Sink garbage disposal on a Septic Tank System. Yea or nay?

We have a spectic tank and it gets pumped on a regular .... fairly regular basis. I'd like to put a garbage disposal in the sink but the data is kind of sketchy on this. I can see where you would not want to grind up a whole lot of stuff and put it down the drain but I'm mainly looking to grind up bit and pieces of crap that get left in the sink when cleaning the dishes or when scraping the plates. I put what I can in the garbage but some stuff is too liquidly and I would like to be able to put this down the drain with the disposal. I cannot see the difference between scraping it from the plate to the sink, to the disposal to the septic tank vs eatting the food, using the toilet and then it going to the septic tank. The food ends up in the same place both ways.
So what is the problem of a disposal unit on a septic tank system? It is a matter of VOLUME? Or a matter of WHAT I put down the drain? As I said earlier, it would only be food I cannot place in the garbage and what is in the sink after doing the dishes. I don't plan to grind up bones so I really can't see the problem. I mean if I have the tank emptied on a regualr basis what does it matter? The stuff should break down any ways, right?
Any advice appreciated. I looked on the net and it seemed to lean towards a "no" but didn't explain why very well.
Thanks snipped-for-privacy@notgmail.com
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On 1/5/2017 1:26 PM, snipped-for-privacy@notgmail.com wrote:

We use ours with no problem and with only two of us home now I don't have tank pumped out more frequently than 4-5 years.
I don't put anything down the sink disposal unit that I can put in the garbage and am most careful with fats and oils which septic cleaner pointed out can form a solid scum on top.
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Thu, 05 Jan 2017 13:26:41 -0500, snipped-for-privacy@notgmail.com responded:

I also have septic, where I've lived here about a decade, and I don't even know where the septic system is, which means it has never once been pumped out (4 people in the house).

You haven't asked your question yet, but my experience on garbage disposal is power. Like in horses. I would go for the 3/4 horsepower ones. In my experience, they're a good compromise in cost, size, and capability.
But, I haven't seen your question yet..........

Bingo!
I have a rental unit where the lady living there with her family calls me up almost every Easter saying the drain clogged. It's filled to the core with egg shells she ground up but which she didn't flush down in stages (or whatever caused them to clog the plumbing).
My use model on garbage disposal is kind of simple: 1. It's not for getting rid of compost 2. That's what a compost heap is for 3. It's for stopping everything else that goes down the sink from clogging the sink.

If you can swing it, I'd put everything you can in the compost heap, but, you're right, I think, that the less you put down the drain, the better.
However, if you grind up stuff and use plenty of water to flush it down the drain, I can't see the harm in that it will decompose in the septic system (or, I think it should). Did I mention that I've never had mine pumped out? So I really don't know how much gets in there and how much gets eaten while it's in there.

Well, there is a difference, but when you put it that way, it's the same amount of digestible gunk. However, egg shells, bones, peels, apple cores, bacon fat, etc., aren't gonna get eaten so they have to go somewhere.
Me? I put all that "big stuff" in the compost (yes, bones and bacon fat too!).
But you can grind up that stuff in the garbage disposal and "my take" (TM) on that is that it will get eaten up by the bacteria in the septic system.
BTW, how many people do you have in the house versus the number of bathrooms (since, I think, they size septic systems by the number of bathrooms)?
Mine has fewer people than bathrooms, so, I think I'm under utilizing my septic, which may be why it's never needed to be pumped out (since I'm told it will tell me when it wants to be pumped out).

I think it's normal to have a disposal unit on a septic system. If nothing else, the disposal prevents some clogging of the pipes.

I don't think water volume matters but I'll let someone else say whether the water just leaks out no matter how much you flush down the drain.
The solids get eaten by the good bacteria, is my assumption.
However, my wife literally pours bleach down the toilet so I wonder if that kills the good bacteria?

