Water treatment Engineering and Technologies

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INDUSTRIAL WASTE WATER (I.W.W.)

A specific apparatus is associated to each treatment.

Secondary Treatments - Aerobic Processes

When preliminary treatments have as objective the removal of coarse substances and a part of the solids in suspension, secondary treatments have as objective to eliminate the rest of the suspended solids and also a maximum of the dissolved salts. When a biological process is used, the removal of organic material (or carbon-load) is the principal objective. Simultaneous removal of a small part of the nitrogen and phosphorus-loads occur.
When a higher level of C, N et P-removal must been obtained, a tertiary treatment must complete the scheme.

• Fixed biomass reactors

  • one or two steps

  • on support in movement – biodiscs principle
  • on support without movement

    BIOFIX

   

• Free floating biomass reactor (complete mixed)

  • one or more steps

    All processes mentioned below are compatible with further tertiary treatments (see "tertiary biological treatments")

    • single reactor for aeration

      Single bioreactor

    • two or more serial tanks (with or without flow inversion, periodically or in function of the pollution load)

      AERO-S

    • two or more parallel tanks (with eventually loading repartition in function of the chosen scheme)

      AERO-P

    • with or without "contact tank" (high load sludge recirculation tank in front of the aeration tank)

    • continuous process

    • SBR process ("sequencing batch reactor") – Waste water flows into the aeration tank only during the first period (some twenty hours) and aeration is performed. In the second period, without aeration, settling occurs in the same tank. A the end, part of the clarified water is discharged, followed by the removal of a small part of the sludge. Finally the cycle restart with aeration and waste water inlet.

  Tanks built in :

  • inox 304 or 316

  • concrete
  • steel (with coating, with galvanisation, ….)
  • ...

Position of the different tanks may be, regarding the erection possibilities :

• concentrically
• in one or more rows
• ...

Supply of air by :

• Surface aeration

  • low speed aerators

  • high speed aerators

• Immersed diffusers

  • mechanically

  • compressed-air injection through immersed diffusers

    • with or without lifting possibility
    • fine or medium bubbles
    • hard or flexible porous material
    • with volumetric or centrifugal compressor
    • with or without horizontally forced flow

• Secondary settling for clarification and sludge extraction

  • settling tank with sludge scraper

    • peripherally driving device

    • centrally driving device

  • settling tank with sludge suction system

  • settling in the same tank as the aeration

    • alternated periods of aeration and settling in a discontinuous process

      S.B.R. (Sequencing batch reactor)

    • alternated periods of aeration and settling in a continuous process

      ALTERCYCL A/D

Tanks, circular or rectangular, built in :

• inox 304 or 316
• concrete
• steel (with coating, with galvanisation, ….)
• ...

• Secondary flotation for clarification and sludge extraction

  • dissolved air flotation with indirect pressurisation

    HYDROFLOT - CLi

• Clarification on porous membranes for clarification

  Water is separated from biomass by passing through porous membranes.

  • B.R.M. reactor with internal ultrafiltration membranes

    AERO-MiCl ("Réacteur Aérobie avec Membranes Internes de Clarification")

  • BRM reactor with external ultrafiltration membranes

    AERO-MeCl ("Réacteur Aérobie avec Membranes Externes de Clarification")

  • B.R.T. reactor with textile membranes

    AERO-MtCl ("Réacteur Aérobie avec Membranes Textiles de Clarification")

• Sludge recirculation :
  • with or without intermediate thickening
  • by centrifugal, volumetric or Archimedes pumps

For some examples, click here.