'w'

 

L.
r

(X);
NM
0000 ‘

A... HN‘-‘

 

\ USED AS
‘ TREATM‘EN

o

.
x
x.
n
‘ Q
'._ \
K .
. . -
‘ '.
‘. ~

~ \

‘1 ~ ‘
‘
.
n
.
.
- .
\
.‘ ;
‘ ‘
.
.
. ~-
. .‘
. s . ~_. ~
._ . .
‘ ‘
~
.
- ~
.

o. '
| -
s

.
- . .
‘ »
. .
. x
‘x
.
.
‘
' u
. ‘ _
‘ ‘
. . -.
I.
‘ -. .
‘
.‘ ..
g- ‘
.

LHRb

\

T IN

Thesisi’foftheio

‘ ' . ‘5

. ~.
.
-
\
~
0
. _
. .-
.
s
‘
.

- "J“ inf-'5”. w". n. . '
I. . V

‘u

for: J_THE'[ZEOL1TE' Bowman;

u‘

fie-ye:

.
a
s
- .
~
. ‘ _
. ~ . <
~

-
n

a

or B.

~

¢

' \

‘

 

\

 

-

n
§

\
'.

§
\
.
.
\
\
v
‘
-
‘
m
‘
A
.
u
s
~
-
x
0
.
\
I
.

DETERMINATION OF; PORT‘QN‘fOF f
THE RECOVERY. gBRHINE-‘fTQ: ”BE“;
-‘ THE PRELIMINARy;

‘ ~
~ \
~.

. . .-
~
‘ \k
.

x
-u
x
s
\
0
~
-
‘ ~
\
‘ ‘
s
.
.
~
\

\
~. .
o

‘.
-‘
~u
.
.
‘
.
u

x

. "r:"“ '

 

.
‘
-
~
.
.
. ~ ‘
. \.
-
. . .
' , \
‘ .
s .
. _
' .
\. a
' ‘
.
- “
-> ~
~.
. —,_‘
‘ .
¥ -
~ .
V
.
x
s . . ..
u
.
\ - .
.
x
-. ~ .
. . .
.
‘ ' . .
.
- .
, .
. . ‘
. \
.
. .
. ~ _~ .
_ ,‘ .. ..
' - -
, - -.
.
. ' ~ ' .
‘ . ‘
- -
‘
a
' ‘
' -.
H
.
. .-
.
\ _
‘ ‘ ._
. . ‘ ‘
‘ ~
\
.. -
.
.' .
--
~
~
.
o
. B \
x .
-

 

 

 

a... T9... .03.. “JFJH

‘ II“: . pr!

 

(/x .‘-..mm Band 6 Y0.

 

 

 

I”L II! I D
‘0‘ by . 2'1
. . 1| :0

 

Determination of Portion of The Recovery Brine
To be Used as The
Preliminary Treatment in Regeneration of
The Zeolite Softeners

(East Lansing)

A Thesis Submitted to
The Faculty of
MICHIGAN STATE COLLEGE
OF
AGRICULTURE AND APPLIED SCIENCE

By 7'Y

Leo H; Rothe

———_

Candidate For The Degree of

Bachelor of Science

June 1935

\HE—M'
. d

{I

J

 

 

‘_ x L‘— i“ 'V\<x \

~~V My" v'

x

. -"\\.\"~

“4"“\. ‘ :\,~1~ »

East Lansing Water Softening Plant

I

:1.
v .

a .8
1.3....
w! a.

ACKNOWLEDGMENT

I wish to take this Opportunity to acknowl-
edge my appreciation to Professor Theroux for
the advice and c00peration rendered me on this
thesis, and also for the use of the laboratory

and equipment.
L.H.R.

INTRODUCTION

Zeolites have been used for over 25 years
in this country and abroad for water softening.
During this period, the application of this
method of water softening has grown to be an
industry of world wide scOpe. In addition to
their use for softening industrial waters for
laundry , textile, boiler feed, etc., zeolites
have established a definite place in the field
of water softening for general use, such as is
required in the home. This has been reflected
in the steady increase in the number of instal-
lations made for this purpose, until they now
total well over 150,000. More recently, the ten-
dency to use zeolites for general purposes has
made itself evident in.the increasing number of
installations made by municipalities in order
to give entire communities the benefits of zeo-
lite softened water.

One of the most important characteristics
of zeolite softened water is the fact that there
is no sludge formed during softening as there is
in other methods of softening water. The advan-
tage of having no sludge formed is that it en-

ables the plant to be located in a limited area

II.

where-as if sludge is to be disposed of it
would require a much larger area.

The economy of operation of a zeolite plant
depends mainly upon the cost of salt, therefore
in order to Operate most economically an effort
must be made to economize as much as possible
in its use.

In a zeolite softener, after the tank has
become exhausted of its softening capacity, the
zeolite must be regenerated. This regeneration
is accomplished by passing salt brine through
the zeolite sand bed which restores the zeolite
to its original form (NaZ).

At the East Lansing, Michigan water soften-
ing plant, a definite volume of a saturated
salution of salt brine is pumped into the zeo-
lite softening tank then it is rinsed out. The
rinse water is pumped into a brine recovery
tank and is used as a preliminary treatment in
the regeneration of the succeeding tank. At the
present time the rinse period is about 22 min-
utes of which the first 16 minutes of flow is
saved the remaining portion being allowed to dis~
charge into the sewer.

As far as this investigation could determine

there has been no work done to determine whether

III.

or not there is any advantage in the using of
the rinse water, from a newly brined tank, as
a preliminary treatment in the brining of a
succeeding tank, and if there is any value in
the rinse Just what portion of it should be
saved.

In this paper an attempt has been made to
determine if there is any value in the recovery
brine as well as determining which portion of
the rinse it is best to save in order to secure

the best part of the rinse.

DESCRIPTION OF E. LANSING WATER WORKS

EAST LANSING MICHIGAN

The water works is located on the west side 3*

of town and serves a pepulation of approximately
8000. The water is obtained from 2 deep wells,
which are 420 feet deep and 12 inches in diameter.
The casing is sunk to a depth of 180 feet with a
strainer at a depth of 169 feet from the floor

of the pumping pit, which is about 10 feet below
the surface of the ground.

The waters obtained from these two wells
are of excellent sanitary quality. Chemically
they are hard waters and also contain objection-
able amounts of iron and free carbon dioxide
both of which are corrected at the plant and
will be discussed later.

The hardness is the most objectionable (har-
acteristic of the water. It is softened by passing
it through beds of sodium zeolite, which process
will be discussed later. Hardness results in a
very large waste of soaps as the hardness must
be overcome by the soap before any lather is
formed. Hard water also causes incrustations to
be formed on the inside of hot water pipes, which

results in inefficient heating and reduced capacity.

1’! J

Before entering into the discussion of the
Operation of the plant we should first determine
just what constitutes soft water.

Soft water is a relative term and it was
first brought to the public eye by the variation
in the amount of soap required to produce a
lather in water. The consumer judges the water
to be hard if much soap is required tonproduce
a lather, and soft if it lathers freely. Inves-
tigations have shown that hardness in water is
directly prOportional to the amounts of the
following minerals in the water.

(a) Calcium bicarbonate (limestone).
(b) Magnesium.bicarbonate (magnesite).
(c) Calcium sulfate (gypsum).

(d) Magnesium sulfate (epsom salts).

Accordingly, a water having a large amount
of these minerals is termed a hard water, while
one with a low content is termed Isoft". It is
generally conceded throughout water works lit-
erature, that a water containing less than 100
parts per million of the above mentioned miner-
als OXpressed as calcium.carbonate (CaCOg) is
soft, while anything over that amount is consid-
ered hard. It is therefore necessary to remove
these minerals in order to obtain a soft water,

if they occurs in sufficient quantity to pro-

duce hardness.