Seems like it's almost nothing so I would agree with your decision to get the garbage disposal, if for no other reason than to chop up stuff so that it doesn't clog the pipes.
Plus, I think, chopping it up makes the bacteria eat it faster.
But that assumes the bacteria eat it, which is my assumption, where I assume that food gets so eaten up that it disappears in the septic system with the water leaking out (once the bacteria digest the food to glop).

Now you're thinking like I think. It's my assumption that you shouldn't even have to clean it out ever.
This is my second septic system (two houses in twenty years) and I've never once had it cleaned out. I'm told it will let me know if it wants to be cleaned out, by the smell if not the ooze, and I've just never had either.
As I said, I've been here a decade and I don't even know where my septic system is, it's been that trouble free.

I think a garbage disposal is only a good thing with no drawback other than it takes up some room under the sink. I suggest you put it in the bigger basin if you have two sinks (mine is in the smaller basin but my wife cuts up food in the bigger basin so I constantly have to dig out her scraps).
My recommendation is 3/4 HP but that may be too big for your cabinet. But, I must repeat, I am just guessing as I've never had a problem with mine but I have more bathrooms than people and anything that fits in my hand goes in the compost heap and not down the drain.
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On Thu, 5 Jan 2017 19:29:12 +0000 (UTC), Lacopo Ferrari

Yeah, the question is whether it tells you before the drain field is clogged too. If the scum gets deep enough to go out the back, it will plug the field. Then you are digging.
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On 1/5/2017 4:17 PM, snipped-for-privacy@aol.com wrote:

Some are naive enough to wait until the septic backs up to have it pumped. Can be a costly mistake.
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Thu, 5 Jan 2017 18:22:31 -0500, Frank responded:

I'm sure I'm naive, but I don't see what the problem is. If it clogs, it gets pumped. If it doesn't clog, it doesn't get pumped.
Where is the costly mistake?
I saw above that the "drain field gets clogged" which I find impossible to consider. At least where I live it seems to be impossible since it's utterly vast (acres upon acres).
I realize I'm naive so I just want to ask this question. How on earth does a "drain field get clogged"?
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On 1/5/2017 8:08 PM, Lacopo Ferrari wrote:

In a perfect septic tank world, the only thing that goes out into the field itself is liquid - dirty, nasty smelling, bacteria laden water!
The septic tank is a settling tank. Solids and semi-solids break down there over time, become more liquid and move out to the field. That which doesn't break down settles to the bottom as sludge. As that builds up, if it's not removed, then solids make their way into the drain field and plug up the system. That becomes a major PITA and $$$$ to repair, replace.
So, if you don't clean out the sludge in the septic tank in a timely fashion, you are making a costly mistake if it causes the field to fail.
Follow the plumber's or PE's recommendation for pumping out the tank until you get a handle on how often cleaning is required. Each household is different. My wife regularly tosses packages of yeast into the toilet and flushes away.
The first time we pumped the tank (1500 gallon oversized by our request), there was less than 7" of sludge buildup even though we went about two years beyond the recommendation. We've now been in the home, raised two children and now entertain them and three grandchildren from time to time and the system will be 42 years old this summer when we pump it out for the 4th time. Septic tank cleaner has never found more than 16" of sludge in the tank.
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Thu, 5 Jan 2017 21:21:41 -0600, Unquestionably Confused responded:

That's what I'm thinking, which is only gooey black smelly liquid leaches out of the septic tank, in which case that's what the tons upon tons upon tons of soil are supposed to filter from any potable water supply.
I think code here is 100 feet from a potable water supply, which is nothing whatsoever when there are acres involved.

That's what I was thinking which is that solids eventually turn into liquidy goop, which follows the water out into the filtration field.

I wasn't accounting for this insoluble sludge stuff. I've actually toured a sewage treatment plant where they have huge 30-foot diameter rollers which squeeze out the sewage and what cakes off the rollers is basically dried insoluble sludge but this is an active sewage treatment plant which is different than a passive septic system.
So the question becomes how much insoluble sludge is there and how long does it take for that sludge to fill up a septic system?

