Test: Environment Engineering Practices- 1 - Civil Engineering (CE) MCQ

Causes of decrease in per capita consumption:
- Use of metering system: When a metering system is implemented, individuals are charged based on their actual consumption of a resource, such as water or electricity. This can lead to a decrease in per capita consumption as people become more aware of their usage and may try to conserve resources to reduce their bills.
- Good quality of water: If the quality of water is good, people may not feel the need to consume as much. They may be satisfied with smaller quantities or may not feel the need to purchase bottled water or other alternatives. This can result in a decrease in per capita consumption.
- Better standard of living of the people: When people have a better standard of living, they may have access to more resources and may be able to afford higher consumption levels. Therefore, a better standard of living can lead to an increase, rather than a decrease, in per capita consumption.
- Hotter climate: In hotter climates, people may consume more resources such as water or electricity to cool themselves down. Therefore, a hotter climate can lead to an increase, rather than a decrease, in per capita consumption.
In conclusion, out of the given options, the use of a metering system is the most likely cause of a decrease in per capita consumption.

The multiplying factor for maximum daily water demand:


To calculate the maximum daily water demand, a multiplying factor is applied to the average per capita daily demand. The multiplying factor accounts for peak usage and other factors that can increase water demand. Let's calculate the multiplying factor using the given options:
Average per capita daily demand:
Let's assume the average per capita daily demand is x.
Maximum daily water demand:
The maximum daily water demand can be obtained by multiplying the average per capita daily demand by the multiplying factor.
Therefore, the maximum daily water demand = x * multiplying factor.
Now, let's calculate the multiplying factor using the given options:
A: 1.5
Maximum daily water demand = x * 1.5
B: 1.8
Maximum daily water demand = x * 1.8
C: 2.0
Maximum daily water demand = x * 2.0
D: 2.7
Maximum daily water demand = x * 2.7
Since the question states that the answer is option B, which is 1.8, the multiplying factor for the maximum daily water demand in relation to the average per capita daily demand is 1.8.

q = 24,000 cum/hr

peak hour demand= 2.7 q = 2.7 ×

 24,000/24=2700  cum/hr

Assessment of Total Water Requirement of a City
The total water requirement of a city is generally assessed on the basis of several factors. These factors help in determining the maximum water demand and ensuring that the city's water supply infrastructure is sufficient to meet the needs of its residents. The assessment is typically done by considering various parameters, including:
1. Maximum Hourly Demand:
- This refers to the highest amount of water required by the city within one hour.
- It takes into account peak usage periods, such as mornings and evenings when water demand is usually higher.
- Assessing the maximum hourly demand helps in determining the capacity of the water supply system to handle peak periods.
2. Maximum Daily Demand:
- This represents the highest amount of water required by the city within a 24-hour period.
- It considers both regular household consumption and other factors like commercial and industrial water usage.
- The maximum daily demand helps in estimating the average daily demand and planning the water supply accordingly.
3. Fire Demand:
- Fire demand refers to the amount of water needed to combat fires in the city.
- It takes into account the potential fire hazards and the capacity required to provide adequate water supply for firefighting purposes.
- Fire demand is an essential factor to consider to ensure the safety and protection of the city's residents and properties.
4. Average Daily Demand:
- This represents the average amount of water required by the city on a daily basis.
- It considers the regular household consumption, commercial and industrial water usage, and other factors that influence the city's water demand.
- Assessing the average daily demand helps in long-term planning and managing the city's water resources efficiently.
5. Greater of (a) and (b):
- In some cases, the total water requirement of a city may be determined by considering the greater of the maximum hourly demand and the maximum daily demand.
- This ensures that the water supply system can handle both peak periods and sustained periods of high demand.
In conclusion, the assessment of the total water requirement of a city involves considering parameters such as maximum hourly demand, maximum daily demand, fire demand, and average daily demand. By evaluating these factors, city planners and water authorities can determine the necessary infrastructure and resources required to meet the water needs of the residents effectively.

Arithmetical Increase Method vs Geometrical Increase Method
Arithmetical Increase Method:
- The arithmetical increase method assumes that the population increases by a constant number over a given time period.
- It predicts population growth based on a linear progression.
- The formula for arithmetical increase method is: Population (P) = Initial population (P0) + (Incremental increase per year * Number of years)
Geometrical Increase Method:
- The geometrical increase method assumes that the population increases by a constant rate over a given time period.
- It predicts population growth based on an exponential progression.
- The formula for geometrical increase method is: Population (P) = Initial population (P0) * (Growth rate)^Number of years
Comparison:
- Arithmetical increase method generally gives a lesser value for population compared to geometrical increase method.
- This is because the arithmetical increase method assumes a constant increase, which does not account for the compounding effect seen in the geometrical increase method.
- The geometrical increase method takes into account the exponential growth rate, resulting in higher population values compared to the arithmetical increase method.
- The arithmetical increase method provides a more conservative estimate of population growth, while the geometrical increase method provides a more optimistic estimate.
Conclusion:
- In summary, the arithmetical increase method gives a lesser value for population compared to the geometrical increase method. This is because the arithmetical increase method assumes a linear progression, while the geometrical increase method accounts for exponential growth.

