List of top Questions asked in GATE ES

Water from a hand pump located near a landfill has 1 mg/L arsenic (oral carcinogenic potency factor = 1.75 (kg-day)/mg). A person who lives nearby drinks 2 L/day of water from this hand pump for 10 years. Assume a body weight of 70 kg and an average life duration of 70 years. The chances of this person getting an excess risk of cancer is ________ × 10-3 (rounded off to three decimal places).
An industry releases three greenhouse gases (GHGs), CO2 (5 kg/day), CH4 (0.5 kg/day), and N2O (0.1 kg/day). The industry flares the CH4 before it is released to the atmosphere. The Global Warming Potential (GWP) are as follows: CO2 = 1, CH4 = 21, N2O = 310. The annual GWP of GHGs released from the industry is ________ kg CO2 equivalent (rounded off to the nearest integer).
A solid waste of composition \( C_{60}H_{135}O_{50}N_5 \) is to be composted aerobically in a closed vessel mechanical composting facility. Given: all ammonia generated escapes the facility; air contains 23% of Oxygen by weight; 100% excess air requirement for the closed vessel composting facility. The atomic weights: C – 12, H – 1, O – 16, N – 14. The actual air required for composting is:

Length of the streets, in km, are shown on the network. The minimum distance travelled by the sweeping machine for completing the job of sweeping all the streets is ________ km. (rounded off to nearest integer)


 

An incandescent light bulb operated for two hours per day uses 12.2 kWh of energy per month. Burning of one kg of coal generates 2 kWh of electrical energy and releases 7 g of PM10. The reduction in PM10 emitted per month, if this incandescent bulb is replaced with a light emitting diode (LED) bulb which consumes 1/6th of energy, is ________ g (rounded off to one decimal place).

A particle dispersoid has 1510 spherical particles of uniform density. An air purifier is proposed to be used to remove these particles. The diameter-specific number of particles in the dispersoid, along with the number removal efficiency of the proposed purifier is shown in the following table:

The overall mass removal efficiency of the proposed purifier is ________% (rounded off to one decimal place).

A boiler burns coal at a rate of 1 kg/s. If the coal has 3% sulfur content, assuming that there is no sulfur in ash, SO2 emitted is ________ kg/day. (rounded off to nearest integer)
A common effluent treatment plant with a capacity of 2 million litres per day (MLD) employs reverse osmosis (RO) for water reuse. The RO unit removes 95% of the total dissolved solids (TDS) and the water recovery rate is 70%. If the TDS concentration in the RO feed is 8000 parts per million (ppm), the TDS in the RO reject is ________ g/L. (rounded off to one decimal place)
A circular sewer pipe, having Manning’s coefficient (n) of 0.01, is laid at a bed slope of 1:100. If it is flowing 80% full for a discharge of 2 m\(^3\)/s, then its diameter is ________ m. (rounded off to three decimal places)
Diameter ($d$) and length ($l$) of each pipe are as presented in figure and all pipes are of same material having friction factor ($f$) of 0.02. Assume acceleration due to gravity ($g$) as 10.0 m/s$^2$. If the head difference between $P$ and $Q$ is 10 m, then the head loss between $Q$ and $R$ is ________ m. (rounded off to two decimal places)

The following table and figure (not to scale) show characteristics of a catchment

The hyetograph resulting from a storm that occurred uniformly over the catchment, is as follows

Assuming a constant base flow of 40 m$^3$/s, the peak of the runoff hydrograph produced by storm for the catchment at the outlet $O$ is ________ m$^3$/s. (rounded off to two decimal places)

The following figure (not to scale) depicts a rainfall hyetograph for a storm over a catchment

If the storm produced a direct runoff of 12.5 mm, then the $\phi$-index of the storm for the catchment is ________ mm/hour. (rounded off to two decimal places)

Aerobic biomass has a yield coefficient value of 0.4 for glucose (molecular weight = 180 g/mole) substrate. The bacteria is represented as \( {C}_5{H}_7{O}_2{N} \) (molecular weight = 113 g/mole). Assume that no endogenous metabolism occurs. The percentage of carbon going into CO2 from 1 mole/L glucose is ________ % (rounded off to two decimal places).
The value of \( \int_0^\infty \frac{\sin(4x)}{\pi x} \, dx \) is ________

The following is a system of linear equations
x - 2y + z = 34 (1) 
2x + y + z = 102 (2) 
x + y - 3z = 17 (3) 
The value of \( x + y + z \) is ________. (rounded off to two decimal places)

A residential family is considering two cities for relocation. The data related to pollutant exposure and associated health cost per year are given in the following figure.

The pollutant exposure is characterized in high, mild and low exposure categories with respective probability values. The difference in expected value of health cost of City1 with respect to that of City 2 is ________ lakhs/year. (rounded off to two decimal places).

According to the Bio-Medical Waste Management Rules, 2016, choose the correct option(s) from the following
Choose the correct option(s) for removing solids from water.
If microbial growth occurs under substrate unlimited conditions, according to Monod’s kinetics, choose the correct option(s) from the following:
Choose the correct option(s) from the following regarding the solubility in water:
Which option gives the best control strategies for Dioxins and Furans in the flue gas emitted from waste incineration facilities?
At a pressure of 1 atmosphere and temperature of 25\(^{\circ}\)C, 365 µg m\(^{-3}\) of a pollutant corresponds to a mixing ratio of 139 parts per billion (ppb). The atomic weights: C – 12, H – 1, O – 16, N – 14 and S – 32. Which one of the following options most closely represents the pollutant?

Consider the following statements: 
(i) Sound pressure changes with distance from the source 
(ii) Sound power is a property of the source 
(iii) Sound intensity is sound power per unit volume 
Choose the correct option from the following:
 

Consider the following figure of an activated sludge process (ASP), depicting the flow (Q), substrate (S), and microorganism concentration (X) at various points in the system, where subscripts “0”, “r”, “w”, “e”, and “i” indicate influent, recycle line, wastage, effluent, and flow from aeration tank to settling tank, respectively. Note that influent to the ASP has microbes too. V is volume of aeration tank. Choose the correct option for net rate of formation of microorganisms in the system at steady state, from the following

Consider the following statements on microbial metabolism: 
(i) Utilization of carbon for cell synthesis is termed as anabolism. 
(ii) During catabolism, adenosine triphosphate (ATP) is converted into adenosine diphosphate (ADP). 
Choose the correct option from the following: