Design of effluent treatment plant

ASeminar on
DESIGN OF EFFLUENTTREATMENT PLANT
Submitted by :
Mr. Shankar Yelmame
F.Y.M.Pharm (QAT)
Amrutvahini College Of Pharmacy,
Sangamner

INTRODUCTION
Effluent treatment Plant covers the mechanisms and processes used to treat
such waters that have been contaminated in some way by anthropogenic
industrial or commercial activities prior to its release into the environment or
its re-use.
This effluent contains several pollutants, which can be removed with the help
of an effluent treatment plant.
ETP treat water and make free from all objectionable impurities present in
suspension, colloidal or dissolved form.

Why do weneed to treat Effluent?
To prevent groundwater pollution
To prevent sea shore
To prevent soil
To prevent marine life
Protection of public health
To reuse the treated effluent
For agriculture
For groundwater recharge
For industrial recycle
Solving social problems caused by the accumulation of wastewater

MajorTreatment units in ETP
Preliminary Treatment
Screens
Detritor /scrapers
Grit Chamber
Skimming Tanks
Aeration
Primary Treatment
Sedimentation/ Settling tank
Clarifloculator
Equalization Tank
Neutralization Tank
Secondary Treatment
Activated Sludge Process (ASP)
Trickling Filter
Aerated Lagoons
UASB
Multiple Evaporator (ME) Plant
Rotating Biological Contactors (RBC)
Tertiary Treatment
Sand/ Membrane Filters
Activated Carbon Filters
Disinfection
Ion-exchange/ESP
Nutrient Removal

Preliminary Treatment
Preliminary treatment removes gross solids and materials that can be easily
collected from the effluent and can damage or clog the pumps and skimmers of
primary treatment clarifiers.
These are in-organic materials and insoluble organic pollutants (i.e. large
floating and suspended solid matter, grit, oil & grease) which are inert and
cause problems to further chemical and biological treatments.
The presence and sequence of preliminary treatment units are totally depend
upon the characteristic of effluent that is to be treated.
All preliminary treatment consist of physical separation techniques by
controlling flow rate of effluent.

Mechanical medium screen Fine screen
Corse bar screen

Preliminary Treatment- Grit chamber
 Grit Chamber is used for removal of inert inorganic material consist of sand,
ash, cinder, silt, clay, glass pieces, etc.
 It provides safeguard against ant damage to pumps, pipes and other
equipments by avoiding settling in pipe bends and channels.
 The eliminated material is collected from chamber and used for land-filling,
road making and on sludge drying beds.
Major objectives :
Protection of pumps, valves, piping, etc.
Minimizing chances of pipe chocking with in-organic inert material.
Preventing grit from occupying volume in primary and biological treatment
units.

Preliminary Treatment- Skimming tank
 Skimming Tank is used for removal of oil and grease consist of fats, waxes,
fatty acids, soaps, mineral oils, etc. present in emulsified condition in effluent.
 These materials have low solubility in water, therefore not readily available for
biological treatment and often accumulate on surface in form of scum causing
foul odors.
 The efficiency can be improve by aeration, chlorination or vacuum floatation.
Objectives:
Removal of scum (oil & grease) which can otherwise create problem in
biological treatment units.
Increases DO content and remove undesirable gases.
Enhances flocculation of suspended particles.

Skimming Tank with separated oil & grease at top
Collection of separated oil & grease at edge

Primary Treatment
Primary treatment consists of temporarily holding the sewage in a inert
basin where heavy solids can settle to the bottom while oil, grease and
lighter solids float to the surface.
The settled material go for sludge treatment and floating materials are
skimmed off. The remaining liquid is passed to secondary treatment.
Tanks are usually equipped with mechanically driven scrapers that
continually drive the collected sludge towards a hopper in the base of the
tank where it is pumped to sludge treatment facilities.
Primary treatment can be either only physical or can be combined with
chemical methods depending upon the effluent characteristics.
At this stage, over 70% of the suspended solids and 40% of the BOD is
removed from effluent.

Circular Primary Settling Tank Rectangular Settling Tank
Working of Settling Tank

Secondary treatment
Secondary treatment is a biological treatment of effluent which is typically
performed by indigenous, water-borne micro-organisms in a managed habitat.
The most common micro-organisms are bacteria (aerobic or anaerobic),
protozoa and rotifers; least common are fungi and algae.
After secondary treatment almost 70-90% of BOD and 80-90% of dissolved
solids are removed from effluent.
Example : Rotating Biological Contactor

ROTATING BIOLOGICAL CONTACTOR
Consists of a series of closely spaced plastic circular
disks
Disks are submerged in wastewater and rotated slowly
through it.
 Operation : biological growths become attached to
the surfaces of the disks and form a slime layer over the
entire wetted surface.
The rotation of the disks contacts the biomass in the
wastewater ,then with the atmosphere for adsorption of
oxygen.
Biomass uses the oxygen & organic matter for food thus
reducing the BOD in the wastewater.

Trickling filters bed
• Spread wastewater over
microorganism
• made of coke
(carbonized coal),
limestone chips or
specially fabricated
plastic media
• Optimize their thickness
by insect or worm
grazing

SUSPENDED FILM SYSTEMS
Stir & suspend microorganisms in waste water.
They absorb organic matter &nutrients from waste water.
After hours, they settle as sludge……..
Ex…..Activated sludge system..etc

LAGOON SYSTEMS
 Consist of in-ground earthen basins in which the waste is detained for
a specified time and then discharged.
They take advantage of natural aeration and microorganisms in the
wastewater to remove sewage.

Tertiary Treatment
Tertiary treatment is the final treatment, meant for ‘polishing’ the
effluent and removal of pollutants which are not removed in primary
and secondary treatment.
These pollutants may include soluble inorganic compounds such as
phosphorous or nitrogen which may support algal growth in receiving
waters.
Treatment stages – Tertiary treatment :
• Remove disease-causing organisms from wastewater
• 3 different disinfection process
• Chlorination
• UV light radiation
• Ozonation

Chlorination
• Most common
• Advantages: low cost &
effective
• Disadvantages: chlorine
residue could be harmful to
environment

UV light radiation
• Damage the genetic
structure of bacteria,
viruses and other
pathogens.
• Advantages: no chemicals
are used
• water taste more natural
• Disadvantages: high
maintenance of the UV-
lamp

Ozonation
• Oxidized most pathogenic microorganisms
• Advantages: safer than chlorination
fewer disinfection by-product
• Disadvantage: high cost

What can effluent use for?
• Discharged into a stream, river, bay, lagoon or wetland
• Used for the irrigation of a golf course, green way or park
• If it’s sufficiently clean, it can be used for groundwater recharge

Design of effluent treatment plant

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