Recycling Nitrate Rich Runoff into Fertilizer

 The usage of nitrogen based fertilizer has allowed the farming industry to increase the overall capable yield therefore allowing more people to be fed per similar plot of land. It is estimated that around half of the world's food production is grown with the use of nitrogen based fertilizers allowing for food production to meet the ever growing world population demands. The use of this excessive amount of nitrogen based fertilizer results in water runoff rich in nitrates that leads to eutrophication allowing algae blooms that deplete water of natural oxygen therefore causing this ecosystem to suffocate. 

An article in SciTechDaily¹ discusses efforts that are focusing on converting this nitrate rich water runoff into ammonia so it can be used to create fertilizer or power fuel cells. The most recent promising study by Yu², is with the use of special strained Ru nanoclusters electrodes that promote the generation of hydrogen radicals, therefore accelerating the hydrogenation of nitrate reduction products leading to the desired ammonia. This end product may be familiar in the case of fertilizer since ammonia used to produce it comes from the famous Haber-Bosch process that would be in competition with this new discovered process. This new process does have advantages over its century old competitor process due to the fact that this process is able to run at ambient temperature and can source its electricity from green renewable energy sources such as solar and wind power. Electrolysis has another great advantage in which a large amount of ammonia does not have to be stored in containers helping in reducing accidental explosions like the incident in Beirut this past year. 

Before this process can be implicated into industry there are still a few hurdles to get over the main one the numerous plants that produce ammonia through the Haber-Bosch process that has mainly monopolized the way it's produced. Another factor in the study found was that directly using agricultural runoff did not have a high enough concentration of nitrates to be viable for this method, so a preceding process will be required for this to become a viable option to produce ammonia. This process is a step in the right direction of helping to eliminate eutrophication of our waterways as well as recycling materials easily accessible helping to reduce carbon emissions put into our atmosphere.

Sources:

1. “Polluted Water as a Source of Fertilizer.” SciTechDaily, 4 Feb. 2021, scitechdaily.com/polluted-water-as-a-source-of-fertilizer/.

2. “Efficient Ammonia Electrosynthesis from Nitrate on Strained Ruthenium Nanoclusters.” Journal of the American Chemical Society, pubs.acs.org/doi/abs/10.1021/jacs.0c00418. 

3. “Electrocatalytic Nitrate Reduction for Sustainable Ammonia Production.” Cell, 26 Jan. 2021, www.cell.com/joule/fulltext/S2542-4351(20)30624-3.

4. EPA damns itself with faint praise in response to Inspector General's Gulf Dead Zone report | NRDC