Exam Study Guide - March 2021

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By Rick Lallish

When defining confined spaces in your facility, who makes the determination whether the space is nonpermit confined space or permit-required confined space?


B. Local health department

C. Operator

D. Employer

Answer: D. Confined spaces are very common in the water/wastewater industry. OSHA standard 29 CFR 1910.146 states the employer evaluates the workplaces and makes the determination of what type of confined space each one is. The definition of confined spaces can be found in the standard. If the space is defined as a permit-required confined space, then the employer must inform the employees of its existence, its location and hazards it poses. These procedures are important for the operator to understand, especially when performing duties in confined spaces. Remember, safety first. More information may be found in the OSHA standard, 29 CFR 1910.146 or the OWP CSU-Sacramento textbook: Operation and Maintenance of Wastewater Collection Systems Vol. 1 (Eighth Ed.), Chapter 3.


By Drew Hoelscher

Using the table below, what finished water quality parameter(s) should the operator try to improve?

Analyte Concentration

Fluoride 0.7 mg/L

Iron 0.6 mg/L

Manganese 0.04 mg/L

Calcium as CaCO3 85 mg/L

Magnesium as CaCO3 35 mg/L

Nitrate - N 4 mg/L

Chloride 200 mg/L

A. Fluoride is too low and nitrate is too high

B. Manganese, calcium and magnesium are above the SMCL

C. Iron is above the SMCL

D. Chloride is extremely high

Answer: C. Iron is listed on the National Secondary Maximum Contaminant Level (SMCL) list at 0.3 mg/L. At or above this level, iron may cause discolored water complaints at the point of use and/or staining on plumbing fixtures. The SMCLs are unenforceable and are only set as guidelines for public water supplies. More information about National Primary Maximum Contaminant Levels and National SMCLs can be obtained at https://www.epa.gov/sites/production/files/2016-06/documents/npwdr_complete_table.pdf.

About the authors

Rick Lallish is water pollution control program director and Drew Hoelscher is program director of drinking water operations at the Environmental Resources Training Center of Southern Illinois University Edwardsville.  


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