Example of treatment of a mixture of
pollutants in industry
innovative "One-pot" process consists in capturing gaseous
pollutants in a physicochemical treatment whose liquid
effluents are subsequently digested by the aerobic bio-purification
process in the treatment plant.
process of absorption (capture) and organic chemical
modification of Volatile Organic Compounds (organic
This operation is carried out in a single operation
on a collection installation by physico-chemical washing.
The final destruction of the capture
products after the simultaneous process of absorption
and chemical modification
This ultimate operation (B) is carried out in a biological
The organic compounds present and formed During the
condensation reaction are digested by the process of
natural aerobic bio-purification of the purification
originality of the process resides firstly in the choice
of the reagent which combines with the pollutants to
be treated and secondly in the final natural destruction
in the wastewater treatment plant that does not generate
any new gaseous pollution.
The example below describes the
treatment of a mixture of pollutants in a single operation
gas scrubbing column joins the vents of three "pilot"
reactors in chemical industry:
1 - Synthesis of an Acid Chloride
Reactor 2 - Synthesis of methyl ethyl sulfide
3 - Decarboxylation of an Acid
gaseous and volatile pollutants are composed of:
(sulfur dioxide) 6,418 mg/m3
(hydrochloric acid) 3 810 mg/m3
of dichlorethane (solvent)
of SOCl2 (thionyl chloride)
(methylmercaptan) 615 mg/m3
(ethylmercaptan) 5 810 mg/m3
(hydrogen sulfide) 4 000 mg/m3
(carbon dioxide) 52 200 mg/m3
traces of alcohools
base and reagent quantities are calculated on
of flows and loads.
Absorption column 3000 liters (column + tank),
trays packing, demister outgoing air.
Fluid circulation pump adjustable from 0 to
pollutant effluent gas supply valve from 0 to
Operating load for a batch
soda: 2,010 kg
reactive: 475 kg or 190 kg pure
the suction tank is charged the additional water determined
in the worksheet corresponding to 20 volumes of the
pure reagent and then in order the calculated amounts
of alkaline solution of potassium hydroxide, then the
40% solution of the reagent.
The reaction medium displays a pH value> 11.
The circulation pump is activated then the gas flow
valve is gradually released and controlled at the desired
The end of the reaction is determined and controlled
by pH <9.
The operations took place over a period of 10 hours
with a gas flow rate of 500 m3/h.
The end of the reaction is controlled by pH-metry (about
9-10), and the absence of H2S and mercaptans checked
with lead acetate paper and pH paper.
clear, colorless and odorless reaction medium is then
discharged to the plant's self-neutralization pit before
being discharged to the network to be subjected to the
aerobic bio-purification process in the treatment plant.
Results on the unfiltered reaction
medium before rejection to the biological station of
35 ° C
BOD5: 695 mg/L
this test, it is clear that for the destruction of sulfur
compounds, treatment with bleach would return 12 times
more expensive than treatment with the PTC system.
ClO2 or H2O2 treatments are even more expensive.
example of chemistry treatment includes:
elimination of sulfur compounds.
(complete elimination of CO2).
elimination of hydrochloric acid.
removal of traces of thionyl chloride.
total elimination of the solvents present in the state
Cost of treatment 627 €
similar competitor treatment with bleach would have
cost € 1,030
For CO2 alone 1,582 liters of soda were consumed 30%
for € 395
flow calculation sheet to determine the quantities of
also the examples of the DAVID Process - Odors