Texas Wastewater Class A (Test 3)
(Updated for 2026) Exam Prep Pack | A+ Questions
130+
& Verified Answers
VERIFIED ANSWERS
Question 1
What removes Total Suspended Solids from a sample (TSS)
Correct Answer
filtration
Rationale:
Filtration is the correct process because it involves passing the sample through a physical barrier, such as a membrane or filter paper, that traps
and retains the suspended particles, effectively removing them from the sample. This process exploits the physical differences in size between
the suspended particles and the liquid, allowing the liquid to pass through while retaining the particles as Total Suspended Solids.
Question 2
What chapter of the Texas Water Code gives T C E Q authority to control discharges in Texas.
Correct Answer
Chapter 26
Rationale:
The Texas Water Code grants the Texas Commission on Environmental Quality (TCEQ) its authority to control discharges in Texas, and Chapter
26 specifically addresses waste discharge prohibitions and requirements, underscoring its relevance to discharge regulation. By examining the
specific provisions and regulatory powers outlined in Chapter 26, it becomes clear that this chapter is the primary source of TCEQ's authority in
controlling discharges in Texas.
Question 3
Inorganic solids include
Correct Answer
sand, grit and minerals
Rationale:
Inorganic solids are non-living, non-carbon-based substances that are naturally occurring or synthesized, which is why "sand, grit and
minerals" are included in this category because they fit this description. This classification is based on the composition and origin of these
substances, rather than their biological or organic properties.
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,Question 4
Organic solids include
Correct Answer
organic materials from plants, animals or humans
Rationale:
The term "organic" in chemistry refers to compounds that contain carbon, often in combination with other elements, and are typically derived
from living organisms such as plants, animals, and humans. This definition is a key concept in distinguishing organic solids from inorganic
solids, which are typically derived from non-living sources like minerals.
Question 5
A good plant influent pH is about
Correct Answer
7.2
Rationale:
A good plant influent pH for wastewater treatment is typically considered to be around 7.2 because this pH range allows for optimal microbial
growth and activity, enabling the effective breakdown and removal of organic pollutants. This pH also helps to control the precipitation of
heavy metals and other inorganic compounds, preventing their accumulation in the treatment process and potentially toxic byproducts.
Question 6
A simple method for indicating when to waste sludge is
Correct Answer
30 minute settling test
Rationale:
The 30-minute settling test is a simple method for indicating when to waste sludge because it allows wastewater treatment operators to
visually observe the rate of solids settling to the bottom of a container, providing a clear indication of when the sludge is sufficiently settled to
be removed. This method is preferred due to its ease of use, low cost, and immediate visual feedback, making it an effective tool for
determining when to waste sludge in a wastewater treatment process.
Question 7
What is the expected organic loading of a stabilization pond and what is the detention time in days?
Correct Answer
35 pounds, of B O D, per acre, per day, and a detention time of 30 Days
Rationale:
The term "35 pounds, of B O D, per acre, per day" refers to the expected organic loading of a stabilization pond, which is a measure of the
amount of organic matter (measured as biochemical oxygen demand or BOD) that a given area of the pond can handle per day, typically
expressed in pounds per acre per day. The detention time of 30 days represents the average time it takes for wastewater to remain in the pond
and undergo treatment, allowing for adequate time for microbial decomposition and stabilization to occur.
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,Question 8
Calcium Hypochlorite or HTH, is a
Correct Answer
strong Oxidizer and reacts violently with oil and hydro carbons.
Rationale:
This answer is correct because it identifies a critical characteristic of Calcium Hypochlorite or HTH, which is a strong oxidizer that poses a
significant risk when it comes into contact with oil and hydrocarbons due to its violent reaction. This is a crucial aspect of handling and storing
HTH, emphasizing the importance of proper safety precautions and equipment to prevent accidents.
Question 9
When added to water what does chlorine form
Correct Answer
it forms Hypochlorite, and Hydrochloric acid
Rationale:
When chlorine is added to water, it reacts with the water molecules to form hypochlorous acid (HOCl) and hydrochloric acid (HCl) because
chlorine is highly reactive and tends to gain an electron to form a stable compound, and the oxygen and hydrogen in water provide the
necessary electrons for this reaction. This reaction is a classic example of an acid-base reaction, where chlorine acts as an oxidizing agent and
water acts as a reducing agent.
Question 10
When ammonia is present in wastewater and
reacts with chlorine what is formed
Correct Answer
When ammonia is present in wastewater, and
reacts with chlorine, Chloramines are formed.
Rationale:
The formation of chloramines from the reaction between ammonia and chlorine in wastewater is a well-documented chemical process,
supported by established chemical reactions and principles. Specifically, the reaction between ammonia (NH3) and chlorine (Cl2) in the
presence of water produces a compound called chloramine (NH2Cl or NHCl2), which is a stable and commonly encountered disinfection
byproduct in wastewater treatment.
