Environmental Engineering-II

Which of the following is a primary treatment process in sewage treatment?

Which of the following is a potential source of sewage pollution?

What is the role of anaerobic bacteria in sewage treatment?

What is the purpose of a sewage treatment?

What is the main purpose of secondary treatment in sewage treatment?

Which of the following materials is most commonly recycled?

What is the waste management hierarchy?

Which of the following is a challenge in solid waste management?

What is the primary goal of solid waste management?

Which legislation in the United States focuses on waste management and resource recovery?

Evaluate the impact of population growth and urbanization on the design of sewerage systems. What strategies can be employed to address these challenges?

A residential area is expected to have a population of 5,000 people. The average water usage is estimated at 150 liters per person per day. The design engineer plans to use a gravity sewer system.
(i) Calculate the average daily flow in liters per second. If the sewer is designed to handle peak flow, which is estimated to be 2.5 times the average flow, calculate the peak flow in $ L/s $.
(ii) If the sewer has a diameter of 200 mm, calculate the minimum slope required to ensure a flow velocity of at least $ 0.6~m/s $, using the Manning's equation. (Take Manning's coefficient = 0.013)

Discuss the key design considerations for a sewage pumping station. Include operational efficiency selection, hydraulic design, equipment specification and impact.

A sewage pumping station is required to handle a peak flow of 150 $ L/s $, total dynamic head (TDH) needed is estimated at 15 meters.
(i) Calculate the horsepower (HP) required for the pump (Assume pump efficiency as 70%).
(ii) Convert the flow rate from $ L/s $ to GPM. (Given, 1 $ L/s $ = 15.85 GPM)

Analyze the role of stormwater management in the design of sewerage systems. How can integrated approaches enhance system efficiency?

A city has a combined sewer system serving an area of 10 hectares. The design flow is comprised of 70% sewage and 30% stormwater. The average sewage generation rate is 200 liters per capita per day, and the city has a population of 20,000. During a rain event, the rainfall intensity is $ 50~mm/hour $, and the runoff coefficient is 0.8.
(i) Calculate the average sewage flow in $ m^{3}/s $.
(ii) Calculate the stormwater generated from the rain event in $ m^{3}/s $.
(iii) Determine the total design flow (combined sewage and stormwater).

Discuss the key components and challenges of solid waste management systems. Include aspects like generation, collection, transportation, treatment, and disposal, and analyze the importance of sustainable practices in managing solid waste effectively.

A city has a population of 250,000 residents. The average waste generation rate is 1.2 kg per person per day.
(i) Calculate the total waste generated by the city in a year (in MT).
(ii) If the city aims to recycle 30% of its waste, how much waste (in MT) will be recycled annually? Determine the amount of waste sent to landfills annually (in MT).

Examine the concept of the circular economy in relation to solid waste management. How can this model reduce waste generation and promote resource recovery? Provide examples of successful circular economy initiatives.

A municipality incurs various costs associated with solid waste management. The following costs are estimated for a year: Collection costs: ₹500,000; Transportation costs: ₹300,000; Treatment and disposal costs: ₹400,000.
1. Calculate the total annual cost of solid waste management.
2. If the municipality serves 200,000 residents, determine the cost per capita for solid waste management.
3. If the total waste generated is 100,000 metric tons, calculate the cost per metric ton for managing solid waste.

Compare and contrast aerobic and anaerobic treatment systems used in wastewater management. Discuss their operational principles, advantages and disadvantages, and specific applications. Provide examples of each system and analyze their roles in sustainable wastewater management.

An anaerobic digester processes organic waste with the following characteristics: the digester has a volume of $ 500~m^{3} $ and processes waste with a total solids (TS) concentration of 6% by weight. The digester operates at a hydraulic retention time (HRT) of 20 days.
1. Calculate the total mass of organic waste (in kg) processed in the digester at any given time.
2. If the anaerobic digestion process achieves a volatile solids (VS) reduction of 60%, calculate the mass of volatile solids reduced (in kg).
3. Determine the total biogas produced if 0.4 $ m^{3} $ of biogas is produced per kg of volatile solids reduced.

Analyze the environmental impacts of landfills and discuss the strategies that can be employed to mitigate these impacts.

A landfill has a total capacity of 500,000 cubic meters. The compacted waste is approximately 0.8 metric tons per cubic meter.
(i) Calculate the total weight capacity of the landfill in metric tons.
(ii) If the landfill receives an average of 120 tons of waste per day, determine how long the landfill will last (in days) before reaching capacity.
(iii) Convert the lifespan of the landfill into years.

Compare between Bangalore method and the Indore method of composting. Discuss their principles, operational procedures, advantages, and disadvantages. Which method would you prefer if you were the environmental officer in charge? Also mention the reason for your selection.

Write short notes on any two of the following:

Which of the following is a primary treatment process in sewage treatment?

Which of the following is a potential source of sewage pollution?