The iron content in the water is removed by
passing it through beds of manganese zeolite.
Iron in water results in discoloration of the
water and stains plumbing fixtures. The iron con-
tent is reduced from 1 part per million to less
than 0.1 part per million. The zeolite consists
of sodium zeolite that has been treated with man-
ganese chloride to convert it to manganese zeolite
by base exchange, and then oxidized by sodium or
potassium permanganate.

Reactions:-
Na202-+ MnClg = MnOZ'+ 2NaCl
MnOZ + 2NaMn04 = Na20Z +-Mn0Mn207

The higher oxides of manganese formed in the
second reaction are carried to the surface of the
grains of the zeolite. When water containing iron
is passed through the sand, these oxides give up
oxygen to the water.

Reactions:- ‘
MnOZ-F'MnOMn207 +—4Fe(HC05)2 B
MnOZ-+-3Mn0 4-2Fe203 + 8C02-k'4H20

There are two storage reservors in the dis-
tribution system. The one on the east side has a
capacity of 100,000 gallons and the one on the
west side with a capacity of 50,000 gallons. 1‘

This amount is much too small for a city the

\‘J "

size of East Lansing due to the fact that a cer-
tain amount of water must be left in the bottom
of the tank to act as cushion, which leaves an
available storage capacity of about 100,000
gallons, which will supply only two hours flow
at average demand.

Pumpage varies from 350,000 gallons per day
in the winter to from 800,000 to 1,000,000 gal-
lons per day in the summer. The pressure at which
the water leaves the station is approximately 50
pounds per square inch. Water leaves the plant
through an 8 inch main and is distributed to the
city through 8 inch, 6 inch, 4 inch, and 2 inch
pipes.

The water treatment plant forms a part of
the distribution system. The water comes direct-
1y from the wells to the plant where three-four-
ths of it is passed through the softening units
and the remaining portion is passed through the
iron removal units.

The two water pumps are of the centrifugal
type, one being a five stage and the other is a
six stage.

As was previously stated in this paper the

.

main treatment of the water is that of softening,

which is accomplished by means of zeolite soften-

ers.

The plant consists of a battery of 5 zeo~
lite softening tanks each of which contains 200
cubic feet of zeolite sand. The zeolite sand 4bw‘
costs $5.00 a cubic foot. The tanks are '7 feet 1&0. fl”
in diameter and are 9.0 feet high, "straight fi/fi;
sides". Three fourths of the water is passed
through these 5 tanks and is softened to zero
hardness.

There are also two tanks of the same size,
each of which contains 100 cubic feet of zeolite
sand, and it is the sole purpose of these tanks
to remove the iron from.the remaining portion of
water that is not passed through the 5 softening
tanks.

The first step in the Operation of the
plant is that of softening the water. Raw water
(untreated well water) enters the tOp of the
tank through a 5 inch pipe. The water passes
downward through the zeolite sand bed during
which time the water is softened to zero hard-
ness by means of the hardness compounds being
replaced by the non-hardness compounds,and the
iron content is also reduced at the same time.

The softened water enters a set of small

orifices at the bottom of the sand bed and then

enters a 5 inch pipe through which it leaves

-6...

the softening tank and joins the flow from the
other softening units.

After a definite time interval, equivalent
to the passage of 28,000 gallons of water
through the tank, the zeolite sand in the tank
has practically exhausted its softening capacity
and is ready for regeneration, the first step of
which is washing the sand.

By means of an automatically glectricly 0p-
erated multiport valve, the raw water is now . I
directed into the tank through a 3 inch pipe and
orifice system in the bottom of the tank. Water
passes upward at a sufficient velocity to wash
out material deposited during the softening 0p-
eration. The wash water leaves the tank through
a 3 inch pipe at the tOp of the tank and flows
into the sewer. The rate of wash is controlled
by an orifice-constant-head-box, with a float
controlled valve. After a definite time inter-
val of washing (10 minutes at 230 gallons per
minute for this plant) the tank is ready for
its next step in Operation, which is dosing
with brine.

