France, it is well known, we have no more oil but we still
discomfort of unpleasant odors has become a social problem.
Some bad smells are, moreover, detrimental to our health
like other products with little or no odor.
The odors harmful or not, that we breathe daily are
decisive for our well-being and our health.
Over time, the individual manages to get used to the
bad smells and these being invisible, no provision is
generally taken to protect themselves from it.
is the inventor?
inventor, French chemical engineer of Research & Development
in pharmaceutical industry, now retired and independent researcher,
is the nephew of André
Bondouy, the founding President of the Société
process was born from the imagination of this Normand
chemist born in the mythical village who saw circulating
the first car equipped with an engine designed by
(1856 to 1901) who had the idea in 1883 to equip a hunting
wagon with a gas engine.
But the experiment ended abruptly with the explosion
of the gas container.
The following year he designed and ran the first petrol
car powered by an internal combustion engine.
How was born P.T.C. System
idea of the process is the result of the observation of the
reaction of an organic molecule with a sulfur derivative very
malodorous, in this case the condensation between chloroethanol
and dodecylmercaptan, giving rise to a new organic molecule
perfectly odorless very easily biodegradable.
This observation was the trigger to look for a simple and
inexpensive reagent and if possible easily accessible.
The DAVID process is born.
Research has been undertaken for the choice of an organic
molecule already marketed, affordable, easy and safe to use.
Innovation is therefore based on the implementation of an
original formulation, without oxidant, which acts on the pollutant
by transforming it into a bio-available organic compound.
This formulation is based on a molecule well known and used
in chemistry since the 19th century for the synthesis of various
specialties. The use of this molecule in the fields we are
interested in is the key to the process, which represents
a very important advance on the technical and economic levels.
System is a newly patented technology for the purification
of gaseous, liquid or vesicular aerosol compositions containing
pollutants that are harmful to health and the environment,
or simply malodorous.
Pollutants are Volatile Inorganic Compounds (VIC)
COS, NOx, halohydric acids, H2S, SO2, SOCl2, SO2Cl2,
are Volatile Organic Compounds (VOC)
amide, nitrile, aldehyde, ketone, ester, carboxylic
acid, alcohol, thiol, disulfide, thioester, halogenated
organic compounds, phosgene and hydrogen cyanide, etc...
How does this new process work ?
innovative process therefore consists of capturing gaseous
pollutants in a physico-chemical treatment, the liquid effluents
of which are subsequently digested by the aerobic bio-purification
process in the treatment plant.
present invention does not require any particular installation
(use of any gas scrubbing column, for example).
invention is characterized in that it comprises:
the alkalization of the effluent to be treated at a pH>
9 in the presence of a base of general formula M-OH in which
M represents an alkali metal, an alkaline earth metal, a condensing
agent between the organic part of a specific reagent and the
sulfur derivative or a phase transfer agent and in particular
a quaternary ammonium or a ligand.
contacting the product obtained in (A) with a specific organic
to an advantageous embodiment of said method, steps (A) and
(B) can be performed simultaneously.
This capture and depollution process also applies to the simultaneous
treatment of several sulfur derivatives.
The final destruction of the capture products after the simultaneous
process of absorption and chemical modification (A + B) The
operation is carried out in biological purification station.
The organic compounds present and formed during the condensation
reaction are digested by the aerobic bio-purification process
of the treatment plant.
originality of the process resides on the one hand in the
choice of the reagent which combines with the pollutants to
be treated and on the other hand in the natural biological
final destruction in a treatment plant not generating new
gaseous pollution. This purification system is unique in its
design and applications. It makes it possible to stand out
from the competition and to improve the productivity of capture
/ treatment facilities, as long as its economic
performance is advantageous.
The new patent is based on the existing patent of the DAVID
process (Process for the purification of gaseous or liquid
effluents containing sulfur derivatives) for which it constitutes
Technical description of P.T.C System
The process is carried out in a physico-chemical process consisting
of a transfer of gaseous molecules to a liquid phase.
This process is characterized by a chemical washing of the
stale air against the current inside a washing tower packed
with inert material which favors the gas-liquid contact.
