Mowing Mowing Septic tank

[Anonymous Poster]

Mr.P. It is possible that horses with their high ground pressure could damage a leach field.
Patrick, Many systems include a gray water drywell to handle that part of waste disposal. My own home was equipped that way, and have seen many installed years ago. It makes sense if your ground conditions allow it, and if it is legal. Here in the Southern Tier of NY, it is not.
Typical installations here (in poor soil) involve a sand filter like you mentioned. I install several every year helping my brother. We use geo cloth on top of the sand filter to prevent any soil infiltration.

 

[Soundguy]

(patrickg)

Sure, anytime.

Soundguy

 

[patrickg]

Bill, NO sweat, friend. Not to worry. Just saying "grey water system" is a pretty wide and varied area and can evoke strong passions pro and con. I have asked the same question to a "septic guy" and was told to put the extra capacity in enlarging the main system. That is not a universally accepted idea. Luckily we have a resident expert in waste water treatment and disposal, who while disguised as a mild mannered moonlighting sound engineer (The SoundGuy) fights the never ending battle against truth, justice, and the ... oops I mean fights the never ending battle against waste treatment and disposal ignorance.

A small community about 6 miles from me recently had the same engineer who did my perk tests design an enlargement/improvement to their waste treatment facility. Their old system was overloaded and discharged raw sewage into a creek not too far upstream of the South Canadian River. Now that excess is caught and treated so well that it is nearly potable. They treat it in batches and spray the liquid on 80 acres of hay land. The land owner signed up gladly when he got the numbers on their worst case quality of discharge. He will be making a lot of hay with that free irrigation.

I am still thinking I would like to use my grey water for subsurface irrigation if it isn't too much hassle. It sort of bothers me to throw water away when it is in short supply and can be put to better use.

Patrick

 

[Soundguy]

From an engineering point of view.. sprayfields are great... you get the use of this huge sand filter ( earth ) and all the local flora & fauna. And as the old saying goes.. the soloution to pollution is dilution. Some feelings may differ about spray fields ( namely those living in close proximity) but as long as the monitoring wells come up clean... it is a great use for the water.


"They treat it in batches and spray the liquid on 80 acres of hay land. The land owner signed up gladly when he got the numbers on their worst case quality of discharge. He will be making a lot of hay with that free irrigation."

Sobsurface will still have the benefit of ground filtration, without as many of the harmfull effects of runnof ( if you have runnof problems / concerns in your area).

"I am still thinking I would like to use my grey water for subsurface irrigation if it isn't too much hassle. It sort of bothers me to throw water away when it is in short supply and can be put to better use."

For simple screening, try a screen angles away from the water flow. Gives you more surface area on the filter, solids will generally collect towards the top, and the system is more or less 'self cleaning' ( incoming water pushes collected material up and away, while allowing the water to filter through) (( Low flow systems will see less benefit from this feature.)) untill the element becomes completely clogged.

Soundguy

 

[Egon]

Septic Tanks:
Been out at the farm working and missed all the fun for the past week.
As I recall concrete is considered as having zero tensile strength. Therefore; if no rebar is used in the manufacture of the tank, the maker cannot specify a load it will take.

Egon

 

[Soundguy]

Actually, non-reinforced concrete, though rarely tested, will have a tensile strength of 7-10% of the ultimate compressive strength.

And no.. I've yet to see a pre-cast structure supplier that will quote -any- load spec. You are just left to calculate it based on materials and measurements, etc. Protuct liability laws are ridiculous in this country...

Soundguy

Soundguy

"As I recall concrete is considered as having zero tensile strength. Therefore; if no rebar is used in the manufacture of the tank, the maker cannot specify a load it will take."

 

[Egon]

That may be but for design purposes it is zero.
Egon

 

[DavidInNH]

They just bought the place - I think they kind of forgot that there was a septic tank out there someplace...

-david

 

[W5FL]

Well, this past week, I pulled a sprayer weighing about 5000# behind my M6800 weighing about 8000# and went over a 1000 gallon and a 600 gallon septic tank about 4 times. It did not crush, but I have heard stories of Concrete Trucks and Gravel trucks busting through them.

I have mowed over my septic tank with my M6800 Kubota and a slightly smaller tractor for the past 7 or 8 years without incident. I have two cows that graze on it and weigh close to 2000#, so I guess it is safe for small Kubota's. /w3tcompact/icons/smile.gif /w3tcompact/icons/smile.gif Call the guy that put it in and ask for his advise.

 

[Anonymous Poster]

Is there a filter that I can add to my washer and sink after they have allready been installed?

 

[Soundguy]

Sorry.. I thought that we had moved beyond the theoreticle, and were now into the emperical study.

Soundguy

"That may be but for design purposes it is zero.
Egon "

 

[Egon]

Soundguy:

Emperical suits me just fine when driving over a sidewalk but when it comes to a tank top where I could fall into a non friendly environment the rose coloured glasses are replaced by just plain clear glass.

