experiment 4-oil water separation

8/18/2019 Experiment 4-Oil Water Separation

1/10

1.0 Introduction

Oil/water separators are devices commonly used on Air Force installations as a method to

separate oils from a variety of wastewater discharges. They are typically installed in industrial

and maintenance areas and receive oily wastewater generated during processes such as aircraft

and vehicle maintenance and washing. The effluent from oil/water separators is typically

discharged to either a sanitary sewer system or a storm sewer. Discharges of domestic and

industrial wastewater are regulated under the Clean Water Act (CWA. !roperly designed"

installed" and operated" oil/water separators provide a treatment system for handling oily

wastewater that prevents the entry of unaccepta#le levels of contamination to a storm sewer or

sanitary sewer system. $owever" oil/water separators are generally not designed to separate

solids or high concentrations of oil from water" such as might occur" for e%ample" when a large

&uantity of oil or sludge is spilled or poured into a wash #ay drain. Thus" it is important for all

personnel who discharge wastewater into an oil/water separator to understand how they function"

including their limitations" in order to prevent them from #ecoming sources of environmental

pollution.

Oil/water separators (O/W's are in)line devices used to remove oils and greases (and

sometimes solids from industrial waste streams and storm water discharges. O/W's operate #y

employing various physical or chemical separation methods" including gravity separation" filters"

coagulation/flocculation" and flotation. $owever" the use of any separation process depends on

the properties of the oil in the oil/water mi%ture. The type of O/W' most fre&uently used #y the

Air Force is the gravity separation system. The performance of gravity separation systems is a

function of the relatively low water solu#ility of petroleum products in water and their different

specific gravities. (*OT+, The specific gravity of a petroleum product is defined as its density

divided #y the density of water. 'ince the density of petroleum products is less than that of water"

they will float. 'olids" if present in the waste stream" will generally collect at the #ottom of the

O/W' holding tan- and can #e periodically removed when the tan- is drained for maintenance.


2/10

A drain connected to an oil/water separator may #e perceived as a convenient place to dispose of

any type of li&uid waste or sludge. This erroneous assumption can result in illegal discharges of

haardous su#stances to installation sewer systems (which eventually discharge to surface

waters or wastewater treatment plants. The illustration in Figure shows" in simplified form" the

operation of a typical gravity O/W' system.

Figure 1: Conceptual Diagram of a Simple Gravity Oil/Water Separator.


3/10

The following chemicalwere prepared:-20 L of

water (heavy phase) andedible oil (light phase)

Ensure that all valves areclosed (screwed in) !essel

"# was feed $lled withwater and feed vessel "2

with oil

!alves !# and !2 waopened %eed pumpsand &2 was switched

and ad'usted the settto give a ow rate o

#0Lhr each

The mi*er +# was swithon and set the speed

,00 rpm

"oth the water (heavy

phase) and oil (light phase)was allowed to enter themi*ing chamber Ensurethat both phases are well

mi*ed

The ow of mi*ed liuids

into the settling chamberto form two layers wasobserved The interfacelevel was watched andad'usted as necessary

using valve L!#

"oth liuid was allowed tooverow into their

respective collectionvessles ". and "/ !essel

". will contain theseparated water (heavy

phase) while vessel "/ willcontain the separated oil

(light phase)

The pumps was stoped

!alves !# and !2 wasclosed

The plant is now ready

e*periment

.0 !et"odology

0eneral 'tart)up !rocedures

0eneral 'hut)Down !rocedures


4/10

"oth pumps and &2 was switched o

The mi*er +# was switched o

!alves !# and !2 was closed

!alves !1 and !#0 was opened to drain alli-uid from the mi*er settler

!alves !#, and !# was opened to drainall li-uid from the receiving vessels ".abd "/