What is the role of anaerobic bacteria in sewage treatment?

What is the purpose of a sewage treatment?

What is the main purpose of secondary treatment in sewage treatment?

Which of the following materials is most commonly recycled?

What is the waste management hierarchy?

Which of the following is a challenge in solid waste management?

What is the primary goal of solid waste management?

Which legislation in the United States focuses on waste management and resource recovery?

Evaluate the impact of population growth and urbanization on the design of sewerage systems. What strategies can be employed to address these challenges?

A residential area is expected to have a population of 5,000 people. The average water usage is estimated at 150 liters per person per day. The design engineer plans to use a gravity sewer system.
(i) Calculate the average daily flow in liters per second. If the sewer is designed to handle peak flow, which is estimated to be 2.5 times the average flow, calculate the peak flow in $ L/s $.
(ii) If the sewer has a diameter of 200 mm, calculate the minimum slope required to ensure a flow velocity of at least $ 0.6~m/s $, using the Manning's equation. (Take Manning's coefficient = 0.013)

Discuss the key design considerations for a sewage pumping station. Include operational efficiency selection, hydraulic design, equipment specification and impact.

A sewage pumping station is required to handle a peak flow of 150 $ L/s $, total dynamic head (TDH) needed is estimated at 15 meters.
(i) Calculate the horsepower (HP) required for the pump (Assume pump efficiency as 70%).
(ii) Convert the flow rate from $ L/s $ to GPM. (Given, 1 $ L/s $ = 15.85 GPM)

Analyze the role of stormwater management in the design of sewerage systems. How can integrated approaches enhance system efficiency?

A city has a combined sewer system serving an area of 10 hectares. The design flow is comprised of 70% sewage and 30% stormwater. The average sewage generation rate is 200 liters per capita per day, and the city has a population of 20,000. During a rain event, the rainfall intensity is $ 50~mm/hour $, and the runoff coefficient is 0.8.
(i) Calculate the average sewage flow in $ m^{3}/s $.
(ii) Calculate the stormwater generated from the rain event in $ m^{3}/s $.
(iii) Determine the total design flow (combined sewage and stormwater).

Discuss the key components and challenges of solid waste management systems. Include aspects like generation, collection, transportation, treatment, and disposal, and analyze the importance of sustainable practices in managing solid waste effectively.

A city has a population of 250,000 residents. The average waste generation rate is 1.2 kg per person per day.
(i) Calculate the total waste generated by the city in a year (in MT).
(ii) If the city aims to recycle 30% of its waste, how much waste (in MT) will be recycled annually? Determine the amount of waste sent to landfills annually (in MT).

Examine the concept of the circular economy in relation to solid waste management. How can this model reduce waste generation and promote resource recovery? Provide examples of successful circular economy initiatives.

A municipality incurs various costs associated with solid waste management. The following costs are estimated for a year: Collection costs: ₹500,000; Transportation costs: ₹300,000; Treatment and disposal costs: ₹400,000.
1. Calculate the total annual cost of solid waste management.
2. If the municipality serves 200,000 residents, determine the cost per capita for solid waste management.
3. If the total waste generated is 100,000 metric tons, calculate the cost per metric ton for managing solid waste.

Compare and contrast aerobic and anaerobic treatment systems used in wastewater management. Discuss their operational principles, advantages and disadvantages, and specific applications. Provide examples of each system and analyze their roles in sustainable wastewater management.

An anaerobic digester processes organic waste with the following characteristics: the digester has a volume of $ 500~m^{3} $ and processes waste with a total solids (TS) concentration of 6% by weight. The digester operates at a hydraulic retention time (HRT) of 20 days.
1. Calculate the total mass of organic waste (in kg) processed in the digester at any given time.
2. If the anaerobic digestion process achieves a volatile solids (VS) reduction of 60%, calculate the mass of volatile solids reduced (in kg).
3. Determine the total biogas produced if 0.4 $ m^{3} $ of biogas is produced per kg of volatile solids reduced.

Analyze the environmental impacts of landfills and discuss the strategies that can be employed to mitigate these impacts.

A landfill has a total capacity of 500,000 cubic meters. The compacted waste is approximately 0.8 metric tons per cubic meter.
(i) Calculate the total weight capacity of the landfill in metric tons.
(ii) If the landfill receives an average of 120 tons of waste per day, determine how long the landfill will last (in days) before reaching capacity.
(iii) Convert the lifespan of the landfill into years.

Compare between Bangalore method and the Indore method of composting. Discuss their principles, operational procedures, advantages, and disadvantages. Which method would you prefer if you were the environmental officer in charge? Also mention the reason for your selection.

