Physical and Financial Performance of Pit Emptying Technologies
Jamie Radford Chloe Underdown, Stephanie Willis, Cameron Law, Jonathan Choksey,
Richard Fenner, Steven Sugden, Saurya Pal, Samrat Gupta,
Sampath Gopalan, George Drummond
Mott MacDonald
1. How strong is the sludge? Strength testing
2. How well do pumps perform? Pump testing
3. How does the business work? Financial
model
How much profit can be made emptying pits?
1. How strong is the sludge?
South 24 Parganas
Patna
Muzaffarpur 0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
0 1000 2000 3000
Dis
pla
cem
ent
(m)
Strength (Pa)
S24P, W Bengal, India – Pit 07
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
0 1000 2000 3000
Dis
pla
cem
ent
(m)
Strength (Pa) Patna, Bihar, India – Pit 35
2. How well do pumps perform?
Freeze-frame a still of the G3 video? Or G2 photo?
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0 100 200 300 400 500 600
Ave
rage
flo
w r
ate
(ℓ/s
)
Average sludge strength (Pa)
Pump testing results
Gulper 1
Gulper 2
Diaphragm
3. How does the business work?
Profit
= + <
Fee Fixed fee
Variable fee
Total Cost
Labour cost
Transportcost
Disposal cost
Hidden cost = + + +
=
-
Willing to pay limit
How much profit can I make emptying pits?
-$5
$-
$5
$10
$15
0,0
0,5
1,0
1,5
2,0
All areas,India
West Bengal Muzaffarpur Patna Kampala,Uganda
Pro
fit
pe
r p
it
Dep
th o
f sl
ud
ge (
m)
0 - 110Pa 110 - 180Pa 180 - 280Pa 280 - 430Pa
430 - 590Pa 590+ Pa Gulper 1 Gulper 2
Profit breakdown by pit
-$10
$0
$10
$20
0,0
1,0
2,0
3,0
4,0
Pro
fit
pe
r p
it
Tota
l dep
th (
m)
Patna, Bihar Muzaffarpur, Bihar S24 Parganas, W Bengal
-$40
-$20
$0
$20
$40
0,0
1,0
2,0
3,0
Pro
fit
pe
r p
it
Tota
l dep
th (
m)
590+ Pa
430 - 590Pa
280 - 430Pa
180 - 280Pa
110 - 180Pa
0 - 110Pa
Gulper 1
Gulper 2
Kampala, Uganda
How can I increase my profit?
Freeboard Emptiable Volume WTP Depth Strength
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Limitations of Gulper 2
India WB Patna Muzaf. Kampala
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Limitations of Gulper 1
India WB Patna Muzaf. Kampala
Which pump should I use?
0 100 200 300 400 500 600 700
0.5
1.0
1.5
2.0
2.5
3.0
Gulper 2Gulper 1
0 100 200 300 400 500 600 700
0.5
1.0
1.5
2.0
2.5
3.0
Gulper 1
Gulper 2
Patna/Muzaffarpur, India Kampala, Uganda
Dep
th o
f sl
ud
ge (
m)
Sludge strength (Pa)
Dep
th o
f sl
ud
ge (
m)
Sludge strength (Pa) 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Sludge strength (Pa)
Conclusion
• Testing sludge strength and pump performance can show how to increase profit for pit emptying
Next steps
• Test more pits – link to treatment and planning
• Test more pumps – mechanised, tankers
• Include more business model options
• Web tool to inform pump selection
Thank you!
Jamie Radford (@RadfordJT) Chloe Underdown, Stephanie Willis, Cameron Law, Jonathan Choksey,
Richard Fenner, Steven Sugden, Saurya Pal, Samrat Gupta,
Sampath Gopalan, George Drummond
Mott MacDonald
2. How well do pumps perform?
0 100 200 300 400 500 600
Ave
rage
Flo
w R
ate
(in
clu
din
g b
lock
ages
)
Shear Strength (Pa)
Impact of debris on Gulper I performance.
No debris
Debris
-25%
-40%
-100%
3. How does the business work?
Total Cost
Labour cost
Transportcost
Disposal cost
Hidden cost = + + +
Time to: - Travel - Negotiate - Set up - Empty - Blockages - Transport - Dispose x Hourly wages
Vehicle (hire) +
Fuel cost
Flat charge +
Fee per volume
Depreciation +
Maintenance +
Interest