Environmental E...

The correct arrangement of lakes based on the increasing level of productivity is

Match the List – I (Parameter in treated effluent) with the List - II (Maximum permissible limit of disposal into inland surface water) and select the appropriate option.

1 L of the mixed liquor is allowed to settle in a graduated cylinder of 1 L and the volume of settled sludge is obtained as 200 ml. The sludge volume index of the given sample considering the mixed liquor suspended solids is 2000 mg/L

A large stream has a reoxygenation constant of 0.45 per day and at a point at which organic pollutant is discharged, it is saturated with oxygen at 12 mg/L (D_o = 0). Below the outfall, the ultimate demand for oxygen is found to be 19 mg/l and the Deoxygenation Constant is 0.2 per day. Calculate, the D.O at 36 km downstream Assume velocity of stream to be 1.2 m/s.

For a colony of 10000 persons having sewage flow rate 250 lpcd with a BOD of 320 mg/l and organic loading of 200 Kg/day/ha, the area of the oxidation pond required for treating the sewage of the colony is _______

A sludge digestion tank is used to treat a sludge flow of 40000 liters of sludge per day. The percentage of digested sludge is 30 percent of the incoming sludge daily. If the digestion period is 8 days, calculate the capacity of the sludge digestion tank assuming the parabolic change in the volume instead of linear.

The river water having a discharge of 200 ℓ/s and BOD_U of 20 mg/ℓ enters a community where a sewage discharge having BOD_U of 400 mg/ℓ raises the BOD_U of the complete mix to 70 mg/ℓ. The dilution ratio from the discharge of the said sewage is ______ (in decimal up to 2 places)

The diameter of a standard rate trickling filter having a depth of 2 m to treat a wastewater discharge of 150 m³/day with an influent BOD₅ of 180 mg/ℓ with an efficiency of 90% is (in m up to 2 decimal places)