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irga5000 [103]
3 years ago
10

If the sludge concentration in the return sludge line from the secondary clarifier were the same as the MLVSS concentration (XV)

, would recycle of return sludge increase the SRT?
Engineering
1 answer:
sergeinik [125]3 years ago
5 0

Answer:

It would decrease the SRT

Explanation:

The SRT is the average time it will take for the activated-sludge solids system to decompose. The concept is expressed in days. The retention time is a very important design and operational parameter in the design of an activated sludge digester. The make-up stream from the second clarifier contains a considerable amount of bacteria which are already active. Therefore, the synergistic action of the bacteria makes the sludge to be digested faster. This, In turn, reduces the time it takes to digest the sludge. Thus, the make-up stream lowers the retention time.

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The production process of rods from machine "A" yields specimen with the following specs. Mean: µ(LA)=20.00mm, STD: s(LA)=0.50mm
Oxana [17]

Answer: the standard deviation STD of machine B is s (Lb) = 0.4557

Explanation:

from the given data, machine A and machine B produce half of the rods

Lt = 0.5La + 0.5Lb

so

s² (Lt) = 0.5²s²(La) + 0.5²s²(Lb) + 0.5²(2)Cov (La, Lb)

but Cov (La, Lb) = Corr(La, Lb) s(La) s(Lb) = 0.4s (La) s(Lb)

so we substitute

s²(Lt) = 0.25s² (La) + 0.25s² (Lb) + 0.4s (La) s(Lb)

0.4² = 0.25 (0.5²) + 0.25s² (Lb) + (0.5)0.4(0.5) s(Lb)

0.64 = 0.25 + s²(Lb) + 0.4s(Lb)

s²(Lb) + 0.4s(Lb) - 0.39 = 0

s(Lb) = { -0.4 ± √(0.16 + (4*0.39)) } / 2

s (Lb) = 0.4557

therefore the standard deviation STD of machine B is s (Lb) = 0.4557

8 0
3 years ago
Determine the deflection at the center of the beam. Express your answer in terms of some or all of the variables LLL, EEE, III,
Rom4ik [11]

Answer:

See explanations for step by step procedures to get answer.

Explanation:

Given that;

Determine the deflection at the center of the beam. Express your answer in terms of some or all of the variables LLL, EEE, III, and M0M0M_0. Enter positive value if the deflection is upward and negative value if the deflection is downward.

4 0
4 years ago
How do we define energy efficiency
marta [7]
Energy efficiency simply means using less energy to perform the same task – that is, eliminating energy waste. ... There are enormous opportunities for efficiency improvements in every sector of the economy, whether it is buildings, transportation, industry, or energy generation.
7 0
3 years ago
Read 2 more answers
The rate of flow through an ideal clarifier is 8000m3 /d, the detention time is 1h and the depth is 3m. If a full-length movable
Fittoniya [83]

Answer:

a) 35%

b) yes it can be improved by moving the tray near the top

   Tray should be located ( 1 to 2 meters below surface )

   max removal efficiency ≈ 70%

c) The maximum removal will drop as the particle settling velocity = 0.5 m/h

Explanation:

Given data:

flow rate = 8000 m^3/d

Detention time = 1h

depth = 3m

Full length movable horizontal tray :  1m below surface

<u>a) Determine percent removal of particles having a settling velocity of 1m/h</u>

velocity of critical sized particle to be removed = Depth / Detention time

= 3 / 1 = 3m/h

The percent removal of particles having a settling velocity of 1m/h ≈ 35%

<u>b) Determine if  the removal efficiency of the clarifier can be improved by moving the tray, the location of the tray  and the maximum removal efficiency</u>

The tray should be located near the top of the tray ( i.e. 1 to 2 meters below surface ) because here the removal efficiency above the tray will be 100% but since the tank is quite small hence the

Total Maximum removal efficiency

=  percent removal_{above} + percent removal_{below}

= ( d_{a},v_{p} ) . \frac{d_{a} }{depth}  + ( d_{a},v_{p} ) . \frac{depth - d_{a} }{depth}  = 100

hence max removal efficiency ≈ 70%

<u>c) what is the effect of moving the tray would be if the particle settling velocity were equal to 0.5m/h?</u>

The maximum removal will drop as the particle settling velocity = 0.5 m/h

7 0
3 years ago
In the engineering design process, what do engineers do immediately before
gulaghasi [49]

Answer:

A

Hope this helps!

Explanation:

You need to find what the problem is and what can or can not be done to solve that issue/compete the task

5 0
3 years ago
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