Stanford University scientists have developed a new system that uses solar energy to create fertilizer from human urine, increasing energy efficiency by up to 60 percent. The system not only provides fertilizer but also makes wastewater safer for agricultural irrigation. Offering a solution to both sanitation and energy problems in developing countries.
Electro-chemical chambers separate ammonia from urine, and the system converts it into ammonium sulfate, a common fertilizer. Waste heat generated from solar panels makes the process faster and more efficient, and keeps solar panels cool.
The project leader and Stanford assistant professor of chemical engineering William Tarpah says the project is an example of “turning waste into opportunity.” According to him, system preserves nutrients that normally becomes a waste and cause environmental damage, not requiring an electrical grid.
Experts say that human urine contains enough nitrogen to meet about 14 percent of the world’s fertilizer demand. With this new system, direct production of fertilizer is possible depending upon need, using only sunlight.
According to the research, by trapping heat behind solar panels through copper tubes, there was an increase in energy production by 60%. Whereas the improvement in ammonia recovery was by 20%. This innovation also prevents solar panels from overheating, which usually reduces their efficiency.
The research team has also developed a model of the system that can predict the effects of sunlight, temperature and electrical settings. In regions like the African country of Uganda, where fertilizer is expensive and electricity is scarce, the technology could bring the cost of nitrogen per kilogram to $4.13, double the income in the United States.
This system not only produces fertilizer, but also removes nitrogen from urine, making wastewater safer. So that it can be reused for agricultural purposes or discharged into the environment. Globally, more than 80 percent of wastewater is discharged untreated, polluting groundwater and affecting ecosystems.
The research team is already working on a larger prototype that will have three times the capacity. And will work faster in bright sunlight. Industrial installments use the results of this project. Such as wastewater plants, where the storage and use of waste heat for other purposes is possible.