Write short notes on any two of the following:

Imhoff cone is used to determine

The main objective of secondary treatment of wastewater is

The ratio of maximum daily sewage flow to the average daily sewage flow for sewer mains of 0.5 to 1 m diameter, is generally taken as

The percentage of activated sludge mixed with the wastewater in activated sludge process of wastewater treatment ranges between

The bacteria which require free oxygen for their survival are called

The most serious environmental effect posed by hazardous waste is

The most suitable section of a sewer in a separate sewerage system is:

The gas which is generally found present in sewers is:

One of the most effective forms of hazardous waste disposal may be

Which one of the following solid waste disposal methods is ecologically most acceptable?

Explain various forces acting on sewer when laid below ground level and running full along with mathematical expressions.

A raw wastewater with the following characteristics is being treated in an activated sludge plant. Given that: $ BOD_{5} $ of raw wastewater = $ 220~gm/l $; effluent $ BOD_{5} $ desired = $ 20~mg/l $; inflow rate to aeration tank = $ 100~m^{3}/d $; mixed liquor volatile suspended solid concentration = $ 2000~mg/l $; volume of aeration tank = $ 500~m^{3} $; water depth in aeration tank = 2.5 m. Determine the:
(i) food to microorganisms (F/M) ratio,
(ii) space loading on aeration tank,
(iii) hydraulic loading on aeration tank and
(iv) detention period in aeration tank.

Explain the various types of solid wastes in detail.

Discuss the types of composition of municipal solid wastes.

Compare between separate and combined systems of sewerage. Enumerate the advantages of egg-shaped sewer over circular sewer. Explain the rational formula for estimation of storm run-off along with assumptions. Determine the size of a circular sewer for a discharge of $ 2.25~m^{3}/sec $ and the sewer is to be laid at a gradient of 1 in 7500. Manning's rugosity coefficient = 0.015.

Explain the difference between compaction and size reduction and their importances in solid waste management.

Explain the types, mode of action and applications of equipments used for size reduction and component separation in detail.

List the various materials which can be recovered from the municipal solid waste generated from a typical Indian city.

Describe in brief the various methods employed for the disposal of municipal solid waste.

Explain the importance of the following in the design of sewers: (i) Self cleansing velocity and (ii) Non scouring velocity.

A 2 m deep trickling filter with a diameter of 18 m is operated with a recirculation ratio of 1.5. The raw wastewater flow rate is 2.5 ML/d and the 5-day BOD of the raw wastewater is $ 210~mg/L $. Assuming that the primary tank BOD removal efficiency is 30%, compute the hydraulic as well as organic load on the trickling filter.

What do you understand by sludge volume index? Discuss in brief.

Design an oxidation pond using the following data: Population = 5000, Sewage generation = $ 120~L/c/d $, $ BOD_{5} $ of sewage = $ 300~mg/l $, Organic loading = $ 300~kg/ha/d $.

Imhoff cone is used to determine

The main objective of secondary treatment of wastewater is

The ratio of maximum daily sewage flow to the average daily sewage flow for sewer mains of 0.5 to 1 m diameter, is generally taken as

The percentage of activated sludge mixed with the wastewater in activated sludge process of wastewater treatment ranges between

The bacteria which require free oxygen for their survival are called

The most serious environmental effect posed by hazardous waste is

The most suitable section of a sewer in a separate sewerage system is:

The gas which is generally found present in sewers is:

One of the most effective forms of hazardous waste disposal may be

Which one of the following solid waste disposal methods is ecologically most acceptable?

Explain various forces acting on sewer when laid below ground level and running full along with mathematical expressions.

A raw wastewater with the following characteristics is being treated in an activated sludge plant. Given that: $BOD_{5}$ of raw wastewater = 220~gm/l $; effluent BOD_{5} $ desired = 20~mg/l $; inflow rate to aeration tank = 100m^{3}/d $; mixed liquor volatile suspended solid concentration = $ 2000mg/l $; volume of aeration tank =$ 500~m^{3} $; water depth in aeration tank = 2.5 m. Determine the:
(i) food to microorganisms (F/M) ratio,
(ii) space loading on aeration tank,
(iii) hydraulic loading on aeration tank and
(iv) detention period in aeration tank.

Explain the various types of solid wastes in detail.

Discuss the types of composition of municipal solid wastes.

Compare between separate and combined systems of sewerage. Enumerate the advantages of egg-shaped sewer over circular sewer. Explain the rational formula for estimation of storm run-off along with assumptions. Determine the size of a circular sewer for a discharge of $2.25~m^{3}/sec$ and the sewer is to be laid at a gradient of 1 in 7500. Manning's rugosity coefficient = 0.015.

Explain the difference between compaction and size reduction and their importances in solid waste management.

Explain the types, mode of action and applications of equipments used for size reduction and component separation in detail.

List the various materials which can be recovered from the municipal solid waste generated from a typical Indian city.

Describe in brief the various methods employed for the disposal of municipal solid waste.

Explain the importance of the following in the design of sewers: (i) Self cleansing velocity and (ii) Non scouring velocity.

