Wastewater Treatment Pacao, Melfren O. (2)

8/12/2019 Wastewater Treatment Pacao, Melfren O. (2)

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WASTEWATERTREATMENT


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METHODS USED FOR

WASTEWATER TREATMENT

PHYSICAL TREATMENT METHODS

CHEMICAL TREATMENT METHODS

BIOLOGICAL TREATMENTMETHODS


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PHYSICAL TREATMENT

METHODS

OPERATION APPLICATION

Screening Removal of coarse and settleable

solids by interception.

Comminution Grinding of coarse solids to a

uniform size.

Flow equalization Equalization of flow and mass

loadings of Biochemical Oxygen

Demand (BOD) and suspended

soils.

Flocculation Promotes the aggregation of small

particles to enhance their removal

by gravity sedimentation.

Sedimentation Removal of settleable solids and

thickening of sludges.


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OPERATION APPLICATION

Floatation Removal of finely divided

suspended solids and particles

with densities close to that of

water; also thickens biological

sludges.

Gas transfer Addition and removal of gas; gas

tripping.

Filtration Removal of fine residual

suspended solids remaining after

biological or chemical treatment.

Microscreening Same as filtration; also removal of

algae from stabilization pond

effluents.


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CHEMICAL TREATMENT

METHODS

PROCESS APPLICATION

Chemical precipitation Removal of phosphorus and

enhancement of suspended solids

removal in primary sedimentation

facilities used for physical-chemical

treatment.

Adsorption Removal of organics not removed

by conventional chemical and

biological methods; also used for

dechlorination of wastewater

before final discharge of treatedeffluent.

Disinfection Selective destruction of disease-

causing organisms, usually with

chlorine or ozone.


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PROCESS APPLICATION

Dechlorination Removal of chlorine residual that

exists after chlorination.

Others Various other chemicals can be

used to achieve specific objectives

in wastewater treatment.


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BIOLOGICAL TREATMENT

METHODS

Biological Treatment involves the

conversion of the dissolved and

colloidal organic matter in wastewater

to biological cell tissue to endproducts.


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HEADWORKSPRELIMINARYTREATMENT


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PUMP STATION

Pumping station is required to raise

the sewage to an appropriate level to

facilitate gravity flow through the plant.


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FLOW MEASUREMENT

Parsall flume - is an empirical rated

measuring device. The dimensions of

the flume are fixed so that there is a

flow transition from subcritical tosupercritical flow. At a critical flow

depth , energy is minimized and there

is a direct relationship between waterdepth and velocity that allows the

flume to act as measuring device.


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Parsall flume


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MAGNETIC FLOW METER


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BAR RACKS AND SCREENS

Bar racks or Coarse screens are used

to remove large solids, rags and

debris. They are installed ahead of

pumps to prevent clogging.

Chain Driven

Reciprocating Rake

Catenary Screen

Continuous Belt


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Reciprocating RakeChain Driven


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Catenary Screen Continuous Belt


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COARSE SOLID REDUCTION

An alternative to capturing coarse

solids using a mechanical device to

shred or grind the solids and return

them to the flow.


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COARSE SOLID REDUCTION

Macerators - are slow-speed grinders

that typically use two sets of

counterrotating blade assemblies. The

tolerance on the macerators bladesassemblies is small enough ( 6 to 9mm

) that the material passing through is

effectively chopped. This choppingaction reduces the potential for

producing ropes of rags and plastic.


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Macerator


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GRIT REMOVAL

Specially designed grit chambers are

used to remove inorganic particles

such as sand, gravel, eggshells and

bone 0.2mm or larger in size toprevent damage to pumps and to

prevent the accumulation of this

material in treatment facilities andsludge digesters.


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GRIT REMOVAL


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ALTERNATIVE PRELIMINARY

PROCESS ARRANGEMENTS


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ALTERNATIVE PRELIMINARY

PROCESS ARRANGEMENTS


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PRIMARYTREATMENTTo remove a significant

fraction of organic

particulate matter(suspended solids).


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SEDIMENTATION

The major function of a plain

sedimentation basin in wastewater

treatment is to remove the larger

suspended material from incomingwastewater.


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SEDIMENTATION

Type I Sedimentation characterized

by particles that settles discretely at a

constant settling velocity. They settle

as individual particles and do notflocculate during settling.

Type II Sedimentation

characterized by particles thatflocculate during sedimentation.


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Type III & IV Sedimentation when

the water contains high concentration

of particles ( for example, greater than

1,000 mg/L ) both Type III ( hinderedsettling ) and Type IV ( compression

settling ) occur along with discrete

and flocculant settling.


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SEDIMENTATION

Circular Tanks Center-Feed Type is more commonly used for primary

treatment wherein wastewater is carried to the center of the

tank by a pipe suspended from a bridge that is encased in

concrete below the tank floor.


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SEDIMENTATION

Rectangular Tanks wastewater is carried to the

tank in a covered channel then enters the tank

through one inlet ports.


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Wastewater Treatment Pacao, Melfren O. (2)

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