Environment Engg

Question 1

Which of the following has the proper unit conversion and system of unit?

Question 2

Water insoluble compounds are often not readily available to organisms for
biodegradation, however, there are some exceptions. A compound that is known as a widely used pesticide and only slightly water soluble is reportedly degraded by one organism, the white rot fungus found on decaying trees. What is the compound being
described?

Answer 2

DDT (dichlorodiphenyltrichloroethane)

Question 3

Which layer of the atmosphere contains the ozone layer?

Answer 3

stratosphere

Question 4

Composition of acid in acid rain?

Answer 4

nitric and sulfuric
HNO3 and H2SO4

Question 5

How does alpha, beta and gamma particle affect the mass number of an atom?

Answer 5

4,0,0

Question 6

Can oxygen be synthesized from nitrogen?

Answer 6

Impossible

Question 7

Which type of radiation is the least penetrating?

Answer 7

alpha radiation

Question 8

Process of breaking down a large isotope into smaller isotopes.

Answer 8

nuclear fission

Question 9

What is the distance of the nearest normal galaxy to the earth?

Answer 9

If Canis Major Dwarf - 25,000 light years

if Andromeda - 2.537 million light years

Question 10

What is the nearest star to the earth aside from the yellow dwarf?

Answer 10

Proxima Centauri

Question 11

Calculate the volumetric flow rate of leachate through a compacted clay liner if the area of the landfill is 10 ha and the liner thickness is 2m. The hydraulic conductivity is 2.3x10-10 m/s. Assume that the head water is 0.4m.

Answer 11

4.6x10^-6 m3/s

Question 12

The High tannery with a wastewater flow of 0.011 m^3/s and a BOD5 of 590 mg/L discharges into the Low Creek. The creek has a 10 year, 7 day low flow of 1.7m^3/s. Upstream of the tannery, the BOD5 of the creek is 0.6vmg/L. The BOD rate constants (k) are 0.115/day for the tannery and 3.7/day for the creek. Calculate the initial ultimate BOD after mixing

Answer 12

9.27 mg/L

Question 13

Compute the theoretical NBOD of a wastewater containing 30 mg/L of ammonia as nitrogen.

Answer 13

137.14 mgO2/L

Question 14

The Nairyosangha landfill located in Peshdadians serves a population of 562,400 people generating MSW at a rate of 1.89 kg/cap-day. The volume of the landfill is 11,240,000 cu.m. At the present time, 63% of the landfill is used. The ratio of the cover to compacted fill is 1.5. Determine projected life remaining for the landfill. Assume the density of the compacted waste to be 490 kg/cu.m.

Answer 14

2.76 yrs

Question 15

Professor Dexter has made measurements of her household solid waste, shown in the table. If the container volume is 0.0757 cu.m., what is the average density (kg/cu.m.) of the solid waste produced in her household during the period of time from Mar 18 through Apr 18? Assume that the mass of each empty container is 2.63 kg.

Answer 15

58.4 kg/m3

Question 16

Given the following data for the Marikina River and Pasig River, determine the best combination of the plant and location to best conserve the environment:

Answer 16

Plant B in Marikina River

Question 17

A farmer has a 7-year rotation of corn, soybeans, and wheat and 4 years of alfalfa. Manure will be applied before corn and wheat and before seeding to alfalfa. The initial soil test results indicate total phosphorus level of 48 kg P · hectare−1. Manure is to be
surface-applied in mid-March and disk-incorporated within 2 days of application. One-third of the organic nitrogen and 50% of the nitrogen from NH4 is available to the corn
crop. To obtain the desired yield of corn, the local extension agent has told the farmer to apply 100 kg of nitrogen per hectare

Answer 17

20, 000 kg manure/ha

Question 18

A solution is initially supersaturated with CO2^−3 and Ca^2+ such that the concentrations are both 40.0 mg · L−1. What will be the final concentration of Ca2+?

