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Question 1
What is the EPA stream water quality standard for fecal coliform?
Correct Answer:
2 colonies per 1 ml
Explanation:
The EPA stream water quality standard for fecal coliform is set at a threshold to help ensure safe water practices and protect public health, especially in areas where water is used for recreation or as a drinking water source. The correct standard, which is 2 colonies per 1 ml, is established based on the understanding that higher concentrations of fecal coliform bacteria can indicate the presence of harmful pathogens, suggesting that the water may be contaminated with fecal matter from animals or humans. Maintaining this standard helps mitigate the risk of waterborne diseases. When fecal coliform levels exceed this threshold, it prompts further investigation and possible remediation efforts to address the source of contamination, thereby maintaining water quality and safety for human use. In terms of the incorrect options, lower colony counts would not reflect the necessary concern for public health, while higher counts would breach the standard set by the EPA, indicating unacceptable levels of contamination. Therefore, understanding the implications of the 2 colonies per 1 ml standard is critical for environmental monitoring and public safety.
Question 2
Which residential feature can increase the load on a septic system?
Correct Answer:
Additional bathrooms
Explanation:
The presence of additional bathrooms in a residential setting can significantly increase the load on a septic system. This is because each bathroom typically includes fixtures such as sinks, toilets, showers, and bathtubs, all of which contribute to the overall wastewater generated by the household. When a home adds more bathrooms, the consumption of water rises, leading to a larger volume of wastewater entering the septic system. An increase in wastewater can overwhelm the septic system, especially if it is not designed to handle the additional flow. This might lead to issues such as inefficiencies in treatment, reduced functionality, or even system failure if the capacity is exceeded. Therefore, understanding the impact of household features, such as multiple bathrooms, on septic systems is vital for proper maintenance and management of wastewater. In contrast, features like garden irrigation or high-efficiency appliances generally contribute to a more controlled use of water, and low-water use fixtures can even help reduce the load on a septic system by minimizing the volume of wastewater produced. Thus, the correct answer highlights the importance of recognizing how increased water sources in a home can affect septic system operations.
Question 3
How does disinfection work in wastewater treatment?
Correct Answer:
By using chemicals or UV light to kill pathogens
Explanation:
Disinfection in wastewater treatment primarily works by using chemicals or UV light to kill pathogens. This process is essential to ensure that the water is safe for discharge into the environment or for potential reuse. Chemicals such as chlorine, ozone, or hydrogen peroxide can be added to the water to eliminate microorganisms, including bacteria, viruses, and protozoa, which can pose health risks if left untreated. Ultraviolet (UV) light is another effective method of disinfection, where pathogens are exposed to UV light, rendering them inactive and incapable of causing disease. This method is increasingly favored due to its ability to avoid the chemical residues that can remain in water after treatment. Disinfection does not involve increasing the water temperature, filtering out large particles, or adding minerals. Instead, its primary focus is on targeting harmful microorganisms to protect public health and the environment.
Question 4
Ozone is effective against which of the following contaminants?
Correct Answer:
Amoebic cysts, bacteria, and viruses
Explanation:
Ozone is a powerful oxidizing agent that is particularly effective at inactivating pathogens such as bacteria, viruses, and amoebic cysts in water. Its strong oxidizing properties enable it to disrupt the cell walls of microorganisms, leading to their inactivation or destruction. This makes ozone an excellent choice for disinfection in both wastewater and potable water treatment processes. While other contaminants like heavy metals and salts, chlorinated hydrocarbons, and suspended solids can be addressed through different water treatment methods, they do not have the same susceptibility to ozone as microbial contaminants. Heavy metals require removal techniques such as precipitation or ion exchange, while suspended solids and sediment are typically managed through filtration or sedimentation processes. Chlorinated hydrocarbons may require advanced oxidation or other chemical methods for effective removal. Thus, option B correctly identifies the types of contaminants that ozone effectively targets in water treatment.
Question 5
How does nutrient removal affect wastewater treatment efficiency?
Correct Answer:
It prevents eutrophication and improves overall efficiency
Explanation:
Nutrient removal plays a crucial role in enhancing wastewater treatment efficiency, particularly in preventing eutrophication in receiving water bodies. When wastewater is treated without adequate nutrient removal, excess nutrients such as nitrogen and phosphorus can lead to the proliferation of algae in water bodies. This process, known as eutrophication, can severely degrade water quality, deplete oxygen levels, and harm aquatic ecosystems. By effectively removing these nutrients from wastewater, treatment systems help prevent the over-enrichment of water bodies. This not only improves the health of aquatic environments but also decreases the need for additional treatments to address the consequences of nutrient overload, thus improving the efficiency of the overall treatment system. In essence, nutrient removal contributes to a more sustainable and effective approach in wastewater management, ensuring that treated effluent does not adversely impact the waterways into which it is discharged.
Question 1
Exam overview

About this Exam

The Registered Environmental Health Specialist/Registered Sanitarian (REHS/RS) credential is the premier certification for professionals dedicating their careers to environmental health and protection. This prestigious designation, administered by the National Environmental Health Association (NEHA), signals to employers and the public that you possess the knowledge, skills, and commitment necessary to manage diverse environmental health challenges.

