First off. Why do we even need septic systems? Or as we call them, Onsite Waste Water Management Systems. Why can’t we just plumb a pipe into the nearest stream, lake, or river? Or just simply plumb the waste to a road ditch? These are very good questions I get asked more often than you think.
Most people care about their neighbors, their well water, the environment. But when sewage starts to get out, and it’s going to cost money to fix it, these questions come up. For example, “Is it okay to release in the back field, as no one lives back there anyways.” Whew, that one is asked so often, if I had a nickel for every time i was asked, I would be rich. As you read this section, I hope you get a better understanding of why we need to control our “Waste Water” onsite. And everyone has the right to know that their neighbor, up the road or hill, is doing it right, and not contaminating their well water. Believe me, there are nightmare stories about sewage in well water in every health department in the U.S. and it’s a growing concern.
What does Septic Mean? It means that the environment in the septic tank is void of all oxygen. Or it’s gone septic. Why is this important? Well, we have to remember why we are treating wastewater. There are three important types of bacteria in wastewater we must destroy before releasing into the environment.
1. Aerobic Bacteria and Pathogens: Need oxygen to survive
2. Anaerobic Bacteria and Pathogens: Need absence of oxygen to survive
3. Facultative Bacteria and Pathogens: These are harder to destroy, because they don’t care if there’s oxygen or not.
Now how do we treat all three. Well.
1. Aerobic Bacteria and Pathogens: The septic tank is the best place to destroy these. See being a septic tank, if you took a dissolved oxygen measurement out of the wastewater, it would read zero. That’s right, there will be no dissolved oxygen in that water. So the Aerobic Bacteria perish here. But let’s not forget the other reason we need a septic tank. It’s to separate liquid from solids and only allow liquids to enter the drainfield. If you allow your septic tank to get too full, it will lose that ability and will send solids out to the drainfield, essentially plugging it up and needing replacement. (Now I have been asked this) If the septic tank is leaking out the bottom why is it that it needs repair. What’s the difference if the sewage gets out of the septic tank or the drainfield. Please remember, the sewage needs 72 hours of septic tank treatment for clarification and to kill aerobic bacteria found in human wastewater. If we simply flush the water down to a leaking tank, it’s going to head straight down to ground water without adequate anearobic, anaerobic, or facultative treatment. We cannot skip any one of these steps as we can hurt our environment and make others very sick. Oh, and possibly contaminate your very own well water.
2. Anaerobic Bacteria and Pathogens: These don’t like oxygen and will die in the presence of oxygen. In a traditional septic system’s drainfield. It is the drainrock that was installed that they die here. Pretty much as soon as they hit the drainrock. Now beneath the drainrock there is soil, but that’s the next and final step.
3. Facultative Bacteria and Pathogens: These don’t care about oxygen at all. They will survive either way. But through plain old friction alone, in the soil beneath the drainrock, they get hung up. And die. All within six inches of leaving the drainrock.
Pretty cool stuff huh?
Waste enters the tank from the left side of the picture. This inlet pipe is called a baffle. The inlet baffle’s funtion is to keep the tank quiet. The bacteria that makes a septic tank work does not like agitation, and must be left still. So the waste exits the inlet baffle through the bottom into the effluent Layer. (Effluent by definition is water that has been treated by a septic tank. It isn’t fully treated yet, don’t be fooled.) Solids will float to the surface forming the scum layer, or the solids you see when you open the lid on your tank. Bacteria goes to work right away on the solids breaking it down into sludge. That is what forms on the bottom of the tank. It is a thick black goo. Really gross.
As waste is entered into the septic tank, effluent is displaced out the outlet baffle. The outlet baffles funtion is to keep the solids from continuing on. If solids were to get out, it would plug up pumps and drainfield, depending on your system. Either way it is vital in your sewage treatment facility. You may also have an effluent filter in your outlet baffle. It filters down to 1/16th of an inch. An extra addage to be sure solids don’t enter your drainfield, or pumps.
For even further details on how it works, click here.
Now the above is the most basic of septic systems. There are much more complex systems and you want to be sure the technician you call out has the certifications for your system. Below I put a link from the University of Minnesota. I have spent extensive hours training with David Gustufson, and I have his permission to put his link on here. He explains your Aerobic Treatment Unit (ATU) best.
Below is a link about Recirculating Media Filters. These are top of the line for removing nitrates in our waste. In case you were wondering Nitrates are poisonous to children and many have died before the advent of septic systems. Thanks to our greater understanding of how septic systems work, and continuing education to make them better, we have not had a nitrate death in over 80 year.
Now if you have a sand mound filter, you have a huge Mound, in your yard. Please resist the urge to level it. It needs the slope integrity to work. Most of your wastewater treatment is through evaporation, and not through ground absorption. Sand mounds can get soggy if they are overloaded, or if a pump is not set up correctly and is sending out too much effluent, “dirty water,” to the sand mound. You may have to replace an on/off switch, replace a pump, or reset some timers, now it’s highly unusual that it’s all these things, it’s usually just one of them.
You may have a sand filter. There are sand filters with a pump inside and there are sand filters with no pumps. Then the effluent is either discharged out through the bottom of the sand filter to a drainfield, or pumped out. Depending on grade and if the drainfield is a gravity drainfield or pressurized drainfield. You could have a sand filter and a sand mound on the same property. Depending on how your soil can treat wastewater. A soggy sand filter is usually nothing to get too excited about, but it does need corrected soon. See, a sand filter is an aerobic environment, the bacteria there need oxygen. If it goes under water, they will drown and cause all kinds of issues. During our maintenance checks we also check the pumps and alarms if applicable to let you know that a problem maybe developing in those areas.
It is really hard to see this sand filter. But the lush growth in the grass is it. And the open green whole is where the septic pump is housed. Geographically the wastewater gets to the sand filter via a pump just after the septic tanks. There are five distribution lines on this sand filter that extends the entire surface of the sandfilter. The lines are located just beneath the soil. At the end of the sand filter there are flush-ports. It is not necessary to have these installed but it is a really good idea.
If the flush ports are installed I can flush the sand filter lines every year at inspection time. Extending sand filter, and septic pump life. Remember, the pumps job is not to just move water from one place to another, but charge all the lines in the sandfilter, and clean the lines with water volume and pressure.
If the pump is cleaning the lines all year, where does the gunk go that it’s cleaning. Well, to the end of the sandfilter lines, plugging it up in slow motion. Usually about 10 years after the sandfilter is installed, if not flushed, the lines will need jetted. Jetting is expensive and could easily be avoided if the septic sand filter was flushed out yearly.
Now when the pump comes on, it keeps the lines in the drainfield clean. When it cleans it sends all the gunk to this flush port to be collected prior to flushing. If we don’t flush the drainfield, it will clog the drainfield, and can cause premature pump failure.
Also if the pump starts pumping at an unacceptable rate, and starts drooling the water into the drainfield, then the water will not clean the lines. Some may call this scouring of the lines. They both mean the same thing. This is why we always test the pump, to make sure it is working good enough to keep the lines clean. If not, then we replace it before it plugs something up.
Now, I simply remove the cap and manually turn the pumps on, and eject the build-up out of the septic’s pressurized drainfield.
I flushout the remaining drainfield lines and now I am done flushing the drainfield.