Water treatment Engineering and Technologies

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MUNICIPAL WASTE WATER TREATMENT (M.W.W.)

Tertiary Treatments - Elimination of nitrogen and phosphorus pollution load

Removal by biological process

 

In a biological treatment process nitrogen and phosphorus are assimilated in the bacteria-cell and eliminated simultaneously with the excess sludge.

If the nitrogen-load exceeds the assimilation capacities of the excess sludge, supplementary nitrogen removal needs a special nitrification / denitrification process. This needs complementary tanks and / or modification of the periods of aeration and non-aeration (anoxic conditions).

• Anoxic tank upflow the aeration tank (recirculation of the nitrates)

  BACT - A/N

• Two stages anoxic / aeration

  BIBACT - A/N

• Two tanks, each with alternated periods of anoxic and aerobic conditions

  BIO2ALTERCYCL - N/DN

• One tank with alternated periods of anoxic and aerobic conditions

  ALTERCYCL - N/DN

• ...

If the phosphorus-load exceeds the assimilation capacities of the excess sludge, supplementary phosphorus removal needs a special dephosphatation process. This needs complementary tanks with anaerobic conditions. It is installed as a complement to the nitrification / denitrification process.

• Anaerobic tank upflow the aeration tank with simple recirculation

  BACT - DP/A/N

• Anaerobic tank upflow the aeration tank with multiple recirculation

  MULTIBACT - DP/A/N

• Anaerobic tank upflow the aeration tank with multiple recirculation and intermediary anaerobic tank.

  MULTIBACT - DP/A/N/DP

• ...

• Chemical precipitation of phosphorus (ferric chloride, aluminium salts, ...)

  R.A.P.T. ("Réacteur d'Agrégation de Particules par Transport") connected with a settling or flotation unit.

• Settling with plates (with or without sludge recirculation)

  Solid – liquid separation is improved by forcing the flow between plates mounted at an angle in the clarification zone

  HYDROPAC CL

  HYDROPAC - R CL