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SEWAGE TREATMENT AND MANAGEMENT

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					SEWAGE TREATMENT AND
    MANAGEMENT
              DHEEMAN BHUYAN,
     DEPARTMENT OF MECHANICAL ENGINEERING
DISHA INSTITUTE OF MANAGEMENT AND TECHNOLOGY
         ORIGIN OF SEWAGE

Each time you flush the toilet or you wash
something down the sink's drain, you create
sewage.
"Why not simply dump this wastewater onto
the ground outside the house, or into a nearby
stream?"
        WHY IS TREATMENT
          NECESSARY?
  There are three main things about wastewater
  that make it something you don't want to
  release into the environment:
1.It is putrescent.
2.It contains harmful bacteria.
3.It contains suspended solids and chemicals
  that affect the environment.
       SEWAGE TRANSPORT
 Sewage is transported by sewers to either
 water treatment plants or directly into water
 bodies.
 Sewer systems may be classified as
1. Effluent sewer
2. Sanitary sewer
3. Storm drain
4. Combined sewer
       TREATMENT PROCESS
  Treatment of sewage can be either private or
  public.
1.Private treatment
  Where it is too expensive to install large scale
  treatment plants, sewage treatment may be
  done using septic tanks.
SCHEMATIC DIAGRAM OF A SEPTIC TANK
2. Treatment in water treatment plants
   In urban and suburban areas where people
   are packed closer together and where there is
   a lot more wastewater to treat, the community
   will construct a sewer system that collects
   wastewater and takes it to a wastewater
   treatment facility.
Process Flow Diagram for a typical large-scale
              treatment plant
                 Pre-treatment
• Pre treatment involves
  the removal of waste
  matter that can easily be
  removed.




                          Primary   Screw pumps
                          screen
               Primary treatment
• This involves primary
  sedimentation in the
  primary clarifiers.
• The tanks are large enough
  for the sludge to settle and
  floating material such as
  grease and oils to rise to
  the surface so that they
  may be skimmed off.
    Purpose of primary treatment
• The main purpose of the primary
  sedimentation stage is to produce both a
  generally homogeneous liquid capable of
  being treated biologically and a sludge that can
  be separately treated or processed.
• Primary treatment removes half of the solids,
  organic materials and bacteria from the water.
           Secondary treatment
• Secondary treatment is
  designed to
  substantially degrade
  the biological content of
  the sewage derived
  from human waste, food
  waste, soaps and
  detergents.
                              Secondary clarifier
• The majority of
  municipal plants treat
  the settled sewage
  liquor using aerobic
  biological processes.
• Secondary treatment,
  removes organic
  materials and nutrients.   Aeration Tank
  This is done with the
  help of bacteria
               Tertiary Treatment
The third stage, known as tertiary
treatment, varies depending on
the community and the
composition of the wastewater.

Typically, the third stage will use
chemicals to remove phosphorous
and nitrogen from the water, but
may also include filter beds and
other types of treatment. Chlorine
added to the water kills any          Final Clarifier
remaining bacteria, and the water
is discharged.
                Disinfection
The purpose of disinfection in the treatment of
wastewater is to substantially reduce the number of
microorganisms in the water to be discharged back
into the environment. The effectiveness of
disinfection depends on the quality of the water being
treated (e.g., cloudiness, pH, etc.), the type of
disinfection being used, the disinfectant dosage
(concentration and time), and other environmental
variables.
             Odour Removal
• Early stages of processing tend to produce
  gasses like hydrogen sulfide. Large process
  plants in urban areas will often contain a foul
  air removal tower, composed of air circulators,
  a contact media with bio-slimes, and
  circulating fluids to biologically capture and
  metabolize the obnoxious gasses previously
  contained by reactor enclosures.
Treatment of Sludge
     SEWAGE AND WASTE WATER
    MANAGEMENT IN CHHATTISGARH
• The iron and steel industry      • Industrial as well as
  at Bhilai, cement industries       domestic wastewaters are
  at Durg and Raipur, textile        being discharged into the
  industry of Rajnandagaon,          River Hasdeo directly as
  aluminium and thermal              well as through river Ahiran
  power plants at Korba are          and Dengur Nala. The major
  the major polluting industries     source of pollution in the
  in the Mahanadi river basin.       river is due to Thermal
                                     Power Plants, Bharat
                                     Aluminium Company,
                                     Captive power plant of
                                     BALCO, IBP (explosive unit)
                                     and coal mining operations
      Water Quality Status of River
              Mahanadi
•   pH range: 6.11-8.65
•   Conductivity: 646 μmohs/cm in Sheorinarayan
•   DO: 4.5-10 mg/l
•   BOD: 0.2-16.0 mg/l
•   Nitrite (NO2-) concentration :0.01-0.30 mg/l
•   Nitrate (NO3-):0.04-14.6 mg/l
WHAT CAN THE GOVERNMENT
          DO?
The government can make it compulsory by
legislation for waste water to be treated before
discharge.
It can also make sure that the legislation is put
to effect.
latest technological developments can be
incorporated by the government in treatment
plants.
      WHAT CAN WE DO???
There is a lot that we can do in order to save our
water resources. It is not just the government’s
responsibility to treat waste water, it is our duty to
reduce the amount of waste water generated. It is
also our duty to see to it that sewage is not directly
released into our rivers.
Rivers are the life line of the people. Lets not cut
them.
This will be the condition of our
 water bodies if we do not act
               now.
Questions