I think there's a difficult argument there, because if they are truly insoluble sludge, then they'll either float or sink. If they sink, they will just stay on the bottom of the septic system, won't they?
If they are so deep that they fill up the septic tank with insoluble sludge, then sure, they'll need to be pumped out.
Now you're intimating that they're semi-solid and that they float and that they kind of clog up all the dirt just outside the septic system. I can see this as being a problem, if it happens, since you have to basically remove it like they did the Love Canal dumpings.
But is a septic system really that prone to clogging the leach field?

I can see that if the field fails, then that's it for the field. You basically have to dig it out as there's no such thing as reverse flushing it back into the septic system.
Searching, I see it's called "soakaway bed failure" and, apparently only about half the solids that go into the septic system leach out: https://extension.umd.edu/learn/how-can-i-repair-my-failing-drainfield
OK. So it's worse than I had thought. https://fremontcountywy.org/wp-content/uploads/2009/11/WhySepticSystemsFail.pdf

I understand that she's inoculating the septic system, but I would guess that feces inoculates it plenty already.

I guess I need to start looking for a septic system cleaner guy. It seems they can't tell if it's sludged up without pumping. http://www.edcgov.us/Government/EMD/EnvironmentalHealth/Homeowner_Manual_Septic_Tanks.aspx
I have no idea how big my septic system is, but they do that stuff by number of bathrooms where I have 5 so it's probably in the local code.
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On 1/5/2017 9:40 PM, Lacopo Ferrari wrote:

Pretty sure that is the requirement here (northern Illinois) and elsewhere per code.

[snip]

That is, and forever shall be, the $64,000 question.

"Sink or swim" for sure. There are baffle plates in the septic tank itself which, I think, tend to prevent the migration of that s**t which floats on the surface from migrating into the field. Obviously, if I were to suddenly dump 500 gallons of water into my system all at once, most likely that which floats would fly out into the field and I'd be up the proverbial creek. ;)

That's what I think as well, but she's not referred to as SWMBO for nothing! ;)
[snip]

When we've had ours pumped, the first thing the guy does is stick a long pole into the tank, straight down, and then slowly withdraw it like an oil dipstick on the car.

When we built in 1974, I had the system designed by a professional engineer (required) and the plans filed with the county who confirmed it met code. Presumably the plans for it and the house were archived so you may have access that way. Regardless, if the system was permitted by the local authority, you would be safe in assuming that the code minimum was observed. In our case, I think the PE specified a 1,000 or maybe 1,200 gallon tank. I upped it to 1,500 against a possible addition to the house and other consideration not germane to this discussion.
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Fri, 6 Jan 2017 08:23:33 -0600, Unquestionably Confused responded:

All your advice was nicely logical in that it made sense. If the guy can stick a stick in my septic hole, I should be able to stick a stick into it too.
Now I only have to find it ... :)
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On Fri, 6 Jan 2017 02:08:43 +0000 (UTC), Lacopo Ferrari

The traditional drain field has perforated pipe feeding it and the perforations plug up or the gravel right outside the holes gets slugged with sludge. Then the crud starts backing up in the pipes. When I rebuilt mine I used a chamber system so you do not have the perforated pipe. As for the paper, cellulose does not break down as fast as poop. Some brands are worse than others.
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On Thursday, January 5, 2017 at 9:08:49 PM UTC-5, Lacopo Ferrari wrote:

I guess if you have a rental unit, or kids, or adults who are clueless, they could flush an upstairs toilet 10 times and have it coming out as a flood downstairs. Or pull the plug on a bathtub upstairs, etc.

I can assure you that your drain field is not acres upon acres. The drain field is the area right after the tank where perforated drain pipe is laid and it's typically a small fraction of an acre. How large it needs to be depends on the percolation of the soil, but I've never heard of one that is anywhere near an acre for a home.
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Fri, 6 Jan 2017 07:10:59 -0800 (PST), trader_4 responded:

I probably misled you by mistake by saying it's acres. What I mean is that there is a drain field. And there are acres of property.
As you can imagine, I would have no idea how large the drain field is, and I agree with you that it's just the area around the leach field as per whatever code was in the 1990s when the house was built for the number of bathrooms it has.
All I can say is: a. Now I'm sensitized to the fact that it needs to be periodically pumped b. The $64 question is when.
I think, to my advantage on the when, we have fewer people than bathrooms (kids are all in college or beyond by now) and we never throw anything but TP in the toilet and nothing goes down the sink (since we compost everything that is food that is not eaten).
I think, from what I read about septic systems, even the feces has to eventually be pumped out as "sludge" though. Is that right? If so, then it goes against the "if you didn't eat it, it has to be pumped out" mantra.
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On Thursday, January 5, 2017 at 2:29:17 PM UTC-5, Lacopo Ferrari wrote:

+1
And that's how the OP intends to use it. I'd make a tenant pay if they continually clogged the drain with egg shells after being told not to put them down it. The only thing that goes down mine are the remaining scraps of food after I've put all the bigger pieces into the trash.
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On 1/6/2017 10:06 AM, trader_4 wrote:

I'm on town sewer but do the same. Makes no sense to put compostable stuff down the drain, especially egg shells. They can be used in the garden but can just go in the trash with no odor or side effects.
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Fri, 6 Jan 2017 07:06:08 -0800 (PST), trader_4 responded:

I have a renter in another house who puts eggshells down the sink, but, it's on a city sewer line, so, I think that's OK, isn't it?
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snipped-for-privacy@notgmail.com says...

YOu should try not to put anything in the tank that has not been ran through a person. Idon't see why you have to have the tank pumped very often. Maybe too many chemicals.
If you are going to have it pumped every year or two, then I don't think it will matter what you put in the tank.
Just my wife and I are in a house we bought almost 15 years ago that was about about 15 years old when we bought it. We have never had the tank pumped, or any problems with it. The washing machine does go to a seperate outlet so never goes to the tank.
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On Thu, 5 Jan 2017 16:01:04 -0500, Ralph Mowery

Pumping is mostly for things that do not get consumed by the microbes. That can be excessive amounts of grease, hair, plastic and most of all, toilet paper. When I did an addition on my house I needed a septic inspection so I got to spend some time with the licensed operator (the guy on the pump truck will not actually have a license most of the time). He told me a lot about how septic systems work and what goes wrong with them. He also echoed the advice, you can put anything you want in a septic system if you eat it first. He told me you can have a garbage disposal but plan on pumping it a lot and you still may have trouble.
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Thu, 05 Jan 2017 16:34:22 -0500, snipped-for-privacy@aol.com responded:

That was what I was thinking, which is that the only things that aren't turned to mush are those that the microbes can't digest.
Pretty much that should be plastic, and, that's about it. What else goes down a toilet, washing machine, shower or sink that microbes can't eat?

1. Grease (realistically, can only come from the kitchen) 2. Hair (probably mostly comes from the shower) 3. Plastic (shouldn't be there in the first place) 4. Toilet paper (comes from the toilet)
Seems to me that the hair is inevitable, but that it's keratin, which means I would "think" it would be digested by microbes. Same as toilet paper, which is cellulose, which microbes can digest, can't they?
Grease shouldn't be there. IMHO Neither should plastic. IMHO
I dump grease outside in the compost heap.

Depends on what you put into the garbage disposal, I'm sure.
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Thu, 05 Jan 2017 13:26:41 -0500, snipped-for-privacy@notgmail.com responded:

Now that I read two or three articles, I are an expert on septic systems.
http://www.doh.wa.gov/Portals/1/Documents/4450/WW-SM-007.pdf
"Garbage disposals have a dramatic impact on how often you?ll need to pump your septic tank. Food particles usually are not digested by the bacteria and accumulate as scum. If a large amount of water enters the tank, it can then push the food particles into the drainfield, causing clogging. If you must use a garbage disposal, your tank will need to be pumped more frequently."
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