A 90-m³ basement in a residence is found to be contaminated with radon coming from the ground through the floor drains. The concentration of radon in the room is 1.5 Bq L- (becquerels per liter) under steady-state conditions. The room behaves as a CMFR, and the decay of radon is a first-order reaction with a decay rate con- stant of 2.09 x 10-s. If the source of radon is closed off and the room is vented with radon-free air at a rate of 0.14 ms, how long will it take to lower the radon concentration to an acceptable level of 0.15 Bq -L-¹?

A 90-m³ basement in a residence is found to be contaminated with radon coming from the ground through the floor drains. The concentration of radon in the room is 1.5 Bq L- (becquerels per liter) under steady-state conditions. The room behaves as a CMFR, and the decay of radon is a first-order reaction with a decay rate con- stant of 2.09 x 10-s. If the source of radon is closed off and the room is vented with radon-free air at a rate of 0.14 ms, how long will it take to lower the radon concentration to an acceptable level of 0.15 Bq -L-¹?

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

See similar textbooks

Related questions

Q: A river is traveling at a velocity of 0.06 m/s. At x = 0 km, the river has a dissolved oxygen…

A: Introduction : Biochemical oxygen demand (BOD) : BOD is a measurement of the quantity of oxygen…

Q: An activated sludge reactor produces the wasted sludge with 1% of the solid content. What is the…

A: 1 % SOLID CONTENT

Q: Diffusion of a pollutant into a semi-infinite soil layer can be described by the following…

A: Given Data: The effective diffusion coefficient of the pollutant in the soil is D. The decay rate of…

Q: If the 3-day BOD (BOD3) of a waste is 75 mg/L and the BOD decay constant, k, is 0.345 day-1 , what…

A: Appreciate if there is detailed work with explanation and finds you helpful for ease of…

Q: The concentration of a certain chemical in a sealed tank follows the expression C(t) = Co exp…

Q: 1-6. Įn a biological waste treatment system, solids may enter (b) Solids decay in the reactor at a…

A: Consider the given equation rs=-k1s2XS2+KsWhere,X=VSS concentration in the reactorAlsok1=8 mg DOCmg…

Q: Water with 90 mg/L of a degradable contaminant flows through a reactor. The influent flow rate…

A: Given, Degradable contaminant flow,D0=90 mg/lFlow rate = 100 m3/dReactor Volume V=200 m3kd=1.0 d-1

Q: According to Bowen's reaction series, which one of the following statements is true? Mafic igneous…

A: This question is related to the Engineering Geology from Soil Mechanics from Civil Engineering. This…

Q: If the reaction rate coefficient of BOD is 0.3 1/d at 20 oC, what will it be if the temperature is…

Q: Consider CSTRs in series follows a first-order reaction with the same rate constant as shown in…

A: SOLUTION:

Q: a pond is used to treat a dilute municipal wastewater before the liquid is discharged into a river.…

A: The objective of the question is to determine the BOD concentration at the outflow of the pond and…

Q: A nuclear fuel pellet consists of an aluminum cladding [E1 = 90 GPa; α1 = 42.2 × 10-6 /°K] with an…

A: There will be compression in Al as Alpha is more.

Q: (a) Prove that for a first order decay reaction (k1= 2 days-1) taking place in reactors of identical…

A: k = 2 days-1 (first order rate constant)V=Reactor volume= 15 LCin=Inlet contaminant concentration =…

Q: When you touch a hot object with your finger, the heat transferred to your finger is by Group of…

A: When two bodies are direct in contact with each other then heat is always transferred from the body…

Q: (a) What is the maximum contaminant concentration that is expected at a location 2 km downstream of…

A: a) - Discharge(Q) = 2m3/s B= 5m D= 1m Velocity = QB*D V= 25*1 = 0.4m/s Time taken to travel…

Q: A liquid waste at 20 deg. celcius has ultimate BOD of 250 mg/L, and a decay rate constant of…

A: a) BOD ultimate of river after mixing BODu=QRBODuR+QwBODuwQR+Qw BODu=960+12509+1…

Q: 250°C the diffusion coefficient D' and activation energy *O for Cu in Si are D (250°G) - 6.9 ×…

A: Diffusion coefficient -D - 250oC D (250°G) - 6.9 × 10-11 m™ Qd =46.5 kJ/mol To find- diffusion…

Q: The flow of a river is 1.5 m3/s, the river is polluted with the pesticide permethrin and flows into…

A: The given data for the problem is: The flow rate of a river is 1.5 m^3/s The river is polluted with…

Q: A river, flowing at 1.5 m3/s, is polluted with the pesticide permethrin and flows into a lake (100 m…

A: Answer (a) Calculation of Concentration of permethrin entering the lake In order to determine the…

Q: eight at 0kpa: 396 g Weight at -33kpa: 325 g Weight at -1500kpa: 291 g Weight at -3100kpa: 280g…

A: Weight at 0kpa: 396 gWeight at -33kpa: 325 gWeight at -1500kpa: 291 gWeight at -3100kpa: 280gWeight…