#.0 $e%ult%


5/10

&a'le #.1: (reparation of Den%ity again%t Compo%ition (lot

)olume of Oil *m+, )olume of Water

*m+,

Oil Compo%ition

*-t ,

Den%ity *g / cm#,

1 11 1 1.2234

1 21 1 1.2253

51 41 51 1.2464

61 71 61 1.2891

91 81 91 1.2857

31 31 31 1.2938

81 91 81 1.2665

71 61 71 1.256441 51 41 1.2551

21 1 21 1.276

11 1 11 1.2182

0 #0 20 .0 /0 ,0 0 30 40 10 #0004

044

01

012

01/

01

014

#

Density vs Composition


6/10

Figure #.1: Grap" of Den%ity *g / cm#, again%t OilWater Compo%ition *-t ,

&a'le #.: Compo%ition again%t flo- rate

Oil Flo-

rate *+ /

"r,

Water

Flo- $ate

*+ / "r,

&otal

Flo- $ate

*+ / "r,

Separated Water Separated Oil fficiency

Den%ity

*g / cm#,

Oil

Compo%ition

*-t ,

Den%ity

*g / cm#,

Water

Compo%ition

*-t ,

1 1 51 1.228 *ot :alid 1.2286 *ot valid )

51 51 91 1.2237 1.616 1.228 *ot :alid 1.22

61 61 81 1.2237 1.616 1.2237 1.616 1.2291 91 41 1.2238 1.818 1.2299 9.595 1.22

.0 Di%cu%%ion

Oil water separation is a physical process of water treatment to remove partition of oil toachieve #etter &uality of water. With constituent of oil presence in water" it can adversely

affected the &uality of water as it had loss the purpose of water to serve for drin-ing purpose. *ot

only have that" oil)water separation also vital in preliminary treatment to allow #etter efficiency

in primary treatment. A coagulation process is not satisfying enough when there is oil present in

water" leading to cause only slight tur#idity reduction. Although the water is not utilied for

drin-ing purpose" oil is still re&uired to #e removed to a certain level as prescri#ed under

+nvironmental ;uality (ective of e%periment was to operate a li&uid)li&uid separation e%periment

using a single stage mi%er settler. The principle of oil)water separation is #ased on differential in

density. First" oil and water from separated tan- were pumped out at e&ual flow rate" allowing

them to physically contact to each other. ?oth of the flow rate first were set to 1 @/ hr. At

interval of 1 minutes" the flow was read>usted to 51" 61 and 91 @/ hr. Then" at a rendevous


7/10

point" the mi%ture achieved total flow rate #efore entering a single stage mi%er settler. The settler

is named single stage #ecause it involve only one time of mi%ing process as well one time

settling process. On the other hand" for multiple stage mi%er settler" mi%ing and settling steps are

repetitive depending on the num#er of stages. At mi%er settler" a rotating #lade is installed

vertically" operated to promote coalescence of oil. This will ma-e the oil particle accumulated

into #igger sie. There" the layer of oil can #e seen clearly and start to separate from water.

?ecause the density of oil is lower than water" oil partition tend to float due to action of

gravitational force.

Then" a coalescing plate is installed vertically.


8/10

2.0 Conclu%ion

Oil)Water separation process was done #y their differential in physical properties which

is the density. The density factor ensure the efficiency of separation. ?esides" the composition

also #ecame one of the main factor. The efficiency was possi#le to #e achieved at high value if

the content of oil in wastewater is significant.

?ased on the e%periment conducted" the efficiency achieved for all three valid flowrates

was 1.22. This showed that" regardless of flowrate applied" the separation #etween oil and water

is successful. $owever" an improvement have to #e made for ac&uiring #etter data relia#ility.

$eference%

Davis" ." B asten" '. (5119. Principles of environmental engineering and science. *ew

or-" *, c0raw)$ill.

@ee" D." ?ateman" W." B Owens" *. (5117. +fficiency of Oil/Water 'eparation Controlled #y

0as ?u##le 'ie and Fluid Dynamics within the 'eparation :essel.


9/10

3ppendi4

'ample Calculation for efficiency"

+fficiency E (Amount of oil in separated water / Amount of oil entering the mi%er settler

) ((1.616 % 51 @ / hr of average flowrate % 1 minutes of residence time

GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG

51 @ / hr of average flowrate % 91 minutes of residence time

1.22


10/10

experiment 4-oil water separation

Documents