Environmental Engineering-II - B.Tech. 6th Semester Examination, 2023

Imhoff cone is used to determine

1. settleable solids
2. suspended solids
3. dissolved solids
4. None of these

The main objective of secondary treatment of wastewater is

1. COD removal
2. BOD removal
3. nutrient removal
4. All of the above

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

1. 1.5
2. 2.0
3. 3.0
4. None of these

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

1. 10 to 20
2. 20 to 40
3. 40 to 60
4. None of these

The bacteria which require free oxygen for their survival are called

1. aerobic bacteria
2. anaerobic bacteria
3. facultative bacteria
4. None of these

The most serious environmental effect posed by hazardous waste is

1. air pollution
2. contamination of ground water
3. increased used of land for landfills
4. None of these

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

1. rectangular
2. circular
3. new egg shape
4. parabolic

The gas which is generally found present in sewers is:

1. \( H_{2}S \)
2. \( CO_{2} \)
3. \( CH_{4} \)
4. all of these

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

1. land fills
2. deep well injection
3. Incineration
4. Surface impoundments

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

1. Sanitary landfill
2. Incineration
3. Pyrolysis
4. Composting

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 = \( 300~kg/ha/d \).