1. Using Safer Treatment chemicals

2. City of san Diego's otay water treatment plant
Pic of plant

3. Otay Water Treatment Plant
Conventional Treatment Plant
34 MGD
Chlorine Dioxide / Sodium Hypochlorite
Ferric Chloride
Granular activated carbon filter caps

4. Factors and conditions that drove the change
Acutely toxic water treatment chemicals
CalArp Risk Management Plan Program
San Bruno pipeline explosion and Martinez refinery fire
Chlorine gas as a weapon in the Middle East
Otay’s gas chlorine system life span and required
significant upgrades to the alarm and SCADA system
Safety of employees and community

5. CHLORINE GAS RELEASES
CSB.Gov
DUGWAY.ARMY.MIL

6. Worst case release 34,000 lbs of chlorine gas

7. Cost / Benefit of the change
Costs- Sodium Hypochlorite and Liquid Ammonia Sulfate
Safety and training
Regulatory compliance

8. costs Sodium Hypochlorite On-Site Generation of Hypochlorite-
Retrofit building
Two hypo generators
Three 9,100 gal storage tanks
One 18,000 gal brine tank
New DI system
On-Site Generation of Hypochlorite-
$4,975,443
Liquid Ammonia Sulfate
Clean existing ammonia tank and dispose
of waste- Ocean Blue
Purchase and install 7,500 gal fiberglass
tank
Install piping and new fill station
Modify existing chemical feed pumps
Costs 50% more than Ammonium
Hydroxide
Liquid Ammonia Sulfate-
$105,000

9. Safety & training Sodium Hypochlorite Liquid Ammonia Sulfate
8 hour training plus 2 weeks
of an initial run
Liquid Ammonia Sulfate
No training required
Review S.D.S.

10. Regulatory compliance
No longer under CalArp Risk Management Plan Program
Removed from program July 2016

11. Completed project
BEFORE
AFTER

12. Completed project Design Parameters
Runs at night during off peak hours
Each generator produces 1,000 lbs / day
Fully automated and runs on flow pace

13. To see video, go to 4psi.net, Microclor, Video & Brochure

14. Microclor On-Site Sodium Hypochlorite Generation (OSHG)
By Process Solution, Inc. (PSI)

15. A typical Microclor OSHG system includes:
Water Softener
Brine Tank
PLC Control Panel
Electrolytic Cells
Hydrogen Dilution Blower
Hypochlorite Storage Tank
Hypochlorite Metering Pump
D.C. Rectifier
Brine Pump

16. Hypo generator / generator control

17. P.l.C. Box / control screen

18. Log sheet / di system

19. Hypo feed / 12.5% dilution system

20. Brine tank / hypo tanks

21. Lessons Learned
Tank levels
Taking tanks out of service
Amount of salt

22. Conclusions / Outcomes
Safer environment for employees
Elimination of transport of acutely hazardous material through the
community
No CalArp / EPA Risk Management plans
Required training vastly reduced (SCBAs no longer necessary)
Improved control of chlorination process eliminates backwash overfeed
spike, reducing TTHM formation

23. Questions?
Patrick Cory Boyd City of San Diego Otay Water Plant Operator, T5