 Hello and welcome. My name is Natni El Demise. I'm a PhD candidate environmental engineering at Swedish University of Agriculture Science. Our research group is among a handful in the world that's working with source separation, an approach that we believe can disrupt how we treat and manage wastewater. In this presentation I will share to you our experience and what we have learned till now. We are accustomed to hear that we are what we eat and we have been saying that what we eat is what we excrete. Even if human urine makes up just one percent of the wastewater produced in our homes, it contains majority of the nitrogen, the phosphorus and the potassium. But also urine contains water which consists 90 percent, 96 percent. So in our research we focus on developing technologies that can capture urine nutrients without the water. But recycling urine nutrients requires a number of steps from collection to fertilizer production to final consumer product. I'm going to work you through each of these steps focusing on what we have already learned and where the knowledge gap exists. So the first step is in source separation step is to collect urine apparently from the rest of the wastewater and this can be done using urinals and urine directing toilets. There are a number of choices available in the market which cater to both high income and low income markets. Going forward the challenge will be to reduce the volume of flesh water that ends up in the urine collection tank. For example in the lafond toilets which you will see on the right hand side around 200 ml of water per flesh is collected along with the separated urine. So after collection the next step is stabilization. To preserve the nutrients especially nitrogen urine must be stabilized as soon as it's collected otherwise urine enzyme along the wastewater pipes breaks down urine into ammonia which can be lost from the system in the form of ammonia gas thus reducing the nitrogen content. Urine can be stabilized in two ways alkaline stabilization and acid stabilization methods and in these methods the pH will be kept above pH 10 and below pH 3 where urine enzyme is inactive and loss of ammonia is prevented. Alkaline stabilization can be done using alkali hydroxide like potassium hydroxide and sodium hydroxide but since these hydroxides are completely soluble in urine an active dosing system is required to add them at the toilet and active dosing system is systematically challenging to implement it at toilet scale. On the other hand stabilization using alkaline earth hydroxide is more feasible as these hydroxides are sparingly soluble in urine therefore they can be dosed passively. The advantage of using magnesium hydroxide over calcium hydroxide is that it favors formation of steroids which captures the free ammonia nitrogen actually present in the urine and the disadvantage of alkaline stabilization is that during storage of alkalized urine carbon dioxide present in the air is absorbed which lowers the pH of the system and which in return reactivates the urase. On the other hand urine can be stabilized using acids like organic acids like citric acid and inorganic acids like sulfuric acid. The advantage of dosing organic acids is that they are naturally present in food and in our urine and they are also can be bought very easily at grocery stores and even if far less acid dosing is required with sulfuric acid will command issues only in centralized urine cycling systems where the systems can be more effectively and safely monitored. Going forward the challenge is to develop reactors that can safely dose these chemicals at the toilet as well as create service chains that safely store and deliver them to users. So after stabilization the next step is trying and after the urine is stabilized it can be dehydrated to remove water without the loss of nutrients and we have developed tires that can be integrated below and beside household and public toilets. We are also working to develop a mobile drying system that can work with toilet retail companies to cater public events like festivals. The challenge with drying urine is to keep the energy demand as low as possible especially when removing the last 10% of the water. After drying the next post is stabilization. So basically dehydration concentrates nutrients in urine so that only small amount of solids needs to be collected. After collection dried urine is pelletized so that it can be integrated with existing farming equipment for spreading of fertilizers. So pelletizing urine requires blending agents like brown instra but the challenge here is to form right pellet size that can keep ship and fit the farm equipment. Depending on the choice of stabilization the final product contains between 11 and 21% of the nitrogen making it comparable to blended mineral fertilizers which are available in the market. So after pelletization the next step is to try the manufacturer product in the field trial. Field application of dried urine was tested in Gotland, Costa Sweden where we produce barley and we found that set 5% decrease in yield with no fertilizer compared to mineral fertilizer and there was no significant difference in yield between urine and mineral fertilizer fertilized barley. But different crops have different requirements so the challenge going forward is to identify other substrates that can be blended with dried urine so that the final fertilizer composition matches the specific nutrient requirement of other crops. So after field trial the next step is to produce a product that we can consume and since we get an amazing performance on the field trial the next step is to close the loop by bringing the product into our table and we have also partnered with manufacturer industries to further process the barley which melts it and then produce a beer out of it. Earlier this year we had a beer testing workshop and most of the participants found that the beer tastes like normal beer and the challenge here is that to scale up the whole service chain so that enough dried urine fertilizer is produced to meet the large fertilizer requirement of the agriculture as well as the food processing industry. However people have concerns in using products fertilized by urine and one of the concerns is the presence of pharmaceuticals in urine so to reflect on this concern we have also developed an on-site treatment step using UV-based advanced oxidation process that can be performed before the urine is dehydrated. So in this study we have looked at the degradation of 75 microcoltants and we found that an average degradation of more than 55 percent. To give you some insights some pharmaceuticals like Atenelol, Zetromycin, Bisoprolol and Trimetoprol they didn't show any degradation whereas environmentally relevant compounds like carbamazapine, amythryptaline and seprofloxacin showed average degradation. On the other hand dichlofenax, sulphametroxazole and norfoloxetine showed more than 90 percent degradation. So the way forward is to optimize this process so that all the pharmaceuticals can be degraded. So overall our research shows that every step necessary to recycle urine can be performed to create a radically new sanitation system. We have shown this in practice in Sweden where we have multiple pilot projects running. We think such a system can be and should be a serious contender in shaping the wastewater treatment needs of growing cities worldwide. I couldn't say everything over here so thank you for your attention. If you have any questions you can visit our blog or you can contact me after. Thanks so much for your time. See you later on.