A Cascade aerator is used in a groundwater treatment plant to reduce the concentration of methane (CH4) and in the same time to increase the oxygen concentration. The height of each step of the cascade is 0.40 m. The design temperature is 10 0C. The following data is given:
Item
CH4
O2
CW,0
1.50 mg/L
0.70 mg/L
Cg
2 ppb
210000 ppm
kd
0.043
0.039
k (efficiency per step)
27%
25%
Calculate the saturation concentration of CH4 and O2 in water under 1 atmospheric pressure.
What is the required number of cascade steps (n) needed to achieve 91.94% removal of CH4 from water? What is the concentration of CH4 in water in mg/L after aeration in this cascade?
What is the concentration of oxygen in water in mg/L after aeration in this cascade?
What is the length of the Cascade aerator if its capacity is 15 m3/h per 1 m length of the step? The total water flow to be treated is 990 m3/h.
What is the total surface area of the cascade if the width to height ratio of the steps is 1:1?
In: Other
In: Other
Hydrogen sulfide is removed from natural gas through a “sweetening process” as it is toxic and its combustion produces corrosive substances. A proposed process is given below:
2H2S(g) + SO2(g) --> 3S(s) + 2H2O(g)
In a test process, a gas stream which contains 20.0% H2S and 80.0% CH4 was combined with a stream of pure SO2 prior to entering the reactor. The process produced 5000 lb of solid S, and in the product gas, the ratio of SO2 to H2S was equal to 3.00, and the ratio of H2O to H2S was 10.0. Draw the diagram. Using the extent of reaction balance, determine the following:
a.) limiting reactant (LR)
b.) fractional conversion of the LR
c.) Feed rates of the two input streams
In: Other
It is well known that the emission of greenhouse gases such as
carbon dioxide presents a very
grave threat to the environment. Attempts are ongoing to absorb
(sequester) this gas by several
means. One such approach involves the use of vegetation, as plants
utilize the gas by means of
photosynthesis.
One such plant, which has shown great promise, is the “Spekboom”
(Portulacaria Afra) which
is endemic to the semi-arid Karoo region of the Eastern Cape.
It has been estimated that fully-grown Spekboom can absorb 3.8
tonnes of carbon per
hectare of plants per year.
If the system is fully functional, South Africa can generate
234.5 × 10ଽ ܹ݇ℎ of electricity
per year.
Assume that 1559 pounds of CO2 is emitted per year per
Megawatt-hour (MWh) of
electricity generated in the country.
Determine, by means of the use of conversion factors, how many
square kilometres of
Spekboom could theoretically absorb all of this carbon
dioxide?
Given: 1 hectare = exactly 10000. m2
; 1 pound = 453.59237 g; 1 tonne = exactly 1000 kg
[9]
1.2 Consider the molecule, CℓPO2. (The phosphorus atom is the
central atom)
1.3 Draw the 3-D Lewis dot structure of the molecule, including
all possible resonance structures.
Your structures must not show any hyper-valency. Use different
symbols for the valence
electrons of the different atoms. Do not use dashes to represent
bonds. Indicate all lone electron
pairs.
[4]
1.2.2 Calculate the formal charges of all atoms in all the Lewis
structures. Write these values on the
structures you have drawn in question 1.2.1.
[2]
1.2.3 Calculate the bond order of the P–O bond(s). Briefly explain
the meaning of your answer.
[2]
In: Other
A flow rate of Va (in) = 300 [mL / min] of water is mixed in a static mixer with an aqueous solution containing an active ingredient B, at the concentration Cb (in) = 0.2 [mM]. Water density = 1003 [kg / m ^ 3], density of the aqueous solution = 1010 [kg / m ^ 3] Calculate the volumetric flow rate, V (in) in [mL / min] of the aqueous solution containing the active ingredient B entering the static mixer, to obtain, upon exiting the mixer, an aqueous solution with a final concentration of active principle equal to C (out) = 9.5 [microM]
**i assume density mixed solution =1010 kg/m^3**
In: Other
Identify and explain the three parts of the epidemiological triangle.
In: Other
In: Other
Dynamic and control process
in a water tank in the toiled
what is the controlled variable?
what is the disturbance variable?
what is the manipulated variable?
In: Other
Air at 25°C is flowing over 400°C hot iron ball with a velocity of 10 m/s. The diameter of the iron ball is 10 cm diameter and (p =7874 kg/m3 and cP = 450 J/kg.K). After a while the surface temperature of the ball drops to 300°C.
In: Other
Explain the procedure for defining the hysteresis loop
class for adsorption and
desorption isotherms?
Minimum word limit 600
Plagiarism 10%max
In: Other
There are 4 factors that can affect the rate of a chemical reaction:
A. A) viscosity, nature of the reactants, temperature, and hydrogen bonding B. B) nature of the reactants, catalyst, temperature, and density C. C) density, temperature, catalyst and concentration D. D) nature of the reactants, temperature, the order of the reactants, and half life E. E) concentration, nature of the reactants, temperature, and order of reactants. F. F) none the above
In: Other
A fuel mixture consists of 90% octane (C8H18) and 10% ethyl alcohol (C2H5OH), by volume. This fuel mixture is burned with 200% theoretical dry air in a combustion chamber at atmospheric pressure.
a) Write the balanced reaction equation for complete combustion of this fuel mixture.
b) Determine the theoretical air-fuel ratio.
c) Actual air-flow rate for a fuel mixture flow rate of 5 kg/s.
d) Calculate the molar mass of the mixture product gases.
In: Other
Discuss the role of warm water in the formation and persistence of a hurricane, referencing your observations about Sea Surface Tempature in the Atlantic and Gulf and what happened to Katrina after landfall.
In: Other
During a formal debate on the hazards of air pollution, one team argues that ozone is helpful to the atmosphere, and the other team argues that it is destructive. Explain why both teams are correct.
Please write clear.
In: Other
What is the definition of pe? How does it differ from Eh? What is ORP? How does ORP relate to pe and Eh?
In: Other