The automatic multiport valve now Opens
and closes the prOper valves for dosing with

brine, and the brine pump automatically starts

~7-

to pump brine from the brine recovery tank. This
brine is the used brine from the rinsing of the
previously regenerated tank. This recovery brine
enters the tank through a pipe near the tOp of
the tank, and flows down through the zeolite sand
and the effluent from the tank is discharged into
the sewer. This old brine is pumped at a rate of
115 gallons per minute for a period of 15 minutes.
When the brine recovery tank has been emptied a
float switch shuts Off the brine pump and Opens

a diaphram valve on a water pressure line just
ahead of an ejector, which Operates to pump new
brine from the brine measuring tank.

Brine from the brine measuring tank is
pumped by the ejector to the tOp of the softener
and flows down through the zeolite sand, the eff-
luent from the tank going into the sewer. This
flow continues until the prOper amount of satur-
ated brine is added to the tank (HQQSgallons),
after which a float switch closes the diaphram
valve on the water pressure line near the ejector,
Opens the diaphram valve on the brine pipe from
the brine storage, closes the diaphram.valve on
the brine inlet pipe near the tOp of the soften-
er tank and actuates the multiport softening tank
valve to the rinse position.

In the rinsing Operation, raw well water

goes in at the tOp of the tank through the 3
inch pipe. The used brine leaves through the 3
inch pipe at the bottom of the tank, enters an
elevated rate-of-flow control box, which assures
a uniform rate of flow during rinsing, from
which it flows into the brine recovery tank.

After rinsing for a definite time interval
(20 minutes at 115 gallons per minute) the mul-
tiport valve moves again to the softening posi-
tion and a complete cycle of Operation has been
completed.

The fundamental principle in the Operation
of a zeolite softener is the base exchange pro-
cess and is based on the following react10n83~

Softening:-

NaZ-+ Ca or Mg(salts) =
Na salts-t CaZ or MgZ.
Regeneration:-

CaZ or MgZ—+ NaCl ' NaZ-+ Cafllg or MgClg.

 

PROCEDURE OF CHEMICAL ANALYSIS OF SAMPLES

Chloride determination (volumetric method).

In this determination the chloride of the
sample is determined by titration with a stand-
ard solution of silver nitrate in the presence
of potassium chromate indicator. The chloride
is precipitated as silver chloride (a white
precipitate).

NaCl-+ AgNOs = AgCl-+ NaN05

The end-point of the titration is reached
when a brown precipitate of silver chromate
first appears, due to the reaction of a slight
excess of silver nitrate with the potassium
chromate (K20r04-P'2AgN03 8 Ag20r04‘f 2KN05)

a correction of 0.2 m1. is made for the excess
silver nitrate required to produce a noticable
amount of brown precipitate. Hydrogen sulfide
interfers with the reaction precipitating
black silver nitrate.
Hgs-+ 2 AgN05 I AgZS + 2HN03
Procedure:-
1. Pipette 50 ml. of the sample into a
porcelain evaporating dish.
2. Place about the same quantity of dis-
tilled water into a second dish for a

color comparison.

-10..

3. Add 1 ml. of potassium chromate indica-
tor to each.

4. Add standard silver nitrate solution to
the sample from a burette, a few drOps
at a time, with constant stirring until
the first permanent reddish coloration
appears. This can be determined by a
comparison with the distilled water
blank.

5. If more than 7 or 8 ml. of silver ni~
trate solution are required, the entire
procedure should be repeated using a
smaller sample diluted to 50 ml. with
distilled water. Record the ml. of sil-
ver nitrate used.

