1.
Within the Occupational and Environmental Health (OEH) Program, which of the following are Bioenvironmental Engineering responsibilities?
Correct Answer
C. Accomplishing OEH risk assessments, recommending and evaluating OEH hazard controls, and communicating risks to the organizational leadership.
Explanation
The responsibilities of Bioenvironmental Engineering within the Occupational and Environmental Health (OEH) Program include accomplishing risk assessments, recommending and evaluating hazard controls, and communicating risks to the organizational leadership. This involves identifying potential hazards in the workplace, assessing the level of risk they pose, and proposing measures to control or mitigate these risks. The communication of these risks to the organizational leadership is crucial for decision-making and ensuring the overall health and safety of the organization.
2.
If upon arriving at an industrial facility, you conducted a quantitative assessment to focus
Bioenvironmental Engineering (BE) resources on occupational and environmental health (OEH)
related hazards that require additional evaluation, then what type of OEH process assessment have
you conducted?
Correct Answer
B. Special
Explanation
The correct answer is "Special." This is because a special OEH process assessment is conducted when there is a need for additional evaluation of occupational and environmental health hazards. This assessment is conducted upon arriving at an industrial facility to determine the specific hazards that require further attention and resources from Bioenvironmental Engineering.
3.
What three pillars are used to describe Force Health Protection?
Correct Answer
A. Healthy and fit force, casualty prevention, and casualty care and management.
Explanation
The three pillars used to describe Force Health Protection are a healthy and fit force, casualty prevention, and casualty care and management. This means that the focus is on maintaining the health and fitness of the force, preventing casualties or injuries, and providing proper care and management for any casualties that do occur. This approach ensures that the force is able to effectively carry out their duties and missions while minimizing risks to their health and well-being.
4.
Which Code of Federal Regulation deals with protecting human health and welfare as related
to the workplace?
Correct Answer
B. Title 29, Labor.
Explanation
Title 29, Labor is the correct answer because it specifically deals with protecting human health and welfare as related to the workplace. This title of the Code of Federal Regulations contains regulations and standards related to occupational safety and health, including requirements for workplace safety, health standards, and worker protections. It covers a wide range of topics such as hazardous materials, occupational exposure to harmful substances, workplace safety standards, and employee rights and protections.
5.
What organization is responsible for publishing the Threshold Limit Values (TLVs) and
Biological Exposure Indices (BEIs)?
Correct Answer
C. American Conference of Governmental Industrial Hygienists.
Explanation
The American Conference of Governmental Industrial Hygienists (ACGIH) is responsible for publishing the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs). TLVs are guidelines that determine the acceptable levels of exposure to various chemical substances in the workplace, while BEIs are biological monitoring guidelines for assessing occupational exposure to chemicals. ACGIH is a professional organization that consists of industrial hygienists and is recognized as a leading authority on occupational and environmental health and safety issues. They regularly review and update TLVs and BEIs based on the latest scientific research and expert consensus.
6.
Which of the following web-based application systems is the AF-approved occupational and
environmental health management information system?
Correct Answer
D. Defense Occupational and Environmental Health Readiness System.
Explanation
The AF-approved occupational and environmental health management information system is the Defense Occupational and Environmental Health Readiness System. This system is specifically designed to manage and track occupational and environmental health data for the Air Force. Phoenix, Command Core, and Aerospace Medicine Management System are not specifically mentioned as AF-approved systems for this purpose.
7.
Which of the following fully qualified people can verify the accuracy and completeness of all
exposure assessment data that is entered into Defense Occupational and Environmental Health
Readiness System (DOEHRS)?
Correct Answer
D. Bioenvironmental Engineer and Civilian Industrial Hygienist.
Explanation
The Bioenvironmental Engineer and Civilian Industrial Hygienist are the fully qualified individuals who can verify the accuracy and completeness of all exposure assessment data entered into DOEHRS. The other options do not include both a Bioenvironmental Engineer and a Civilian Industrial Hygienist, so they are not fully qualified to perform this task.
8.
What is the benefit of standardizing processes and information within the Defense Occupational and Environmental Health Readiness System (DOEHRS)?
Correct Answer
D. Allows installations to devote more resources to high risk operations.
Explanation
Standardizing processes and information within the Defense Occupational and Environmental Health Readiness System (DOEHRS) allows installations to devote more resources to high-risk operations. By standardizing processes, the system ensures consistency and efficiency, reducing the time and effort required for manual tasks. This frees up resources that can be allocated to high-risk operations, improving readiness and effectiveness.