The characteristics of an inert material that promotes packing
(nature, specific surface, volume, height) are calculated
to optimize the gas-liquid contact time and the transfer of
Depending on the nature of the compound to be removed, a basic
neutralizing agent is added to the wash water to accelerate
the transfer. gas-liquid, and thus increase the effectiveness
of the treatment.
The additional addition of a specific reagent in turn not
only helps to intensify this transfer process, but also to
regenerate the washings by chemically modifying the absorbed
molecules which have the property of being odorless and biodegradable.
Equipment required for P.T.C System
DAVID process is carried out in a physico-chemical process
consisting of a transfer of gaseous molecules to a liquid
process is feasible on a single wash tower:
The process is characterized by a physicochemical
washing of the gaseous flow against the current, using
aqueous alkaline solutions, inside the scrubber. The
basic neutralizing agent (soda or potash) is added
to the water to accelerate the gas-liquid transfer,
and thus increase the effectiveness of the treatment.
additional addition of a specific reagent in turn
not only helps to intensify this transfer process,
but also to regenerate the wash water by chemically
modifying the absorbed molecules which have the property
of being odorless and biodegradable.
In the tower, air is introduced from the bottom up
and the washing solutions sprayed countercurrent,
from top to bottom.
These towers are lined with inert material that promotes
The tower is equipped with a recycling pump. The foot
of the tower serves as a retention volume and as a
suction cover for the recirculating bath pump..
calculation workbook includes a tab for calculating the
releases and a tab for calculating the charges making it possible,
on the one hand, to determine the quantities of reagent and
soda or potash of the gas stream under consideration and,
on the other hand, to compare the cost of treatment with bleach.
For that it is important to know and to inform precisely in
the blue boxes:
Hourly flow rate in m3
The daily treatment time
The concentration of the compounds to be captured in mg/m3
process adapts to any type of existing installation:
In the case of an installation with a single tower,
it is a unit operation (batch):
tower is emptied, the liquid effluent is discharged
to the industrial water receiving basin.
The tower can be reloaded for another operation.
In the case of an installation provided with several
towers, it allows a continuous operation:
type of installation with 2 or 3 floors, or more,
will be suitable for continuous treatment.
Once the first round arrived in saturation controlled
by pH-metry (pH <9), the flow is switched to the 2nd
Meanwhile, the 1st turn is reloaded and so on ....
method according to the invention therefore does not require
specific specific equipment.
Biological treatment of liquid effluents in wastewater treatment
process according to the invention makes it possible to obtain
an absolutely odorless and colorless liquid treated product
which can be directly discharged to a self-neutralization
pond or a water treatment basin of a treatment plant, moreover,
acidification does not regenerate mercaptan, SO2 or hydrogen
Aerobic biological treatment in wastewater treatment plants
does not create any new nuisance either at the station itself
or at the level of the sewerage network.
The BOD (Biological Oxygen Demand) and COD (Chemical Oxygen
Demand) measurements are consistent with rejection standards
and improved compared to conventional oxidative destruction
DAVID Process - Odors
Process for the purification of gaseous or liquid
effluents containing sulfur derivatives
present invention relates to a process for the purification
of gaseous or liquid effluents containing sulfur
derivatives (H2S, alkyl mercaptan, SO2).
process has been the subject of a French, European
and US patent.
An improvement is currently the subject of a new
sulphide (H2S) and mercaptides (R-SH)
sulphide is an extremely toxic gas, smelly even when it
is present in very small quantities, and corrosive. Its
presence as well as that of alkyl mercaptans which have
the same disadvantages as H2S from the olfactory point
of view in the effluents (gaseous or liquid), industrial
in particular, represent a considerable danger for the
health of the living organisms or the plant environment.
is therefore of utmost importance in the fight against
pollution, to eliminate hydrogen sulphide as well as the
alkyl mercaptans present in industrial effluents (industries
related to energy, chemistry, wood, paper and viscose,
food industry), waste (industry of animal by-products,
manure, household waste) or in treatment plants.
presence of SO2 in effluents, particularly industrial
ones, also represents a considerable danger for the plant
environment. Indeed, its emission is responsible for an
increase of acidity in the atmosphere and generates the
phenomenon of acidic rain.