This specific practice material is meticulously designed for candidates preparing for the REHS/RS exam, with a dedicated focus on the complex critical domains of Potable Water and Wastewater management. Whether you are a recent graduate or an experienced professional looking to certify your skills, mastering these domains is essential for exam success.

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Additional Information

What the Course Entails and Exam Details

This targeted preparation resource focuses entirely on the critical water-related competencies required for the REHS/RS credential. Candidates must demonstrate comprehensive knowledge across these areas:

Potable Water Supply and Quality

  • Source Water Protection: Understanding groundwater and surface water hydrology, geology, and methods to prevent contamination of drinking water sources.

  • Treatment Processes: Detailed knowledge of coagulation, flocculation, sedimentation, filtration, and disinfection methods (e.g., chlorination, UV, ozone) for public and individual systems.

  • Distribution and Storage: Regulations and best practices for system design, cross-connection control, backflow prevention, and maintaining chlorine residuals.

  • Monitoring and Sampling: Compliance with the Safe Drinking Water Act (SDWA), sampling techniques for microbiological and chemical contaminants, and interpreting lab results.

Wastewater Management and Treatment

  • Onsite Wastewater Treatment Systems (OWTS): Soil science basics, site evaluation (perc tests), design and inspection of septic tanks, absorption fields, and advanced treatment units.

  • Municipal Wastewater Treatment: Understanding primary, secondary (activated sludge, trickling filters), and tertiary treatment stages.

  • Collection Systems and Maintenance: Basics of sewer design, lift stations, and managing inflow/infiltration (I&I).

  • Residuals Management: Regulations for the treatment, beneficial reuse, and disposal of sewage sludge and biosolids.


What to Expect in the Final Exam

The full REHS/RS examination is a rigorous assessment administered by NEHA. To succeed, candidates must understand the final exam structure:

  • Exam Format: The REHS/RS exam consists of 225 multiple-choice questions.

  • Time Limit: Candidates are allowed a total of four (4) hours to complete the entire examination.

  • Scoring: NEHA uses a scaled scoring system. While the raw score needed to pass can vary slightly depending on the difficulty of the specific exam form, the scaled passing score is consistently set at 650.

  • Domain Weighting: The water-related domains represent a significant portion of the total exam. While the exam covers many environmental health topics (e.g., food safety, institutions), the combined weighting for Potable Water and Wastewater usually falls between 20% and 30% of the total raw score, making mastery of these topics non-negotiable.


How to Study and Exam Centers

Preparation for the REHS/RS exam requires a structured approach and dedication. Use these strategies:

  • Utilize the NEHA Study Guide: The REHS/RS Study Guide (currently in its 5th edition) is an indispensable resource. It provides comprehensive outlines of all domains and suggested references for deep study.

  • Focus on the References: NEHA lists the source texts used to develop the exam questions. Prioritize reading key EPA manuals on small water systems and onsite wastewater treatment.

  • Practice with Purpose: Do not just memorize answers. Use practice tests, like this one, to identify your weak points in specific areas, such as calculating dosage or interpreting soil logs.

Where to Take the Exam

The REHS/RS exam is offered globally. Candidates have flexible options for scheduling:

  • Pearson VUE Testing Centers: This is the most common method. Once NEHA approves your application, you will receive an authorization to test (ATT) letter, allowing you to schedule your exam at any authorized Pearson VUE professional testing center worldwide.

  • NEHA Annual Educational Conference (AEC): NEHA typically offers in-person testing in conjunction with their annual conference.


Job Opportunities from the Course

Earning the REHS/RS credential dramatically improves job prospects and career mobility. The certification is recognized across public and private sectors.

Potential job titles and career paths enabled by this certification include:

  • Environmental Health Specialist (Local, State, or Federal Government)

  • Registered Sanitarian

  • Public Health Inspector

  • Water Quality Specialist (Municipal Utilities)

  • Environmental Compliance Officer

  • Onsite Wastewater Inspector/Designer

  • Environmental Health Consultant (Private Sector)

  • Consumer Safety Officer (FDA/USDA)

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