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Sedaia [141]
3 years ago
10

In the 1960s through 1980s, a medical filter manufacturer in Ann Arbor discharged 1,4-dioxane (an industrial solvent) directly i

nto the environment, where it ultimately leached into underlying groundwater aquifers. A plume of 1,4-dioxane has been spreading under Ann Arbor and could pose water quality risks if it reaches Barton Pond, which supplies 85% of the city's drinking water.
a) Barton Pond contains 1.5 billion gallons (5.68 million m3) of water and initially contains no 1,4-dioxane. Assume the pond is perfectly mixed with one stream flowing in and out at a rate of 1 m3/s. Suppose the plume enters the pond at a rate of 0.1 m3/s and contains 50 mg/L of 1,4-dioxane, which has a first-order decay constant of 6.4*105 s1. What is the steady-state concentration of 1,4-dioxane in the pond?

b) Local water authorities find a way to divert the plume such that 1,4-dioxane is no longer entering the pond. How long will it take for the 14-dioxane concentration in the pond to reach the Michigan Department of Environmental Quality's new allowable drinking water level of 7.2 ug/L?

c) The EPA classifies 1,4-dioxane as a probable carcinogen with a potency factor of 0.011 (mg/kg/d)1. If the water contains the EPA's allowable limit of 7.2 μg/L of 1,4-dioxane, calculate the carcinogenic risk based on the default EPA exposure factors over a lifetime for ingestion of potable water in an average adult. Is the water safe to drink based on the "rule of thumb" discussed in class?
Engineering
1 answer:
stepladder [879]3 years ago
5 0

Answer:

<u>Option-</u> C

  • In the 1960s through 1980s, a medical filter manufacturer in Ann Arbor discharged 1,4-dioxane (an industrial solvent) directly into the environment, where it ultimately leached into underlying groundwater aquifers. A plume of 1,4-dioxane has been spreading under Ann Arbor and could pose water quality risks if it reaches Barton Pond, which supplies 85% of the city's drinking water. So, we can evaluate the given information by concluding that the  EPA classifies 1,4-dioxane as a probable carcinogen with a potency factor of 0.011 (mg/kg/d)1. If the water contains the EPA's allowable limit of 7.2 μg/L of 1,4-dioxane, calculate the carcinogenic risk based on the default EPA exposure factors over a lifetime for ingestion of potable water in an average adult. Is the water safe to drink based on the "rule of thumb" discussed in class?                                      

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Two streams of air enter a control volume: stream 1 enters at a rate of 0.05 kg / s at 300 kPa and 380 K, while stream 2 enters
alex41 [277]

Answer:

0.08kg/s

Explanation:

For this problem you must use 2 equations, the first is the continuity equation that indicates that all the mass flows that enter is equal to those that leave the system, there you have the first equation.

The second equation is obtained using the first law of thermodynamics that indicates that all the energies that enter a system are the same that come out, you must take into account the heat flows, work and mass flows of each state, as well as their enthalpies found with the temperature.

 

finally you use the two previous equations to make a system and find the mass flows

I attached procedure

5 0
3 years ago
To increase the thermal efficiency of a reversible power cycle operating between thermal reservoirs at TH and Tc, would you incr
alukav5142 [94]

<u></u>\ T_{c} has greater effect.

<u>Explanation</u>:

\eta_{\max }=1-\frac{T_{c}}{T_{A}}

T_{c}\\ = Temperature of cold reservoir

T_{H} = Temperature of hot reservoir

when T_{c} is decreased by 't',

$\eta_{\text {incre }}$ = 1-\frac{\left(\tau_{c}-t\right)}{T_{H}}

=n \ + \frac{t}{T_{n}}      -(i)

when {T_{H}} is increased by 'T'

\eta_{i n c}=\frac{n+\frac{t}{T_{H}}}{\left(1+\frac{k}{T_{H}}\right)}-(ii)

\eta_{\text {incre }} \ T_{c}>\eta_{\text {incre }} T_{\text {H }}

7 0
3 years ago
Type the correct answer in the box. Spell all words correctly.
Rudik [331]

Answer:ii dant overstand

Explanation:

5 0
2 years ago
In an international film festival, a penal of 11 judges is formed to judge the best film. At
Julli [10]

Answer:

International Film Festival

Judging the best best film:

a. The probability that out of five judges (random sample),  three are in favor of film FA is:

= 33%.

b. The demerits of classical probability are:

1. Classical probability can only be used with events that have definite numbers of possible outcomes.  

2. Classical probability can only handle events where each outcome is equally likely.

3. Classical probability is based on the assumption of linear relationship (which is not always true in real life) between the latent variable and observed scores.

Explanation:

a) Number of judges = 11

Number of judges in favor of FA film = 6

Number of judges in favor of FB film = 5

Probability of judges in favor of FA film = 6/11

Probability of judges in favor of FB film = 5/11

Random sample of judges = 5

Probability that out of five judges, three are in favor of film FA = 3/5 * 6/11

= 18/55

= 33%

b) Classical probability is the simple probability showing that each event has equal chance of happening.  It can be contrasted with empirical probability that is obtained from experiments.

7 0
3 years ago
Which of the following animals can be found in the locality​
erastovalidia [21]

Answer:

c frog

Explanation:

frog have chance that can lived in the locality or in public place like river,lake,farm and other place that they can be lived and hunt foods. In the picture bear, elephant and tiger are can't lived in the locality that have many population of people. little percent of changes that they can hunts foods or lived in the public/locatlity place.

7 0
2 years ago
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