You may be familiar with the idea of wastewater, or water run off from the sewers and other human activities being treated for continued use. This includes storm runoff, industrial sewage, and water containing human waste. Urban areas are huge producers of this dirty water and contaminants such as bacteria, viruses and more thrive in it. Thus, treatment plants like the Point Loma Wastewater Treatment Plant, treat wastewater everyday, removing the water and straining it of solid matter (about 80% of it anyway) before distributing it back into the ocean. The solid particulate matter is then pressed into a concentrated mass that is distributed and used in a variety of ways. This concentrated mass is called biosolid.
The approximately 7 million metric tons of biosolids are treated depending on what class they are categorized into. Class A biosolids are treated to reduce the number of pathogens but are used in parks, home lawns, golf courses, etc. Class B undergo a more stringent pathogen reduction process and are thought to have a lower level of pathogens than animal manure. Class B is used for fertilizers in agriculture and forestry.
Currently, there is a question about the chemicals that remain in biosolids, either before treatment or because of treatment. Things like PFAS which were not previously regulated may pose a significant issue as the currently processes used to make biosolids are not always tailored to reduce or remove PFAS.
Check out this video explanation or the filtration process:
One thing to consider is the impact PFAS will have on this process. We’ve already seen some issues as we learn more about the issue of PFAS in our water supply. Since PFAS do not breakdown, we may need to approach the release of processed waste water back into our natural sources of water. Even the use of biosolids in general may have an unknown impact on our supplies of pure groundwater and thus eventual drinking water. It’s more important than ever that we stay well informed of what is being done to protect our ground water and pure water sources as well as what we are moving towards in the regulation of PFAS.
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