A 2 m deep trickling filter with a diameter of 18 m is operated with a recirculation ratio of 1.5. The raw wastewater flow rate is 2.5 ML/d and the 5-day BOD of the raw wastewater is $ 210~mg/L $. Assuming that the primary tank BOD removal efficiency is 30%, compute the hydraulic as well as organic load on the trickling filter.

What do you understand by sludge volume index? Discuss in brief.

Design an oxidation pond using the following data: Population = 5000, Sewage generation = $ 120L/c/d $,$ BOD_{5} $of sewage =$ 300mg/l $, Organic loading =$ 300~kg/ha/d $.

• National river cleaning plans
• Roles of Govt. authorities in water supply
• Biomedical waste
• Recycling of Sewage
• 3R
• Roles of Govt authorities in control of environmental pollutions

The ratio of maximum hourly flow to the average daily flow of wastewater for mains up to 1 m diameter is

The value of the coefficient of runoff for perfectly impervious surface tends to

The gradient required to generate self-cleansing velocity in a circular sewer of 150 mm diameter, is of the order of

The most suitable section of a sewer in a combined sewerage system is

The primary objective of secondary treatment of wastewater is to remove

Leachate is a dark-coloured liquid generated from

The method generally not adopted for safe disposal of biomedical wastes is

In treatment of sewage, trickling filters falls under the category of

The gas generated from an anaerobic sludge digester is

A manhole is called deep manhole, if its depth is more than

Compare between combined separate and partially separate systems of sewerage.

A population of 50000 is residing in a town having an area of 100 hectares. If the average coefficient of runoff for this area is 0.65, and the time of concentration of design rain is 30 minutes, calculate the discharge for which the sewers of a proposed combined system be designed for the town. Assume that the rate of sanitary sewage production as 120 lpcd. Make any other suitable assumptions, if required.

A rectangular sewer with its width 2 times its depth is hydraulically equivalent to a circular sewer of diameter D. Find the relationship between the width of rectangular sewer and the diameter of circular sewer. Assume that the roof of rectangular sewer as a part of wetted surface.

Write the importance of BOD/COD ratio. If 5 days $ 25^{\circ}C $ BOD of sewage sample is $ 180~mg/L $ calculate its 5 days $ 20^{\circ}C $ BOD. Assume the deoxygenation constant at $ 20^{\circ}C $, $ K_{20} $ as $ 0.23~d^{-1} $ at base e. Deoxygenation constant varies with temperature $ K_{T} = K_{20}(1.05)^{T-20} $, where T is temperature in °C.

Enumerate the National River Cleaning plans in brief. Classify various types of trickling filters.

A single-stage trickling filter is to treat a flow of 5 MLD of raw sewage with influent BOD of $ 200~mg/L $. It is to be designed for a loading of 12000 kg of BOD in raw sewage per hectare-metre, and the recirculation ratio is to be 2:1. What will the strength of the effluent, according to the recommendations of the National Research Council of USA?

Give a detailed comparison between aerobic and anaerobic treatments.

What do you understand by solid waste management? Explain the various processes and operations involved in solid waste management with neat flowchart. Enumerate the various techniques of component separation in municipal solid waste.

Discuss the factors that must be considered in the design of solid waste transfer station. Explain the mechanical volume reduction methods for municipal solid wastes.

Explain the area method of landfilling technique stating its merits and demerits. Define leachate and list out the factors that affect the composition of leachate.

Determine the landfill area required for municipality with a population of 50000. Given that solid waste generation rate = 360 g/person/day, compacted density of landfill = $ 504~kg/m^{3} $, average depth of compacted solid waste = 3 m.

Describe and explain the importance of recycle and reuse of solid waste. Enumerate the effects of solid wastes dumping on air, soil and underground water.

Explain the categories of biomedical wastes and methods of their disposal.

List the advantages and disadvantages of open dumping and ocean disposal of solid wastes.

The ratio of maximum hourly flow to the average daily flow of wastewater for mains up to 1 m diameter is

The value of the coefficient of runoff for perfectly impervious surface tends to

The gradient required to generate self-cleansing velocity in a circular sewer of 150 mm diameter, is of the order of

The most suitable section of a sewer in a combined sewerage system is

The primary objective of secondary treatment of wastewater is to remove

Leachate is a dark-coloured liquid generated from

The method generally not adopted for safe disposal of biomedical wastes is

In treatment of sewage, trickling filters falls under the category of

The gas generated from an anaerobic sludge digester is

A manhole is called deep manhole, if its depth is more than

Compare between combined separate and partially separate systems of sewerage.

A population of 50000 is residing in a town having an area of 100 hectares. If the average coefficient of runoff for this area is 0.65, and the time of concentration of design rain is 30 minutes, calculate the discharge for which the sewers of a proposed combined system be designed for the town. Assume that the rate of sanitary sewage production as 120 lpcd. Make any other suitable assumptions, if required.

