How is bacteria added to a septic tank?

[sevensages]

TL;DR Summary

A septic tank needs bacteria to function. How is the bacteria added to a septic tank?

I am enrolled in an Online Plumbing Course with Stratford Career Institute. My plumbing textbook claims that the bacteria in a septic tank breaks down feces so that the raw sewage becomes all liquid so that the raw sewage can be dispersed into the ground via the leach lines. My plumbing textbook says that a septic system cannot function properly without this bacteria in the septic tank.

How is the bacteria that makes a septic system function properly added to the septic tank?

Is the bacteria that makes a septic system function properly added to the septic tank at the factory where the septic tank is manufactured?

Or does the plumber who installs the septic tank at a house typically add the bacteria to the septic tank?

Or does the homeowner have to add the bacteria to the septic tank himself or herself once the septic tank is installed?

How is the bacteria added to the septic tank? Does the bacteria come in a tablet form that you just flush down the toilet or what?

I asked my instructor this question at Stratford Career Institute, and he said that he can only answer questions that are test questions in the study guide. So he won't help me with this.

 

[Baluncore]

How is the bacteria added to the septic tank? Does the bacteria come in a tablet form that you just flush down the toilet or what?

The bacteria is added, unknowingly, by the first user of the system. The microflora is then augmented by all those who follow. If you eat a balanced diet, and so feed the system a balanced diet, it will thrive.

It is sometimes an advantage to add a small quantity of chemical, to give the ecosystem a nudge in the right direction. I would add a touch of cloudy ammonia, or a handful of ammonium nitrate fertiliser, if it gets hot and oxidative in summer.

 

[sevensages]

The bacteria is added, unknowingly, by the first user of the system. The microflora is then augmented by all those who follow. If you eat a balanced diet, and so feed the system a balanced diet, it will thrive.

It is sometimes an advantage to add a small quantity of chemical, to give the ecosystem a nudge in the right direction. I would add a touch of cloudy ammonia, or a handful of ammonium nitrate fertiliser, if it gets hot and oxidative in summer.

Are you saying that the bacteria is added to the septic tank by someone defecating into a toilet and flushing the feces into the septic tank? If so, I am a little bit confused. My plumbing textbook says not to ever flush or pour Draino or other drain opening liquids into a septic tank because it will kill the bacteria in a septic tank, causing the septic system not to function properly. Why would pouring draino into the septic tank be a threat if the raw feces always have bacteria in them anyway?

 

[Baluncore]

Why would pouring draino into the septic tank be a threat if the raw feces always have bacteria in them anyway?

Draino, NaOH, would destroy the bacterial cell walls, and form a dead hydroxide sludge.

You need to feed the living community, not sterilise it. Urine and small quantities of ammonia select the beneficial bacteria that you want to support.

 

[sevensages]

Draino, NaOH, would destroy the bacterial cell walls, and form a dead hydroxide sludge.

You need to feed the living community, not sterilise it. Urine and small quantities of ammonia select the beneficial bacteria that you want to support.

Is the bacteria added via feces?

 

[Filip Larsen]

TL;DR Summary: A septic tank needs bacteria to function. How is the bacteria added to a septic tank?

How is the bacteria that makes a septic system function properly added to the septic tank?

I remember my dad some times would "boot up" his summer house septic tank after long periods without use by dumping in raw meat that had been left out in the open for a while (not sure how long, probably days or until the it started to smell rotten). He mentioned he hung the meat so blowflys would have a chance to lay eggs in them, so I guess he also wanted maggots to help keep his tank running.

 

[Baluncore]

Is the bacteria added via feces?

Faeces, yes.
There are many other ways to seed a septic tank, most of which are accidental. A sample could be transferred from a healthy tank to an unhealthy one, but that should not be needed normally. It is usually sufficient to throw in a handful of ammonium fertiliser when the system is first commissioned. That selects the wanted bacteria from the start.

 

[sevensages]

I remember my dad some times would "boot up" his summer house septic tank after long periods without use by dumping in raw meat that had been left out in the open for a while (not sure how long, probably days or until the it started to smell rotten). He mentioned he hung the meat so blowflys would have a chance to lay eggs in them, so I guess he also wanted maggots to help keep his tank running.

How would your dad add the raw meat to the septic tank? Would he flush the raw meat down the toilet or what?

 

[Baluncore]

He mentioned he hung the meat so blowflys would have a chance to lay eggs in them, so I guess he also wanted maggots to help keeping his tank running.

Fat and oil are not good for a septic tank, or a compost heap. Maggots and flies are not wanted either, they are an indication of insufficient ammonia in the system. Flies will spread unwanted bacteria from the system to places you do not want it.

 

[Filip Larsen]

How would your dad add the raw meat to the septic tank? Would he flush the raw meat down the toilet or what?

I recall there was a large circular cement block over a hole. I assume he slid the block over a bit and let the meat drop in, but I never saw him do it (it was in the 70' so I was only around 8 or so). He tinkered with making things himself most of his life so his use of this may well, as Baluncore hints, be something he just imagined would be a good idea.

 

[sevensages]

I recall there was a large circular cement block over a hole. I assume he slid the block over a bit and let the meat drop in, but I never saw him do it (it was in the 70' so I was only around 8 or so). He tinkered with making things himself most of his life so his use of this may well, as Baluncore hints, be something he just imagined would be a good idea.

Based on baluncore's post, I think your dad would have helped the septic tank more if he defecated into it than if he dropped raw meat into it.

 

[Averagesupernova]

I've been told to flush soured milk when disposed of. Admittedly there is a certain amount of fat in at least whole milk. Not sure if that is enough to offset the aid of the bacteria in the milk.

 

[jrmichler]

The bacteria is added, unknowingly, by the first user of the system. The microflora is then augmented by all those who follow. If you eat a balanced diet, and so feed the system a balanced diet, it will thrive.

This is the secret to proper operation of a septic system. Feed it human waste, pump it every three years or so, and keep out anything that kills bacteria. A septic pumper told me that he could tell when somebody was on antibiotics because of the effect on the contents of the septic tank.

Our septic tank has been pumped every 3 to 4 years since we bought the house in 1995. We have never added anything to "help" the septic tank, only normal usage. The pumper has given it a clean bill of health every time. The scum layer looks proper, the sludge layer is not too deep and is easily pumped out, and the clear liquid in the middle is not clogging the drain field. We do take care to not dump fats or chemicals into the septic tank.

 

[Rive]

How is the bacteria that makes a septic system function properly added to the septic tank?

Human feces has high (24-50% of dry matter) and diverse bacterial content as a 'starter pack'.
If there are issues then there are various commercial products available for 'seeding'. But usually these are not needed.

My plumbing textbook says not to ever flush or pour Draino or other drain opening liquids into a septic tank because it will kill the bacteria in a septic tank, causing the septic system not to function properly. Why would pouring draino into the septic tank be a threat if the raw feces always have bacteria in them anyway?

The content of a 'halthy' and septic tank (if there is enough content) can deal with some (occasional) amount of material with extreme PH and/or salt but extreme amounts will push the PH (and/or salinity) of the tank out of the acceptable range and in such cases even new bacteria will not be able to restart the system for a while.

Fat and oil are not good for a septic tank

Human feces can contain decent amounts of fats in itself. As long as it's not excessive amount (or: form), fats will cause no harm.