Welcome to the

21st Century Distribution System

Onno Koelman

BSME, Stanford University

Focus on Tanks

Treatment plant

Distribution Piping

Tanks

Welcome to the 21st century

treatment site

(Boost) (Improve)

Maintain

Mixing

RCS Reservoir Control System

TRS THM Removal System

Three New Technologies for Managing the Distribution System

Audience – Who are you?

Cl en Pwt

RCS Reservoir Control System

TRS THM Removal System

Three New Technologies for Managing the Distribution System

Mixing

EPA’s Stage II looks for hotspots

Problem!

Problem!

Tanks

Sample points

Tanks might store 50% of your water.

Tanks might store 50% of your water.

Problem: They’re vulnerable …

Problem: They’re vulnerable …

Tanks might store 50% of your water.

3 Problems with Tanks

2. Water Age due

sun exposure

1. Water Age due

lack of turnover

3. Water Age due

short circuiting

Cl2 Cl2 Cl2 Cl2 Cl2 Cl2

Worst Water Quality

1. Low Turnover & Hydraulic Dead Zones

• Future build-out needs • Hard to expand later • 30% sized for fire flow • Seasonal demands change

Tanks are usually OVER-SIZED during design

2. Persistent Thermal Stratification

Many tanks… • have common inlet/outlets • are exposed to sunlight • fill with cold water

How does stratification happen?

Tank fills …

How does stratification happen?

Sun warms tank …

How does stratification happen?

Hot water rises …

Cool water drains out …

Strong and persistent thermocline established

Cool water fills tank …

Cool water drains out … again. Top water is now getting older

Cool water fills at night … again Top layer floats like a piston, still not mixed

?@$#!!

Deep cycling may not fully disrupt this thermal layer One day, too much demand Bad sample reading Customer complaints, biofilm, etc

Bad sample

Customer Complaints

Deep cycling is NOT a mixing solution…

10

15

20

25

30

Wat

er

leve

l [ft

]

12

14

16

18

20

22

tem

pe

ratu

re [

C]

0

0.5

1

1.5

2

2.5

7/2 7/4 7/6 7/8 7/10 7/12 7/14 7/16 7/18 7/20

Ch

lori

ne

[m

g/L

]

Top

Middle

Bottom

Water level cycled 60%

Tank remained stratified Float temp

Bottom temp

Thermocline

Inlet Outlet

Older water

Fresh water

Beware Seasonal “Inversions”

Winter: Snow/cool air cools the tank

Upper water cools, then “sinks” to the bottom

Worst water leaves tank first …

Summer: Sun/warm air heats the tank

→ Customer Complaints → Surprise Bac-T samples

“Optimistic” Sample ~1% of tank

Why do regulators recommend mixing?

How did we deal with this problem?

Dose

Flush

Juggle

• Manual • Spot-treatments • Reactionary • Not “management”

Cl2 Cl2 Cl2

Cl2

Cl2 Cl2

Cl2

Innovation for operators

Treatment plant

Tanks

Tanks

time

Chlorine

Install Mixers 1) Water Age reduced 2) Residual decay slows 3) Consistency

Residual with mixer

Baseline: Residual with NO mixer Water Age

time

30% Reduction in Chlorine At Treatment Plant

Residual with mixer

Baseline: Residual with NO mixer

Chlorine

Treatment plant

How much mixing does my client need?

Depends on shape and size of tank

– Small, flat tanks

– Large flat tanks, square tanks

– Standpipes (wide)

– Massive tanks (10 MG+)

– Standpipes (narrow)

Easy

Hard

Hard Easy

How much mixing does my client need?

Depends on what they are trying to do

– Maintaining well-mixed conditions

– De-stratification (thermal load)

– Blending a dose

– Aeration/Ice Prevention

Easy

Hard

THMs THMs

THMs THMs THMs

Hard Easy

But … what if mixing isn’t enough?

Mixing

TRS THM Removal System

Three New Technologies for Managing the Distribution System

RCS Reservoir Control System

PAX Reservoir Control System (RCS)

• Monitor chlorine

• Boost chlorine

• Intelligent controls to gradually feed

Residual Loss in Tanks

Many miles from the treatment plant ….

Treatment plant

Almost zero residual entering tank!

CL2

t

Range of Residual

in System

Residual Loss in Tanks

Many miles from the treatment plant ….