The SO2-producing industries include refineries, hydrocarbon
waste processing industries, chemical industries (mineral
chemistry: sulfuric acid and titanium oxide production,
organic chemistry), paper industries, agro-industries
food and materials industries.
Various solutions have been proposed for eliminating these
various sulfur compounds from the effluents (gaseous or
the articles: Competitive
Techniques and Industrial
Deodorization by Bleach.
description of DAVID process
process is carried out in a physico-chemical deodorization
process consisting of a transfer of odorous gas
molecules to a liquid phase.
This process is characterized by a chemical washing
of the stale air against the current, with the aid
of alkaline aqueous solutions, inside series placed
towers are lined with inert material that promotes
gas-liquid contact. Depending on the nature of the
compound to be removed, a basic neutralizing agent
is added to the wash water in order to accelerate
the gas-liquid transfer, thereby increasing the
efficiency of the treatment.
The additional addition of the specific reagent,
claimed in the DAVID process, in turn contributes
not only to intensifying this transfer process,
but also to regenerating the washings by chemically
modifying the absorbed molecules which have the
property of being odorless. and biodegradable.
process makes it possible to treat highly concentrated
gaseous effluents from odorous compounds. Highly
reliable, this technique achieves purifications
greater than 99% guarantee the total absence of
characteristics of an inert material that promotes
packing (nature, specific surface, volume, height)
are calculated to optimize the gas-liquid contact
time and the transfer of molecules.
process for the purification of gaseous, liquid or vesicular aerosol
compositions containing pollutants which are harmful to health and
the environment or which are simply odor-causing.
first experience in the field of odors has led this Engineer to
reflect and guide his research in other areas of industry and the
research quickly led to innovative improvements and a complete overhaul
of the DAVID process towards Sustainable Development with the invention
of the P.T.C. (Pollution Trap Concept).
This brand new system is currently the subject of an international
P.T.C. is currently mainly in the field of methanization of waste
(purification of biogas), a particularly advanced area. According
to Ademe, the sector could provide more than 14% of French gas consumption
In its document "Contribution to the development of energy visions
2030-2050", the agency estimates that with 600 biogas plants per
year (ie almost half as much as in Germany), the accessible deposit
would be 6 Mtep primary in 2030 (ie 20% of the estimated gas consumption
for this period).
the nature of the biogas, the PTC system separates the biogas from
its impurities (CO2, H2S, VOC, Siloxanes). The methane content of
biogas then increases from 45% to 98% and can be directly injected
into the national gas distribution network. The advantage of our
PTC process is that it uses reliable, robust, widely proven technology
that comes directly from industry.
This system adapts according to the variation of the methane richness
according to the composition of the incoming raw biogas.
main sources of biogas
Beyond the new public support mechanisms expected by market players,
it is above all "the structuring of the sector that is required
as a necessity.
Inputs, the most common sources of biogas (containing biomethane),
come from voluntary or involuntary organic material stores that
Livestock effluents (manure)
Slurry (composed of liquid and solid excrement of animals)
(mixing manure with animal litter: straw, hay ...).
They represent the major part of the effluents.
effluents are derived from livestock activities, particularly cattle
and pigs, and are located in livestock buildings.
These are crops grown primarily for energy production purposes.
They can be used as inputs in biogas plants that will use the energy
power of these plants.
Energy Intermediate Crops (CIVE) & Intermediate Nitrate
Trap Crops (CIPAN)
An intermediate energy culture (CIVE) is a culture implanted and
harvested between two main crops in a crop rotation.
CIVE can be harvested for use as an input into an agricultural
A nitrate trap intermediate culture (CIPAN) is a temporary crop
of fast-growing plants intended to protect plots between two main
crops. These cutlery are mandatory in some areas or areas because
of nitrate pollution.
By using them for their growth, the canopy plants trap the remaining
nitrates at the end of the previous main crop.
Agricultural waste from crops (eg corn cane).
Sludge and by-products of the agro-food industries
The agri-food industries generate all sorts of co-products during
the technological processes they use to develop their finished products
(dairy products, meat, grain products, fruits and vegetables, etc...).