9.
Which of the following terms refers to the Defense Occupational and Environmental Health
Readiness System (DOEHRS) data stored on an individual worker’s history of pre-deployment,
deployment, and post-deployment exposures?
Correct Answer
C. Longitudinal exposure record.
Explanation
The correct answer is "Longitudinal exposure record." This term refers to the DOEHRS data that is stored on an individual worker's history of pre-deployment, deployment, and post-deployment exposures. It tracks and records the worker's exposure to occupational and environmental hazards over time, providing a comprehensive record of their exposure history.
10.
Accurate routine and special assessment data in Defense Occupational and Environmental
Health Readiness System (DOEHRS) is used for what purpose?
Correct Answer
D. Make recommendations to protect workers from health threats and risks.
Explanation
The accurate routine and special assessment data in Defense Occupational and Environmental Health Readiness System (DOEHRS) is used to make recommendations to protect workers from health threats and risks. This data helps identify potential hazards and risks in the work environment, allowing for proactive measures to be taken to ensure the safety and well-being of workers.
11.
What is the first step in the Occupational and Environmental Health Site Assessment
(OESHA) process?
Correct Answer
D. Pre-deployment/baseline activities.
Explanation
The first step in the Occupational and Environmental Health Site Assessment (OESHA) process is to conduct pre-deployment/baseline activities. This involves gathering information about the site, such as its location, potential hazards, and any previous assessments or studies that have been conducted. This step is important because it allows for the identification of potential risks and the development of appropriate strategies and protocols for the assessment. By completing these activities before deploying personnel to the site, it ensures that the assessment can be conducted efficiently and effectively.
12.
If you are validating the health threat information collected during the pre-deployment and baseline activities and identified additional threats not foreseen, then which step of Occupational and Environmental Health Site Assessment (OESHA) are you working on?
Correct Answer
B. Site reconnaissance.
Explanation
The correct answer is Site reconnaissance. In the context of Occupational and Environmental Health Site Assessment (OESHA), site reconnaissance involves collecting information about the site and its surroundings to identify any potential health threats. During this step, if additional threats are identified that were not previously anticipated, it indicates that the health threat information collected during the pre-deployment and baseline activities is being validated.
13.
Which of the following is not a bioenvironmental engineering (BE) role in the occupational
and environmental health site assessment/health risk assessment/health risk management
(OESHA/HRA/HRM) processes?
Correct Answer
A. Initiate a concise course of action.
Explanation
The correct answer is "Initiate a concise course of action." In the occupational and environmental health site assessment/health risk assessment/health risk management processes, bioenvironmental engineering (BE) roles involve identifying and analyzing occupational and environmental health risks at both garrison and deployed locations, determining appropriate control options, and communicating information through the chain of command. However, initiating a concise course of action is not specifically mentioned as a BE role in these processes.
14.
What step of the Occupational and Environmental Health Site Assessment (OESHA)
process is a written depiction that shows the link between occupational and environmental health
(OEH) threats and personnel working in similar working groups?
Correct Answer
C. Conceptual Site Model.
Explanation
The correct answer is Conceptual Site Model. The Conceptual Site Model is a written depiction that shows the link between occupational and environmental health threats and personnel working in similar working groups. It provides a visual representation of the potential pathways for exposure to hazards and helps in understanding the relationship between the site conditions and the health risks to the workers. This step is important in identifying and assessing the potential risks and developing appropriate control measures to protect the workers and the environment.
15.
Why is initial assessment screening beneficial?
Correct Answer
C. It can narrow the parameters for analysis by ruling out the presence of high potential threats.
Explanation
Initial assessment screening is beneficial because it helps narrow the parameters for analysis by ruling out the presence of high potential threats. By conducting this screening, potential threats can be identified and eliminated early on, allowing for a more focused and efficient analysis process. This helps save time and resources by prioritizing the analysis of only the most relevant and significant threats.
16.
Which step in health risk assessment (HRA) parallels the reassessment step in the
occupational and environmental health site assessment (OESHA) process?
Correct Answer
A. Supervise and review.
Explanation
The step in health risk assessment (HRA) that parallels the reassessment step in the occupational and environmental health site assessment (OESHA) process is "Supervise and review." In both processes, this step involves overseeing and evaluating the assessment or results to ensure accuracy and effectiveness. It includes monitoring the implementation of controls and measures, reviewing data and findings, and making any necessary adjustments or improvements. This step is crucial in both HRA and OESHA to ensure the ongoing assessment and management of health risks in the workplace or environment.
