Environmental Engineering - II 2025

(a) Quantity of sewage mainly depends on:

1. Temperature
2. Soil type
3. Water supply rate
4. pH of water

(b) Peak factor in sewer design is used to account for:

1. Slope
2. Variation in sewage flow
3. Sewer blockages
4. Structural load

(c) Activated sludge process is an example of:

1. Anaerobic attached growth
2. Aerobic suspended growth
3. Anaerobic suspended growth
4. Aerobic attached growth

(d) Trickling filter is an example of:

1. Aerobic attached growth
2. Anaerobic attached growth
3. Anaerobic suspended growth
4. Chemical treatment

(e) Municipal Solid Waste (MSW) mainly includes:

1. Hazardous chemicals
2. Household waste
3. Nuclear waste
4. Agricultural waste only

(f) One of the most effective forms of hazardous waste disposal may be:

1. Land fills
2. Deep well injection
3. Incineration
4. Surface impoundments

(g) The bacteria which require free oxygen for their survival are called:

1. Aerobic bacteria
2. Anaerobic bacteria
3. Facultative bacteria
4. None of these

(h) Biomedical Waste Rules are notified by:

1. MoEF&CC
2. Home Ministry
3. Ministry of Health
4. NITI Aayog

(i) Incineration is suitable for waste with:

1. High calorific value
2. High moisture content
3. High metal content
4. Inert material

(j) BOD stands for:

1. Basic oxygen demand
2. Biochemical oxygen demand
3. Biological oxidation demand
4. Bio-organic decomposition

(a) Explain how central and state agencies coordinate in managing solid waste, sewerage, and pollution control in India.

(b) Explain the environmental impacts of biomedical waste. Describe its segregation, collection, treatment, and disposal as per Biomedical Waste Management Rules.

(a) Rectangular grit chamber is designed to remove particle with a diameter $0.2\text{ mm}$ and specific gravity $2.65$. The settling velocities of these particles are found to be $0.02\text{ m/s}$. A flow through velocity of $0.30\text{ m/s}$ will be maintained by the proportioning weir. Determine the channel dimensions for a maximum wastewater flow of $10,000\text{ m}^3\text{/day}$.

(b) Define hazardous waste. Explain the types and characteristics of hazardous wastes as per the Hazardous Waste Rules and CPCB schedules.

(a) Discuss in detail the various shapes of sewers used in sewerage systems. Explain their suitability, advantages, and limitations.

(b) A city has a projected population of $60,000$ spread over an area of $50\text{ hectare}$. Assume rate of water supply of $250\text{ litres}$ per capita per day, and out of this total supply only $75\%$ reaches in sewer as wastewater. Assume a peak factor of $1.5$. Design a separate circular sewer line running half full. Consider Manning's rugosity coefficient of $n = 0.012$, and gradient of sewer $S = 0.0001$.

(a) Explain the importance of the following in the design of sewers:

1. Self cleansing velocity
2. Non scouring velocity

(b) A $2\text{ m}$ deep trickling filter with a diameter of $20\text{ m}$ is operated with a recirculation ratio of $1.5$. The raw wastewater flow rate is $3\text{ ML/d}$ and the 5-day BOD of the raw wastewater is $210\text{ mg/L}$. Assuming that the primary tank BOD removal efficiency is $40\%$, compute the hydraulic filter as well as organic load on the trickling filter.

(a) An oxidation pond is to be constructed in a hot climatic area for treating the sewage from a residential colony with $5000\text{ persons}$ contributing sewage at $120\text{ litres/capita/day}$. The 5-day BOD of sewage is $300\text{ mg/litre}$. Assume organic loading in the pond as $300\text{ kg/hectares/day}$. Calculate the dimensions required for the tank and its detention time.

(b) Explain the features of a sludge digestion tank with a neat sketch.

(a) Explain the following:

1. Pyrolysis
2. Open dumping
3. Refuse derived fuel
4. Biogasification

(b) Discuss in detail the zones of pollution in a river or stream.

(a) Design an Imhoff tank to treat the sewage from a small town with a population of $20,000\text{ persons}$, with sewage flow rate of $180\text{ litres}$ per day.

(b) What are the main challenges in MSW management in Indian cities? Provide engineering, administrative, and community-based solutions.

(a) A raw wastewater with the following characteristics is being treated in an activated sludge plant. Given that: $\text{BOD}_5$ of raw wastewater $= 220\text{ mg/l}$; effluent $\text{BOD}_5$ desired $= 20\text{ mg/l}$; inflow rate to aeration tank $= 100\text{ m}^3\text{/d}$; mixed liquor volatile suspended solid concentration $= 2200\text{ mg/l}$; volume of aeration tank $= 500\text{ m}^3$; water depth in aeration tank $= 2.5\text{ m}$. Determine the:

1. Food to microorganisms (F/M) ratio
2. Space loading on aeration tank
3. Hydraulic loading on aeration tank
4. Detention period in aeration tank

(b) Distinguish between aerobic and anaerobic wastewater treatment processes. Explain suspended and attached growth systems with suitable examples.