Environmental E...

A synthetic sample of water is prepared by adding 100 mg Kaolinite (a clay mineral), 200 mg glucose, 168 mg NaCl, 120 MgSO₄, and 111 mgCaCl₂ to 1 litres of pure water. The concentrations of total solids (TS) and fixed dissolved solids (FDs) respectively in the solution in mg/L are equal to

Aerobically treated effluent has MPN of total coliform as 10⁶/100 ml. After chlorination, the MPN value declines to 10²/100 ml, the percent removal (% R) and log removal (log R) of total coliform is ________

The solid waste generated in a city is required to be disposed by using composting method and digestion is supposed to be carried out anaerobically. For proper development of digestion, the optimum value of carbon and nitrogen ration i.e. C/N ratio required is 45. This disposal is carried at two different location of city say A and B. At both locations A and B, samples were collected and tested for C/N ratio X and Y respectively. Location A witness the liberation of ammonia gas and location B witnessed the incomplete digestion of Organic Matter. Which of the following is true?

The design parameter for flocculation is given by a dimensionless number Gt, where G is the velocity gradient and t is the detention time. Values of Gt ranging from 10⁴ to 10⁵ are commonly used, with t ranging from 10 to 30 min. the most preferred combination of G and t to produce smaller and denser flocs is

The Sludge Volume Index for mixed liquor having suspended solids concentration of 2000 mg/l and showing a settled volume of 200 ml from a one litre sample would be

Two water sample X and Y are collected from a sewage treatment plant and analyzed for the presence Coliforms in them. The sample X collected at the inlet of sewage treatment unit and sample Y is taken from the sewage effluents. Which of the following may be true?

The efficiency of the High Rate Trickling Filter for stage one and stage two are 80% and 70%, then the overall efficiency of the trickling filter is

Which of the following Estimation method and corresponding indicator are correctly matched

The disinfection efficiency of chlorine in Water treatment

A settling basin is designed to have a surface overflow rate of 32.6 m³/day/m². The water flowing through the tank carries 4 types of suspended particles. 20% of particles travel with settling velocity 0.5 m/hour, 30% of particles travels with settling velocity of 0.4 m/hour, 25% of particles travels with settling velocity of 0.6 m/hour and remaining particles travel with settling velocity of 0.3 m/hour. Calculate the overall efficiency (in percentage) of sedimentation.

3 degree of hardness will be equivalent to _________ mg of calcium carbonate.

The following composition of a solid waste is given below:

The difference in the energy content on ash-free dry bases and on a dry basis (in kJ/kg) is ______.

(Consider moisture content of waste as 25% and ash content as 6%.)

A waste water is diluted 10% with tap water for conducting BOD test. The DO content in waste water sample was 1.2 mg/lit and water was 6 mg/lit. After the sample is incubated for 5 days at 20° C. The DO of the sample was found as 0.5 mg/lit. (Assume K₂₀ = 0.12 day^-1)

A combined of sewer of circular section is laid to serve a population a 90000 with an average per capita water demand of 250 lpcd (Only 25% of the water supplied is consumed by occupants). For precipitation over an area 100 hectares, time of entry = 3 minutes, time of flow = 17 minutes, and impermeability factor = 0.50. Calculate the minimum diameter of sewer required (in m) to carry the combined discharge of sewage and precipitation, if maximum velocity through sewer is restricted to 3 m per second.

The treated domestic sewage of a town is to be discharged in a natural stream. Calculate the percentage purification required in the treatment plant with the following data?

Population = 40000

BOD contribution per capita = 0.07 kg/day

BOD of the stream on the U/S side = 3 mg/l

Permissible max. BOD of the stream on D/S side = 5 mg/l

Waste water flow, Q_w = 0.081 m³/s

The sludge from the aeration tank of the ASP has solids content (by weight) of 2 %. This sludge is put in a sludge thickener, where sludge volume is reduced to half. Assume solids in supernatant from the thickener is negligible, the specific gravity of sludge solids is 2.2 and the density of water is 1000 kg/m³. 

Convert 80 μg/m³ of SO₂ Concentration present in ambient atmosphere into ppm

Given: \(\frac{{\rm{P}}}{{{\rm{RT}}}}\) = 41.6 mol/m³

Where P = Pressure, T = temperature, R = Universal Gas Constant, Molecular weight of SO₂ = 64.

A rapid sand filter is proposed for water supply treatment plant for a town with a population of 75000. The average rate of water supply is 150 lit/capita/day. Rate of filtration is 100 litre/min/sq.m Assume 4 % of filtered water is required for washing filter every day. There is 1 hour lost time in washing the filter. Then

A single-stage trickling filter of 100 ha-m is to treat 10 MLD of sewage. The BOD load concentration on the filter is 150 mg/l and it is designed for a recirculation ratio of 1.15. The efficiency of the trickling filter in percentage up to two decimal places is ________

Which of the following statements is correct regarding the soda lime method of hardness removal in the treatment water?

The drawdown at the face of a 30 cm diameter fully penetrating well in a confined aquifer in 3 m. The radius of influence of this well is 3 km. For the same discharge and aquifer condition, the drawdown at 300 m away from the center of the well is _____ m.