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Difficulty: MediumNegative Detail Identification

Reverse Osmosis Water Purification Units (ROWPU) provide potable water in field operations by filtering fresh, brackish, or saline water sources. Incoming raw water first undergoes chemical pretreatment with coagulants and passes through multimedia sand filters to eliminate suspended solids and turbidity. Next, cartridge filters capture finer particulate matter before high-pressure pumps force the water through semipermeable polyamide membranes that block dissolved salts, heavy metals, and biological pathogens. Treated water is subsequently chlorinated to maintain residual disinfection during storage. However, ROWPUs cannot treat water contaminated with petroleum products, as hydrocarbons rapidly degrade the reverse osmosis membranes.

According to the passage, which of the following statements about the ROWPU is NOT true?

  1. A
    Chemical coagulants and sand filters are used during pretreatment to reduce turbidity.
  2. B
    Cartridge filters remove fine particulate matter before high-pressure pumping occurs.
  3. Reverse osmosis membranes are utilized to extract dissolved petroleum hydrocarbons.Answer
  4. D
    Chlorine is introduced after membrane filtration to maintain residual disinfection.

Answer

Reverse osmosis membranes are utilized to extract dissolved petroleum hydrocarbons.
The statement claiming that reverse osmosis membranes are utilized to extract dissolved petroleum hydrocarbons is directly contradicted by the passage. The text explicitly points out that ROWPUs cannot treat petroleum-contaminated water because hydrocarbons rapidly degrade the membranes.

Step-by-Step Solution

1
Analyze the question stem to identify the core task and qualifiers.
The capitalized qualifier 'NOT true' requires identifying the single statement contradicted by or absent from the text, while eliminating supported details.
Negative detail questions test the ability to isolate inaccurate statements from factual text references.
2
Cross-reference each option against the stimulus passage.
The passage states that pretreatment uses coagulants and sand filters for turbidity, cartridge filters capture fine particulates prior to high-pressure pumps, and chlorine maintains residual disinfection. However, it notes that petroleum cannot be treated because hydrocarbons destroy the membranes.
Systematic verification prevents selecting true statements that merely repeat passage facts.
3
Select the statement that directly contradicts the passage.
The claim that membranes are utilized to extract dissolved petroleum hydrocarbons directly contradicts the text's assertion that petroleum degrades the membranes and cannot be treated.
The contradicted statement represents the only inaccurate assertion among the choices.

Key Concept

Negative Detail Identification
Estimated Time:1m 0s
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Negative Detail Identification

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