Recent questions in Environmental Engineering

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

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 ...

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

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 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...

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...

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

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 ...

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

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

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...

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 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...

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...

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 \: \...

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 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...

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

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 ...

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

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...

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...

​​​​​​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...