PRIMARY WASTE WATER TREATMENT

SUBMITTED BYKANCHANB.Tech 3RD YEAR(CE)BANASTHALI UNIVERSITY

WHAT IS WASTE WATER? Wastewater is a liquid waste ,which consists of animal, vegetable or chemical matter in water.

Waste water contain pathogens(disease causing organisms).

It must be treated before it can be used or released back into the environment.

5 major Sources of waste water

InsdustrialIrrigationDomestic/Residen-tialPublic Supplied In-dustrial,CommercialMining

Purpose Of Wastewater Treatment

To manage water

discharged From homes,

businesses, and industries to reduce the threat of water

pollution.

Primary Treatment

Secondary Treatment

Tertiary Treatment

3 Stages Of Wastewater Treatment

-Typical Materials That Are Removed During Primary Treatment Include # Fats, Oils, And Greases (Aka FOG) #Sand, Gravels And Rocks (Aka Grit) #Larger Settleable Solids Including Human Waste, And Floating Materials .

- Protects Pumps And Equipment From Damage

PRIMARY TREATMENT

METHOD USE IN PRIMARY TREATMENT

ScreeningComminutarGrit removalPrimary sedimentation

SCREENINGScreening Devises Are Used To Remove Solids From Waste Water. Solids Consists Of Sticks, rags, boards And Other Large Object.

TYPES OF SCREENS

SCREENS

Coarse screens6 to 50mm

Hand cleaned

Mecanically cleaned

Reciprocating rake screen

Microscreens<0.5 micrometer

Fine screens<6 mm

drumStaic

wedge wire

THESE TYPE OF

SCREEN ARE USED

TO PROTECT

PUMPS , VALVES

AND PIPELINES

FROM DAMAGE OR

CLOGGING BY RAGS

AND LARGE OBJECTS.

COARSE SCREEN

HAND CLEANED CORSE SCREEN

They Are Also Known As Bar Screens.Bar Spacing Traditionally OfApproximately 6 To 50mm And Inclined At 45° To 60° To The Flow. Screens Are Cleaned Manually If The Object Caught Is Larger.The Main Advantage Is That No Power Required.The Main Disadvantage Is That Manual Labour Required To Clean The Screen.

MECHANICALLY CLEANED SCREENS

RECIPROCATING RAKE(CLIMBER) SCREEN

The advantage is that parts which required maintenance are above water line.

The disadvantage is that screen may have limited capacity in handling heavy screenings loads.

MICROSCREENS

The Filter Fabrics Have Openings Of <0.5 micrometer And Are Fitted On The Drum Periphery. The Waste Water Enters The Open End Of The Drum And Flows Outward Through The Rotating Drum Screening Cloth. These Type Of Screen Are Used In Secondary Treatment.

FINE SCREENS

1. STATIC WEDGE WIRE

They Have 0.2 To 1.2mm

Clear Openings And Are

Designed For Flow rates

Of About 400 To

1200 L/m2.min.Head Loss

Ranges From 1.2 To 2 m.

2. DRUM SCREENTHE SCREENING MEDIUM MOUNTED IS MOUNTED ON A CYLINDER THAT ROTATES IN A FLOW CHANNEL.THE WASTEWATER FLOWS INTO ONE END OF THE DRUM AND OUTWARD THROUGH THE SCREEN WITH SOLID COLLECTION ON THE INTERIOR SURFACE.

COMMINUTORA comminutor, also known as the grinding pump, cutting screen. This cutting screen shreds any large chunks of organic matter in the wastewater into smaller pieces. This prevents the large chunks from harming the internal workings of the treatment plant.

GRIT REMOVAL

A grit is pieces of rock, metal, bone, and even egg shells, which are denser than organic materials, to settle out of the waste stream. Removal of grit prevents damage to machinery through abrasion or clogging.

GRIT CHAMBER In these type of

chamber a constant flow rate is passed Through the chamber and the heavy particle of water settle down and collected in the bottom of the channel.

PRIMARY SEDIMENTATION

Remove Organic Solid(oil,grease)from Waste Water.It Proceed Type 2 Settling.Organic Material Settles Down Usually In The Range 1 To 2.5m/HrSludge Should Be Remove Before Anaerobic Condition Develop.

CONCLUSION

Through Primary Treatment,large Particle Or Inorganic Substances Are Removed From The Water.The BOD Present After Primary Treatment Is 140 mg/l And TSS 130 mg/l.