RichardHenshall

In this context my intention was to mean (lined) storage tank(s) without an intentional outlet rather than a system that 'digests' the waste, with clean water continuously draining away.

Pulaski

I am guessing that you don't have much land around your home, so there is no room for a septic drain field - you would need probably at least 5m x10m-ish that isn't built on nor has trees on/near it, nor is too close to a neighboring property, to accommodate the drain field. Otherwise you might be living on ground with drainage issues - either high water table/ saturated ground, or an impermeable layer close to the surface, for example rock that would make a septic drain field unworkable, or at least unpleasant.

andywally

that is part of the issue with the terracing around this new purchase of ours, the house is build into the rock partly, you can see rock coming into the basement, the ground of the terraces are very rocky due to that and not a lot of topsoil, so it wont drain very well, on top of that along the edges of the terracing are some very old vines which apparently produce a good crop, the trees on the terraces are peach and olive trees, these would need either relocating to a higher terrace or chopping down completely..........and to top it all off the drain field would be within 10mtrs of the stream, and the terraces are only 3-4mtrs wide at most............ergo, pump the black water up to a cesspit (no chemical reaction required or drain field just a large holding tank essentially) and then make a drainage soakaway into the land for the grey water.............I think !!

zoff

Thanks for the info but I don't think any of that applies here. There is a lot of open space and the soil is like beach sand. In the eighties property owners sold the sand to construction companies. The name of the road/street is Rua dos Areeiros
I looked into a fossa biologica but it starts at €5.000 plus labor!

andywally

anyway ..........finally an update, according to the estate agent (informed by the daughter of the deceased who part rebuilt the house, so not the estate agents fault) it was advertised as not having a fossa, and we bought it on that basis........... anyway we moved in last week, and digging around in the garden next to the side of thouse lo and behold, a waste pipe coming out of the floor 5 mts of wire later later we determined its at least 5 mts to the end of the first chamber............ so we have a fossa and I have a couple of quid more in my pocket than if we didnt have one........... and if its been done with a fraction of the professionalism of the rest of the partial rebuild of the house then happy days ............ just to give anybody who contributed a final update that is , boa tarde amigos.

Alan PT

Not often that you can describe an unexpected septic tank as a happy surprise

andywally

eh........I did a little jig amigo and celebrated I can tell ya !!!

Jim San

I have the same problem with 2 inspection covers that underneath that is just concrete (not discernible hatches to open). Would love to know how you approached this problem?

BillBullock

If that is the location of your sceptic tank, you need to remove the inspection covers and then clear away the concrete underneath the covers. It is possible that this concrete is a square slab like mine and it can be lifted off. If not, then the concrete will have to be broken into at which stage you will reveal the chambers of the sceptic tank. Goodness knows why builders make life so complicated. The 2 inspection covers is all that is needed for the lids of the tank so long as the smell is not too noticeable.

Pulaski

That looks like someone has poured a concrete driveway over your septic tank!

You will need to work out roughly where the septic tank is, then break up the concrete in that area and dig down to find the hatch(es). Hopefully you have a good idea whete it is already, or whoever you pay to do the work can find the tank.

Ideally, once you've found the hatches you'd build brick boxes around them and install manhole covers on top before recasting the concrete, though there is a risk that a vehicle driving over the manhole cover could put too much stress on the septic tank and crack/ break it. The same would be possible if you didn't recast the concrete slab, that a vehicle driving on packed soil/ rock/ gravel could break the septic tank.

BillBullock

I don't understand why someone has set in the inspection lids if that is not where the entries to the 2 chambers are located.

Pulaski

Ah, sorry, I didn't see those - the picture isn't much more than a thumbnail on my phone.

liveaboard

To inspect the tanks, the concrete slabs have to be lifted; how to do that is dependent on details that are not known from the picture posted.

There should be some sort of system built in. Holes for ring bolts, or groves where a prybar can be used.

If there are no such things, I would drill holes and set in threaded inserts using a 2 component styrene, then screw ringbolts in, then lift.
If the concrete is not strong enough, it will break.
Then you need to cast proper concrete slabs that are strong enough.

I have a similar slab over the inspection cover of my own tank, it's buried in the back garden.
The purpose is to prevent the weight of my tractor from collapsing the tank when I drive over it (which would be bad).

To open it, I find the position by measuring from 2 corners of the house, dig away the grass and soil. and then lift the 80kg slab with a machine.
My slab has a lifting ring cast into it.

I only opened it once, about 5 years ago. There was almost no solids in it so I didn't have it pumped.

In the current drought, the position of the drain field should be pretty obvious.