Q: The secondary NAAQS for SO2 is 0.5 ppm (for a 3-hour averaging time). Calculate the equivalent…

A: Given:- The secondary NAAQS for SO2 is 0.5 ppm To find:- The equivalent concentration in pg/m3

Q: What is the calculated value of the cell potential at 298K for an electrochemical cell with the…

A: Solution; Given Data; EAg+/Ay=+0.80, E°Al3+/Al=-1.66 vTherefore E°ceu=+0.80-(-1.66)…

Q: Poorly treated municipal wastewater is continuously discharged directly into a lake. The discharge…

A: The pollutant balance equation for the steady-state is: In-out-Decomposed=0 Also Accumulation=0

Q: Determine the carbonaceous, nitrogenous, and total ThODs for 300 mg/L sludge cells (C;H;NO2). What…

A: Compound = C5H7NO2Balance Reaction for Carbonaceous oxygen demandC5H7NO2+5O2 → NH3+5CO2+2H2O…

Q: Hydrogen is allowed to diffuse through a palladium plate that is 0.008m thick at 500°C. The…

A: The concentration gradient (dC/dx) across the plate can be approximated by, dxdC=ΔxC2−C1…

Concept explainers

Storm Sewers and Detention

The storm drains system transports rainwater or stormwater and other runoff from roads, parking lots, and roof downpipes directly to nearby creeks, rivers, or the sea without any treatment.

Question

A 90-m³ basement in a residence is found to be contaminated with radon coming from the ground through the
floor drains. The concentration of radon in the room is 1.5 Bq L- (becquerels per liter) under steady-state
conditions. The room behaves as a CMFR, and the decay of radon is a first-order reaction with a decay rate con-
stant of 2.09 x 10-s. If the source of radon is closed off and the room is vented with radon-free air at a rate
of 0.14 m. s, how long will it take to lower the radon concentration to an acceptable level of 0.15 BqL-¹?

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

This is a popular solution!

SEE SOLUTION Check out a sample Q&A here

Step 1: Determine the given data

VIEW

Step 2: Determine the detention time.

VIEW

Step 3: Determine the required time.

VIEW

Solution

VIEW

Trending now

This is a popular solution!

Step by step

Solved in 4 steps with 9 images

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.

Similar questions

A power plant in rough terrain has a 100-m stack with an inside radius of 1 m. The plant emits 300 g/s of SO2 from the stack with an exit velocity of 10 m/s at a temperature of 120oC. Ambient temperature is 6oC and the temperature increases at a rate of 2 K/km. At 10 m above ground, surface windspeed is 1.5 m/s on a mostly cloudy night. Find the concentration (mg/m3) of SO2: Directly downwind at a distance of 2 km. At a point located 2 km downwind and 0.1 km off the downwind axis. At the point downwind where it is a maximum. Approximately how far from the stack does this occur?
5. A certain radioactive material follows the law of exponential change and has a half-life of 38 hours. Find how long it takes for 90% of the radioactivity to be dissipated.
Advection, diffusion, and reaction in a channel Approximately 50 m3 of an agricultural pesticide with an initial concentration of 1.6 × 105 mol/m3 have been spilled into a stream following a train derailment. You have been called in to predict the aqueous concentrations of this pesticide at various points along the stream, and the mass that will be delivered to a lake with critical habitat 70 km downstream. You look up the main component of the pesticide and see that it degrades in water (due to hydrolysis reaction) with a half-life of 1.9 h. The discharge rate of the stream is 75,000 L/min. It has an average depth of 0.3 m and an average width of 1.2 m. a. Calculate the maximum concentration (in mol/L) of the pesticide that will be observed at a town 10 km downstream and at the point where the stream reaches the lake, 70 km downstream. Assume a sheer velocity of 0.40 m/s. b. Plot the concentration of this pesticide entering the town and the lake with time. Care should be taken when…
(4) [Text-problem 4.29] A 90-m³ basement in a residence is found to be contaminated with radon coming from the ground through the floor drains. The concentration of radon in the room is 1.5 Bq L- (becquerels per liter) under steady-state conditions. The room behaves as a CMFR, and the decay of radon is a first-order reaction with a decay rate con- stant of 2.09 × 10-6 s-1. If the source of radon is closed off and the room is vented with radon-free air at a rate of 0.14 m³ s-1, how long will it take to lower the radon concentration to an acceptable level of 0.15 Bq L-¹?
3. A first order decay reaction is occurring in a single CFSTR. Dividing the reactor into two smaller CFSTRs that are operated in series (effluent from one serving as the influent to the other) reduces the overall mixing and therefore makes the flow more PFR-like. Because reaction efficiency is greater in a PFR than a CFSTR, we might expect that dividing the reactor would improve the efficiency. To test that hypothesis, consider a system receiving an influent with C = 100 mg/L of a reactant that undergoes a first order decay reaction with a rate constant of 0.1 min ¹. Assume that the system has a total hydraulic detention time of 1 hour, but that it can be operated in three different ways: as a PFR, a CFSTR, or as two CFSTRs in series with the detention time split equally between the two. Find the effluent concentrations for the three possible operating modes