Sewage Treatment Plant.ppt treatment... · organic matter is aerated in an aeration basin in...

Treatment of Domestic Sewage

QUALICOM solutions pvt ltd.

Basic Water Chemistry

Sewage or Effluent is the waste caused out of adverse anthropogenicimpact on water flowing out of factory , farm , commercialestablishment or a household and discharged in a water body.


Domestic or Sanitary sewage carries body waste , washing and food preparation waste , laundry waste and other waste products of normal living.


All categories of sewage are likely

• To carry pathogenic organisms that can transmit disease to humans and other animals• To contain organic matter that can cause odor nuisance and other problems • To hold nutrients that may cause eutrophication of receiving water bodies • To lead to ecotoxicity


Major contaminants in waste water are

Soluble OrganicsSuspended Solids

Oil , Grease & Floating materialsNitrogen & Phosphorus

Refractory & Trace Organics

Organic Pollution and Its Impact

Organic pollution can happen from sources such as domestic sewage , septic tank leakage / overflow , floor wash etc .

It could also be in the form of inorganics from domestic or industrial sources. Algal blooms grow on inorganic nutrients like nitrates , phosphates calcium etc.


Bacteria which feeds on the dead algae and other dead organic matter and is a part of the decomposition cycle , requires oxygen to survive.

With abnormally high levels of bacterial activities the dissolved oxygen level may fall dramatically.


Oxygen consumed in the decomposition process robs other aquatic organisms of the oxygen that they need to live.

In most cases when the Dissolved oxygen levels go below 5 ppm , fish cannot live for long.

Measure of Organic Pollution

Biological Oxygen Demand ( BOD ) : It is the amount of dissolved oxygen needed by micro organisms in a body of water to break down organic material present in a given water sample at a certain temperature over a specific time period. BOD is most commonly expressed in ppm of O2 consumed during 5 days of incubation at 20 deg C.

design parameters

Sewage Treatment Plant

water consumptionThumb Rules

Housing Colonies : 135 ltrs per person / day

Offices & Commercial : 40 - 70 ltrs per person / day

Hospitals : Wide Variation

200 - 400 Litres / Bed / Day

35 - 40 Litres / Out Patient

135 Litres / Person For Residential

Influent ( input ) Parameters

Biological Oxygen Demand : < 500 mg / ltr

Chemical Oxygen Demand : < 1000 mg / ltr

pH : < 7 ( neutral )

Oil & Grease : < 50 mg / ltr

Suspended Solids : < 400 mg / ltr

Effluent ( output ) Parameters






Parameters for Reuse






STAGES OF TREATMENT

PHYSICAL PHYSICAL SCREENING SCREENING

BIOLOGICAL BIOLOGICAL TREATMENTTREATMENT

FILTRATIONFILTRATION

Physical Screening

It prevents the floatables and bigger It prevents the floatables and bigger suspended solids from entering the suspended solids from entering the biological reactors.biological reactors.

is done by manually operated Bar Screens .is done by manually operated Bar Screens .

EFFLUENTEFFLUENTWATERWATER

TREATED TREATED WATERWATER

TREATEDTREATEDWATERWATER

BACTERIA BACTERIA

IN IN PRESENCEPRESENCEOF OF

AIRAIR

BACTERIA BACTERIA IN IN ABSENCEABSENCE

OF OF

AIRAIR

AEROBIC REACTIONAEROBIC REACTION ANAEROBIC REACTIONANAEROBIC REACTION

Biological Treatment

the the treatmenttreatment philosophyphilosophy

InIn thethe AerobicAerobic processprocess micromicro organismsorganisms feedsfeeds onon thethe biobio

degradabledegradable organicorganic materialmaterial inin presencepresence ofof OxygenOxygen..

There are 2 major processes employed in the Aerobic treatment :There are 2 major processes employed in the Aerobic treatment :

Suspended Growth ProcessSuspended Growth Process

Attached Growth ProcessAttached Growth Process

EVOLUTION OF TECHNOLOGY

Stabilization

and

Oxidation Pond

SUSPENDED GROWTH PROCESS

A stabilization pond or "oxidation pond“ is usually a shallowearthen basin of controlled shape.

The ponds are usually 2 to 4 feet deep. Within an oxidationpond heterotrophic bacteria degrade organic matter in thesewage which results in production of cellular material andminerals.The production of these supports the growth of algae in theoxidation pond. Growth of algal populations allows furtherdecomposition of the organic matter by producing oxygen.

The production of this oxygen replenishes the oxygen usedby the heterotrophic bacteria.

SUSPENDED GROWTH PROCESS – STABILISATION POND

Aerated Lagoons


An aerated lagoon or aerated basin is a treatment pond provided with artificial aeration to promote thebiological oxidation of wastewaters .

SUSPENDED GROWTH PROCESS – AERATED LAGOONS

Aerated lagoons are relatively shallow lagoons in which wastewateris added at a single point either at the edge or middle of the lagoonand the effluent is removed from another point.

The retention time is a function of the percent removal of BOD. Theretention time may vary from 6 to 18 days.

Oxygen is supplied by means of surface aerators or by diffusedaeration units


Activated Sludge Process

SUSPENDED GROWTH PROCESS – ACTIVATED SLUDGE PROCESS

In activated sludge process wastewater containing organic matter is aerated in an aeration basin in presence of microbial suspension.

