PART 3
The new town will be built with a water treatment plant to reduce or remove the pollutants at the site you choose (Town Site A or Town Site B). Diagram 4 below shows some major steps in a water treatment process. This process is similar to the one that will be used in the water treatment plant at the new town site.
Diagram 4
Table 2 below lists the major steps used in the water treatment process.
Use information from Tables 1A and 1B and your knowledge of physical, chemical, and biological processes to identify the pollutant(s) that could be removed or reduced in each treatment process step.
Enter in the last column of the table the water samples (SA, SB, or Both) where each pollutant you identified exceeds water quality standards.
Sample correct student response:
The table below is a transcription of a student response for question 4
Table 2: Water Treatment Processes
Water Treatment
Process Step
|
Pollutant(s) That Could be Removed or Reduced in This Step
|
Site Where Pollutant Exceeds Standards (SA, SB, or Both)
|
Allow Water to Stand in a Settling Tank
(Sedimentation)
|
Turbidity
|
SB
|
Treat Water with Chemicals
(Neutralization, Oxidation-Reduction, Precipitation, Other)
|
Nitrate
Iron
|
SB
SA
|
Remove Solid Particles and Organic Matter
(Filtration, Biodegradation)
|
Turbidity
|
SB
|
Disinfect Water
(Chlorination, Irradiation)
|
Coliform
|
SA
|
Spray Water Through Fountains to Remove Volatile Organic Compounds
(Aeration)
|
Coliform
|
SA
|
This item was scored in 5 parts:
Part A: Sedimentation
Part B: Neutralization/Oxidation-Reduction/Precipitation/Other
Part C: Filtration/Biodegradation
Part D: Chlorination/Irradiation
Part E: Aeration
Part A
Complete:
Student response consists of two parts shown in Table 2: Row 1 (Sedimentation), Columns 2 and 3.
- Indicates in Column 2 at least one of the correct pollutants turbidity (e.g., eroded soil particles, animal waste) that could be removed or reduced by allowing the water to stand in a settling tank, and no incorrect pollutants.
- Indicates in Column 3 any site for which the listed pollutant exceeds standards according to the student’s response in Tables 1A and1B.
Blank in Column 3 is taken as “none”, and is credited if the pollutant is indicated in both Table 1A and Table 1B as not exceeding the maximum allowed levels.
Partial:
Student response is correct for Column 2 or Column 3.
Unsatisfactory/Incorrect:
Student response is inadequate or incorrect.
Part B
Complete:
- Indicates in Column 2 at least one of the correct pollutants nitrate, pH, chloride, iron, copper, lead, or mercury that could be removed or reduced by treating the water with chemicals, and no incorrect pollutants.
- Indicates in Column 3 any site where the listed pollutant exceeds standards according to the student’s response in Tables 1A and1B.
Blank in Column 3 is taken as “none”, and is credited if the pollutant is indicated in both Table 1A and Table 1B as not exceeding the maximum allowed levels.
Partial:
Student response is correct for Column 2 or Column 3.
Unsatisfactory/Incorrect:
Student response is inadequate or incorrect.
Part C
Complete:
Student response consists of two parts shown in Table 2: Row 3 (Filtration/Biodegradation), Columns 2 and 3.
- Indicates in Column 2 at least one of the correct pollutants total coliform or turbidity that could be removed or reduced by filtration/biodegradation, and no incorrect pollutants.
- Indicates in Column 3 any site for which the listed pollutant exceeds standards according to the student’s response in Tables 1A and1B.
Blank in Column 3 is taken as “none”, and is credited if the pollutant is indicated in both Table 1A and Table 1B as not exceeding the maximum allowed levels.
Partial:
Student response is correct for Column 2 or Column 3.
Unsatisfactory/Incorrect:
Student response is inadequate or incorrect.
Part D: Chlorination/Irradiation
Complete:
Student response consists of two parts shown in Table 2: Row 4 (Chlorination/Irradiation), Columns 2 and 3.
- Indicates in Column 2 the correct pollutant total coliform that could be removed or reduced by disinfecting the water, and no incorrect pollutants.
- Indicates in Column 3 any site for which the listed pollutant exceeds standards according to the student’s response in Tables 1A and1B.
Blank in Column 3 is taken as “none”, and is credited if the pollutant is indicated in both Table 1A and Table 1B as not exceeding the maximum allowed levels.
Partial:
Student response is correct for Column 2 or Column 3.
Unsatisfactory/Incorrect:
Student response is inadequate or incorrect.
Part E
Complete:
Student response consists of two parts shown in Table 2: Row 5 (Aeration), Columns 2 and 3.
- Indicates in Column 2 the correct pollutant benzene that could be removed or reduced by aerating the water, and no incorrect pollutants.
- Indicates in Column 3 any site for which the listed pollutant exceeds the standards according to the student’s response in Tables 1A and1B.
Blank in Column 3 is taken as “none”, and is credited if the pollutant is indicated in both Table 1A and Table 1B as not exceeding the maximum allowed levels.
Partial:
Student response is correct for Column 2 or Column 3.
Unsatisfactory/Incorrect:
Student response is inadequate or incorrect.
