Question 1
________ combines aeration basin and secondary clarifier into single unit.
A. Primary clarifier
B. Aerobic unit
C. Sequential batch reactor
D. Secondary clarifier
View Answer
Answer: Option C
Explanation:
An SBR essentially combines the aeration basin and the secondary clarifier of a traditional activated sludge system into a single basin. While the system is in aeration mode, air is supplied by the aeration system and influent enters the basin.
Question 2
Activated sludge process can be used for treating all types of wastewater.
A. True
B. False
View Answer
Answer: Option B
Explanation:
Activated sludge systems are suspended-growth type and are used in conventional high-tech wastewater treatment plants to treat almost every wastewater influent as long as it is biodegradable.
Question 3
Activated sludge process degrade organics and _________
A. Improve nutrients
B. Remove nutrients
C. Remove odour
D. Remove taste
View Answer
Answer: Option B
Explanation:
Highly concentrated micro-organisms are used to degrade organics and remove nutrients from wastewater to produce a high quality effluent that is activated sludge process.
Question 4
Activated sludge process uses micro-organisms to degrade organics from wastewater.
A. True
B. False
View Answer
Answer: Option A
Explanation:
An activated sludge process refers to a multi-chamber reactor unit that makes use of highly concentrated micro-organisms to degrade organics and remove nutrients from wastewater to produce a high quality effluent.
Question 5
For the conversion of particulate organics through Activated Sludge Process (ASP) what would be the Solid retention time considered?
A. 18 hours
B. 1-2 days
C. 2-4 days
D. 5 days
View Answer
Answer: Option C
Explanation:
For the conversion of particulate organics through ASP, the Solid retention time considered would be 2-4 days. Particulate organic carbon is defined as those materials that can pass through a filter which is of size 0.7 to 0.22 um. This usually constitutes soil organic matter that includes plant material, pollen etc.
Question 6
For the removal of BOD through Activated Sludge Process (ASP) what would be the Solid retention time considered?
A. 18 hours
B. 1-2 days
C. 10 hrs
D. 3 days
View Answer
Answer: Option B
Explanation:
For the removal of BOD through ASP, the solid retention time considered is 1-2 days. However, this depends on the temperature. In case the temperature is very low, then the solid retention time considered would be around 5-6 days.
Question 7
For the removal of nitrogen completely through Activated Sludge Process (ASP) what would be the Solid retention time considered?
A. 3-18 days
B. 1-2 days
C. 12 hours
D. 18 hours
View Answer
Answer: Option B
Explanation:
For the complete removal of Nitrogen through ASP, the solid retention time considered is 3-18 days. However, this depends on the temperature. In case the temperature is very low, then the solid retention time considered would be around 15-18 days. For higher temperatures, lower solid retention time is considered.
Question 8
For the development of flocculent biomass for treating industrial water through Activated Sludge Process (ASP) what would be the Solid retention time considered?
A. 18 hours
B. 3-5 days
C. 20 hrs
D. 1-3 days
View Answer
Answer: Option D
Explanation:
For the development of flocculent biomass for treating industrial water through Activated Sludge Process (ASP), the solid retention time considered is 3-5 days. This is a little higher than that of the Solid retention time required to treat domestic waste water. The difference is because the industrial waste water constitutes higher BOD values.
Question 9
For the removal of phosphorous through Activated Sludge Process (ASP) what would be the Solid retention time considered?
A. 18 hours
B. 1-2 days
C. 10 hrs
D. 2-4 days
View Answer
Answer: Option D
Explanation:
For the removal of phosphorous through ASP, the solid retention time considered is 2-4 days. However, this depends on the temperature. In case the temperature is very low, then the solid retention time considered would be around 4 days.
Question 10
SBR operates as ________ process.
A. Batch
B. Continuous
C. Semi-continuous
D. Discontinuous
View Answer
Answer: Option A
Explanation:
SBR operates as a batch process. Because sequential batch reactors operate as a batch process, the level of the basin starts out low and the basin fills over several hours as influent enters.
Question 11
What does SBR stand for?
A. Secondary batch reactor
B. Sequential biological reactor
C. Secondary biological reactor
D. Sequential batch reactor
View Answer
Answer: Option D
Explanation:
SBR stands for a Sequential batch reactor. An SBR essentially combines the aeration basin and the secondary clarifier of a traditional activated sludge system into a single basin.
Question 12
What does the bacterium use to grow?
A. Oxygen
B. Organic pollutants
C. Water
D. Carbon-dioxide
View Answer
Answer: Option B
Explanation:
The bacteria use the organic pollutants to grow and transform it to energy, water, carbon-dioxide and new cell material. The bacterium is present in the form of flocs which are suspended and mixed with wastewater.
Question 13
What is required to keep the activated sludge suspended?
A. Carbon-dioxide
B. Nitrogen
C. Oxygen
D. Ammonia
View Answer
Answer: Option C
Explanation:
To maintain the aerobic conditions and to keep the activated sludge suspended, a continuous and well-timed supply of oxygen is required. Flocs of bacteria, which are suspended and mixed with wastewater is used for the process.
Question 14
What is the typical value of the F/M ratio considered for an ASP process?
A. 0.04 g/g.d
B. 0.1 g/g.d
C. 0.4 g/g.d
D. 0.01 g/g.d
View Answer
Answer: Option A
Explanation:
The typical F/M value considered for an ASP process is 0.04 g/g.d. This is a process parameter that is used to characterize the operating conditions. Based on this F/M value the sizing of the aeration tanks for the ASP is carried out.
Question 15
What is the typical value of the F/M ratio considered for an extended ASP process?
A. 0.04 g/g.d
B. 0.1 g/g.d
C. 0.4 g/g.d
D. 0.01 g/g.d
View Answer
Answer: Option B
Explanation:
The typical F/M value considered for an extended ASP process is 0.1 g/g.d. This is a process parameter that is used to characterize the operating conditions. Based on this F/M value the sizing of the aeration tanks for the extended ASP is carried out.
Question 16
When the aeration system shuts off, the basin begins to perform as a ______
A. Primary clarifier
B. Secondary clarifier
C. Anaerobic unit
D. Aeration unit
View Answer
Answer: Option B
Explanation:
When the filling/ aeration phase is complete, the aeration system shuts off and the basin begins to function as a secondary clarifier. Suspended solids and micro-organisms settle to the bottom of the tank and clarified water is left near the surface.
Question 17
While designing an aeration tank for the ASP what is the volumetric organic loading rate considered?
A. 0.3-3
B. 0.03-0.2
C. 3-5
D. 5-7
View Answer
Answer: Option A
Explanation:
While designing an aeration tank, the volumetric organic loading rate considered is 0.3-3. The volumetric organic loading rate is defined as the amount of COD/BOD applied to the aeration tank volume per day. It is expressed in kg BOD/COD m3d.