Once the product is valued, it will be called "co-product".
Sludges of agro-industrial origin come from slaughterhouses, dairies,
cheese factories, biscuits, breweries, canneries, etc...
Animal by-products (SPA)
European Regulation (EC) No 1069/2009 classifies animal by-products
into three categories.
It defines the manner in which the materials of each category must
or may be eliminated or upgraded for certain uses in order to maintain
a high level of hygiene.
This is waste from households and assimilated waste.
Waste produced by municipal services, waste from collective sanitation,
street cleaning waste, market do not fall within this scope.
Green waste (DV)
Green waste refers to vegetable waste resulting from the maintenance
and renewal of public and private green spaces (parks and gardens,
sports fields, etc.), local authorities, public and parapublic bodies,
private companies and individuals.
Other waste (STEP sludge, etc.)
Sludge treated in urban wastewater treatment plants is the result
of human activity.
Their valuation for biomethane production has been authorized since
Why methanize our waste ?
digestion, still underutilized, appears to be a response to
the dual issue of waste management and the development of
renewable energies; not to mention the fight against greenhouse
gases including CO2.
principle of anaerobic digestion consists of recovering organic
waste in order to recover it in the form of biogas by anaerobic
fermentation. Organic waste can come from agricultural activities
(manure, manure), industrial and tertiary (including waste
from LPNs) or communities (catering waste, grass clippings
Biogas is composed in particular of methane in variable proportion,
which gives it an energy potential.
This biogas, after purification, is used to produce electricity
and / or heat. It can also be injected into the gas distribution
network, or even be used in fuel gas.
purification of biogas requires a succession of operating
The P.T.C. has the advantage of treating all the undesirable
compounds in a single operation.
addition to biogas, agricultural biogas allows the production
of a fertilizer material, the digestate, which can be spread
(as part of a spreading plan, or as a standard product after
composting). The development of anaerobic digestion is fully
in line with the objectives of the energy transition law for
green growth promulgated on August 18, 2015.
wants to develop by 2020 renewable energy up to 23% of the
energy mix, with a strong contribution of biomass to these
objectives (wood energy and biogas). Thus, the State sets
a goal of 1,500 methanizers in 3 years, and methanization
is at the heart of the plan Energy Methanization Nitrogen
Autonomy (EMAA) of March 29, 2013
should be noted that in this configuration, the biogas is
not purified therefore a source of olfactory nuisance due
to H2S and NH3.
On the other hand, fermentation CO2 is released into the atmosphere
current biogas-biomethane sector
uses of biomethane are the same as for natural gas: hot water,
heating, cooking, industrial needs, etc...
One of the relevant valuations still unknown is the valuation
The use of biomethane in transportation fuel (referred to
as bioGNV) would reduce greenhouse gas emissions in this sector.
In addition, it being understood that bioGNV and NGV (natural
gas for vehicles) have the same chemical composition, gas-powered
vehicles and filling stations can be powered by bioGNV without
Diagram of the classical die
of biogas (details)
date, the purification of biogas is carried out mainly for
the valorization of biomethane by injection into natural gas
distribution networks of fossil origin.
diagram below shows the complexity of such a purification
plant comprising several treatment units and it will be noted
that the CO2, momentarily trapped, is released into the atmosphere.
Such installations represent a significant cost in terms of
investment and operation (costs of activated charcoal among
P.T.C. system, innovative in its simple but particularly efficient
technology, finds a predominant place among current biogas
It is the only known to completely eliminate in the same operation
and on a single unit of treatment CO2, N2, O2, H2O, H2S, NH3,
Organochlorines or Organofluorines.
Currently, what is the CO2 balance of
an anaerobic digestion unit ?
m3 of biogas from anaerobic digestion helped to avoid the
release into the atmosphere of 2.3 kg of carbon
dioxide (CO2) responsible for global warming.
An anaerobic digestion unit of 2 MW, by the methanisation
principle, thus prevents the emission of about 9000 t of CO2
into the atmosphere.
