Team:Sorbonne U Paris/Implementation
Implementation
As a reminder, our project The Chlamy Cleaner is a microalgae filter. The aim is to purify Seine’s water using Chlamydomonas reinhardtii as a chassis, designed to be capable of retaining and degrading harmful compounds.
In order to think about how we would implement our project in the real world, we approached Julien Chabrol, expert in instrumentation at Veolia with an expertise in water treatment in purification stations. Wishing to implement our system within wastewater treatment plants, we needed to understand the various challenges we were going to face.
He explained to us certain characteristics that our system had to be equipped with for implementation in wastewater treatment plants. It must be able to take jolts. This can correspond to mechanical disturbances. For example, during a strong thunderstorm, there will be a burst of water that will wash out the wastewater treatment network. It can also correspond to toxic shocks. Also in the event of thunderstorms, deposits will be washed away which will create a very black mud. There are obviously more jolts at the start of the chain than at the end, which can impact the location of our system in the purification chain.
We need to visualize our filter and how to fix our algae on the support. Can we fix the biomass on a support or do we leave our algae in free culture? For the latter, a second filter is needed later to retain the algae, which is also a question that was raised during our interview with Pi Collén from Olmix as well as the removal of dead algae and their remplacement.
Julien Chabrol told us about a system in the form of a reactor that could be integrated between two treatment lines or as a bypass. This reactor would have a thin filter to retain the residues that we want to filter, and it would be complemented by additional equipment. Those additional equipments will be decided according to the conditions in which the algae must live and what is needed for the degradation of the compounds. For example, we could add UV panels, a carbon source, etc.
In addition, our system will create by-products that must be taken into account in the water treatment chain. For example, if we position our system at the end of the station so that it refines the treatments already carried out, we would have to provide a by-pass to redirect the by-products to the start of the chain.
To summarize, depending on the parameters that our algae will be able to withstand and the filter we want to design, we will not be implementing our product in the same place in the water treatment chain.
Working on GMOs, we must also consider the safety aspects. If we leave our algae in free culture as it has been mentioned previously, a second filter is needed to retain the algae. Also, in order not to further impact the environment if algae escaped from the filter, we integrated a "kill-switch" device based on a UV-sensitive nuclease genetic circuit leading to the death of the microalgae. In wastewater treatment plants, it is possible to add UV sections to the treatment chain, which would allow our kill-switch to work.
There are other challenges that we need to consider. Among them, we need to think about how much algae per liter our system needs. It is also necessary to provide for continuous cultivation if there is a need for reseeding. It might be necessary to create biopharms combined with precise protocols for the transport of algae from the production site to the site of use.
Julien helped us think about another possible implementation which would be to use our system to treat industrial effluents. First of all, it targets a specific need and therefore specific pollutants and would allow us to work on a smaller volume with a much higher concentration of compounds.
In this case, there are several solutions: we can build a plant for the industrialist within his enclosure or otherwise collect his wastewater and treat it in a purification plant that would be ours.
As indicated above, this is advantageous because we are operating with much higher concentrations of compounds and the reactor has less difficulty in operating because it detects a greater quantity of elements. On the other hand, this is only possible if the algae can withstand high doses of chemical compounds.
In addition, the government increasingly encourages industries to equip themselves with devices of this type. Manufacturers would therefore represent a second user to whom we would offer our implementation.
Indeed, this can be an interesting target because the treatment plants are currently sized according to the regulations. They are therefore effective in relation to the law. Stricter regulation of wastewater treatment plant discharges would allow upgrading of purification treatments with, for example, the addition of dedicated treatment units such as our filter.
We warmly thank Julien Chabrol without whom we would not have understood all the implications behind our project. His help was invaluable.