Calculations:-
(m1. of AgNO; used - 0.2)500 a p.p.m. C1.
ml. of sample
Preparation of sample for determination of
Calcium & Magnesium;-

Measure accurately 250 ml. samples of the
water to be tested, add a few ml. of concen-
trated hydrochloric acid and evaporate to dry-
ness in dishes bver a water bath. Cool and
moisten each residue with a few drOps of con-

centrated hydrochloric acid. Add about 50 m1.

of distilled water and heat to boiling. Filter

through seperate filter papers, washing the
dishes and the residues on the paper with
small portions of distilled water, and add
the washings to the filtrates. The volumes of
the filtrates should be kept below 50 ml.
Removal of Iron & Aluminum Oxides:-

To the filtrate obtained from above add
a few m1. of bromine water and boil for a few
minutes.Add 20 m1. of 10 per-cent ammonium
chloride solution and an excess of ammonium
hydroxide. 8011 for 5 minutes. Filter the sol-
ution through filter paper, rinsing and wash-
ing the beaker and filter paper with small
portions of distilled water. Save the combin-
ed filtrate and washings for the calcium and
magnesium determination, and discard the pre-
cipitate.

Calcium determination:-

Warm the filtrate obtained from the iron
and aluminum determination, add 10 ml. of a
saturated solution of ammonium oxalate drOp
by drOp with constant stirring, (add more of
the oxalate if it is required to precipitate
all of the calcium), and set in,a warm place
for about 50 minutes. Filter and wash the
beaker and the paper with hot distilled water.

Save the filtrate and the washings for the

-12-

magnesium determination. Pierce the filter
paper and wash the precipitate into the orig-
inal beaker with about 50 ml. of 2 per-cent
sulfuric acid, (use a larger quantity of the
acid if necessary to disolve all of the pre-
cipitate). (I also placed the filter paper in
the beaker to make sure that all of the pre-
cipitate was obtained). Heat to boiling and
titrate with standard permanganate.
Calculations:-

Ml. of KMnO4 x 10 3 p.p.m. calcium (Ca).

Magnesium.determination:—

 

To the filtrate saved from the calcium de-
termination, add concentrated ammonium.hydeox-
ide in sufficient quantity to make about one
ninth its volume. (Make definitly alkaline).
Add 10 ml. of sodium acid phosphate solution,
stir vigorously for five minutes, and allow
to stand for at least four hours. Ignite, cool
and weigh a crucible. Filter the precipitate
onto a quantitative filter paper, wash with a
weak solution of ammonia and place in the Dru?
cible. Heat in the oven at about 105 degrees
until the filter paper and precipitate is
thoroughly dry, then place in oven and ignite,

cool and weigh.

~13-

Calculations:-

Gain in weight (grams) x 875.6 = p.p.m.(Mg)
magnesium.
Determination of specific gravity:-

1. Dry and weigh an empty beaker of about 250
ml. capacity and weigh to the nearest 0.1
gram.

2. Pipette 100 ml. of the sample into the
beaker and reweigh to the nearest 0.1 of
a gram.

Calculations:-

Sp. Gr. 3 Weight of sample
M1 0 or S ampie

Determination of sodium:-
1. Find the reacting values (R) of all the

elements.

R 9 (p.p.m. of the element) x 1
equivalent weight of element

2. Find the sum of the reacting values of
both the negative and positive elements.

5.(Sum of negative R values - sum.of the
positive R values) x 25 = p.p.m. Of
sodium.and p0tassium.expressed in terms

of sodium.

PREPARATION OF REAGENTS AND STANDARD SOLUTIONS

Aluminum hydroxide:-

 

Dissolve 125 grams of pure aluminum sulfate
in one liter of water. Add ammonium hydrox-
ide until the precipitation is complete.
Allow to settle and pour off the supernatent.
Wash the precipitate in a large quantity of d
distilled water to remove chlorides, nitrates
and ammonia.