A rectangular sewer with its width 2 times its depth is hydraulically equivalent to a circular sewer of diameter D. Find the relationship between the width of rectangular sewer and the diameter of circular sewer. Assume that the roof of rectangular sewer as a part of wetted surface.

Write the importance of BOD/COD ratio. If 5 days $25^{\circ}C$ BOD of sewage sample is $ 180mg/L $calculate its 5 days$ 20^{\circ}C $ BOD. Assume the deoxygenation constant at $ 20^{\circ}C $,$ K_{20} $as$ 0.23d^{-1} $ at base e. Deoxygenation constant varies with temperature $K_{T} = K_{20}(1.05)^{T-20}$, where T is temperature in °C.

Enumerate the National River Cleaning plans in brief. Classify various types of trickling filters.

A single-stage trickling filter is to treat a flow of 5 MLD of raw sewage with influent BOD of $ 200~mg/L $. It is to be designed for a loading of 12000 kg of BOD in raw sewage per hectare-metre, and the recirculation ratio is to be 2:1. What will the strength of the effluent, according to the recommendations of the National Research Council of USA?

Give a detailed comparison between aerobic and anaerobic treatments.

What do you understand by solid waste management? Explain the various processes and operations involved in solid waste management with neat flowchart. Enumerate the various techniques of component separation in municipal solid waste.

Discuss the factors that must be considered in the design of solid waste transfer station. Explain the mechanical volume reduction methods for municipal solid wastes.

Explain the area method of landfilling technique stating its merits and demerits. Define leachate and list out the factors that affect the composition of leachate.

Determine the landfill area required for municipality with a population of 50000. Given that solid waste generation rate = 360 g/person/day, compacted density of landfill = $504~kg/m^{3}$, average depth of compacted solid waste = 3 m.

Describe and explain the importance of recycle and reuse of solid waste. Enumerate the effects of solid wastes dumping on air, soil and underground water.

Explain the categories of biomedical wastes and methods of their disposal.

List the advantages and disadvantages of open dumping and ocean disposal of solid wastes.

• Integrated solid waste management
• Mechanisms of substrate conversion in aerobic treatment process
• Types of hazardous wastes and their methods of disposal
• Role of the Government authorities in sewage disposal
• Management of solid wastes from construction activities
• Color-coding of biomedical waste

Imhoff cone is used to determine

The main objective of secondary treatment of wastewater is

The wastewater treatment process which does not require primary sedimentation is

Effective method for the removal of suspended solids is

The bacteria which require free oxygen for their survival, are called

An example of fixed film reactor is

Grit removal tank is generally placed

Recirculation of treated wastewater is generally required in case of

The ultimate BOD of a given sample of wastewater depends on

Septic tank is also known as

Describe in brief the advantages of modern water carried sewerage system over old conservancy system of sanitation.

The drainage area of a sector of Patna city is 12 hectares. The classification of the surface of this area is as follows: (Hard pavement: 20%, Coefficient 0.85), (Roof surface: 20%, Coefficient 0.8), (Unpaved street: 15%, Coefficient 0.2), (Garden and lawn: 30%, Coefficient 0.2), (Wooded area: 15%, Coefficient 0.15). If the time of concentration for the area is 30 minutes, find the maximum runoff employing $ R=900/(t+60) $, where t is time of concentration.

Calculate the diameter and discharge of a circular sewer laid at a slope of 1 in 400 when it is running half full, and with a velocity of $ 1.9~m/s $ (use n in Manning's formula = 0.012).

What are the advantages and disadvantages using circular sewer section? Describe in brief.

A municipal waste having a $ BOD_{5} $ of $ 200~mg/L $ is to be treated by two-stage trickling filter. The desired quality is $ 25~mg/L $ of $ BOD_{5} $. If both the filter depths are 1.83 m and recirculation ratio is 2:1, find the required diameters, if the removal efficiency of both is equal (i.e. $ E_{1}=E_{2} $). Assume: $ Q=7.57~ML/d $, wastewater temperature = $ 20^{\circ}C $, BOD removal efficiency of PST = 35%.

The wastewater flow rate and $ BOD_{5} $ to the secondary treatment system is 1 MGD and $ 300~mg/L $ respectively. The hydraulic retention time of the aeration tank is 6 hours and MLSS is $ 2500~mg/L $. Calculate: (i) BOD loading; (ii) volume of the aeration tank; (iii) volumetric BOD loading; (iv) F/M ratio. (1 gallon = 3.79 litres).

What do you understand by sewage sickness? Discuss in brief.

A stream, saturated with DO, has a flow of $ 1.2~m^{3}/s $, BOD of $ 4~mg/l $ and rate constant of 0.3 per day. It receives an effluent discharge of 0.25 $ m^{3}/s $, having BOD $ 20~mg/l $, DO $ 5~mg/l $ and rate constant 0.13 per day. The average velocity of flow of mix stream is $ 0.18~m/s $. Calculate the DO deficit at point 20 km and 40 km downstream. Assume that the temperature is $ 20^{\circ}C $ throughout and BOD is measured at 5 days. Take saturation of DO at $ 20^{\circ}C $ as $ 9.17~mg/l $.