Answer 18

16.7 mg/L

Question 19

The concentration of a chemical degrades in water according to first-order kinetics. The
degradation constant is 0.3 day−1. If the initial concentration is 100.0 mg · L−1, how many days are required for the concentration to reach 0.14 mg · L−1?

Answer 19

32.9 days

Question 20

A hazardous waste incinerator is being fed methylene chloride at a concentration of 5858 mg/L in an aqueous stream at a rate of 50.5 L/min Calculate the mass flow rate of the feed in units of grams per minute

Answer 20

237.25 g/min

Question 21

A small lake is surrounded by agricultural land. The lake is 100 m long and 120 m wide. The average depth is 30 m. The lake is fed by a small pollution-free stream having an
average flow rate of 1.5 m3/s. A herbicide, Greatcrop, is detected at a concentration of 45.2 μg/L in the lake. Greatcrop degrades biologically with a rate constant of 0.22/day. Assuming that the lake is at steady-state conditions and completely mixed at the time of sampling, what would have been the mass input of herbicide? Assume that the stream is the only source of water to the lake and that evaporation, precipitation, and
seepage can be neglected

Answer 21

11.2 kg/day

Question 22

Acidic rainfall infiltrates into a geological formation that is predominantly dolomite, a
commonly occurring rock-forming mineral. In 1940, the average pH of the groundwater was 4.6. By 1995, the average yearly groundwater pH was 5.6. Assuming that as the groundwater percolates through the dolomite it is at equilibrium, calculate the calcium
and magnesium at pH 4.6 and pH 5.6, respectively. Assume that the temperature is 25°C and that the concentration of calcium, magnesium, and carbonate in the rainwater
is negligible

Answer 22

0.00327 M, 0.0207 M

Question 23

Determine the area required for a new landfill site with a projected life of 30 years for a population of 350,000 generating 2.02 kg · (capita)−1 · day−1. The density of the compacted waste is 470 kg · m−3. The height of the landfill cannot exceed 15 m.

Answer 23

78.4 ha

Question 24

A dose of 2.0 R of gamma radiation was measured in air. From empirical studies, it is known that, on the average, 34 eV of energy is transferred (or absorbed) in the process of forming each ion pair in air. What is the equivalent absorbed dose in 1.0 cubic centimeter of air?

Answer 24

8.70 mGy

Question 25

If the wastewater analysis was reported as 50 mg · L−1 of ammonia (NH3), what would the theoretical NBOD be?

Answer 25

228.57 mgO2/L

Question 26

The following test results were obtained for a wastewater sample taken at the headworks to a wastewater treatment plant. All of the tests were performed using a sample size of 100 mL. The samples used in the analyses were either evaporated, dried, or ignited to constant weight

Answer 26

Total Solids (Ts) = 720 mg/L
Total Volatile Solids (TVS) = 169 mg/L
Total Suspended Solids (TSS) = 121 mg/L
Total Volatile Suspended Solids (VSS) = 44 mg/L
Total Dissolved Solids (TDS) = 240 mg/L
Volatile Dissolved Solids (VDS) = 91 mg/L

Question 27

The following test results were obtained for a wastewater sample taken at the headworks to a wastewater treatment plant. All of the tests were performed using a
sample size of 100 mL. The samples used in the analyses were either evaporated, dried, or ignited to constant weight.

Answer 27

Total Solids (Ts) = 361 mg/L
Total Volatile Solids (TVS) = 169 mg/L
Total Suspended Solids (TSS) = 121 mg/L
Total Volatile Suspended Solids (VSS) = 78 mg/L
Total Dissolved Solids (TDS) = 240 mg/L
Volatile Dissolved Solids (VDS) = 91 mg/L

Question 28

A sample of sewage from a town is found to have a BOD after 5 days of 150 mg/L. Estimate the ultimate BOD of the sewage. Assume that k = 0.1/day for this wastewater.

Answer 28

260 mg/L