17.
Translating qualitative and quantitative data into understandable information for
commanders occurs during which step of the health risk assessment (HRA)?
Correct Answer
B. Communicating HRA Results.
Explanation
During the step of communicating HRA results, the process of translating qualitative and quantitative data into understandable information for commanders takes place. This step involves presenting the findings and conclusions of the health risk assessment in a clear and concise manner, ensuring that the information is easily comprehensible to the decision-makers. By effectively communicating the results, commanders can make informed decisions and take appropriate actions to mitigate any identified health risks.
18.
Which of the following is not a bioenvironmental engineering (BE) role in regard to control
options?
Correct Answer
B. Decide whether or not to implement recommended controls and accept ancillary risks.
Explanation
The correct answer is "Decide whether or not to implement recommended controls and accept ancillary risks." This option does not align with the role of bioenvironmental engineering (BE) in regard to control. BE professionals are responsible for determining and recommending appropriate controls to reduce health threat exposures to acceptable levels. They also communicate control options and their impacts on personnel and the mission. However, the decision to implement controls and accept risks is typically made by higher-level authorities or management, not by BE professionals themselves.
19.
Evaluating the environmental and industrial conditions that could present health threats at
expeditionary locations is the beginning of what process?
Correct Answer
D. Occupational and environmental health site assessment (OESHA).
Explanation
The correct answer is Occupational and environmental health site assessment (OESHA). This process involves evaluating the environmental and industrial conditions at expeditionary locations to identify potential health threats. It focuses on assessing the risks associated with occupational and environmental factors that could affect the health and well-being of individuals in that location. This assessment is crucial in order to develop appropriate measures to mitigate and manage these risks effectively.
20.
As a member of the preventive and aerospace medicine (PAM) team, which will you not be involved with during site selection?
Correct Answer
C. Implement hazard recommendations in support of contingency operations.
Explanation
As a member of the preventive and aerospace medicine (PAM) team, you will not be involved in implementing hazard recommendations in support of contingency operations. This task is typically handled by other teams or departments that specialize in emergency response and contingency planning. Your role as a member of the PAM team would primarily focus on evaluating environmental and industrial conditions, helping in the selection of bed down sites and facility configurations, and developing and communicating the results of site assessments.
21.
Which of the following is not a form of substitution?
Correct Answer
C. Substitution of personnel.
Explanation
The correct answer is "Substitution of personnel." This is because substitution of personnel refers to replacing or exchanging one employee with another, which is not a form of substitution in the context of the question. The other options, such as substitution of process, materials, and equipment, all involve replacing or using alternatives for a specific element or component, making them forms of substitution.
22.
Which of the following is an administrative control?
Correct Answer
D. Air sampling.
Explanation
Air sampling is an administrative control because it involves monitoring and measuring the presence of airborne contaminants in a workplace. This control helps to identify potential hazards and determine if the levels of pollutants are within acceptable limits. By regularly sampling the air, administrators can implement appropriate measures to reduce exposure to harmful substances and ensure the safety and well-being of employees. Isolation, face shields, and ventilation, on the other hand, are examples of engineering controls or personal protective equipment rather than administrative controls.
23.
Changing a hazard source to make it less hazardous is an example of which occupational
exposure control?
Correct Answer
A. Engineering.
Explanation
Changing a hazard source to make it less hazardous is an example of engineering control. Engineering controls involve modifying or redesigning equipment, machinery, or processes to eliminate or reduce hazards at their source. This can include implementing safety measures such as installing machine guards, using ventilation systems to remove harmful substances, or automating processes to reduce human interaction with hazards. Engineering controls are considered the most effective way to control workplace hazards as they eliminate or minimize the need for workers to rely on personal protective equipment or administrative controls.
24.
Which occupational exposure control should be used in conjunction with other controls?
Correct Answer
D. Personal Protective Equipment.
Explanation
Personal Protective Equipment (PPE) should be used in conjunction with other controls in order to provide an additional layer of protection for workers. While engineering controls, administrative controls, and preventive maintenance are important in reducing occupational exposure, they may not always be sufficient on their own. PPE, such as gloves, goggles, masks, and protective clothing, can help to further minimize the risk of exposure to hazards in the workplace. Therefore, it is recommended to use PPE along with other control measures to ensure the safety and well-being of workers.
