WASTEWATER TREATMENT PROCESS
The end users of our product are wastewater treatment plants. In order to understand how SINISENS would function in practice, it is important to understand the steps performed in the wastewater treatment plants. As an example, we are going to use Helsinki Region Environmental Services Authority (HSY) facilities (Fig. 1).
The influent water has to go through screens and grit removal to separate sand and larger objects. In addition to that ferrous sulphate is added for precipitating phosphorus into the sludge. The next step is pre-aeration, which can help sustain aerobic conditions in the tank, remove oil from water as well as aid in the sedimentation process. During primary sedimentation, the number of solids present in water is decreased. The next step in the wastewater treatment process is aeration, which is necessary for aerobic degradation of pollutants by bacteria. Here, most of the nitrogen is released back into the atmosphere. However, it is worth noting that a portion of nitrogen remains in the water flow. The next step includes secondary sedimentation and a biological filter, which ensure that the cells from the previous step will be removed . It is planned to introduce ozonation and activated carbon treatment, where substances such as pharmaceuticals would be removed before the water is released into the sea . In Switzerland, which is currently leading in pharma removal research, clarithromycin is used as one of the marker compounds for assessment of removal efficiency . SINISENS would be used before and after this step in order to optimize it and make it more energy- and resource-efficient.
SINISENS IN ACTION
We envision our biosensor to be used in wastewater plants. It would be located next to the water flow, where the sample is collected and pumped into the device. Ideally the sample would be returned into the flow after the measurement, but in the current design this is not possible due to the risk of biocontamination. We decided it is safer to have it outside of the WWTP flow, since our sensor is a genetically modified organism and, in addition to that, may carry an antibiotic resistance gene. Although the biosensor right now is single-use, it would be preferred that the process of replacing the sensor is automated. This would also limit the employees’ contact with modified bacteria, thus improving the safety of the product. Since our biosensor would be used for removal process optimization, the sample would be taken out after biological filters, where ozonation and activated carbon-based removal begins, and right before the efflux into the sea. The equipment necessary would include a spectrophotometer and possibly an incubator, unless we prove the bacteria can give a satisfactory output in a room-temperature.
Guidelines for the End User
In terms of safety, the prevention of physical contact is important to keep in mind already in the sensor design. The system could also be automated in the part of the process that poses most of the risk, for example periodically getting the strips in and removing them. In the sensing element itself, it would be possible to build a kill switch-system so that the microorganism survives only in the controlled environment. In addition to mentioned points, training of the maintenance staff is important especially during malfunctions in order to be aware of the risks.
ELECTROCHEMICAL BIOSENSOR: A MORE PROMISING OUTPUT?
Our proof-of-concept SINISENS which we developed for this iGEM project gives an optical output signal, but the most sensitive solution and an easier output to read may involve an electrochemical biosensor . Based on this, we have researched a potential pathway that may provide E. coli with an ability to give an electrochemical signal: Mtr pathway. Our general idea is to express the components necessary for the Mtr pathway in E. coli independently of the concentration of erythromycin except for mtrB, which would have been under the erythromycin inducible pMphR promoter (see our design page). It would result in no current being produced when there are no macrolides and a current production if macrolide concentration increases. SINISENS cells would be immobilized to an electrode. A brief overview of Mtr in E. coli for biosensing can be found here.
SAFETY AND ENVIRONMENTAL CONCERNS
Since our biosensor classifies as genetically modified organisms, its proper disposal and handling
are essential. While feedback given by wastewater treatment plant employees highlighted that a
biosensor placed in the water flow itself would be ideal, we decided that biocontainment in such a
setting would be nearly impossible. Hence, we settled on a system where a small sample would be
collected and placed in a tabletop device present on-site. After use, the straps with bacteria in
the measured sample would be placed in separate containers and sterilized.