The new cells formed in the reaction are removed from the liquid stream in the form of a flocculent sludge in settling tanks. A part of this settled biomass, described as activated sludge is returned to the aeration tank and the remaining forms waste or excess sludge.

Trickling Filters

ATTACHED GROWTH PROCESS

Trickling filter is an attached growth process i.e.process in which microorganisms responsible fortreatment are attached to an inert packing material.

Packing material used in attached growth processesinclude rock, gravel, slag, sand, redwood, and a widerange of plastic and other synthetic materials.

ATTACHED GROWTH PROCESS – TRICKLING FILTERS

Rotating Biological Contactors


ATTACHED GROWTH PROCESS – RBC

A series of circular lightweight rotating discs are mountedon a shaft through which wastewater flows. The partiallysubmerged discs rotate through the wastewater slowly.

The disks are most commonly made of high-densityplastic sheets and are usually corrugated to increase thespecific surface area . The surface of the disks providesan attachment site for bacteria and as the discs rotate, afilm of biomass grows on their surfaces.This bio film is alternately exposed to either the air or thewastewater as it rotates. The oxygen necessary for thegrowth of these microorganisms is obtained by adsorptionfrom the air as the bio film on the disk is rotated out of theliquid. As the bio film passes through the liquid phase,nutrients and organic pollutants are taken up.

Submerged Aerobic Fixed Film


ATTACHED GROWTH PROCESS – SAFF

Submerged Aerobic Fixed Film or SAFF is ahigh rate attached growth aerobic treatmentsystem wherein the bacterial growth takes placeon a media submerged in wastewater.

SAFF incorporates the advantages of fixed filmtechnologies and combines with them the finebubble diffused aeration techniques, to get anefficient biological treatment unit.

Moving Bed Bio Reactor


TheThe most effective most effective AEROBIC REACTOR AEROBIC REACTOR

Moving Bed Bio Moving Bed Bio Reactor ( MBBR )Reactor ( MBBR )

Moving Bed Bio ReactorMoving Bed Bio Reactor

Moving Bed Bio ReactorMoving Bed Bio Reactor

Equalization Tank

• Dampens / absorbs fluctuations.

• Homogenizes effluent.

• Uniform feed to biological system

Unique Features of MBBR Unique Features of MBBR

The Carrier Elements provide large surface area for Bacterial growth.

The Carrier Elements are in Continuous Movement ensured by the air bubbles supplied by air diffusers.

Bio Film Carrier ElementsBio Film Carrier Elements

The Most important feature of MBBR is the specially designed floating Carrier Elements .


Bio Film Carrier ElementsBio Film Carrier Elements

High Specific Area

> 400 m2/m3

Supports very high bio mass in a small volume

Low Specific Gravity

< 0.35 kg/m3

Always remain in suspension

High PSA /TSA ratio

> 90 % Ensures that Bio film is more stable

High void ratio > 95 % Ensures of non clogging of media


Air DiffusersAir Diffusers

Air Bubbles are supplied inside the reactor by means of Membrane Diffusers.

The diffusion efficiency of Oxygen is a function of the size of the bubbles and the depth of water present over the Diffuser.


Air DiffusersAir Diffusers

Two functions of Air Diffusers are

1. Supply of Dissolved Oxygen

2. Create fluidisation of the Carrier Elements


Tube SettlersTube Settlers

All modern MBBR designs incorporate a All modern MBBR designs incorporate a Tube Settler Clarifier subsequent to the Tube Settler Clarifier subsequent to the MBBR for proper Separation of Sludge .MBBR for proper Separation of Sludge .


Tube SettlersTube Settlers

Tube settlers , properly designed provide for an increased effective settling area.

The particle settling depth in a tube settler is significantly lesser than a conventional settler , reducing settling time.

Process of Operation (MBBR) Process of Operation (MBBR)

Advantages of MBBR Advantages of MBBR

Space Requirement is almost 30% of Space Requirement is almost 30% of conventional conventional

Activated Sludge Process ( ASP ) Activated Sludge Process ( ASP )


MBBR is a self sustaining design . MBBR is a self sustaining design . Does not require too much of Operator interference.Does not require too much of Operator interference.

In Conventional ASP design , MLSS and other parameters In Conventional ASP design , MLSS and other parameters needs to be monitored daily . needs to be monitored daily .


In MBBR sludge generation in low and In MBBR sludge generation in low and stabilisedstabilised..

It does not require Sludge Recycling as in Conventional It does not require Sludge Recycling as in Conventional designs. designs.


MBBR design can tolerate occasional Power cuts and MBBR design can tolerate occasional Power cuts and shut offs. shut offs. In Conventional ASP designs performance gets affected In Conventional ASP designs performance gets affected during power cut offs.during power cut offs.


In MBBR design capacity enhancement to some extent is In MBBR design capacity enhancement to some extent is possible.possible.

QUALICOM QUALICOM THE THE

QUALITY QUALITY EXPERIENCEEXPERIENCE

QUALICOM as an engineering house has successfully erected and commissioned more than 50 Sewage Treatment Plants of various sizes.

QUALICOM is the first to design , supply and commission sustainable Effluent Treatment Plants for Rice Mills.

With offices in West Bengal and Orissa , QUALICOM is a team of more than 40 engineers employed in Design , Engineering , Execution and Commissioning.

THANK YOU THANK YOU

Sewage Treatment Plant.ppt treatment... · organic matter is aerated in an aeration basin in...

Documents

Transcript of Sewage Treatment Plant.ppt treatment... · organic matter is aerated in an aeration basin in...