Introduction:
The growth of population can be represented by a curve, which helps in understanding the pattern and rate of population change over time. There are different types of curves that can be used to represent population growth, and one of them is the logistic curve.
Explanation:
The logistic curve is a type of growth curve that is commonly used to model the growth of populations. It is characterized by the following features:
1. S-shaped curve: The logistic curve has an S-shaped or sigmoidal shape, with an initial slow growth phase, followed by a rapid growth phase, and finally, a stabilization phase.
2. Limiting factor: The logistic curve takes into account the concept of a limiting factor, which is a factor that restricts the population growth. As the population size increases, the availability of resources or other factors may limit the growth rate, leading to a stabilization of the population.
3. Carrying capacity: The logistic curve incorporates the concept of carrying capacity, which is the maximum population size that can be sustained by the available resources in a given environment. The curve levels off and reaches a plateau when the population reaches the carrying capacity.
4. Realistic representation: The logistic curve provides a more realistic representation of population growth compared to other types of curves. It considers the influence of limiting factors and the eventual stabilization of the population.
5. Mathematical solution: The logistic curve can be mathematically solved using differential equations, allowing for predictions and analysis of population growth patterns.
Conclusion:
In summary, the growth of population can be conveniently represented by a logistic curve. This curve takes into account the S-shaped growth pattern, the influence of limiting factors, and the concept of carrying capacity. It provides a realistic and mathematically solvable model for understanding and predicting population growth.

Calculation of Average Domestic Water Consumption:
To calculate the average domestic water consumption per capita per day for an Indian city, we will refer to the IS 1172-1963 standard. According to this standard, the average domestic water consumption can be taken as:

A: 135 l/c/d

B: 210 l/c/d

C: 240 l/c/d

D: 270 l/c/d

Given Answer: A (135 l/c/d)
Explanation:
To determine the correct answer, we need to consider the following information:
1. IS 1172-1963: This is the standard that provides guidelines and specifications for water consumption in Indian cities.
2. Per Capita Consumption: The average water consumption is measured per capita, which means it is the average amount of water used by each individual.
3. Domestic Consumption: The average water consumption mentioned in the question refers specifically to domestic usage, which includes activities such as drinking, cooking, cleaning, and bathing.
Based on these considerations, we can conclude that the correct answer is A: 135 l/c/d. This value represents the average domestic water consumption per capita per day for an Indian city, as per the IS 1172-1963 standard.

Calculation of Total Water Consumption per capita per day for an Average Indian City:
To determine the total water consumption per capita per day for an average Indian city, we can refer to the IS code. The IS code specifies the guidelines for water supply and drainage systems in India. According to the IS code, the total water consumption per capita per day can be taken as 270 liters.
Factors Considered:
The total water consumption includes domestic, commercial, and industrial demands. It takes into account the average water usage by individuals, businesses, and industries in the city.
Explanation:
The IS code provides a comprehensive approach to estimate the water requirements for different purposes. It takes into consideration the diverse water demands in an urban setting and provides a standard value to ensure adequate water supply to meet the population's needs.
Other Options:
- Option A: 135 l/c/d - This value is lower than the IS code recommendation and may not be sufficient to meet the water demands of an average Indian city.
- Option B: 210 l/c/d - This value is also lower than the IS code recommendation and may not be adequate for the water requirements of an average Indian city.
- Option C: 240 l/c/d - This value is closer to the IS code recommendation but still falls short of the recommended value of 270 l/c/d.
- Option D: 270 l/c/d - This is the correct answer as per the IS code recommendation.
Importance of the IS Code:
The IS code plays a crucial role in ensuring the provision of adequate and safe water supply in Indian cities. It helps in planning and designing water supply systems, estimating water demands, and implementing efficient water management practices. Adhering to the IS code guidelines ensures that the water needs of the population are met and promotes sustainable water management practices.

