At various times, I have addressed potential issues with the discharge of nitrogen in septic tank effluent. There have been some recent discussions, developments, and questions about treating nitrogen, so I thought it would be a good time to look at the issues again.
In our industry, nitrogen is important for several reasons. There are concerns around nitrogen from the perspective of the potential for groundwater contamination and human health impacts, discharge to estuary and wetland environments and impacts on aquatic life and ecosystems, and as valuable plant nutrient when land-applied properly.
In septic tank effluent, about 75 percent of the
