Auto Primary Sludge Tank De-Sludgeing

Alistair Mackinnon

Director of Sales and Marketing

Non Contacting Level and Flow Instrumentation

Continuous level indication

Density differential 0.5%

2 transducer inputs - SludgeInterface or Level

0-10M range

2 x 4-20mA outputs

6 x 2A Relays

Screen display

Self Cleaning transducer

Power Supply 110-240VAC or24VDC

Effective sludge detection and control

Sludgefinder 2

How does the SF2 System Work?

The Viper Transducer must be inserted intothe water to become operational, if the headis out of the water LOE will occur.

A high frequency Ultrasonic Sound wave at700khz is then generated by the Viper andtravels through the liquid at 1482 m/s.

The echoes from any distinct density changesare reflected back to the Transducer and re-excite the crystal. The time taken for theUltrasound path is then Integrated by theunit and a distance to the Interface iscalculated.

ZeroAdjust

Range

Level

TankDepth

Reference Point - Top WaterLevel

InsertionDepth

Range(Distance)

Tank Depth

BlanketLevel

Sludge Display & Echo

Controller Sludge Display

Laptop Echo Display

Background• Stoke Bardolph STW.• Largest waste water

treatment plant inNottingham.

• 8 Primary tanks.• Power generation via

digestion plant.• Measurement and control

of blankets by dips andtime.

• Electrical powergeneration was notefficient due to sludgequality

Project Overview

• To produce sludge atideal density fordigestion (5 /6%).

• Hydraulic pumpsinstalled to handlehigher density sludge.

• Density monitorsinstalled.

• Sludge Finder 2 installedfor auto de sludgeingand alarm indication.

Project Overview

Project Overview

Project Overview

Project Overview

Project Overview

Project Overview

• Controller mountedon rotating bridge.

• Radio Telemetrysystem rejected bycontractor.

• Slip rings used totransmit 4-20mA and3 alarms.

• Slip rings were wellmaintained.

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

45.0%

13/0

4/20

11 1

1:54

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5614

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0015

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0023

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5624

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0826

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4228

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31

Blan

ket

% a

gain

st t

ank

dept

h

Project Overview

Typical SCADA Trace

Conclusion

• The scheme has been a resounding success.• Stoke Bardolph generates 5.5MW (5500KW) at

full power.

• Enough energy is produced, not only to powerequipment on site, but also to return a netsurplus of electricity to the Grid; making thesite energy self-sufficient.

Other Totex Examples

Pump Station Flow Monitoring

DCWW Flow Pulse

• Installation savings of £1.5 million.

• Predictive maintenance information.

• Prioritisation of assets.

• Confined spaces• Limited pipe clearance

DCWW Case Study

DCWW Case Study• 150 units installed so far• Portable system used to identify best position• 100 systems live on Scopex telemetry

DCWW Case Study

DCWW Case Study

Bishopston SPS

Sludge Monitoring andControl

FST Compliance

FST Compliance• The Sludge level in the settlement tanks is maintained

at a level termed ‘healthy’.• If the sludge level rises above that point, reaching a

‘flush’ level, the bellmouth valves are activated,returning the level to the setpoint.

• There may be a number of reasons that a tank reachesthe flush level under normal circumstances, but it mayalso be an indication of a problem. The systemtherefore allows four flush events within an hourbefore an alarm is generated.

• Staff visits to resolve issues are substantially reduced,an important saving in vehicle miles and man hours.

• A further benefit is that the settlement tanks can becontrolled more effectively, reducing pumping hoursand saving further energy.

FST Compliance

FST Compliance

FST Compliance

FST Compliance

Ultimate PumpController

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The next generationpump station controller!

Complete Integration

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