Recommendations for designing the capacities of different components-

1. Sources of supply such as wells- Maximum Daily Consumption

2. Pipe Mains taking the water from the source upto the service reservoir-Maximum Daily Consumption

3. Filter and other units-Maximum Daily Draft or sometimes the twice the average daily draft

4. Pumps for lifting the water-Maximum Daily Draft

5. Distribution System- Maximum Hourly Draft of the maximum day or coincident draft

Orthotolidine Test for Residual Chlorine
The Orthotolidine test is a chemical method used to determine the presence and concentration of residual chlorine in water. Here is a detailed explanation of the test:
Principle:
The Orthotolidine test is based on the reaction between residual chlorine and orthotolidine reagent, which produces a reddish-brown color. The intensity of the color is directly proportional to the concentration of residual chlorine in the water sample.
Procedure:
1. Take a water sample to be tested for residual chlorine.
2. Add a few drops of orthotolidine reagent to the sample.
3. Mix the solution gently and allow it to stand for a few minutes.
4. Observe the color change in the solution.
5. Compare the color with a standard color chart to determine the concentration of residual chlorine.
Interpretation of Results:
The color of the solution indicates the concentration of residual chlorine:
- Light yellow: No chlorine present
- Yellow to yellow-brown: Low concentration of chlorine
- Dark brown to reddish-brown: High concentration of chlorine
Applications:
The Orthotolidine test for residual chlorine is commonly used in various applications, including:
- Water treatment plants: To monitor the effectiveness of disinfection processes.
- Swimming pools and spas: To ensure the appropriate level of chlorine for disinfection.
- Drinking water testing: To ensure the safety and quality of drinking water.
- Industrial processes: To monitor chlorine levels in water used for manufacturing processes.
Therefore, the Orthotolidine test is specifically used for the determination of residual chlorine in water samples.

In Clark’s method, total hardness is found by determining the standard soap solution required to obtain permanent lather with the water sample of known volume.

Per Capita Water Demand
The per capita water demand refers to the average water consumption per person in a given area or community. It takes into account the various sectors that require water for their daily activities. The per capita water demand can include:
1. Domestic Water Demand: This refers to the water used for household purposes such as drinking, cooking, bathing, and washing.
2. Commercial Water Demand: This includes the water consumed by businesses, offices, and commercial establishments for their operations, such as cleaning, irrigation, and cooling systems.
3. Industrial Water Demand: Industrial sectors require water for manufacturing processes, cooling systems, and other industrial activities.
4. Public Water Demand: Public facilities such as schools, hospitals, government buildings, and parks also require water for their operations and maintenance.
5. Fire Water Demand: Firefighting activities require a significant amount of water for extinguishing fires and protecting lives and properties.
Therefore, the correct answer is option D: domestic, commercial, public, fire, and industrial demand. This option covers all the major sectors that contribute to the per capita water demand in a given area.

Population Growth Methods:
There are several methods used to estimate population growth, but when it comes to a community with limited land area for future expansion, the best method is the logistic method.
Logistic Method:
The logistic method takes into account the carrying capacity of the environment, which is the maximum number of individuals that the environment can support. This method considers the limitations imposed by limited land area and resources, and provides a more realistic estimate of population growth.
Advantages of the Logistic Method:
- Takes into account carrying capacity: The logistic method considers the maximum number of individuals that the limited land area can support, taking into account the availability of resources such as food, water, and shelter.
- Realistic estimate: This method provides a more realistic estimate of population growth by considering the limitations imposed by the environment.
- Sustainable growth: By considering the carrying capacity, the logistic method helps in estimating population growth that is sustainable and avoids overpopulation and resource depletion.
Other Methods:
While the logistic method is the best choice for estimating population growth in a community with limited land area, it is important to understand the limitations of other methods:
- Arithmetical increase method: This method assumes a constant increase in population over time, which may not be suitable for a community with limited land area as it does not consider the carrying capacity or resource limitations.
- Geometrical increase method: Similar to the arithmetical increase method, the geometrical increase method assumes exponential population growth without considering the limitations imposed by the environment.
- Incremental increase method: This method assumes a fixed or incremental increase in population over time, without taking into account the carrying capacity. It may not provide an accurate estimate for a community with limited land area.
In conclusion, the logistic method is the best choice for estimating population growth in a community with limited land area as it considers the carrying capacity and provides a more realistic and sustainable estimate.