25.
Who has the responsibility to assess workplaces to identify if hazards are present which
require personal protective equipment?
Correct Answer
D. Workplace supervisors.
Explanation
Workplace supervisors have the responsibility to assess workplaces and identify if hazards are present that require personal protective equipment. They are in charge of overseeing the safety of the workplace and ensuring that all necessary precautions are taken to protect employees from potential hazards. This includes conducting regular assessments to identify any hazards and determining if personal protective equipment is necessary to mitigate the risks. The other options mentioned, such as the BE Officer, BE Technician, and Chief of Safety, may also play a role in workplace safety, but the primary responsibility lies with the workplace supervisors.
26.
Who has the responsibility to ensure that the personal protective equipment recommended
for a particular tasks will do the job for which it is designed?
Correct Answer
A. Bioenvironmental engineering (BE).
Explanation
Bioenvironmental engineering (BE) is responsible for ensuring that the personal protective equipment (PPE) recommended for a particular task will do the job for which it is designed. They have the expertise and knowledge to assess the specific hazards and risks associated with the task and recommend the appropriate PPE to mitigate those risks. The Chief of Safety, workplace employee, and workplace supervisor may also play a role in ensuring PPE is used correctly, but the ultimate responsibility lies with BE.
27.
Who is responsible for establishing standards for safety programs associated with personal
protective equipment?
Correct Answer
B. Air Force Safety Center.
Explanation
The Air Force Safety Center is responsible for establishing standards for safety programs associated with personal protective equipment. They are tasked with ensuring the safety and well-being of Air Force personnel and establishing guidelines and protocols to minimize risks and accidents. The Chief of Safety, Air Force Surgeon General, and Air Force Material Command may also play important roles in safety programs, but the Air Force Safety Center is specifically responsible for setting standards for personal protective equipment.
28.
When should risk communication be used to motivate the audience to action?
Correct Answer
D. Investigation of a suspicious white powder.
Explanation
Risk communication should be used to motivate the audience to action when there is an investigation of a suspicious white powder. In this situation, there is a potential risk or threat, and it is important to communicate effectively with the audience to ensure their safety and prompt action. By providing clear and concise information about the situation and the necessary precautions, risk communication can motivate the audience to take appropriate measures, such as reporting the incident, evacuating the area, or following specific protocols to minimize the risk and protect themselves.
29.
Bioenvironmental engineers (BEs) recommendations to commanders should have which
three basic parts?
Correct Answer
A. Timely, Practical, Effective.
Explanation
The recommendations provided by Bioenvironmental engineers (BEs) to commanders should be timely, meaning they should be provided in a timely manner to address the current situation. They should also be practical, meaning they should be feasible and realistic to implement. Additionally, the recommendations should be effective, meaning they should achieve the desired outcome or result. Therefore, the three basic parts of BEs recommendations should be timely, practical, and effective.
30.
Which is not needed to have successful risk communication?
Correct Answer
B. Complex.
Explanation
Successful risk communication requires clear, consistent, and understandable messaging. Complex messaging can often lead to confusion and misunderstandings, making it difficult for individuals to make informed decisions about risks. Therefore, complexity is not needed for successful risk communication.
31.
Of the factors to consider when developing a risk communication message and determining
how to deliver it, what question should you ask about the audience?
Correct Answer
D. Whom are we communicating with
Explanation
When developing a risk communication message and determining how to deliver it, it is important to ask the question "Whom are we communicating with?" This question helps in understanding the specific characteristics, needs, and preferences of the audience. By knowing the target audience, the message can be tailored to effectively reach and engage them. Different audiences may require different communication strategies, channels, and formats to ensure the message is understood and acted upon appropriately.
32.
Who will decide whether to accept the health risks identified in lieu of operational benefit?
Correct Answer
B. Commander.
Explanation
The Commander will decide whether to accept the health risks identified in lieu of operational benefit. As the highest-ranking officer in charge, the Commander has the authority and responsibility to make decisions that prioritize the overall mission and operational benefit, even if it involves accepting certain health risks. The Commander will consider input from various sources, including the Bioenvironmental Engineering (BE) team, the Civil Engineer, and the Base Safety Officer, but ultimately, the decision rests with the Commander.
33.
What is the process by which water is used by vegetation and passes through grass, plants
and trees, returning to the atmosphere as vapor?