Bromine waterzn

 

Fill a liter bottle almost full of distilled
water. In the hood, carefully pour about 10
ml. of bromine into the bottle. StOpper and
shake. Care should be used in handling bro-
mine as the liquid Or its fumes cause serious
burns.
Ammonium chloride:-(10 %)
Dissolve 100 grams of C.P. ammonium chloride
in distilled and make up to one liter.
Saturated ammonium oxalate:-
Place about 50 grams of C.P. ammonium oxalate
in a liter bottle and fill with distilled

water. Shake and let stand until almost all

of the crystals are dissolved. (Use the su-

pernatent liquid.)

-15-

Sulfuric acid:-(2%)

 

Add 20 m1. of concentrated sulfuric acid
to a liter of distilled water.

Standardgpotassium,permanganate:-(0.125N)

 

Weigh out 5.95125 grams of stock standard
potassium.permanganate and dissolve in one
liter of distilled water.

Di sodium phosphate: - (10%)

 

Dissolve 100 grams of C.P. disodium sul-
fate (NagHP04) in distilled water and make

up to one liter.

-16-

 

Iron Removal Tanks .

-17-

 

Three of The Five Softening Tanks

-184

DISCUSSION

As was stated before in this paper, the econ-
omy of Operation of the softening plant (zeolite
softeners), depends upon the price of salt and the
amount used, and therefore, in order to Operate
most economically, economies must be affected as
much as possible in its use. To do this, the brine
used in the regeneration of a tank is being saved
and used as a preliminary treatment of a succeed-
ing tank.

It is the purpose of this thesis to deter-
mine just what portion of the rinse should be
saved in order to secure the best part of the
used brine.

In collecting the samples for this thesis,
samples were taken at two minute intervals after
the beginning of the rinse period of tank #5.

The rinsing period lasted for about 22 minutes.
Only the first 16 minutes of the flow during the
rinse period is saved at the present time, the
remaining portion being allowed to discharge in-
to the sewer.

Tests were run on these samples to deter-
mine the amounts of chlorine, calcium, magnes-

ium and sodium, in parts per million, by the

-19~

proceedures previously outlined in this paper.

The results of these analysis may be
found in the table on page 21, and by graphs at
end of thesis.

The element of most importance in the re-
generation of zeolite sand is sodium, due to
the fact that softening is accomplished by base
exchange reactions which consists of the hard-
ness compounds, calcium and magnesium, being
replaced by sodium which does not cause hard—
ness. Therefore it is evident that we should
save that portion of the rinse that contains
the largest amounts of sodium. As is shown in
the sodium graph, the first 16 minutes of the

rinse period will give the largest amount of

 

sodium. This is exactly the portion of the
rinse that is being saved at the present time.
During the brining of the tank 80 gallons
of saturated new brine is added to the tank.
A saturated brine solution at 60 degrees F.
contains theoretically 26 per cent of salt. It
is coustomary to ignore solubility as affected
by temperature and to assume an average sol-
ubility of 25 per cent. This solution has a
specific gravity of 1.19228. One gallon of a
saturated brine solution contains practically
2.479 pounds of salt. Eighty gallons of satur-

ated salt brine would contain 198 pounds of

salt of which 79 pounds is sodium.

The average concentration of sodium obtain-
ed by saving the first 16 minutes of the rinse
is 6,059 parts per million. This amount of sodium
is obtained during a flow of 1840 gallons, there-
fore there is 95 pounds of sodium in the rinse
water saved.

Conclusion Drawn:-

It is evident from the above results that
there is some value in the use of the recovery
brine, but just what this value is it is imposs-
ible to say without running mere tests.

Although there is more sodium obtained from
the recovery brine, than there is in the new
brine that is added, the dilution is so great
that it is doubtful as to its value in the regen-
eration of zeolite. The used brine contains 0.051
pounds of sodium per gallon while the new brine
contains 0.265 pounds per gallon.

