Water Treatment

Fecal Coliform (FC) concentration in river water was measured as 10780 cfu/100 ml. The FC concentration after the conventional water treatment, but before chlorination, was measured as $23 \mathrm{cfu} / 100 \mathrm{ml}$...

Free residual chlorine concentration in water was measured to be $2 \mathrm{mg} / \mathrm{l}$ (as $\mathrm{Cl}_2$ ). The pH of water is 8.5. By using the chemical equation given below, the HOCl concentration (in $\mu$ mo...

Aeration is employed as a treatment option for the removal of several pollutants from contaminated water. Identify the pollutant(s), where aeration is employed as a part of their removal:

The analyses results of a water sample are given below. The non-carbonate hardness of the water (in $\mathrm{mg} / \mathrm{L}$ ) as $\mathrm{CaCO}_3$ is __________ (in integer). $$ \begin{aligned} & \mathrm{Ca}^{2+}=150...

The Surface Overflow Rate (SOR) in a rectangular sedimentation tank is $45 \mathrm{~m}^3 / \mathrm{m}^2 / \mathrm{d}$. Minimum diameters of spherical inorganic and organic particles expected to be completely removed in t...

A hypothetical multimedia filter, consisting of anthracite particles (specific gravity: 1.50), silica sand (specific gravity: 2.60), and ilmenite sand (specific gravity: 4.20), is to be designed for treating water/wastew...

A water treatment plant treats 25 MLD water with a natural alkalinity of 4.0 mg/L (as CaCO 3 ). It is estimated that, during the coagulation of this water, 450 kg/day of calcium bicarbonate (Ca(HCO 3 ) 2 ) is required ba...

Identify the waterborne diseases caused by viral pathogens:

Which of the following is/are NOT active disinfectant(s) in water treatment?

In the following table, identify the correct set of associations between the entries in Column - 1 and Column-2. Column-1 Column-2 P: Reverse Osmosis III: Concentration Polarization Q: Trickling Filter I: Ponding R: Coag...

In the context of water and wastewater treatments, the correct statements are:

A flocculator tank has a volume of 2800 m 3 . The temperature of water in the tank is 15°C, and the average velocity gradient maintained in the tank is 100/s. The temperature of water is reduced to 5°C, but all other ope...

Which of the following processes can be used for conversion of salt water into fresh water?

Henry's law constant for transferring O 2 from air into water, at room temperature, is 1.3 $${{mmol} \over {liter - atm}}$$. Given that the partial pressure of O 2 in the atmosphere is 0.21 atm, the concentration of diss...

In a water sample, the concentrations of Ca 2+ , Mg 2+ and HCO$$_3^ - $$ are 100 mg/L, 36 mg/L and 122 mg/L, respectively. The atomic masses of various elements are : Ca = 40, Mg = 24, H = 1, C = 12, O = 16. The total ha...

A 100 mg of HNO 3 (strong acid) is added to water, bringing the final volume to 1.0 liter. Consider the atomic weights of H, N, and O, as 1 g/mol. 14 g mol. and 16 g/mol, respectively. The final pH of this water is (Igno...

The total hardness in raw water is 500 milligram per liter as CaCO 3 . The total hardness of this raw water, expressed in milligram equivalent per liter, is (Consider the atomic weights of Ca, C, and O as 40 g/mol, 12 g/...

A water treatment plant has a sedimentation basin of depth 3 m, width 5 m, and length 40 m. The water inflow rate is 500 m 3 /h. The removal fraction of particles having a settling velocity of 1.0 m/h is ________. (round...

Two discrete spherical particles (P and Q) of equal mass density are independently released in water. Particle P and particle Q have diameters of 0.5 mm and 1.0 mm, respectively. Assume Stoke's law is valid. The drag for...

The hardness of a ground water sample was found to be 420 mg/L as $$CaCO_3$$. A softener containing ion exchange resins was installed to reduce the total hardness to 75 mg/L as $$CaCO_3$$ before supplying to 4 households...

A groundwater sample was found to contain 500 mg/L total dissolved solids (TDS). TDS (in %) present in the sample is ________.

Some of the nontoxic metals normally found in natural water are

A water sample has a pH of 9.25. The concentration of hydroxyl ions in the water sample is

Ion concentrations obtained for a groundwater sample (having pH=8.1) are given below. Ion $$Ca^{2+}$$ $$Mg^{2+}$$ $$Na^+$$ $$HCO_3^-$$ $$SO_4^{2-}$$ $$Cl^{-}$$ Ionconcentration(mg/L) 100 6 15 250 45 39 Atomic Weight Ca=4...

Ion concentrations obtained for a groundwater sample (having pH=8.1) are given below. Ion $$Ca^{2+}$$ $$Mg^{2+}$$ $$Na^+$$ $$HCO_3^-$$ $$SO_4^{2-}$$ $$Cl^{-}$$ Ionconcentration(mg/L) 100 6 15 250 45 39 Atomic Weight Ca=4...

The presence of hardness in excess of permissible limit causes

The alkalinity and the hardness of a water sample are 250 mg/L and 350 mg/L as $$CaCo_3$$, respectively. The water has

1 TCU is equivalent to color produced by

If tomato juice is having a pH of 4.1, the hydrogen ion concentration will be

Most of the turbidity meters work on the scattering principle. The turbidity value obtained is expressed in

In natural water, hardness is mainly caused by

Two Samples of Water A and B have pH values of a 4.4 and 6.4 respectively. How many times more acidic sample A is than sample B

Temporary hardness in water is caused by the presence of

The microbial quality of treated piped water supplies is monitored by

Alkalinity of water can be defined correctly in one of the following ways

MPN index is measure of one of the following: