Do you think that adding a volume of undigested solids to the normal sewage load on the septic tank is a good idea? The YES or NO answer will answer both questions.

If you use it wisely, a garbage disposal will not harm your septic. By wisely, I mean you should always clean out what you can from your sink and use the disposal only for those incidental items that are left. NEVER scrape plates into it or use it to dispose of peelings etc.

Used toilet paper is an undigested solid. Are you suggesting this item not be flushed down a toilet connected to a septic system?

Household use of a waste disposal with a septic system is perfectly fine. The volume of food waste that gets added to the tank in this way is miniscule. There are abundant health/safety code rules and permitting procedures for septic systems. If waste disposals presented a problem, they wouldn't be allowed, or their use might require larger tanks for a given size house. Such is not the case to my knowledge.

Use common sense. An example, egg shells are perfectly fine for the disposal but won't break down in the tank, so those should go into the trash bag. Same with coffee grounds.

PS - Garburator is a funny word, never heard it before.

"normal sewage load" How does that exclude the paper?

While not a fun activity, it is instructive to inspect some of the material that is in the effluent when a tank is pumped out. Some things do not decompose in the septic tank. Grease. Hair does not change at all in the septic tank. The husks of corn kernels, the very thin outer skin of apples eaten with the peeling included, some of the portions of lettuce, can be identified visually.
Eating the named foods is considered to be good for parts of the alimentary canal.
Such materials are the reason that a tank will accumulate solids. Adding more shortens the time intervals at which pumping will be mandatory.

Your thought is now clear, the words were not at first reading.

Greae/oil/fat are not good for household drain pipes and even less so for the system the drain pipe leads to. Whether a septic tank or a municipal/regional wastewater system, the greasy stuff isn't easy to handle. Which is why restaurants have grease traps.

Watching a pump out is indeed useful. In my area, pump outs are often required when a home is sold, so residents new to the septic tank world theoretically have a chance to start their experience with a view of what doesn't break down. I'd guess few are interested and fewer care, which keeps the septic contractors fully employed.

"I'd guess few are interested and fewer care"

Usually right up till when they clog a field and get proposals to install a new field (if they have room) or replace the field in the same location (if they even can under new rules that may have been put in effect).

Use of garbage disposals will definetely shorten the life of the system since it grinds particles up so fine they dont have a chance to settle before moving out to the soil drainfield where they clog soil pores and accelerate biomat buildup. If you must have one, install two tanks in serial with effluent screens on each outlet.

piedmontnc,

I accept your comment that NOT adding particles is better than adding them. But then if you add that material, what's the practical consequence?

Leach fields have a limited life no matter what. Over 25 years in one house, I've heard of a few neighbors (all of whom most certainly have disposals) needing to rework their leach fields. Frequently? No. Very many of them? No. Much fewer than 10 percent over that period of time. The soil is sandy and the water table is low, that may help, but what would you conclude?

Rather than two tanks, maybe the better answer is two fields, to allow recovery time?

Alternating fields would also help but with the disposals they key is providing more tankage for settling and effluent filterss if not already required by code. Sandy soils do have the potential tto last longer and usually easier to repair because less area is required for new trenches. Septic field life is determined by use and maintenance, so regular pumping, mainting grass cover, avoiding fine particles, no fogs down the drain, water conservation, no heavy cleaners/solvents, etc all go too extending field life

The solids that clog a field do not usually 'recover.'

They are insoluble, non-digestible solids.

They fill in the 'pores' in the soil of the field.

It slowly cannot leach enough water fast enough to be useful any more.
Though 'clean' at this point, the water still needs to be able to drain away.

My 45 year old field tells me it's had enough when I see damp soil above it. Then I switch to the 25 year old field, which is much deeper. I think could it could go forever but I'll make a calender notation to switch it back in a year or two. I'd avoid the damp soil over the older one if I switched it sooner, and maybe I should do that

Switching back to the old one, it's good for another 18-24 months. The old one has been showing this saturation behavior for the last 20 years.

To me, that's a recovery after resting. You can call it whatever you want. I accept that adding more solids curtails the useful life of a field. However, my experience would say that the effect isn't dramactic, I have one field at double the expected life and one already past it, both work fine.

My comments are based solely on personal experiences. Yours can be different, that doesn't change mine.