Membrane Processes for Waste Water Treatment

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Membrane Processes For Waste Water

Treatment

By:

Rohit Chaurasia

3rd B. Tech. Civil Engineering

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ContentsContents1. Introduction2. Stages in waste water treatment

3. Conventional waste water treatment techniques

4. Processes and equipments

5. Membrane bioreactor processes

6. Advantages and Disadvantages of MBR

7. Conclusions


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IntroductionIntroduction

y Wastewater treatment is the process of taking

wastewater and making it suitable for discharge back

into the environment.

y Wastewater can be formed by a variety of activities.

y

Using advanced technology it is now possible to re-usesewage effluent for drinking water.


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Stages in waste water treatmentStages in waste water treatment

PRIMARY

SECONDARY

TERTIARY


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CONVENTIONALCONVENTIONAL

WASTE WATERWASTE WATER

TREATMENT TECHNIQUESTREATMENT TECHNIQUES


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Physical/Chemical TreatmentPhysical/Chemical Treatment

SystemsSystems

Physical Process

The water is pumped into large tanks where matter settles or sinks,just like in a biological treatment system.

aided by the addition of flocculants and dissolved air.

Chemical Process

Chemical processes include added chemicals to precipitate dissolvedmaterials.


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Biological Treatment SystemBiological Treatment System

y Biological treatment systems use bacteria

and other biological matter to break

down waste.

wastewater isscreened to

eliminate easily

removed objects

the wastewateris taken to a

primary settlingbasin where

matter can float

or sink in thetank

The remainingwater is thensent to thesecondary

treatment tank


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PROCESSES AND

PROCESSES ANDEQUIPMENTSEQUIPMENTS


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Screening Removal System

Grit Removal System

Clarification

Filtration

Sludge Dewatering

Solar Drying of Sludge


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MEMBRANE BIOREACTORMEMBRANE BIOREACTORPROCESSESPROCESSES


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Introduction to MBRIntroduction to MBR

y Membrane bioreactor(MBR) technology combines the use of

biological processes and membrane technology to treat

wastewater and provide organic and suspended solids removal.

y Produces a tertiary standard effluent of 5: 5: 5 BOD: Suspended

Solids: Ammonia.

y Contains an ultra-filter or micro-filter membrane unit.

y It can be operated in either an AEROBIC or ANAEROBICmode,increasing the spectrum of chemicals suitable for biological

treatment.


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Membrane TechnologyMembrane Technology

y These processes differ depending on the

type of substance to be removed.

y Membrane types can be broadly placed

into four categories as shown ahead:


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Micro FiltrationMicro Filtration

y Filtration by particle size.

y Removes e.g. colloidal silica, oil emulsion, Collidocillus

staphylococcus.

y Used for wastewater treatment.

y Membrane size: 0.1 - 10 m.


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Ultra FiltrationUltra Filtration

y Selectively filters only molecules of a specified size and

weight.

y Removes various viruses.

y Used for sterilization, clarification, wastewater

treatment.

y Membrane size 1 - 0.01 m.


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NanofiltrationNanofiltration

y Used for partial desalination.

y Removes e.g. sucrose, egg albumin.

y Used for blood osmosis, blood fitration, water

purification.

y Membrane size: 10 - 0.001 m.


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Reverse OsmosisReverse Osmosis

y A filtration process used for complete desalination.

y Used for blood osmosis, blood filtration, water

purification.

y Membrane size: 10 - 0.001 m


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Electro dialysisElectro dialysis

y This is a process in whichelectrically chargedmembranes are used toseparate ions from watersolutions by the effect of adifference of electricpotential.

y May have up to 400 cationicand anionic membranes.

y Convenient for very highconcentrations (between 0.5and 1 gram per litre)


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Membrane materialsMembrane materials

y Some of the polymers most frequentlyused as materials for membranes are:

Polycarbonate.

Polyvinylidene-flouride. Polytetrafluoroethylene.

Polypropylene.

Polyamide.

Cellulose-esters.

Polysulfone.

Polyetherimide.


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Membrane ProcessesMembrane Processes

Cross Flow Filtration

Dead End Filtration


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ADVANTAGES ANDADVANTAGES ANDDISADVANTAGES OFDISADVANTAGES OF

MBRMBR


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AdvantagesAdvantages

Cost-effective - low life-cycle costs.

Difficult contaminants degraded.

High-quality effluent produced.

Recovery of high-value products. Recovery of energy.

Increase of productivity.

Improvement of quality.

Creation of new products. Easy to expand the system.


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DisadvantagesDisadvantages

y The disadvantages include:

The problem ofFOULING.

Membrane malfunctioning.


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ConclusionsConclusions

y Study of the effluent quality produced by conventional

secondary treatment processes reveals that such

treatment methods do not remove many pollutants.

y The advantages of MBR show that it is the best option

economically, socially, environmentally and sustainably.

y Can achieve cost effective wastewater regulatory

compliance.


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Membrane Processes for Waste Water Treatment

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