Treatment plant

Boost residual

CL2

t

Residual Loss in Tanks

Many miles from the treatment plant ….

Treatment plant CL2

t

Residual Loss in Tanks

Many miles from the treatment plant ….

Treatment plant

Boost residual

CL2

t

More consistent water throughout

system

Residual Loss in Tanks

Many miles from the treatment plant ….

Treatment plant

Boost residual

CL2

t

Fewer DBPs

More Control

Less Cost

Mixing + Chemical Injection

RCS Installation layout

RCS Installation layout

PAX Mixer

Injection

lines

Complete Mixing Flow Pattern with option for chemical addition onsite

Mixer 2. Optional chemical

injection line

1. Dose through hatch 3. Dose through center vent

Stabilize this tank at 1.5 ppm ALWAYS …

GREAT for Consecutive Systems

Stabilize this tank at 1.5 ppm ALWAYS …

GREAT when Purchasing Water

What is the PAX TRS?

hint: nothing to do with Star Trek

Mixing

RCS Reservoir Control System

Three New Technologies for Managing the Distribution System

TRS THM Removal System

Take control of your THMs

Option 1: Tackle at Treatment Plant

Option 2: Tackle in Distr. System

Tanks are a FREE air/water interface

THMs

THMs

THMs THMs

THMs THMs

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs THMs

THMs THMs

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

At equilibrium, a

ratio in THM

concentration

between the air

and the water That ratio is the

Henry’s Law

constant

THMs are volatile …

Henry’s Law constants for THMs

Chloroform is the most “volatile”

(easiest to remove)

Confidential and Proprietary

THM species Henry's law constant

@ 20 C

Chloroform 0.13

Bromodichloromethane 0.08

Chlorodibromomethane 0.04

Bromoform 0.02

Bromoform is the least “volatile”

(hardest to remove)

Some aeration happens all by itself…

THMs

THMs

THMs THMs

THMs THMs

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

Poor mixing

prevents THMs

below the

surface from

escaping

Evaporation

stops

Diffusional

barrier

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs THMs

THMs

Powerful Mixing Enhances Aeration (5-10%)

Different In-tank Aeration Technologies

Bubble aeration Surface aeration Spray aeration

Any of these technologies can be made to work… but capital and energy costs vary greatly

Bubble aeration – How it works

Pop!

Air injected here

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

Surface Aeration – Mixing needed

THMs

THMs

THMs THMs

THMs THMs

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

Zone of THM removal

THMs trapped (mixing needed)

Spray Aeration

THMs

THMs

THMs THMs

THMs THMs

THMs

THMs

THMs

THMs THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

THMs

Pump

© 2011 PAX Water Technologies, Inc.

CFD for Tank Aeration Spraying

efficiency (X)

0

40

80

120

160

9/7/2010 9/8/2010 9/9/2010 9/17/2010

Entering the tank

Leaving the tank

Leaving the tank (Model)

THM [ppb]

Model shows accurate removal

What are the other options?

Treatment plant

Distribution System

GAC Reverse Osmosis

Enhanced Coagulant

Ozone Chloramines

UV PAX TRS

99% of the Money here ….

PAX Mixer

10x expense and multi-year projects

In summary …

Welcome to the 21st century

treatment site

(Boost) (Improve)

Maintain

Contact

• Teresa Corrington

• (253) 779-4160

• John Kitchen

• (503) 577-4194

PAX Mixer – The Active Solution

Mixer Details

• Stainless Steel 316

• Installs easily through hatch

• Sits on foot-pads, no attachment/scratching

• 60 Lbs, 4 feet tall

Power Source

• DC Motor

• 1/3 HP, $0.50/day

• Water-filled motor (no leaks)

• 5 yr warranty, 15 year expected life

PAX - Any Tank, Any Size

20 MGAL 9 MGAL 7 MGAL 1.5 MGAL 1.5 MGAL 0.2 MGAL

6 MGAL 3 MGAL 2 MGAL 2 MGAL 0.5 MGAL 1 MGAL 0.5 MGAL

Simple Installation

Motor power cable

Control Center

Tank Hatch

Biomimicry

Biology + Mimicry

Copy the high efficiencies found in nature

Biomimetic design of impeller

THM Removal Systems - Customized