Grey water filtering

I have this idea for filtering kitchen water.
This is for a small cottage that I rent out in the summer months so I want to water the garden when there are guest and I cannot be there.
Currently the water is just led to the garden through a flexible pipe.
See the attached drawing (vertical water filter.png)  - i want to use 3 or 4 buckets in a vertical formation to filter the water and clear out the kitchen waste. Food waste  it can build up in the pipe and clog the holes for the plants.

Has anyone got experience of doing this?

So the kitchen water feeds into the top bucket that is half full of bark (i have plenty of that) and earth worms.
holes in the bottom of the bucket will filter the water (food free) into a gravel half filled bucket and then into a bucket with small volcanic rocks/scoria.
These i want to place in a large rubbish bin with the garden pipe leading out the bottom.

My questions how do i stop the worms escaping?
I provide eco friendly washing up liquid so it will be kinder to the worms and trees in the garden.

In my first homestead,  I had a composting toilet, so all water was grey water.  I has a similar arrangement of  five 55 gallon drums.  I did not use earth worms nor charcoal. To answer your question, I don't think a few escaping earthworms will be a significant issue.

I've done something like this but we used wood chunks leftover from construction. In our first version, there were a lot of wood shavings so after a couple of months it clogged and went anaerobic and stank. So make sure your bark chips or wood chips are big and coarse enough not to clog up. I didn't want to use gravel or rocks, because those will eventually clog up and need to be cleaned. Wood chips just gradually compost and dissolve, so you just check them every few months, and add more when needed.

I made ours for greywater after seeing one for a flush toilet made by Ana Edey of Solviva on Martha's Vineyard. She had had it going for 11 years and just added more wood chips once in a while. She said the old composting wood chips in there just get broken down into soluble nutrients. Her effluent was going into a buried perforated pipe in a gravel trench near trees, but since ours is just for greywater, I think it's fine to have the effluent go into a little canal open to the air.

Ana Edey's design uses compost worms. Ours didn't because our school kitchen sometimes drains a huge pot of boiling water. I don't think the worms are necessary for greywater, because compost happens anyway, even without worms, but if you've got worms, chuck some in.

Since it's just greywater, a single bucket of bark or wood chips might be good enough, or maybe two similar buckets in series. I dunno, three sounds like overkill to me, and do you really have enough elevation to do three buckets vertically and still drain through without pumping?

Thanks Rebecca and John for your feedback.

I am wondering if this idea may work in a linear open-air trench type design.  I am building an offgrid "outhouse" that will house a sawdust toilet, shower, vanity and washing machine.  I plan to drain into a 300 gallon grey water tank that will eventually feed trees.  Currently the plan is to drain to open air away down the slope towards a crick in the back edge of the property.  Instead of letting it naturally filter I might try piping to a trough or ditch lined with filter media, wood chips, manure worms etc.  If I pipe a little further to a shady area I might be able to grow some winecaps in the wood chips but not sure the fruiting fungi would adequately filter out any potential contaminates.  Anyone done something similar?  Concerns with the winecaps?  

Hello Denny
I have heard that one shouldnt use gray water for "soft" food that you are going to eat. Gray water is best used on trees that fruit as in your idea. But i guess if you are filtering and treating the water along the way it should be OK. Do you know what is going into the water all the time? like bleaches and soap etc?
Are you planning on including the sawdust toilet in the open air drain? If yes, wont that be black water you are using?
Currently I have a buried cess pit that has various stages to it and naturally seeps away to the surounding downhill trees - i assume this as the trees near it do the best without any help from me.
Good luck with plans.