Biological greywater filter

[Stefan (S.T.E.F.)]

After I had a treatment plant approved by building control for our new build I went ahead and got some quote from manufacturers.
One very nice guy pointed out that we had composting toilets, so the treatment plant would not be effective as it needed solids to work.

Back to the drawing board... I thought of a system where the grey water + urine passes through a grease trap with biological filter media
containing wood chips and straw, to then filter slowly through  large filter with the same media. The whole lot will then be discharged amongst
a large area of willow and alder.

I have thought of adding clay pipes to the filter media to harbour bacteria even when I change the other filter media.

SEPA seems to think it's viable, the one thing I can't work out is what to use for the large filter housing. I thought of an IBC container, but I
would struggle to get the filter media changed after a couple years as there isn't really any access to it.

Anybody got any ideas for a large container that has large enough access to empty the filter media out? Should be able to hold 600-1000L roughly
and withstand being buried bar the lid.
And of course be ideally a recycled item. But I would buy new if I had to.

[tz0c0s]

Ibc

[Stefan (S.T.E.F.)]

Like I said in my post, an IBC is not suitable unless you have a clever idea on how to scrape the straw out of the bottom though a tiny whole at the top...

[Justme]

Wont it have rotted down by the time it need changing so in effect you will only need to keep topping it up?

Or a suction tanker could suck it all out if you can fit flow valves so its full of fluid at the time.

[Stefan (S.T.E.F.)]

It's possible it only needs topping up, but nobody knows for sure...
Suction tanker ? I don't own one of them...