ACTIVATED SLUDGE AND NUTRIENT REMOVAL
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A wastewater treatment plant based on activated sludge with biological phosphate and nitrogen removal via pre-denitrification. The influent flow (dwf) is 30,000 m3/day and the influent BOD concentration is
300 mg BOD/l. The suspended solid concentration in the influent is 150 mg/l of which 40% is removed in the primary clarifier. The sludge recycle flow ratio (fr) is 0.5, the sludge yield (Y) is 0.6 kgX/kgBODremoved and the SVI is 130 mL/g.
The treatment plant consists of different process units, namely:
Final clarifier
Screen
Aerobic tank
Primary sedimentation
Anoxic tank
Grit chamber
Anaerobic tank
Sludge dewatering
After dewatering the sludge will be directly transported to the sludge incineration plant.
Q1:What is the minimum size (volume) in m3 of the aeration tank?
Calculate with a biomass concentration in the aeration tank of 4 g/l and take into account that the primary settler removes 33% of the BOD.
Q2:What would be the size (volume) in m3 of the anaerobic tank (don’t forget the sludge recycle flow to the anaerobic tank)?
Q3:What would be the waste activated sludge (or surplus sludge production) in kg dry weight per day?
Calculate the biomass production assuming all BOD entering the biological process is removed. Also add the primary sludge production, but for simplicity neglect the remainder of the suspended solids.
The biomass production (kg biomass per day) is:?
The primary sludge production (kg per day) is:?
Q4:The sludge is directly dewatered to a final dry solid concentration of 18%. How much trucks, that can transport a load of 30 ton, will be needed per year for sludge transport to the incineration plant?
Q5:How can the produced sludge be reduced maximally, to minimize transport costs?
a//Application of chemical conditioning .b//Application of sludge digestion.c// By thickening of the primary sludge
61 answers
grit chamber -->xxx
primary sedimentation -->xxx
anaerobic tank-->xxxx
anoxic tank--->xxxx
aerobic tank-->nitrification
final clarifier-->xxxx
sludge dewatering -->remove water from the sludge
help me with Q3C Q3D Q3E
2. Grit chamber>>sand
3.Primary Sedimentation >>Suspended solid & settle able part of BOD
4.Anaerobic tank >>Hydrolysis of Xs & uptake of Ss
5.Anoxic tank >>Denitrification
6.Aerobic tank >>Nitrification
7.Final clarifier >>Separating Biomass & effluent
8.Sludge De watering >> remove water from sludge.
What is the minimum size (volume) in m3 of the aeration tank?
Calculate with a biomass concentration in the aeration tank of 4 g/l and take into account that the primary settler removes 33% of the BOD.
Answer =10050
What would be the size (volume) in m3 of the anaerobic tank (don’t forget the sludge recycle flow to the anaerobic tank)?
Answer =1875
What would be the waste activated sludge (or surplus sludge production) in kg dry weight per day?
1. Calculate the biomass production assuming all BOD entering the biological process is removed. Also add the primary sludge production, but for simplicity neglect the remainder of the suspended solids.
The biomass production (kg biomass per day) is: Answer=3618
The primary sludge production (kg per day) is: Answer=1800
2:The sludge is directly dewatered to a final dry solid concentration of 18%. How much trucks, that can transport a load of 30 ton, will be needed per year for sludge transport to the incineration plant? Answer=365
3:How can the produced sludge be reduced maximally, to minimize transport costs?
Answer=Application of sludge digestion
1,500 m3/h. The dry weather flow (Qdwf) amounts 7,500 m3/day, with a BOD concentration of 300 mg/l.
Additional information
After this pre-treatment the water is fed to a trickling filter. The diameter of this trickling filter is 30 m and its height is 3 m.
Assume for the next question no BOD removal in the pre-treatment, so influent BOD concentration is 300 mg/l.
QUESTION 2E
Calculate the loading rate (kg/m3/day) of the trickling filter.
QUESTION 2D-2 (4 points possible)
Assume 4 channels. Take a W:L ratio of 1:15
Dimension the rectangular sand removal channels.
Length (m):
Width (m):
Maximum water height (m):
Allow a free waterboard of 15 cm and a maximum grit accumulation height of 20 cm. Give the total height in m of the grit channel.
thank you :)
Determine how many parallel channels you will design.ANS 4
What is a common W:L ratio? ANS 1:10
To prevent settling of organic matter a Vs should be Ans---higher than 0.03m/s
Calculate Qdwf in m3/s.---my answer is wrong
Calculate Qrwf in m3/s.my answer is wrong
2D3
Calculate the liquid velocity during Qdwf (in m/s) in the channel.my answer is wrong
Organic matter will settle in the channel during Qdwf.Ans-False
PLEASE 2C1 AND 2C2,2D2
4
1:10
higher than 0.03 m/s
please any one know correct answer
please help I.G
Denitrification takes place inside the granule +
Due to reduction of oxygen in the outer layer, anoxic conditions will exist inside the granule +
Aerobic granules make settling tanks superfluous
i got 3F and 3G wrong answerCRAZY ONE,
Please 2C1, 2C2,2D2,2E please answer
2C2=0.34 (velocity) 2C2=32(head loss)
2D2 length=11.85
width=0.79
hight= 0.43
grit chanel=0.78
2E
False (correct)
Many tks
The maximum scouring velocity or slip velocity is 0.3 m/s and the maximum surface load or Hazen velocity is 40 m/h.
Question 2a
0.0/2.0 points (graded)
Assume 4 channels. Take a W:L ratio of 1:15
Calculate the vertical surface area Avertical in m²:
unanswered
Calculate the horizontal surface area Ahorizontal in m²:
unanswered
3 answers