Veolia Water Technologies Techno Center Netherlands B.V. - MPP Systems

- Model DAF - Dissolved Air / Gas Flotation System

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The Veolia Water Technologies  TiPSS DAF (Dissolved Air Flotation) system has unique design that contains a plate pack section for enhanced efficiency and reduced footprint requirements and a pneumatic scraper system that optimizes the thickening of the float layer.

  • The DAF technology uses extremely small air bubbles to lift suspended solids and oil to the top surface. The formed sludge layer is scraped into a sludge holding tank. The addition of coagulation and flocculation chemicals may be required to enhance the performance.
  • Removal efficiency is usually superior to gravity bases systems and often applied as polishing step (downstream of CPI)
  • The DAF can be supplied with a gas-tight cover, coagulation & flocculation dosing and mixing equipment and air-saturation by special pumps or in separate pressure vessel.

  • Produced water polishing (off and onshore)
  • Refinery effluent polishing
  • (Petro)chemical in-process flows or effluents
  • Food, textile, automotive and steel industry

  • Oil removal 30 - 99% up to 2 - 10 ppm
  • COD reduction 30-90%
  • TSS removal 50 - 99%
  • Up to 10-30 ppm
  • Floated sludge thickening 4 - 8%

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The waste water enters the unit through the distribution pipe (1).The distribution pipe distributes the water evenly over the plate pack (4). Part of the treated water is recycled to the feed with a special dissolution pump (10).The pump is capable of pressurising relatively large amounts of air together with water, while forcing the added air bubbles to dissolve.The pressurised and air saturated recycle flow is mixed with the waste water. The free air separator (9) removes large unwanted gas/air bubbles. Special designed bubble generator valves (9) create a sharp pressure drop causing the dissolved gas to be released as very small micro bubbles.

The micro bubbles attach to the particles in the waste water and force them to float and form a floating layer (3) on the surface of the unit. Very small particles having lower up-flow velocity will be separated in the plate pack. The treated water is discharged through an outlet weir pipe into the effluent (pump) compartment. The floating layer is removed by means of a pneumatic operated skimming device (6).The separated sludge is collected in an integrated sludge compartment (5). Settled bottom sludge is intermittently removed by means of manually operated butterfly valves.

Optional pre-treatment

Chemical pre-treatment of the wastewater is required when emulsified oil orvery small particles are present.

In some cases laboratory jar tests and investigation of type and quantity of chemicals, mixing intensity and reaction time is required in order to obtain a separable floc.These tests are carried out by vws mpp 's process specialists who have broad experience with various kinds of waste water.

Coagulation -Flocculation methods

Coagulation-flocculation can be established in large tanks (CSTR or Continuously Stirred Tank Reactor) or in a coiled pipeflocculator (CPF).The choice for a specific mixing/reactor device is based on the characteristics and the treatment requirements of the raw water.

The CSTR'sare applied when long reaction times are required and available space is not limited.

The CPF is based on a concept of accelerated flocculation which results in a low distribution in size, shape and structure of the generated flocks.The flocculator acts as a plug flow reactor, and saves on addition of chemicals due to the very direct and intense mixing. Reaction takes place as a combination of residence time and mixing energy. These values can be determined on laboratory scale, and thus the flocculator can be accurately designed to the requirements.

The flocculator can be excecuted in HDPE, PE and (stainless/coated) steel.

From single units to turnkey projects.

TheTPFcan be combined with several other VWS MPP Svstems seoaration svstems to improve the quality of the effluent process water.

Upstream:

  • Screens: removal of coarse material
  • TPI / CFI: Plain gravity separators

Downstream:

  • Biological: SBR, Activated Sludge, MBR treatment
  • ACF/RSF: activated carbon filters/ rapid sandfilters
  • Membrane: Ultra filtration, ROfiltration

The vws mpp scope of supply:

  • turnkey deliveries
  • design
  • engineering
  • fabrication
  • site-erection, commissioning and start-up
  • after sales service
  • laboratory and field research

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