Building a grease trap: or making the best of a cock-up

[ToughButterCup]

@jack it was who told me  -years ago- to make a plan and stick to it - and then to take photos of what actually happens and tag them so the photos are searchable. 

Or repent at leisure.

Well thats what I'm doing now : repenting.

This post is about trying to make the best of it  - by building a grease trap. This thread is about how to design build and install one 

 

We had no idea where our kitchen sink was going to be. So instead of being able to duct the foul drain out under the foundation, I had to bodge. Drill a 50mm hole in the wall after the sink was installed, pipe it to a trap outside the house.  It worked for a while, and worked well.

 

Until she decided that it would be great to have a kitchen garden. 

 

Some plant roots push soil up and outwards. Not a lot of people know that. I do - now. The plants picked up the pipe bedding that was round the drain and dumped a great deal of it inside the drain. It took me a year or more to notice it.

 

I had no idea that pipe bedding  was really good at filtering kitchen fat and waste. Man did it stink ! But through it all, the kitchen sink drained fine. Slowly, but well enough for us not to notice a problem: until I did.

 

Based on @saveasteading 's post here  I thought I'd  design, build and install our own - in parallel with the current system. And then switch systems once the grease trap is shown to work properly.

 

I've looked at grease traps online now for a while. They're either to expensive or too small, or frankly sloppily designed. 

 

The trap needs to be easily maintained. Easy and quick to empty as well as easy to clean.

 

My first question is how big ( volume ) should it be? Some advice says 40 to 50 litres.  Ideas?

[jack]

34 minutes ago, ToughButterCup said:

@jack it was who told me  -years ago- to make a plan and stick to it - and then to take photos of what actually happens and tag them so the photos are searchable. 

 

Do as I say etc. I can't tell you how much time I've wasted over the years trawling through poorly categorised photos of the walls before plasterboarding.

[ProDave]

Why do you need a grease trap?  It seems you just need more robust detail on the drain you have to stop soil entering and blocking it?