Our wastewater Treatment Technology
Wastewater treatment overview

Water is an essential ressource for both human activities and biodiversities. Though it is abundant, usable surface and underground water is becoming scarcer throughout the years.
Moreover, water, as we find it in nature, is not simple H2O molecules put together. Water can contain dissolved minerals and fluids. It can even contains micro-organisms. And all of these compounds are essentials to sustain the ecosystem where it flows.
In most cases, water is withdrawn from the environment to be used in human activities in which it is contaminated. This polluted water cannot be rejected into the environment. Wastewater must then receive a prior treatment before being rejected.

Depending on the water pollution and the constraints of the site, different types of water treatment technology can be found:

Biologic Processes
They consist in injecting a culture of bacteria into the wastewater selected in such ways that the bacteria consume the polluting compound present in the wastewater. Once there is no more nutrient, the bacteria dies and the wastewater can be released into the environment free from polluting compound.
Physical-Chemical Processes
Physical-Chemical processes use multiple steps to treat the water. There are physical steps such as filtration, centrifugation and floculation; and chemical steps where the goal is to remove the pollutant by injecting chemicals to favour some chemical reactions.
Evaporative Processes
Evaporative processes are focused on separating water from the pollutant. The principle is simple: by heating the wastewater, pure water will boil and evaporate while the pollutants remain in the concentrate. To save energy, the energy of the generated vapor is usually used to sustain the evaporation process. In such process, the vapor is condensed and the condensate can be released into the environment, or can be used in other processes.
Membrane Separation Processes
Some material allow the flow of a compound while forbiding other compound through a phenomenom called permeation. Membrane Separation is a process where such materials are used to separate water from the other compound. Water produced from membrane filtration is of high purity.
Our evaporative process technology

There are multiple design of evaporators which have each their benefits and drawbacks. The design of the evaporator depends on the wastewater management strategy and the available energy source. Our technology is based on the MVC process which is the most energy efficient evaporative process.

Our MVC wastewater evaporator works according to the following steps:

  1. The system is put under deep vacuum.
  2. Wastewater is sucked into the evaporator.
  3. Wastewater is circulated using a circulation pump. It is pulverized into small droplet at the top of the evaporator.
  4. The compressor is turned on. The depression caused by the compressor is forcing water to evaporate. The vapor is then compressed to be released into the condenser.
  5. The vapor, in thermal contact with the cold wastewater through the heat exchanger pipe, is condensed. When the level is high enough, the distilled water, or distillate, is extracted.
  6. Once there is no more water to evaporate in the liquid waste, the concentrated waste, of concentrate, is extracted. It can be then be processed using traditional means.
Our innovation resides in the enhancement of traditional MVC evaporator design by integrating our compressor technology. The perfect tightness of our compressor allows operation under deep vacuum. While traditional MVC evaporators evaporate the water at 80°C, our design allows evaporation at 35°C.

This low temperature operation has a lot of benefits:

  • Lower construction cost: polypropylen is used for most parts of the evaporator and no pre-heating heat exchanger is required
  • Higher energy efficiency: we have nearly no heat loss due to operation near ambient temperature and we use our high efficiency centrifugal compressor instead of inefficient roots compressor
  • Easier maintenance: polypropylen parts are light and can be easily removed, cleaning in place possible with installed circulation pump

Overall, with our smart low temperature design, our technology has better performances (energy consumption lower than 30kWh/m3 of treated wastewater vs 80kWh/m3 for traditional evaporator) while being more affordable.

When is evaporation relevant ?

Evaporative process for wastewater treatment can be apply to all kind of wastewater. The philosophy behind evaporative treatment plant is to value the treated water while biological and physical-chemical wastewater treament method is to reduce pollutant level enough to release the water safely into the environment.
Evaporative process is mainly relevant in two cases:

  1. When the pollution level is high or unknown and non-organic
    Chemical pollution cannot be treated with biological treatment plant. Physical Chemical treatment plants can deal with chemical pollutant but if the level of pollution is too high, it requires expensives chemicals, a lot of handling and analysis. Indeed, to dose the correct amount of chemical to inject in the wastewater, an initial water analysis is required and to release the treated water into the environment, another water analysis is required.
    Evaporative process is lowly dependant of the nature and the level of the pollutant. The distillated water can have traces of alcohol and aromatic compounds at levels largely lower than what is authorised by regulation.
  2. When there is not enough space to install a biological of physical chemical wastewater plant
    Biological treatment plant uses bacteria to treat the water. The speed of depollution cannot be greatly enhanced because biology has its own pace. To treat high volume flow rate of wastewater, a lot of space is required.
    When space is scarce and wastewater volume is high, biological process cannot be used. In such cases, evaporative method can be a good alternative since evaporative treatment plant are much more compact than biological treatment plant.

In all cases, membrane separation method can be an alternative to evaporative method. However, membrane separation plants are quite expensive. Though they use less energy to operate than evaporative method, they require a lot of pre-filtration and maintenance because the membranes used are not very tolerant to particule, to fouling and scaling.

Biological
Physical Chemical
Evaporative
Membrane
Pollutant type
Organic
Chemical
All
All
Compacity
Very big
Big
Compact
Compact
Initial cost
Exploitation cost
Water quality
Recovery of treated water?
No, but possible with additional filtering steps
No, but possible with additional filtering steps
Yes
Yes