A wastewater treatment plant consists of primary treatment units followed by an activated-sludge secondary system. The primary and secondary sludges are mixed, thickened and send to further treatment. The wastewater flow is 19000 $ m^{3}/d $, Influent Suspended Solids (SS) = $ 200~mg/L $, Influent BOD = $ 225~mg/L $, Effluent BOD = $ 20~mg/L $. Primary clarifier diameter = 25 m. Aeration tank volume = $ 2900~m^{3} $, MLSS in aerator = $ 3500~mg/L $. Primary Sludge = 5.0% solids, Secondary = 0.75% solids, Thickened = 4.0% solids. Determine the solids loading (kg/d) to the sludge disposal facilities and the percent volume reduction by the thickener. (Assume efficiency of clarifier for SS removal = 58% and BOD removal = 32%, biomass conversion factor Y = 0.35).

Describe in brief the common variations in activated sludge processes.

Define the term 'sludge bulking'. What are the factors and disadvantages assist on the development of sludge bulking? What are the remedial measures to adopt for controlling the bulking of sludge?

Describe in brief about the various pollution zones in a polluted river-stream.

Calculate 1 day $ 37^{\circ}C $ BOD of a sewage sample whose 5 days $ 20^{\circ}C $ BOD is $ 100~mg/L $. Assume $ K_{D} $ at $ 20^{\circ}C $ as 0.1.

Imhoff cone is used to determine

The main objective of secondary treatment of wastewater is

The wastewater treatment process which does not require primary sedimentation is

Effective method for the removal of suspended solids is

The bacteria which require free oxygen for their survival, are called

An example of fixed film reactor is

Grit removal tank is generally placed

Recirculation of treated wastewater is generally required in case of

The ultimate BOD of a given sample of wastewater depends on

Septic tank is also known as

Describe in brief the advantages of modern water carried sewerage system over old conservancy system of sanitation.

The drainage area of a sector of Patna city is 12 hectares. The classification of the surface of this area is as follows: (Hard pavement: 20%, Coefficient 0.85), (Roof surface: 20%, Coefficient 0.8), (Unpaved street: 15%, Coefficient 0.2), (Garden and lawn: 30%, Coefficient 0.2), (Wooded area: 15%, Coefficient 0.15). If the time of concentration for the area is 30 minutes, find the maximum runoff employing $ R=900/(t+60) $, where t is time of concentration.

Calculate the diameter and discharge of a circular sewer laid at a slope of 1 in 400 when it is running half full, and with a velocity of $ 1.9~m/s $ (use n in Manning's formula = 0.012).

What are the advantages and disadvantages using circular sewer section? Describe in brief.

A municipal waste having a $ BOD_{5} $ of $ 200~mg/L $ is to be treated by two-stage trickling filter. The desired quality is $ 25~mg/L $ of $ BOD_{5} $. If both the filter depths are 1.83 m and recirculation ratio is 2:1, find the required diameters, if the removal efficiency of both is equal (i.e. $ E_{1}=E_{2} $). Assume: $ Q=7.57~ML/d $, wastewater temperature = $ 20^{\circ}C $, BOD removal efficiency of PST = 35%.

The wastewater flow rate and $ BOD_{5} $ to the secondary treatment system is 1 MGD and $ 300~mg/L $ respectively. The hydraulic retention time of the aeration tank is 6 hours and MLSS is $ 2500~mg/L $. Calculate: (i) BOD loading; (ii) volume of the aeration tank; (iii) volumetric BOD loading; (iv) F/M ratio. (1 gallon = 3.79 litres).

What do you understand by sewage sickness? Discuss in brief.

A stream, saturated with DO, has a flow of $ 1.2~m^{3}/s $, BOD of $ 4~mg/l $ and rate constant of 0.3 per day. It receives an effluent discharge of 0.25 $ m^{3}/s $, having BOD $ 20~mg/l $, DO $ 5~mg/l $ and rate constant 0.13 per day. The average velocity of flow of mix stream is $ 0.18~m/s $. Calculate the DO deficit at point 20 km and 40 km downstream. Assume that the temperature is $ 20^{\circ}C $ throughout and BOD is measured at 5 days. Take saturation of DO at $ 20^{\circ}C $ as $ 9.17~mg/l $.

