ALL septic systems require oxygen so the bacteria can properly convert complex molecules into basic molecules like CO2, H2O, Nitrogen, and eat viruses like e.Coli. So the major difference between the tertiary systems is how the oxygen gets to the bacteria. Some pump air into the sewage, some put the sewage into an area with oxygen. I can’t explain it any simpler.
So what ones pump air to the sewage? (The most popular trade name will be used) Aquarobic, FAST, Bionest, Clearstream, Whitewater, Aqua Safe, Nayadic, Norweco, and WSB clean
What are the advantages of a system that puts air into the sewage?
– There is typically no media that has to be replaced. Some have a plastic surface area that the bacteria live on that might get plugged but typically only needs to be cleaned.
– They can typically have a recirculating feature that will aid in nitrate removal.
What are the disadvantages?
– They all require an air pump that typically lasts around 5 years.
– The air pump must run 24 hrs/day to provide the right amount of oxygen to the bacteria.
– The air diffuser can easily get plugged and prevent proper amounts of oxygen from getting into the sewage.
– A yearly inspection is not only required but very important to keep them operating properly. If that air pump isn’t working at peak performance then it WILL fail.
What ones move the sewage to an area with oxygen? Biolan Greywater System, Puraflo Peat Fiber Biofilter, EcoFlo, Enviro-Septic, Orenco Advantex, Waterloo Biofilter.
What are the advantages of these systems?
– No electricity unless the site doesn’t allow gravity and pumping of the sewage is required.
– Less maintenance due to lack of moving parts.
– Research still needs to be conducted but because atmospheric air contains 250,000 ppm of oxygen, the bacteria always have ample oxygen to breath and therefore more advanced colonies of bacteria are present. Water can only hold about 10 ppm of oxygen when air is being pumped into it and therefore bacteria living in the sewage are constantly in competition for it and don’t develop large colonies.
What are the disadvantages?
– The media may need to be replaced periodically or it can plug up and needs to be cleaned. The units that use peat require complete replacement of the peat every 8 years.
What is the best tertiary system? Unfortunately I really can’t give you an exact recommendation that will be best for your situation. Each system has a little different setup and therefore it depends on your site conditions and level of maintenance that you are willing to undertake.