The CT values for inactivation of E. coli is given in the following table: Log removal CT (mg/L.min) 0.5 log 0.75 1.0 log 1.40 2.0 log 3.0 log 4.0 log 2.10 2.95 3.65 What is the required time for disinfection to achieve 99.9% removal if the concentration of disinfectant is 2 mg/L7

Structural Analysis
6th Edition
ISBN:9781337630931
Author:KASSIMALI, Aslam.
Publisher:KASSIMALI, Aslam.
Chapter2: Loads On Structures
Section: Chapter Questions
Problem 1P
icon
Related questions
Question

can you please help me solve the homework problem. I need a step by step solution i am very confused on it. and please write clear and box answer. thank you 

### CT Values for Inactivation of *E. coli* 

The following table provides the CT values (mg/L·min) required for different log removals of *E. coli*:

| Log Removal | CT (mg/L·min) |
|-------------|---------------|
| 0.5 log     | 0.75          |
| 1.0 log     | 1.40          |
| 2.0 log     | 2.10          |
| 3.0 log     | 2.95          |
| 4.0 log     | 3.65          |

#### Explanation

- **Log Removal**: This column represents the log reduction (a logarithmic scale used to show the relative number of live microbes eliminated). For example, 1.0 log represents a 90% reduction, 2.0 log represents a 99% reduction, and so forth.
- **CT (mg/L·min)**: This value represents the concentration of the disinfectant (mg/L) multiplied by the contact time (minutes) needed to achieve the corresponding log removal efficiency.

### Problem Statement

To determine the required time for disinfection to achieve 99.9% removal of *E. coli* if the concentration of disinfectant is 2 mg/L.

#### Calculation:

1. **99.9% removal** corresponds to a 3.0 log reduction.
2. From the table, the CT value for 3.0 log removal is 2.95 mg/L·min.
3. Given that the concentration \( C \) of the disinfectant is 2 mg/L, we need to find the required contact time \( T \).

\[ CT = C \times T \]

\[ 2.95 \, \text{mg/L·min} = 2 \, \text{mg/L} \times T \]

\[ T = \frac{2.95}{2} \]

\[ T = 1.475 \, \text{minutes} \]

So, the required time for disinfection to achieve 99.9% removal of *E. coli* with a disinfectant concentration of 2 mg/L is approximately **1.475 minutes**.
Transcribed Image Text:### CT Values for Inactivation of *E. coli* The following table provides the CT values (mg/L·min) required for different log removals of *E. coli*: | Log Removal | CT (mg/L·min) | |-------------|---------------| | 0.5 log | 0.75 | | 1.0 log | 1.40 | | 2.0 log | 2.10 | | 3.0 log | 2.95 | | 4.0 log | 3.65 | #### Explanation - **Log Removal**: This column represents the log reduction (a logarithmic scale used to show the relative number of live microbes eliminated). For example, 1.0 log represents a 90% reduction, 2.0 log represents a 99% reduction, and so forth. - **CT (mg/L·min)**: This value represents the concentration of the disinfectant (mg/L) multiplied by the contact time (minutes) needed to achieve the corresponding log removal efficiency. ### Problem Statement To determine the required time for disinfection to achieve 99.9% removal of *E. coli* if the concentration of disinfectant is 2 mg/L. #### Calculation: 1. **99.9% removal** corresponds to a 3.0 log reduction. 2. From the table, the CT value for 3.0 log removal is 2.95 mg/L·min. 3. Given that the concentration \( C \) of the disinfectant is 2 mg/L, we need to find the required contact time \( T \). \[ CT = C \times T \] \[ 2.95 \, \text{mg/L·min} = 2 \, \text{mg/L} \times T \] \[ T = \frac{2.95}{2} \] \[ T = 1.475 \, \text{minutes} \] So, the required time for disinfection to achieve 99.9% removal of *E. coli* with a disinfectant concentration of 2 mg/L is approximately **1.475 minutes**.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 9 images

Blurred answer
Knowledge Booster
Storm sewers and detention
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.
Recommended textbooks for you
Structural Analysis
Structural Analysis
Civil Engineering
ISBN:
9781337630931
Author:
KASSIMALI, Aslam.
Publisher:
Cengage,
Structural Analysis (10th Edition)
Structural Analysis (10th Edition)
Civil Engineering
ISBN:
9780134610672
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Principles of Foundation Engineering (MindTap Cou…
Principles of Foundation Engineering (MindTap Cou…
Civil Engineering
ISBN:
9781337705028
Author:
Braja M. Das, Nagaratnam Sivakugan
Publisher:
Cengage Learning
Fundamentals of Structural Analysis
Fundamentals of Structural Analysis
Civil Engineering
ISBN:
9780073398006
Author:
Kenneth M. Leet Emeritus, Chia-Ming Uang, Joel Lanning
Publisher:
McGraw-Hill Education
Sustainable Energy
Sustainable Energy
Civil Engineering
ISBN:
9781337551663
Author:
DUNLAP, Richard A.
Publisher:
Cengage,
Traffic and Highway Engineering
Traffic and Highway Engineering
Civil Engineering
ISBN:
9781305156241
Author:
Garber, Nicholas J.
Publisher:
Cengage Learning