A wastewater treatment plant consists of primary treatment units followed by an activated-sludge secondary system. The primary and secondary sludges are mixed, thickened and send to further treatment. The wastewater flow is 19000 $ m^{3}/d $, Influent Suspended Solids (SS) = $ 200~mg/L $, Influent BOD = $ 225~mg/L $, Effluent BOD = $ 20~mg/L $. Primary clarifier diameter = 25 m. Aeration tank volume = $ 2900~m^{3} $, MLSS in aerator = $ 3500~mg/L $. Primary Sludge = 5.0% solids, Secondary = 0.75% solids, Thickened = 4.0% solids. Determine the solids loading (kg/d) to the sludge disposal facilities and the percent volume reduction by the thickener. (Assume efficiency of clarifier for SS removal = 58% and BOD removal = 32%, biomass conversion factor Y = 0.35).

Describe in brief the common variations in activated sludge processes.

Define the term 'sludge bulking'. What are the factors and disadvantages assist on the development of sludge bulking? What are the remedial measures to adopt for controlling the bulking of sludge?

Describe in brief about the various pollution zones in a polluted river-stream.

Calculate 1 day $ 37^{\circ}C $ BOD of a sewage sample whose 5 days $ 20^{\circ}C $ BOD is $ 100~mg/L $. Assume $ K_{D} $ at $ 20^{\circ}C $ as 0.1.

The hydraulic mean depth in a circular sewer of diameter D is

The dry weather flow is taken as

The ratio of maximum daily sewage flow to the average daily sewage flow for sewer mains of 0.5 to 1 m diameter, is generally taken as

The percentage of activated sludge mixed with the waste water in activated sludge process of wastewater treatment ranges between

Bacteria which brings about the digestion of cow dung slurry in gobar gas plant are

A high value of COD/BOD ratio indicates

A high rate biological wastewater treatment system should have the solid retention time (SRT) and hydraulic retention time (HRT) as

For good settling of sludge in settling tanks, the sludge volume index should preferably be

Which one of the following solid waste disposal methods is ecologically most acceptable?

If D is the diameter of upper circular portion, the overall depth of standard egg-shaped sewer is kept as

Explain various forces acting on sewer when laid below ground level and running full along with mathematical expressions.

A raw wastewater with the following characteristics is being treated in an activated sludge plant. Given that: $ BOD_{5} $ of raw wastewater = $ 220~gm/l $; effluent $ BOD_{5} $ desired = $ 20~mg/l $; inflow rate to aeration tank = $ 100~m^{3}/d $; mixed liquor volatile suspended solid concentration = 2000 mg/l; volume of aeration tank = $ 500~m^{3} $; water depth in aeration tank = 2.5 m. Determine the (i) food to microorganisms (F/M) ratio, (ii) space loading on aeration tank, (iii) hydraulic loading on aeration tank and (iv) detention period in aeration tank.

Write down the important characteristics of E-coliform group of bacteria. Explain the different phases of microorganism's growth in a substrate limited growth medium.

Calculate the head loss through a clean bar rack inclined at $ 70^{\circ} $ with horizontal, using the following data: Total width of bar = 1.0 m; total clear spacing = 3.0 m; dimension of screen chamber = $ 9~m \times 4~m $; velocity of flow through rack = $ 0.9~m/sec $ and bar shape factor = 2.42.

Discuss the standards set for discharge of treated wastewater into water bodies and on to land. What should be the desirable dilution factor if the untreated waste water is discharged into river fully saturated with dissolved oxygen?

The observations made on a 2% dilution of wastewater sample are as follows: Dissolved oxygen of aerated water used for dilution = $ 4.0~mg/l $; dissolved oxygen of original wastewater sample = $ 0.4~mg/l $; dissolved oxygen of diluted wastewater sample after 5 days incubation at $ 20^{\circ}C $ = $ 0.8~mg/l $. Calculate the 5-day BOD and the ultimate BOD of waste water sample. Given that the de-oxygenation constant at $ 20^{\circ}C $ = $ 0.12~d^{-1} $ (base 10).

What is activated sludge? Give the causes and control measures for various problems encountered in activated sludge process of wastewater treatment.

Explain the symbiotic relationships between algae and bacteria in waste stabilization ponds. Design an oxidation pond for treating domestic sewage of 10000 persons supplied water @ 200 lpcd. The $ BOD_{5} $ of raw wastewater and suspended solids concentration are 180 mg/l and 300 mg/l respectively. Effluent BOD desired = 30 mg/l. Assume other required data as per design criteria.

Explain the principle of oxidation of organic mater in Trickling filter. Using NRC equation, design the diameter of a single-stage trickling filter treating 10000 $ m^{3}/d $ wastewater at $ 20^{\circ}C $. Use the given data: $ BOD_{5} $ of raw wastewater = $ 200~mg/l $; effluent $ BOD_{5} $ desired = $ 20~mg/l $; depth of filter = 1.8 m, recirculation factor = 1, BOD removal in primary sedimentation tank is 20%.

Compare between separate and combined systems of sewerage. Enumerate the advantages of egg-shaped sewer over circular sewers. Explain the rational formula for estimation of storm run-off along with assumptions. Determine the size of a circular sewer for a discharge of $ 2.25~m^{3}/sec $ and the sewer is to be laid at a gradient of 1 in 7500. Manning's rugosity coefficient = 0.015.

