

What are the four general hood classifications?

Open, slot, canopy, enclosing.

How does a receiving hood differ from other open hood types?

It does not capture contaminants.