Correct Answer
D. Transpiration.
Explanation
Transpiration is the correct answer because it refers to the process by which water is taken up by vegetation, including grass, plants, and trees, and then released back into the atmosphere as vapor. During transpiration, water is absorbed by the roots, transported through the plant, and eventually evaporates from the leaves. This process helps to cool the plant, transport nutrients, and maintain the water balance in the plant.
34.
What is the natural process where there is a constant circulation of water and water vapor
powered by energy from the sun and gravity?
Correct Answer
A. Hydrologic cycle.
Explanation
The correct answer is the hydrologic cycle. This is a natural process where there is a constant circulation of water and water vapor, powered by energy from the sun and gravity. It involves processes such as evaporation, condensation, precipitation, and runoff, and is responsible for the distribution of water on Earth.
35.
What type of aquifer would cause water to be forced up a well shaft?
Correct Answer
C. Artesian.
Explanation
An artesian aquifer is a confined aquifer that is under pressure, causing water to be forced up a well shaft. The pressure is created when water is trapped between layers of impermeable rock or clay, and the aquifer is tilted or inclined, allowing the water to flow upwards. This upward flow of water is what causes it to be forced up a well shaft.
36.
The upper layer where water and air are present in varying amounts that change
over time is known as the
Correct Answer
D. Unsaturated zone.
Explanation
The upper layer where water and air are present in varying amounts that change over time is known as the unsaturated zone. In this zone, the soil and rock have some empty spaces or pores that are not completely filled with water. The amount of water present in this zone is less than its maximum capacity, allowing air to occupy some of the spaces. This zone is also referred to as the vadose zone or the zone of aeration.
37.
What type of aquifer requires a pump to push water to the surface?
Correct Answer
C. Unconfined.
Explanation
Unconfined aquifers are those in which the water table is not confined by impermeable layers of rock or soil. This means that the water is free to move vertically and can naturally flow to the surface without the need for a pump. In contrast, confined aquifers are surrounded by impermeable layers, which create pressure and require a pump to push the water to the surface. Therefore, the correct answer is unconfined.
38.
What ground characteristics allow water to move freely?
Correct Answer
C. Sand and gravel layers.
Explanation
Sand and gravel layers have larger pore spaces compared to other ground characteristics like clay, rock, and caliche rock layers. These larger pore spaces allow water to move more freely through the ground. The water can easily flow through the gaps between the sand and gravel particles, resulting in better drainage and less water retention in the soil. This makes sand and gravel layers ideal for groundwater recharge and infiltration.
39.
Which constituent is not commonly found in groundwater?
Correct Answer
A. Nitrate.
Explanation
Nitrate is not commonly found in groundwater because it is highly soluble and easily leaches out of the soil into surface water. It is more commonly found in surface water sources such as rivers and lakes. Calcium, fluoride, and magnesium are commonly found in groundwater as they are naturally present in rocks and minerals that make up the Earth's crust.
40.
Where is groundwater found?
Correct Answer
D. Unsaturated and saturated zones.
Explanation
Groundwater is found in both unsaturated and saturated zones. The unsaturated zone, also known as the vadose zone, is the area above the water table where the soil and rock contain air and water. The saturated zone is the area below the water table where the soil and rock are completely filled with water. Groundwater can be found in both of these zones depending on the level of saturation.
41.
What is one reason groundwater sources are generally preferred over surface water sources
for drinking?
Correct Answer
A. Groundwater has a low turbidity.
Explanation
Groundwater is generally preferred over surface water sources for drinking because it has a low turbidity. Turbidity refers to the cloudiness or haziness of a fluid caused by suspended particles. Groundwater, being located underground, is naturally filtered through layers of soil and rock, which helps to remove impurities and particles, resulting in a clearer and cleaner water source. In contrast, surface water sources such as rivers and lakes are more prone to contamination from pollutants and sediment, leading to higher turbidity levels. Therefore, the low turbidity of groundwater makes it a safer and more desirable option for drinking water.
42.
Which Environmental Protection Agency (EPA) drinking water standard is a guideline that
applies to the aesthetic aspects of drinking water?
Correct Answer
D. Secondary.
Explanation
The EPA drinking water standard that applies to the aesthetic aspects of drinking water is the Secondary standard. This standard addresses non-health-related contaminants that may affect the taste, odor, or appearance of drinking water. It includes guidelines for substances such as color, odor, taste, and certain specific contaminants that may cause cosmetic effects. The Primary standard, on the other hand, focuses on contaminants that have potential health risks and sets maximum allowable levels for these substances in drinking water.