Classify the municipal solid wastes generated from a society. Enumerate various properties of solid wastes. Describe the procedure for determination of any one of these properties.

What is digested sludge? Discuss the working along with merits and demerits of an anaerobic high-rate digester with neat sketch.

The hydraulic mean depth in a circular sewer of diameter D is

The dry weather flow is taken as

The ratio of maximum daily sewage flow to the average daily sewage flow for sewer mains of 0.5 to 1 m diameter, is generally taken as

The percentage of activated sludge mixed with the waste water in activated sludge process of wastewater treatment ranges between

Bacteria which brings about the digestion of cow dung slurry in gobar gas plant are

A high value of COD/BOD ratio indicates

A high rate biological wastewater treatment system should have the solid retention time (SRT) and hydraulic retention time (HRT) as

For good settling of sludge in settling tanks, the sludge volume index should preferably be

Which one of the following solid waste disposal methods is ecologically most acceptable?

If D is the diameter of upper circular portion, the overall depth of standard egg-shaped sewer is kept as

Explain various forces acting on sewer when laid below ground level and running full along with mathematical expressions.

A raw wastewater with the following characteristics is being treated in an activated sludge plant. Given that: $BOD_{5}$ of raw wastewater = 220~gm/l $; effluent BOD_{5} $ desired = 20~mg/l $; inflow rate to aeration tank = 100m^{3}/d $; mixed liquor volatile suspended solid concentration = 2000 mg/l; volume of aeration tank = $ 500m^{3} $; water depth in aeration tank = 2.5 m. Determine the (i) food to microorganisms (F/M) ratio, (ii) space loading on aeration tank, (iii) hydraulic loading on aeration tank and (iv) detention period in aeration tank.

Write down the important characteristics of E-coliform group of bacteria. Explain the different phases of microorganism's growth in a substrate limited growth medium.

Calculate the head loss through a clean bar rack inclined at $70^{\circ}$ with horizontal, using the following data: Total width of bar = 1.0 m; total clear spacing = 3.0 m; dimension of screen chamber = 9~m \times 4~m $; velocity of flow through rack = 0.9~m/sec $ and bar shape factor = 2.42.

Discuss the standards set for discharge of treated wastewater into water bodies and on to land. What should be the desirable dilution factor if the untreated waste water is discharged into river fully saturated with dissolved oxygen?

The observations made on a 2% dilution of wastewater sample are as follows: Dissolved oxygen of aerated water used for dilution = $ 4.0mg/l $; dissolved oxygen of original wastewater sample = $ 0.4mg/l $; dissolved oxygen of diluted wastewater sample after 5 days incubation at$ 20^{\circ}C $=$ 0.8mg/l $. Calculate the 5-day BOD and the ultimate BOD of waste water sample. Given that the de-oxygenation constant at $20^{\circ}C$ = $ 0.12d^{-1} $ (base 10).

What is activated sludge? Give the causes and control measures for various problems encountered in activated sludge process of wastewater treatment.

Explain the symbiotic relationships between algae and bacteria in waste stabilization ponds. Design an oxidation pond for treating domestic sewage of 10000 persons supplied water @ 200 lpcd. The $ BOD_{5} $ of raw wastewater and suspended solids concentration are 180 mg/l and 300 mg/l respectively. Effluent BOD desired = 30 mg/l. Assume other required data as per design criteria.

Explain the principle of oxidation of organic mater in Trickling filter. Using NRC equation, design the diameter of a single-stage trickling filter treating 10000 $m^{3}/d$ wastewater at $ 20^{\circ}C $. Use the given data:$ BOD_{5} $of raw wastewater =$ 200mg/l $; effluent $BOD_{5}$ desired = $ 20mg/l $; depth of filter = 1.8 m, recirculation factor = 1, BOD removal in primary sedimentation tank is 20%.

Compare between separate and combined systems of sewerage. Enumerate the advantages of egg-shaped sewer over circular sewers. Explain the rational formula for estimation of storm run-off along with assumptions. Determine the size of a circular sewer for a discharge of $2.25~m^{3}/sec$ and the sewer is to be laid at a gradient of 1 in 7500. Manning's rugosity coefficient = 0.015.

Classify the municipal solid wastes generated from a society. Enumerate various properties of solid wastes. Describe the procedure for determination of any one of these properties.

What is digested sludge? Discuss the working along with merits and demerits of an anaerobic high-rate digester with neat sketch.

• Flow sheet for conventional wastewater treatment system along with functions of each unit.
• Comparison between high-rate and hybrid anaerobic reactors.
• Various modifications in activated sludge process with neat sketch.
• Design procedure for a rotating biological contactor (RBC).
• Design procedure for a septic tank with neat plan and section.