1. Streaming Current Monitoring and Control in Paper Processes
The Milton Roy Company
Jim Carling: Mgr. Water Treatment Group
Bob Bean: Mgr. Industrial Group

2. Milton Roy The leader in Chemical Injection Pumps and Controls
Is the world’s largest manufacturer of chemical injection pumps and controls.
Is a division of Sundstrand. A technology leader in the Aerospace and Industrial markets with two billion dollars in sales.
Sets the industry standard for performance,
accuracy, and durability.

3. Milton Roy Engineering & Manufacturing Sites
Flow Control: Ivyland, PA
Williams Instrument: Valencia, CA
Dosapro: Pont St. Pierre, France
LMI: Acton, MA
ASIA LMI: Madras, India
International Sales Support Sites
Singapore
Shanghai, P.R. China
Beijing, P.R. China
Shenzhen, P.R. China
ChengDu, P.R. China
Latin America - Key Biscayne, Florida

4. What’s Streaming Current?
Technically: one of the electrokinetic effects in surface chemistry related to zeta potential
Streaming Current
Streaming potential
Electrophoresis
Electroosmosis
Sedimentation potential
Ionic Conductance

5. What’s Streaming Current?
Practically: Streaming Current Instruments measure the “electrical charge” of particles in a liquid.
SC allows continuous, online, monitoring & control of coagulent feed in water clarification processes
SC provides effective polymer control in dewatering processes
SC is used in the process industries measuring and controlling colloidal chemistries

6. Basic principles of Operation
Immobile ion layer “held” on probe surface
“Loose” counter ion layer swept downstream each piston stroke
Net electrical field at electrodes drives electrons through circuit
Piston
Sample
Amps
Electrons
Electrodes

7. Application Notes
Sample times from chemical addition to SCD measurement should be kept at 3-5 minutes
A sampling point should be selected to ensure adequate mixing has occurred. The sample point should not be near a wall.
Sample flows should be 1 to 2 quart/min
Responds to materials in both sub-colloidal and colloidal ranges including surfactant and humic substances.

8. Application Notes
pH adjustments will impact SCD readings (as it will zeta readings). However, the SCD reading will still correctly characterize the net surface charge levels.
High fluid conductivity levels can reduce SCD sensitivity (greater than 10% salt)
Cleaning may be required from every several days to every several months.
For successful online monitoring in high solid content fluids the SCD should be equipped with a low shear probe, an automated probe wash, and signal phase correction

9. SCD & Influent Clarification
Coagulant Feed
River
Clarifier
Effluent
SCD
Mix Tank
Settling Basin
Pump
Coagulant
Feed
Mix Tank
Sludge Draw Off

10. Influent Clarification Case Study
Dentel & Kingery, AWWA 1998:
The SCD provides information similar to that provided by zeta potential
In clarification processes the SCD reading correlates with turbidity removal especially when charge neutralization is the dominant factor
The SCD cuts chemical use significantly especially under changing process conditions (10% to 25%)
The SCD is a useful indicator of system failures: pumps, mixers, feed lines, etc
Consistent Water Quality maintained especially under changing conditions

11. SCD & Wastewater Clarification
Typical Wastewater Clarification System
Waste Sludge
Wastewater
Inlet
Effluent
Primary
Clarifier
Aeration
Basin
Secondary
Clarifier
Mix Tank
Return Sludge
SCD
Sample
Polymer
Feed

12. SCD and Waste Treatment (Dewatering- Belt Filter Press)
Typical Belt Filter Press System
Polymer Feed
Belt Filter Press
Thickener
Waste Sludge
Mixer
From
Secondary
Clarifier
or Process
SCD
Sludge
Cake
Sample (Filtrate)

13. Dewatering - Belt Filter Press Case Study:
Abu-Orf & Dentel, Water Env. Research 1998
The benefit of automatic control of polymer dosage is evident as the optimum polymer dosage was not constant due to changes in the solids’ characteristics
The SCD was capable of automatically controlling the polymer dose to produce good solids recovery and low filtrate total solids.
Total savings yielded a payback period of 97 days
A thorough, weekly cleaning of the probe was recommended
Clogging difficulties may be resolved by larger sampling lines and use of automatic and manual backwash

14. Dewatering - Screw Press
SCD sample point

15. SCD and Paper Mill Stock Preparation
Chemical Feed
Paper Mill Stock
Controller Feedback
SCD
Head Box
Sample

16. Crown Vantage Stock Preparation Case Study:
Short Production Runs
Output tons/day
Dhamo Srinivasan
Senior Process Engineer

17. Crown Vantage Stock Preparation Case Study:
Very useful in controlling product consistency
up to 30% savings in dye costs
1/10 the cost of competing technologies
Gains control of color quicker
Target point depends on grade structure
Offline titrations not needed
1 month cleaning and calibration
Working off filtrate in suction box with
.03 to .1 solids

18. Milton Roy SCD Product Line
SC base unit with phase corrected electronics
SC phase corrected, display, gain and zero.
SC phase correction, display and PID control
Available Options: High Solids Probe, Jetwash, Remote Wall Mount Controls

19. Jet Wash SCD opens solenoid valve based on user configured interval
and duration.
SCD maintains last
output signal during
jetwash cycle and
for a short time after.
Probe
Sample Line
Plant Water
Solenoid Valve

20. What Can Milton Roy Offer?
Application support
Cost effective, patented technology
Demo units available on request
Delivery of new units in 2 weeks or less
Trade in for older SCD units

21. Streaming Current
Colloidal Particle + -

22. Typical Continuous Bowl Centrifuge

23. SCD and Waste Treatment (Dewatering- Centrifuge)
Typical Centrifuge Dewatering System
Influent
Slurry
Feed
Slurry Discharge
Polymer Feed
SCD