Plants in wetlands can help clean up nitrogen from wastewater. A study in China found that wetlands filled with salty soil can also do this job well. The researchers used a computer model to see how well the wetlands removed nitrogen. They found that the best time for the water to stay in the wetland was 4 days. The amount of nitrogen removed varied a lot, but overall, the wetlands could clean up between 17% to 79% of total nitrogen. This study will help design better wetlands in areas with salty soil.