Recent activity in Environmental Engineering

In an industry, a cyclone collector with $80 \%$ efficiency is installed for air purification, followed by an electrostatic precipitator with $50 \%$ efficiency. The conc...

Anaerobic bacteria are being utilized for the destruction of biodegradable organic content of wastewater measured in terms of Chemical Oxygen Demand (COD). The yield coef...

The analysis of major cations and anions in a water sample collected from a city's water supply is given below. Ions present in minor concentrations are not given.\[\begi...

The $2.4$ ml of raw sewage is diluted to $240$ ml. The Dissolved Oxygen (DO) of the diluted sample at the beginning of Biochemical Oxygen Demand (BOD) test was $8 \mathrm...

The grown algae are useful in the operation ofoxidation pond.slow sand filter.cyclone separator.septic tank.

One-third of the solid matter in a sludge containing $90 \%$ water is composed of fixed mineral solids with specific gravity $2.5$, and two-third is composed of volatile ...

Column $\text{I}$ presents common air pollutants, and column $\text{II}$ presents treatment technologies commonly employed to control air pollutants.\[\begin{array}{|c|l|...

The maximum demand at a water purification plant has been estimated as $12$ million litres per day. For the raw supplies, a rectangular sedimentation tank is to be design...

An Activated Sludge Process $\text{(ASP)}$ has an inlet wastewater flowrate of $20000 \mathrm{~m}^{3} /$ day with a Biochemical Oxygen Demand $\text{(BOD)}$ concentration...

The average sewage from a city is $90$ million litres per day and the average $5$-day Biochemical Oxygen Demand ($\text{BOD5}$) is $300 ~\mathrm{mg} / \mathrm{l}$. Averag...

Which of the following components is/are NOT removed in the secondary treatment of sewage?Suspended settleable organic solidsColloids including dissolved organic matterPa...

The settling velocity of inorganic particles in the sedimentation tank of a water treatment plant is governed byDarcy's lawStokes' lawDupuit's lawBernoulli's law

A rapid sand filter bed of depth $0.8$ m has $40 \%$ porosity during service cycle. It is recommended that during backwash operation, the expanded filter bed should have ...

A settling chamber is used for the removal of discrete particulate matter from air with following conditions. Horizontal velocity of air $=0.2 \mathrm{~m} / \mathrm{s}$; ...

A compound has a general formula $\mathrm{C}_{\mathrm{a}} \mathrm{H}_{\mathrm{b}} \mathrm{O}_{\mathrm{c}} \mathrm{N}_{\mathrm{d}}$ and molecular weight $187$. A $935 \: \...

Free residual chlorine concentration in water was measured to be $2 \mathrm{mg} / 1\left(\right.$ as $\left.\mathrm{Cl}_{2}\right)$. The pH of water is $8.5$. By using th...

Organic fraction of municipal solid waste (OFMSW) with bulk density of $315 \mathrm{~kg} / \mathrm{m}^{3}$ and water content of $30 \%$ is mixed with municipal sludge of ...

​​​​​$\mathrm{MgCl}_{2}$ and $\mathrm{CaSO}_{4}$ salts are added to $1$ litre of distilled deionized water and mixed until completely dissolved. Total Dissolved Solids (T...

​​​​​A hydrocarbon $\left(\mathrm{C}_{\mathrm{n}} \mathrm{H}_{\mathrm{m}}\right)$ is burnt in air $\left(\mathrm{O}_{2}+3.78 \mathrm{~N}_{2}\right)$. The stoichiometric f...

A hypothetical multimedia filter, consisting of anthracite particles (specific gravity: $1.50$), silica sand (specific gravity: $2.60$), and ilmenite sand (specific gravi...

An organic waste is represented as $\mathrm{C}_{240} \mathrm{O}_{200} \mathrm{H}_{180} \mathrm{~N}_{5} \mathrm{~S}$.(Atomic weights: $\mathrm{S}-32, \mathrm{H}-1, \mathrm...

A circular settling tank is to be designed for primary treatment of sewage at a flow rate of $10$ million liters/day. Assume a detention period of $2.0$ hours and surface...

​​​​​​For assessing the compliance with the emissions standards of incineration plants, a correction needs to be applied to the measured concentrations of air pollutants....

Activated carbon is used to remove a pollutant from wastewater in a mixed batch reactor, which follows first-order reaction kinetics.At a reaction rate of $0.38 /$ day, t...

In the context of Municipal Solid Waste Management, 'Haul' in 'Hauled Container System operated in conventional mode' includes the __________.time spent by the transport ...

Which of the following is/are NOT active disinfectant(s) in water treatment? $\cdot \mathrm{OH}$ (hydroxyl radical)$\mathrm{O}_{3}$ (ozone) $\mathrm{OCl}^{-}$(hypochlorit...

For the elevation and temperature data given in the table, the existing lapse rate in the environment is _______________ $\text{C}^{\circ} / 100 \mathrm{~m}$ (round off t...