Question 11
Besides disinfection, chlorine has other uses
at the wastewater treatment plant such as
Correct Answer
Reduces BOD, Odor, Algae growth, Helps with Grease
Rationale:
Chlorine is effective in reducing Biochemical Oxygen Demand (BOD) because it breaks down organic matter, thereby eliminating excess
nutrients that contribute to algae growth and unpleasant odors. By controlling these factors, chlorine also helps to prevent the buildup of
grease, which is often associated with wastewater.
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, Question 12
TCEQ allows the reuse of wastewater, some of these include
Correct Answer
Irrigation, aquifer recharge, cooling towers and fire protection
Rationale:
The TCEQ allows the reuse of wastewater for non-potable purposes such as irrigation, where the water is used to water plants and crops, and
aquifer recharge, which involves recharging underground water sources, both of which are beneficial to the environment. Additionally,
wastewater can also be reused for industrial purposes like cooling towers and fire protection, where it serves as a cost-effective and
sustainable alternative to potable water sources.
Question 13
All reclaimed water piping must be the color
Correct Answer
purple
Rationale:
In the plumbing industry, specific color-coding is used to identify the type of water flowing through pipes, and purple is typically reserved for
reclaimed or recycled water. This color-coding system helps plumbers, maintenance personnel, and inspectors quickly determine the type of
water being handled, ensuring proper handling and protection of public health.
Question 14
When a municipal wastewater effluent has a high nitrate
level, and low ammonia level, this most likely means
Correct Answer
a high degree of aerobic treatment
Rationale:
A high degree of aerobic treatment is the correct answer because aerobic treatment processes, such as activated sludge, favor the conversion
of ammonia into nitrate through nitrification, resulting in high nitrate levels and low ammonia levels in the effluent. This process relies on the
presence of oxygen to support the growth of nitrifying bacteria, which are responsible for converting ammonia into nitrate.
Question 15
Total solids in wastewater are the sum of
Correct Answer
Settleable and volatile solids
Rationale:
The key concept here is that "total solids" encompasses all forms of solids present in wastewater, which can be further categorized into
settleable and volatile solids. Settleable solids are those that can settle at the bottom of a container due to gravity, such as suspended solids,
while volatile solids are those that can be burned off or vaporized, like organic matter, resulting in the complete decomposition of the solids.
Trusted by thousands of students and professionals worldwide Page 4 of 35
(Updated for 2026) Exam Prep Pack | A+ Questions
130+
& Verified Answers
VERIFIED ANSWERS
Question 1
What removes Total Suspended Solids from a sample (TSS)
Correct Answer
filtration
Rationale:
Filtration is the correct process because it involves passing the sample through a physical barrier, such as a membrane or filter paper, that traps
and retains the suspended particles, effectively removing them from the sample. This process exploits the physical differences in size between
the suspended particles and the liquid, allowing the liquid to pass through while retaining the particles as Total Suspended Solids.
Question 2
What chapter of the Texas Water Code gives T C E Q authority to control discharges in Texas.
Correct Answer
Chapter 26
Rationale:
The Texas Water Code grants the Texas Commission on Environmental Quality (TCEQ) its authority to control discharges in Texas, and Chapter
26 specifically addresses waste discharge prohibitions and requirements, underscoring its relevance to discharge regulation. By examining the
specific provisions and regulatory powers outlined in Chapter 26, it becomes clear that this chapter is the primary source of TCEQ's authority in
controlling discharges in Texas.
Question 3
Inorganic solids include
Correct Answer
sand, grit and minerals
Rationale:
Inorganic solids are non-living, non-carbon-based substances that are naturally occurring or synthesized, which is why "sand, grit and
minerals" are included in this category because they fit this description. This classification is based on the composition and origin of these
substances, rather than their biological or organic properties.
Trusted by thousands of students and professionals worldwide Page 1 of 35
,Question 4
Organic solids include
Correct Answer
organic materials from plants, animals or humans
Rationale:
The term "organic" in chemistry refers to compounds that contain carbon, often in combination with other elements, and are typically derived
from living organisms such as plants, animals, and humans. This definition is a key concept in distinguishing organic solids from inorganic
solids, which are typically derived from non-living sources like minerals.
Question 5
A good plant influent pH is about
Correct Answer
7.2
Rationale:
A good plant influent pH for wastewater treatment is typically considered to be around 7.2 because this pH range allows for optimal microbial
growth and activity, enabling the effective breakdown and removal of organic pollutants. This pH also helps to control the precipitation of
heavy metals and other inorganic compounds, preventing their accumulation in the treatment process and potentially toxic byproducts.
Question 6
A simple method for indicating when to waste sludge is
Correct Answer
30 minute settling test
Rationale:
The 30-minute settling test is a simple method for indicating when to waste sludge because it allows wastewater treatment operators to
visually observe the rate of solids settling to the bottom of a container, providing a clear indication of when the sludge is sufficiently settled to
be removed. This method is preferred due to its ease of use, low cost, and immediate visual feedback, making it an effective tool for
determining when to waste sludge in a wastewater treatment process.