Egon

 

[Inspector507]

I never really thought about it much............mowing over the tank. Did for a long time with the rider, just continued with the tractor. It weighs much more but goes over it a little quicker too. Now you guys have me worrying.

 

[Soundguy]

For theory and calculation purposes, you, and I, and the manufacturing industry accept that there is no established standard carried load for the septic tank tops we are refering to. In practice, as evidenced here, tank/top failure rate is extremely low. I believe we have had one reported failure, and it was an enormious piece of equipment, carrying a load as well..... not a riding lawnmower, or a compact tractor.
Is the practice 'endorsed' -obviously not-... It is a "do at your own risk" situation, and as always, each situation is unique, and your mileage may vary.
If it scares you and others, the answer is obviously... don't do it.

Actually not rose collored... I was quoting specs about concrete strength. When item "a" has a determined strength of "x" ( where x is above 0 ), and you arbitrarilly undervalue that strength to 0, then claim that the surface has no load carrying capability, that is introducing significant error into the whole picture. A fudge and safety factor is fine. But that non-reinforced concrete top has positive load carrying capability.. otherwise you could not backfill it. We're splitting hairs anyway. We both agree that the top has limited capacity, and there is a risk associated with driving over it.


"the rose coloured glasses are replaced by just plain clear glass."


Soundguy

"Emperical suits me just fine when driving over a sidewalk but when it comes to a tank top where I could fall into a non friendly environment the rose coloured glasses are replaced by just plain clear glass."

 

[Egon]

Mowing over septic tank:

I probably take an overly cautious stance on tank tops as work safety training had very extensive coverage on this item and it has just carried over with me into retirment. I'm quite sure each situation should be evaluated on its own merits.
Now there may be some carryover to other items like cisterns and larger holding tanks where more though should be given.

Egon

 

[Soundguy]

Can't argue with you there. When it comes to safety, common sense has to occour, and it is always better to err on the side of safety.

""I probably take an overly cautious stance on tank tops as work safety training had very extensive coverage on this item and it has just carried over with me into retirment. I'm quite ""

""sure each situation should be evaluated on its own merits.
Now there may be some carryover to other items like cisterns and larger holding tanks where more though should be given.""

I've worked with box culverts, metal ( squash ) and concrete pipe, steel casing, various other rigid and non rigid pipes, as well as precast drainage structures.

So far, in the 18 years our company has been in business, we have never had a piece of heavy equipment cause a failure in a drainage structure. Keep in mind that box culverts are designed to carry heavy loads, and many municipalities youe large box culvert sections as bridges, etc.
Also, many ( most ? ) comercial precast structures are wire reinforced, and also buried deeper than a septic tank generally is.
I have seen metal squash pipe failure but only in extreme circumstances. Still it is a good thought to keep in mind. Equipment manufacturers are keeping this in mind with their product line as well. Many of our bull dozers are wide track models and have a lower ground pressury than some of the older models.. quite an improvement , and less damaging to existing sitework.

Soundguy

 

[Egon]

Mr. Soundguy:

Strangely enough I have also worked with concrete pipe and even mutiplate culverts of up to 30 ft.in Dia. and somewhere around 300 ft. long, maybe more but can't remember. Used to drive my pickup through them. They were covered with at least 150 ft. of fill.
Uh, the company I worked for then had started in business around 1887 or so, so they had been around for a few years.
Now as to the width of the dozer tracks' if I can recall correctely' on rock you use narrow pads and when working in muskeg the widest you can find.
Deepest I had trench experience with was around 30 Ft. Thats all the hoe could reach at full extension.

Egon

 

[Soundguy]

We don't deal with anything quite that big. Probably our biggest stuff is box culvert sections, probably 12 tons or so.
We are currently setting them as bridge componets, using in place footers, and pre-cast wing wall sections.

""somewhere around 300 ft. long, maybe more but can't remember. Used to drive my pickup through them. They were covered with at least 150 ft. of fill. ""

""Uh, the company I worked for then had started in business around 1887 or so, so they had been around for a few years.
Now as to the width of the dozer tracks' if I can recall correctely' on rock you use narrow pads and when working in muskeg the widest you can find. "

We even use the LGP wide track dozers on finish grade projects. Better traction, and less impact on the sitework.

We have a dragline with 4' paddle style tracks for use in muck ponds.. and have even gotten that stuck before.
Sometimes there just isn't enough soil stability.

Soundguy

 

[Egon]

Dragline getting stuck: Where are your swamp pads?

Egon

 

[Soundguy]

They time I remember it getting stuck was about 12 years ago, and the dragline was situated on a (dry?) bank, being used as a dredge to clear muck. After a few days of no use due to rain, the dragline was found to be situated on hard silt... well it wasn't hard any more.... By that time, the whole areas was a mess. A vain attempt was made to pull it out with a dozer, which sank un to the rollers as well. As far as i know, they let them set a week, and walked them out on their own.

Soundguy