Composite Score:
Student response received one of five possible composite scores (Complete, Satisfactory, Essential, Partial, Unsatisfactory/Incorrect) based on the student's combined performance on Parts A, B, C, D, and E of the item. For example, a student response Complete for Part A, Complete for Part B, Complete for Part C, Complete for Part D, and Partial for Part E received a composite score of Satisfactory.
Composite Score
|
Score for Parts A, B, C, D, E
|
Complete
|
Complete for all 5 parts
|
Complete for 4 parts and Partial for 1 part
|
Satisfactory
|
Complete for 4 parts and Unsatisfactory/Incorrect for 1 part
|
Complete for 3 parts and Partial for 2 parts
|
Complete for 3 parts, Partial for 1 part, and Unsatisfactory/Incorrect for 1 part
|
Complete for 2 parts and Partial for 3 parts
|
Essential
|
Complete for 3 parts and Unsatisfactory/Incorrect for 2 parts
|
Complete for 2 parts, Partial for 2 parts, and Unsatisfactory/Incorrect for 1 part
|
Complete for 1 part and Partial for 4 parts
|
Complete for 1 part, Partial for 3 parts, and Unsatisfactory/Incorrect for 1 part
|
Partial for 5 parts
|
Complete for 2 parts and Unsatisfactory/Incorrect for 3 parts
|
Complete for 1 part, Partial for 2 parts, and Unsatisfactory/Incorrect for 2 parts
|
Partial for 4 parts, and Unsatisfactory/Incorrect for 1 part
|
Partial
|
Complete for 1 part, Partial for 1 part, and Unsatisfactory/Incorrect for 3 parts
|
Partial for 3 parts and Unsatisfactory/Incorrect for 2 parts
|
Complete for 1 part and Unsatisfactory/Incorrect for 4 parts
|
Partial for 2 parts and Unsatisfactory/Incorrect for 3 parts
|
Partial for 1 part and Unsatisfactory/Incorrect for 4 parts
|
Unsatisfactory/Incorrect
|
Unsatisfactory/Incorrect for 5 parts
|
Percentage of twelfth-grade students in each response category: 2009
Complete |
Satisfactory |
Essential |
Partial |
Unsatisfactory/ incorrect |
Omitted |
2 |
8 |
30 |
31 |
13 |
16 |
Which of the potential town sites is a better location for building a new town?
A. Town Site A
B. Town Site B
C. Either Town Site A or Town Site B (neither site would be better than the other)
Support your choice using information from Table 1A, Table 1B, and Table 2.
Sample correct student response:
Complete:
Student response selects (A) Town Site A, (B) Town Site B, or (C) Either Town Site A or Town Site B. Response justifies the selection by discussing the level of at least one specific pollutant at one site or both sites (required for (C) selection) consistent with student’s results in Tables 1A and/or 1B. Response also addresses at least one specific pollutant that would be treated in a water treatment plan, and this pollutant appears in student’s Table 2 in one of the water treatment process steps.
Partial:
Student response selects (A) Town Site A, ( B) Town Site B, or (C) Either Town Site A or Town Site B. Response justifies the selection by discussing the level of at least one specific pollutant at one site or both sites (required for (C) selection) consistent with student’s results in Tables 1A and/or 1B. Response does not discuss treating any specific pollutant, or discussion is inconsistent with Tables 1A and/or 1B.
OR
Student response selects (A) Town Site A, (B) Town Site B, or (C) Either Town Site A or Town Site B. Response does not justify the selection, but addresses at least one specific pollutant that would be treated in a water treatment plan, and this pollutant appears in student’s Table 2 in one of the water treatment process steps.
OR
Student response selects (A) Town Site A, (B) Town Site B, or (C) Either Town Site A or Town Site B. Response justifies the selection by comparing the levels of pollutants at both sites without mentioning specific pollutants. Response is evaluated based on comparing the pollutants exceeding maximum allowed levels consistent with student’s results in Table 1A and Table 1B, and/or comparing the pollutants for which treatment is needed at the two sites consistent with student’s results in Table 1A, Table 1B, and Table 2.
Unsatisfactory/Incorrect:
Student response is inadequate or incorrect.
Percentage of twelfth-grade students in each response category: 2009
Complete |
Partial |
Unsatisfactory/ incorrect |
Omitted |
11 |
50 |
39 |
# |
Describe specific physical, chemical, and biological processes you would need to use in the water treatment plant at the site(s) you chose. Refer to Table 2 in your answer.
Sample correct student response:
Student response identifies one or more pollutants and provides a valid description of one or more of the steps that are needed to remove the pollutant. The pollutant and the step need to match with each other to receive full credit.
For example, allowing water to stand in a settling tank (Sedimentation) is a (physical) process that allows heavy particles (turbidity) to settle to the bottom of the settling tank. Disinfecting water (Chlorination) is a (chemical) process that kills potentially harmful microorganisms (total coliforms) in the water.
Partial:
Student response identifies one or more pollutants and provides an incomplete description of one or more of the processes that are needed to remove the pollutant(s). Response may paraphrase the information in Column 1 of Table 2.
Unsatisfactory/Incorrect:
Student response is inadequate or incorrect.
Percentage of twelfth-grade students in each response category: 2009
Complete |
Partial |
Unsatisfactory/ incorrect |
Omitted |
6 |
20 |
71 |
# |
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2009 Science Assessment.