Wastewater Management

01

PYQ 2022

medium

water-wastewater-treatment-and-management ID: gate-es-

A river water sample has pH of 4 and suspended solids concentration of 100 mg/L. If alum is chosen as a coagulant, what will be the coagulation mechanism?

1

Ionic layer compression only

2

Sweep coagulation and Polymer bridging

3

Polymer bridging only

4

Charge neutralization, surface adsorption, ionic layer compression

02

PYQ 2023

medium

water-wastewater-treatment-and-management ID: gate-es-

A flask (100 mL volume) has wastewater with 0.12 mg/L geosmin. Activated carbon adsorbs geosmin as per Freundlich isotherm: where is mg adsorbate/mg adsorbent, and is equilibrium concentration (mg/L). Activated carbon is added to reduce final geosmin concentration to 0.05 mg/L. Activated carbon dose required is ________________ (in mg/L, rounded off to three decimal places).

03

PYQ 2024

medium

water-wastewater-treatment-and-management ID: gate-es-

With respect to particle settling in wastewater treatment systems; the correct statement(s) is/are

1

Settling in grit chamber and primary sedimentation tanks are examples of Type-I settling

2

Settling in primary sedimentation tank and secondary sedimentation tank are examples of Type-II settling

3

Settling in grit chamber is an example of Type-I settling, whereas settling in primary sedimentation tank is an example of Type-II settling

4

Settling in secondary sedimentation tank is an example of Type-III settling, whereas settling in primary sedimentation tank is an example of Type-II settling

04

PYQ 2024

medium

water-wastewater-treatment-and-management ID: gate-es-

One million liters per day (MLD) of wastewater with a soluble BOD of 200 mg/L is treated in an activated sludge process. The BOD of treated wastewater is 20 mg/L. The observed yield coefficient of the biological system is 0.35. The daily biomass generation in the system is _____________kg (an integer value).

05

PYQ 2024

medium

water-wastewater-treatment-and-management ID: gate-es-

An industry discharges 2 million liters per day (MLD) of wastewater with a temperature of 45°C and a pH of 2, whereas the neighboring industry produces 3 MLD of wastewater with a temperature of 30°C and pH of 8. If both the wastewaters are mixed and carried through a pipeline, then the resultant pH of mixed wastewater is ___________ (rounded off to 2 decimal places). Neglect buffering capacity of the system and the temperature effect on pH.

Chapter Questions
5 MCQs