43.
What law passed by congress established a Federal program to monitor and increase the
safety of all publically and commercially supplied drinking water?
Correct Answer
A. Safe Drinking Water Act.
Explanation
The Safe Drinking Water Act is the correct answer because it is a law passed by Congress that established a Federal program to monitor and increase the safety of all publicly and commercially supplied drinking water. The other options, such as the Well Head Protection Program, Safe Drinking Water Surveillance Program, and National Primary Drinking Water Regulation, are not the correct answer because they do not specifically refer to the law passed by Congress.
44.
When is water from a surface source considered safe?
Correct Answer
A. After it is tested and approved.
Explanation
Water from a surface source is considered safe only after it has been tested and approved. This means that it has undergone a thorough analysis to ensure that it meets the required standards for drinking water. Testing is necessary to identify any potential contaminants or pollutants that may be present in the water, and approval is given only if the water meets the necessary quality and safety criteria. Therefore, this is the correct answer as it highlights the importance of testing and approval in determining the safety of water from a surface source.
45.
Water obtained in the field from rivers, streams, ponds, lakes, wells, ice, or snow is referred
to as what type of source?
Correct Answer
A. Raw water.
Explanation
Raw water refers to water that is obtained directly from natural sources such as rivers, streams, ponds, lakes, wells, ice, or snow without any treatment or purification. It is called raw water because it has not undergone any processes to make it safe for consumption. Raw water may contain various impurities, such as bacteria, viruses, chemicals, and sediments, which can pose health risks if consumed without proper treatment.
46.
When examining proposed water source sites, which factor considers if the source will
provide an adequate supply of potable water for all personnel for the expected duration of
operations?
Correct Answer
B. Quantity.
Explanation
The factor that considers if the water source will provide an adequate supply of potable water for all personnel for the expected duration of operations is quantity. This means that the amount of water available from the source is sufficient to meet the needs of all personnel for the entire duration of their operations. Quality refers to the safety and purity of the water, availability refers to the presence or existence of the water source, and accessibility refers to the ease of reaching and using the water source.
47.
How do bioenvironmental engineering (BE) personnel accomplish their role as part of the
Preventive Medicine (PAM) Team?
Correct Answer
C. Sample and analyze drinking water sources for contamination.
Explanation
Bioenvironmental engineering (BE) personnel accomplish their role as part of the Preventive Medicine (PAM) Team by sampling and analyzing drinking water sources for contamination. This allows them to identify any potential hazards or pollutants in the water that may pose a risk to public health. By conducting regular analysis, they can ensure that the water is safe for consumption and take appropriate measures if contamination is detected. Disinfecting drinking water sources and drilling wells are not mentioned as part of their role in the given options.
48.
What do reverse osmosis water purification unit (ROWPU) operators add to the filtered
water to conclude the purification process before storing the water as potable?
Correct Answer
D. Disinfectant.
Explanation
After the water has been filtered, reverse osmosis water purification unit (ROWPU) operators add a disinfectant to conclude the purification process before storing the water as potable. This is done to kill any remaining bacteria, viruses, or other microorganisms that may still be present in the water, ensuring that it is safe for consumption. Adding calcium, magnesium, or fluoridation are not part of the purification process and are not necessary for making the water potable.
49.
For reverse osmosis water purification unit (ROWPU)-treated water, how long of a contact
time must a 2.0 ppm free available chlorine (FAC) residual be maintained prior to use?
Correct Answer
C. 30 minutes.
Explanation
For reverse osmosis water purification unit (ROWPU)-treated water, a contact time of 30 minutes is required to maintain a 2.0 ppm free available chlorine (FAC) residual prior to use. This contact time allows the chlorine to effectively disinfect the water and ensure it is safe for use.
50.
Concerning breakpoint chlorination, after breakpoint, what causes an increase in residual
chlorine that is primarily free available chlorine (FAC)?
Correct Answer
A. Oxidation of ammonia.
Explanation
After breakpoint chlorination, the oxidation of ammonia causes an increase in residual chlorine that is primarily free available chlorine (FAC). Ammonia is commonly found in water sources, and during breakpoint chlorination, chlorine is added to the water until all the organic matter, including ammonia, is oxidized. This oxidation reaction converts ammonia into chloramines, which are a combination of chlorine and ammonia. As more ammonia is oxidized, more chloramines are formed, leading to an increase in residual chlorine, specifically free available chlorine (FAC).