Since the environment is at heart of SINISENS, we were mindful whether our biosensor may have a negative impact on other aspects, such as CO2 production and energy use. Since SINISENS cells are self-replicating, the resources required for manufacturing include only an incubator and growth media. Additionally, we envision cells to be immobilized on a cellulose nitrate strip, which after use can be sterilized and reused. We imagine that the carbon footprint connected to transportation would be minimal given the size of a sensor. We are also not certain in what conditions the cells would be stored, for example being kept in -80°C, which would increase the amount of resources required for SINISENS to be implemented.
In order to gain insight on what kind of challenges we might face when commercializing our SINISENS biosensor, we held a workshop for all of our team members. We also explored the advantages of our product, team and competitors as well as channels to reach potential customers and investors. The format of the workshop was provided by the team Stockholm as we collaborated with them on multiple aspects of our projects.
Key matrices are the features that give SINISENS an advantage over other techniques for measuring
Key matrices of SINISENS:
- Fast results.
- A small, easy-to-use device. No need to add external reagents.
- Uses an organism that is easy to grow in the sensor.
- On-site detection. No need to send the sample to a laboratory.
- Could be improved to detect all of the seven indicator substances.
We compared both the advantages we have over other competitors and what advantages other competitors, for example large companies, might have (Table 1).
|Advantages of Aalto-Helsinki||Advantages of potential competitors|
|A lot of time already spent on research for the SINISENS biosensor||Expertise in various aspects, such as commercialization, scaling up production, patents and science|
|Start-up events, connections to wastewater treatment plants and sponsors||Funding, connections to industry|
|A motivated student-driven team||Large companies have better facilities and more employees|
The three top problems that were identified were the hardware, the easy-usability of the sensor and legislation (Table 2).
|Making the hardware with sensor and concentration method for macrolides||How to ensure that the biosensor is easy and convenient for the user?||Legislation concerning GMOs||Legislation concerning pharmaceutical removal|
|Research on concentrating||Proper training and clear instructions||Extensive safety analysis||Lobbying for new legislation|
|Electrochemical biosensor||Contacting end-users for feedback and testing rounds||Proper discarding system||Promoting SINISENS as the possible solution to change legislation|
|Numerical output signal from the device||Numerical output signal from the device||Making the device as biosafe as possible - for example by removing antibiotic resistance from SINISENS||Raising awareness on pharmaceutical pollution|
|-||A device that transports the data straight to an analysis program on the computer||Partnering with big names in the industry||More research on the harmful effects of pharmaceuticals|
Customer Segments and Investors
We have developed our biosensor to be used to optimize the removal process of antibiotics. However,
for a successful commercialization of a product having various customer segments can be beneficial.
Besides wastewater treatment plants, the SINISENS would also be useful for the pharmaceutical
industry, hospitals, animal farms, environmental organizations and municipalities as well as for
Due to our extensive human practices work, we have already acquired quite a few contacts in wastewater treatment plants, universities and the Finnish environmental ministry. Our sponsors would be a great way to reach the industry. Possible channels to reach new investors and clientele include organizing and participating in different seminars, conferences, start-up events and workshops to pitch our product. In addition, publishing our results could help us reach potential customers. Our personal networks could be utilized as well.
1. Viikinmäki wastewater treatment plant. (2020). Retrieved 17 October 2020, from
2. Jätevedenpuhdistus pääkaupunkiseudulla 2018. (2020). Retrieved 19 October 2020, from https://julkaisu.hsy.fi/jatevedenpuhdistus-paakaupunkiseudulla-2018.html#c_11_otsikko_6
3. Verordnung des UVEK zur Überprüfung des Reinigungseffekts von Massnahmen zur Elimination von organischen Spurenstoffen bei Abwasserreinigungsanlagen, 814.201.231 § 2 (2016). https://www.admin.ch/opc/de/classified-compilation/20160123/index.html#a2
4. Yi, H., Li, M., Huo, X., Zeng, G., Lai, C., & Huang, D. et al. (2019). Recent development of advanced biotechnology for wastewater treatment. Critical Reviews In Biotechnology, 40(1), 99-118. doi: 10.1080/07388551.2019.1682964