The document describes the AzurairTM B-Twin biological air treatment system. It uses two sequential biofilters - an acid pH tower to eliminate hydrogen sulfide followed by a neutral pH tower to remove mercaptans. This two-stage biological process can remove over 95% of hydrogen sulfide and mercaptans from air streams. The document provides an example of its use to treat odors from a wastewater treatment plant in France, eliminating over 94% of hydrogen sulfide and mercaptans from the air exhaust.

1. Azurair™
B-Twin
BIOLOGICAL TREATMENT OF AIR
HYDROGEN SULFIDE AND MERCAPTANS
ODOR POLLUTION CONTROL WITH A
SUSTAINABLE DEVELOPMENT APPROACH
P-PPT-A-002-EN-1107

2. AIR
CONTENTS
Azurair™ • Azurair™ B-Twin in the odor removal solutions range
B-Twin
• Description of the Azurair™ B-Twin technology
• Operating Principle
• Advantages of Azurair™ B-Twin
• Case Study: Chevrières Grandfresnoy, FRANCE
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3. Azurair™ B-Twin IN THE
AIR
ODOR REMOVAL SOLUTION RANGE
Azurair™
B-Twin
Air Flow Rate
Model Process Treated Compounds Plant Size
(per unit)
H2 S
From
Azurair™ B Biological (low and medium-level
300 to 20,000 Nm3/h
< 100,000 PE
concentrations)
H2 S
Azurair™ B-Twin Biological in 2 stages
and mercaptans
From 700 to 5,000 Nm3/h < 20,000 PE
Biological Pretreatment+ H2 S From 300 to 16,000 Nm3/h
Azurair™ Boost physicochemical Polishing (high concentrations) (Biofilter stage)
> 250,000 PE
Sulfured and nitrogenous From 3,000 to
Azurair™ C Physical & Chemical
compounds 80,000 Nm3/h
> 15,000 PE
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4. DESCRIPTION OF THE Azurair™ B-Twin
AIR
TECHNOLOGY
Azurair™ Coupling of 2 identical Azurair™ B towers
B-Twin
Neutral pH finishing
Acid pH tower for Azurair™
elimination of H2S
+ tower for reinforced
elimination of
mercaptans
= B-Twin
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5. OPERATING PRINCIPLE
Biological deodorization according to the trickling biofilter principle .
• The foul air extracted from the plenum is sent to
the towers in series with the help of a fan.
• The air is introduced at the top of the first tower in
which it goes through an acid pH biofilter which is
mostly for elimination of H2S.
• The air is removed at the bottom of the tower.
• This is a co-current process with sequential
sprinkling.
• This addition of water is optimally adjusted to
ensure the development of bacteria and to
compensate for the evaporation.
• This biofilter has an integrated washing system for
efficient cleaning of the media, avoiding all
clogging.
• The principle is repeated in the second “finishing”
tower at neutral pH in order to optimally eliminate
the mercaptans (and H2S).
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6. AIR
ADVANTAGES OF THE Azurair™ B-Twin
Azurair™ SUSTAINABLE DEVELOPMENT:
B-Twin
• A 100% biological solution
• No chemical reagents use
• Compact equipment
PERFORMANCE AND SAVINGS :
• Up to 95% elimination of H2S and mercaptans
• Advantageous investment and use costs compared with
other air treatment technologies.
EASE OF USE:
• Inalterable mineral media (no replacement or reloading),
• Natural process that does not require regulation,
Integrated system for unclogging of the media.
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7. CASE STUDY:
CHEVRIÈRES GRANDFRESNOY (60), FRANCE
CONTEXT:
• Reconstruction of a 5,000 PE WWTP
• Client: Syndicat intercommunal
d'assainissement de Chevrières-
Grandfresnoy
DESIGN:
• Commissioning: 2012
• Ventilation flow: 3,200 Nm3/h
• Excerpt from requested guarantees:
PROJECT DETAILS: - [H2S] < 0.1 mg/Nm3/h
- [Mercaptans] < 0.07 mgS/Nm3
The water treatment plant, built in 1979, - [NH3] < 0.7 mg/Nm3/h
was dilapidated and frequently in hydraulic
overload and consequently polluting the • Azurair™ B-Twin: speed of 1,200 m/h
source receiving water - the Nancy brook.
In order to allow for the expansion of the RESULT:
collection network and to meet the new • >94% of H2S and RSH eliminated
discharge standards, a new plant was
designed.
• Savings of 10 tons of bleach per year
(if bleach tower chosen)
As the new plant adjoins a residential area,
the customer wanted biological odor
treatment.
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8. CASE STUDY:
CHEVRIÈRES GRANDFRESNOY (60), FRANCE
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