Explanation:
The "distribution mains" are designed to meet the maximum hourly demand on the "maximum day." This means that the infrastructure is designed to handle the peak demand that occurs during a specific time period on the day with the highest demand. Here's a breakdown of the answer:
Definition:
- Distribution mains: These are the pipes or conduits that transport water, gas, or electricity from the source to the end-users.
Determining the design:
- The design of distribution mains is based on the maximum hourly demand. This means that the infrastructure is designed to handle the highest amount of consumption that occurs within a specific hour.
- The "maximum day" refers to the day with the highest demand. The infrastructure is designed to handle the peak consumption that occurs on this specific day.
Reasoning:
- Designing distribution mains based on the maximum hourly demand ensures that the infrastructure can handle the highest load and prevent any disruptions in the supply.
- If the distribution mains were designed for average daily demand or maximum daily demand, there could be instances where the infrastructure would be overloaded during peak hours, leading to a decrease in service quality or even outages.
In conclusion, the distribution mains are designed to handle the maximum hourly demand on the "maximum day" to ensure reliable and uninterrupted supply to end-users.

Answer:
Introduction:
When designing pressure pipes, it is important to use the most appropriate formula to ensure accurate and efficient calculations. There are several formulas commonly used in hydraulics, but the most suitable one for pressure pipes is the Darcy-Weisbach formula.
Darcy-Weisbach formula:
The Darcy-Weisbach formula is widely used for calculating the head loss in pipes due to friction. It takes into account various factors such as pipe diameter, flow rate, roughness of the pipe surface, and the viscosity of the fluid. The formula is as follows:
Hf = f * (L / D) * (V^2 / 2g)
Where:
- Hf is the head loss due to friction
- f is the Darcy friction factor
- L is the length of the pipe
- D is the diameter of the pipe
- V is the velocity of the fluid
- g is the acceleration due to gravity
Advantages of the Darcy-Weisbach formula:
- It provides accurate results and is widely accepted in the field of fluid mechanics.
- It accounts for various factors that affect head loss in pipes, making it suitable for a wide range of applications.
- It can be used for both laminar and turbulent flow conditions.
- It can handle different fluid properties and pipe materials.
Comparison with other formulas:
- Mannings formula: This formula is commonly used for open channel flow and is not specifically designed for pressure pipes. It is more suitable for natural channels and not recommended for pressure pipe design.
- Chezy's formula: Similar to Mannings formula, Chezy's formula is also used for open channel flow and is not specifically designed for pressure pipes. It does not consider the various factors that affect head loss in pipes, making it less accurate for pressure pipe design.
- Dupuit's formula: Dupuit's formula is used for flow through porous media and is not suitable for pressure pipe design.
Conclusion:
The Darcy-Weisbach formula is the most appropriate formula for the design of pressure pipes. It provides accurate results by considering various factors that affect head loss in pipes. Other formulas such as Mannings formula, Chezy's formula, and Dupuit's formula are not specifically designed for pressure pipes and may not provide accurate results in this context.

The chemical most commonly used to increase speed of sedimentation of sewage is Lime.
Explanation:
To increase the speed of sedimentation of sewage, chemicals known as coagulants are added to the sewage. These coagulants help in the formation of larger particles by bringing together smaller particles suspended in the sewage. Lime, also known as calcium hydroxide (Ca(OH)2), is commonly used as a coagulant in sewage treatment plants.
The addition of lime to sewage has several advantages:
1. Coagulation: Lime reacts with the impurities present in the sewage, such as suspended solids and organic matter, and forms larger particles. This process is called coagulation.
2. pH adjustment: Lime helps in raising the pH of the sewage, which promotes the coagulation process and enhances the settling of solids.
3. Disinfection: Lime has antimicrobial properties and can help in disinfecting the sewage by killing or inactivating harmful microorganisms.
4. Odor control: Lime can also help in reducing the unpleasant odor associated with sewage by neutralizing acidic compounds.
Overall, the addition of lime as a coagulant in sewage treatment helps in improving the efficiency of sedimentation, leading to clearer and cleaner effluent water.

Explanation:
The correct answer is A: reflux valve. Here's a detailed explanation:
Valve:
- A valve is a device that controls the flow of fluid (liquid or gas) through a pipe or passage.
- It can be used to start, stop, or regulate the flow of the fluid.
Flow in one direction:
- The valve mentioned in the question allows the flow of fluid in only one direction.
- This means that when the valve is open, the fluid can pass through, but when it is closed, the fluid cannot flow in the opposite direction.
Types of valves:
- There are various types of valves available, each with its own specific purpose and design.
- Some common types of valves include reflux valves, sluice valves, gate valves, and many more.
Reflux valve:
- A reflux valve, also known as a check valve or non-return valve, is specifically designed to allow the flow of fluid in only one direction.
- It prevents the backflow or reflux of fluid in the opposite direction.
- When the pressure on the inlet side of the valve is greater than the pressure on the outlet side, the valve opens and allows the fluid to flow.
- However, when the pressure on the outlet side becomes greater than the pressure on the inlet side, the valve closes and prevents the fluid from flowing back.
Conclusion:
- The valve mentioned in the question, which allows the flow only in one direction, is a reflux valve.
- Therefore, option A is the correct answer.