The value of the recovery brine depends upon
the amount of sodium removed from it in passing
through the zeolite. To determine this you would
have to run the recovered brine through the sand
bed without adding new brine, and then collect
the brine after it has passed through the sand
and re-run the analysis. This determination

would be a problem in itself.

-21-

ANALYSIS OF SAMPLES

 

Time
After
Beginning
of Cholorides Calcium Magnesium Sodium
Rinse LEOReme) (202.31.) (EeEeme) (EeEeme) SE. Gr.
1 min. 1900 569 151 1,050 1.001
5 " 15200 1650 550 5,660 1.015
5 " 15950 1400 515 6,460 1.015
7 “ 27400 5167 680 12,800 1.055
9 " 40600 5065 562 21,700 1.055
11 " 16500 548 458 9,400 1.015
15 " 7500 198 so 4,560 1.004
15 " 4400 .89 55 2,680 1.005
17 " 5150 51 19 1,960 1.002
19 “ 2525 55 14 1,600 1.001
21 " 1925 16 15 1,200 1.001

 

P.P.M.

081011113.

r. .

P.P.M. of calcium taken at 2

   
 
  

minute intervals after the be-

ginning of rinse period.

 

 

 

 

I

 

 

 

I 3' 5’ 7' 9 IV l3 /5’ /7' [9 27

Time of Rinse (In Minutes“ [dc/.2

 

.al

.39 T . i a .P.P.M. of chlorides taken at 2

’minute intervals after the be-

ginning of rinse period.

so
27--~
24
~—2/
As
.flf-

[2 ’

,P.P.M,_thoride$,(Ln.Thoutanda);

.3" — —u. .

O

- 5.41/50 _ =i= 70 Snare—J
135_7'9// /5 If/7/9 2/

 

 

 

Time ,Of Rinse (In, Minutes). 4.11.9

 

      
 

i
I ' - g
b
1- L L -
i i t
; i- t
1: % .
? ;.
’ . i
5 ;-¢ o- __
700 j ' 1 P.P.M. of magnesium taken at
2 minute intervals after the
f "600

beginning Of rinse xtriod.

 

 

 

 

ma Set/£27 . \ 5:76:81
I 3 5' 7 9 fl 3 7 2/

~ v Time Of-Rinse (In-Minutes). .Afiflfi

6
— ~-..._ -- 4.. -.-.—.-- ----

._;.22_.-_-f ' -i '_ . .
. I - - i P.P.M. of sodium taken at 2
. i ‘
;20 ; 3. minute-intervals after the

A5 ' L'" ' ' beginning of rinse period.

A6

A?

~/e

 

 

 

~ I 5.414.627 ' , a 70' Sauce—fl
I 3': z :9 // l3 [3' /7 /9 z/

 

 

.. . Time of-Rinse (Inuinutes). 4MB

 

 

l...: .10!. \oednv ‘l

 

 

 

3 ,
/I 0‘}
I/; 4
A 1 m1
. 3 N. .VreJ 1
xx0 \
“xx/x
J
.. T1. , RM... \Nv
. 41.. -
11... E
80 n0
2... .
__,....w. a...
1......u v.1.
1. .x g...
1 a f
1
'III uolIn-IIII...) dfi.. b... v - I- .l .I u a I a n In I u I . Ilefl lef..h I: I . in It I H. .I II .n I . - |Iu

/.3 3
€23
7%?5

\
I ‘ - f /
'7) foe/’1': (

MICHIGAN STATE UNIVERSI

ll” iulllllflil

3 1293 314

:11)

 

   

w" — e—ii_ .1

n9.

'l'l. '

 

1. ,, . r
{86%. s...» .,

we}. ‘Nl.‘.l.0|b"§“ .

 

 

. .. .343... n .4 0.68... . £553-34}:

     
 

.
. t O . .
In...” his. 00...“!u‘.1‘0).elll.beoes.lo.

.

 

..0 :l‘” 'h .00.. .

I.‘

«A... .4 . .339“... vs