However, it must be borne in mind that each m3 of biogas produced
always contains between 20 and 40% of CO2, ie between 3 kg
and 6 kg, which are finally released into the atmosphere,
or during biomethane purification by competing techniques,
either in the use of biogas without purification.
It should be noted that this same methanisation unit of 2
MW, which consumed about 4 Mm3 of biogas, still emitted between
800 t and 1,600 t of CO2 in the atmosphere depending on the
nature of the methanised substances.
composition of biogas and thus its impurities varies according
to the nature
Boues de station d’épuration
Déchets de l’industrie
50 - 60
60 - 75
60 - 75
38 - 34
33 - 19
33 - 19
1 - 0
1 - 0
H2O % vol
6 (à 40 ° C)
6 (à 40 ° C)
6 (à 40 ° C)
6 (à 40 ° C)
100 - 900
1000 - 4000
3000 – 10
50 - 100
20 - 250
Organochlorés ou organofluorés mg/m3
100 - 800
INERIS report (15/12/2009) mentions carbon oxysulfide (COS)
concentrations in the order of 0.047 to 0.29 mg / m3 in biogas
from methanisation of sewage sludge.
Biomethane: Towards a cost of production
finally competitive ?
P.T.C. System is the only technology known to date, making
it possible to sustainably eliminate and recover CO2 from
methanisation in the form of carbonates, which is particularly
valuable in industry.
It allows the total capture, sustainable and in a single operation
of the CO2 but also of all polluting volatile compounds (N2,
O2, H2O, H2S, NH3, , Siloxanes,
Organochlorines or Organofluorines).
P.T.C. System allows a cost of production of biomethane 3
times cheaper than the competition and therefore reduces the
cost difference between fossil-based methane and biomethane
to incorporate it into the network.
valorization of biogas
Consisting mainly of methane and carbon dioxide, biogas is
efficiently recovered in biomethane
through purification processes.
This technique, called anaerobic digestion, is caused in digesters,
during the treatment of household waste, industrial or agricultural
waste and sewage
Biogas, resulting from the fermentation of this waste, is
a source of renewable energy which after purification can
replace natural gas of fossil origin.
Farmers, industrialists and local authorities thus treat their
waste while enhancing their energy and economic potential.
The purification solution P.T.C. allows the valorization of
all biogas for the injection to the natural gas network, the
production of vehicle fuel (biomethane gas or liquid) or the
production of renewable hydrogen after reforming the biomethane.
purification technology by the P.T.C. System
In order to transform biogas into a substitute for natural
gas, it must be rid of all pollutants.
The P.T.C. System proposes a technical solution that today
allows biogas producers to use it effectively in biomethane
through its purification process.
The technology used makes it possible to eliminate carbon
dioxide (recyclable CO2) sustainably, and to eliminate in
the same operation N2, Siloxanes,
Organochlorines or Organofluorines.
based on anaerobic digestion, should logically find its place
in the near future.
cycle of sustainable elimination of pollutants
P.T.C. System is part of this new concept of purification
system is currently the only known to permanently eliminate
CO2 and can be recycled in the
In a period that is particularly conducive to the development
of alternative energies to fossil fuels, the prospect of integrating
biogas into the French energy landscape is of interest from
a political, economic and environmental point of view.
fact, the valorization of domestic, industrial and agricultural
organic residues or the treatment of wastewater meet the notions
of sustainable development and renewable energy, clearly explained
in recent international agreements and commitments.
environmental impact of the implementation of biogas recovery
channels results in a significant reduction in the greenhouse
fluctuations in the costs of importing fossil fuels have also
positively influenced the renewed economic interest in energy
production from biogas, whether directly in the form of high
purity methane gas. or in the form of electricity.
cost price of biomethane completely purified by P.T.C. System
is 0.054 € / kWh. when the cost price in competing systems
0.15 €/ kWh.
P.T.C. System allows a cost of production of biomethane
3 times cheaper than the competition and therefore reduces
the cost difference between fossil-based methane and biomethane
to incorporate it into the network.
On the other hand, the technology of P.T.C. allows extremely
simple biogas purification equipment whose investment cost
is incommensurate with the currently existing processes.