Question 7
What is the expected organic loading of a stabilization pond and what is the detention time in days?
Correct Answer
35 pounds, of B O D, per acre, per day, and a detention time of 30 Days
Rationale:
The term "35 pounds, of B O D, per acre, per day" refers to the expected organic loading of a stabilization pond, which is a measure of the
amount of organic matter (measured as biochemical oxygen demand or BOD) that a given area of the pond can handle per day, typically
expressed in pounds per acre per day. The detention time of 30 days represents the average time it takes for wastewater to remain in the pond
and undergo treatment, allowing for adequate time for microbial decomposition and stabilization to occur.
Trusted by thousands of students and professionals worldwide Page 2 of 35
,Question 8
Calcium Hypochlorite or HTH, is a
Correct Answer
strong Oxidizer and reacts violently with oil and hydro carbons.
Rationale:
This answer is correct because it identifies a critical characteristic of Calcium Hypochlorite or HTH, which is a strong oxidizer that poses a
significant risk when it comes into contact with oil and hydrocarbons due to its violent reaction. This is a crucial aspect of handling and storing
HTH, emphasizing the importance of proper safety precautions and equipment to prevent accidents.
Question 9
When added to water what does chlorine form
Correct Answer
it forms Hypochlorite, and Hydrochloric acid
Rationale:
When chlorine is added to water, it reacts with the water molecules to form hypochlorous acid (HOCl) and hydrochloric acid (HCl) because
chlorine is highly reactive and tends to gain an electron to form a stable compound, and the oxygen and hydrogen in water provide the
necessary electrons for this reaction. This reaction is a classic example of an acid-base reaction, where chlorine acts as an oxidizing agent and
water acts as a reducing agent.
Question 10
When ammonia is present in wastewater and
reacts with chlorine what is formed
Correct Answer
When ammonia is present in wastewater, and
reacts with chlorine, Chloramines are formed.
Rationale:
The formation of chloramines from the reaction between ammonia and chlorine in wastewater is a well-documented chemical process,
supported by established chemical reactions and principles. Specifically, the reaction between ammonia (NH3) and chlorine (Cl2) in the
presence of water produces a compound called chloramine (NH2Cl or NHCl2), which is a stable and commonly encountered disinfection
byproduct in wastewater treatment.
Question 11
Besides disinfection, chlorine has other uses
at the wastewater treatment plant such as
Correct Answer
Reduces BOD, Odor, Algae growth, Helps with Grease
Rationale:
Chlorine is effective in reducing Biochemical Oxygen Demand (BOD) because it breaks down organic matter, thereby eliminating excess
nutrients that contribute to algae growth and unpleasant odors. By controlling these factors, chlorine also helps to prevent the buildup of
grease, which is often associated with wastewater.
Trusted by thousands of students and professionals worldwide Page 3 of 35
, Question 12
TCEQ allows the reuse of wastewater, some of these include
Correct Answer
Irrigation, aquifer recharge, cooling towers and fire protection
Rationale:
The TCEQ allows the reuse of wastewater for non-potable purposes such as irrigation, where the water is used to water plants and crops, and
aquifer recharge, which involves recharging underground water sources, both of which are beneficial to the environment. Additionally,
wastewater can also be reused for industrial purposes like cooling towers and fire protection, where it serves as a cost-effective and
sustainable alternative to potable water sources.
Question 13
All reclaimed water piping must be the color
Correct Answer
purple
Rationale:
In the plumbing industry, specific color-coding is used to identify the type of water flowing through pipes, and purple is typically reserved for
reclaimed or recycled water. This color-coding system helps plumbers, maintenance personnel, and inspectors quickly determine the type of
water being handled, ensuring proper handling and protection of public health.
Question 14
When a municipal wastewater effluent has a high nitrate
level, and low ammonia level, this most likely means
Correct Answer
a high degree of aerobic treatment
Rationale:
A high degree of aerobic treatment is the correct answer because aerobic treatment processes, such as activated sludge, favor the conversion
of ammonia into nitrate through nitrification, resulting in high nitrate levels and low ammonia levels in the effluent. This process relies on the
presence of oxygen to support the growth of nitrifying bacteria, which are responsible for converting ammonia into nitrate.
Question 15
Total solids in wastewater are the sum of
Correct Answer
Settleable and volatile solids
Rationale:
The key concept here is that "total solids" encompasses all forms of solids present in wastewater, which can be further categorized into
settleable and volatile solids. Settleable solids are those that can settle at the bottom of a container due to gravity, such as suspended solids,
while volatile solids are those that can be burned off or vaporized, like organic matter, resulting in the complete decomposition of the solids.
Trusted by thousands of students and professionals worldwide Page 4 of 35