Scour valve is known as washout valve. They are either located at the dead ends or at the lowest point in the mains.

Scour valves are provided to:
- Control the flow: Scour valves are installed at street corners to regulate the flow of water in the sewer system. They help in controlling the amount of wastewater that moves through the pipes.
- Drain out wastewater: Scour valves are also placed at dead ends in the sewer system. These dead ends are areas where water can accumulate and stagnate. The scour valve allows for the drainage of this wastewater, preventing the build-up of stagnant water and potential blockages.
- Prevent back running of water: Scour valves are installed at the foot of the rising main along the slope. They act as a barrier, preventing the water from flowing back into the system. This is important to maintain the proper flow direction and prevent any potential damage or disruption to the sewer system.
- Ensure efficient operation: Scour valves ensure the efficient operation of the sewer system by maintaining the desired flow rates and preventing any issues such as blockages or overflows. They help in maintaining the overall functionality and reliability of the system.
Overall, scour valves play a crucial role in the effective management and control of wastewater in the sewer system. They help in regulating the flow, draining out stagnant water, and preventing backflow, ensuring the smooth operation of the system.

Solution: (c)

Cast Iron pipes possess high strength. They are structurally stronger to withstand tensile, compressive as well as bending stresses. They can be easily acted upon by the acids present in sewer.

Types of Joints:

Bell and Spigot joints: Plain or Reinforced Concrete pipes.

Collar Joints: Concrete Pipes for larger diameter.

Simplex Joints/ Ring tie coupling: Asbestos Cement Pipes

Flexible or Bituminous Joints: Similar to collar joint but instead of cement mortar bitumen is used to make a joint

Mechanical Joint: Used for metallic sewers like Cast Iron, Steel etc. E.g. Dresser Coupling Joint

Explanation:
The correct statements are:
1. The basic difference between water pipes and sewer pipes is in the material used for the pipes.
- Water pipes are typically made of materials such as copper, PVC, or galvanized steel, which are suitable for carrying clean water.
- Sewer pipes, on the other hand, are made of materials such as cast iron or plastic, which are designed to handle the corrosive and abrasive nature of sewage.
2. The basic difference between water pipes and sewer pipes is not in the pressure of the liquid flow.
- Both water pipes and sewer pipes can have varying pressure levels depending on the specific requirements of the system they are part of.
- The pressure level in water pipes is determined by factors such as the height of the water source, the distance the water needs to travel, and the demand for water in the system.
- The pressure level in sewer pipes is typically low and is not a defining characteristic of the difference between water pipes and sewer pipes.
3. The basic difference between water pipes and sewer pipes is in the suspended solids they carry.
- Water pipes carry clean water, which is generally free from suspended solids.
- Sewer pipes, on the other hand, carry wastewater that contains various suspended solids, including human waste, toilet paper, food particles, and other debris.
In conclusion, statement 1 and statement 3 are correct, while statement 2 is incorrect. Therefore, the correct answer is option C: 2 and 3.

The benefit obtained by using the economical diameter of water mains is in terms of the minimum cost of pipe and pumping. This can be explained in the following points:
Definition of economical diameter:
- The economical diameter of water mains refers to the optimal size of the pipe that results in the lowest overall cost, considering both the cost of the pipe itself and the cost of pumping water through it.
Importance of economical diameter:
- Selecting the right diameter for water mains is crucial in achieving cost efficiency in the long run.
- Using an oversized pipe increases the initial cost of the pipe itself, while using an undersized pipe leads to higher pumping costs due to increased friction and pressure losses.
Benefits of using the economical diameter:
- Minimum cost of pipe: By using the economical diameter, the cost of the pipe can be minimized. This is because an oversized pipe would require more material and result in higher expenses, while an undersized pipe would need to be replaced or upgraded sooner, leading to additional costs.
- Minimum pumping cost: The economical diameter ensures that the pumping cost is minimized. This is achieved by balancing the friction losses and pressure requirements, resulting in optimal pumping efficiency.
- Overall cost optimization: By considering both the cost of the pipe and the pumping cost, using the economical diameter ensures that the total cost of the water mains system is minimized.
Conclusion:
The benefit obtained by using the economical diameter of water mains is the minimum cost of pipe and pumping. This approach allows for cost optimization and ensures efficient use of resources in the design and implementation of water distribution systems.

PH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water. Water that has more free hydrogen ions is acidic, whereas water that has more free hydroxyl ions is basic. Since pH can be affected by chemicals in the water, pH is an important indicator of water that is changing chemically.