I have made a cone bottomed wash tank from a 205L drum with a steep 500mm deep cone bottom.
Mist washing into the open top doesn't create any white emulsion at the surface but after allowing time for settling, 24 hours +, the water drains out very well but then a mixture of white emulsion and BD drains out entrained together.
My questions are;
1. what should i do with this mixture which contains useful BD.
2. how can I make the transition from wash emulsion to BD quicker so I don't waste all the mixed volume,
3. how many times should I wash each batch by this mist method. (I have been putting about 15L of water as mist into a 100L of BD
4.after a few mist washes should i leave the volume ofwater in the bottom and do a bubble wash using an aquarium pump
5. and what are the environemtnal hazards of disposal for the waste wash water containing the emulsion gunk.What do others do with this.

Thanks for any hints and help.

I Posted a reply on the method I used to make my 'cone bottomed tank' on the thread by that name if anyone's interested.

I get this from time to time. I find washing with warm water helps, or washing during hotter parts of the day.

With the white bio/water it actually isnt a lot of fuel lost I find. If you let it settle with heat (in the sun etc) you will find it is actually a small amount of fuel involved at the top.

Failing this, you could stop draining the water once you hit the white mix, and continue another wash. I dont know what overall affect this has but i find the last wash is then much better to drain ie a clear separation between water and fuel. heat is always the key though, it will get easier in summer.

Farmy

when i wash and the water / bio is close i drain into 3 ltr milk containers then let settle upside down.
then open lid a couple of turns then wash acouple of times then put back in main drum. doing this a saved about 8 ltrs of usable bd. maybe some will see as waste of time but hey whats time.
cheers glenn

In answer to what should I do with the mixture which contains BioD?
We drain 5 or 6 Ltrs of this mixture after each wash, and put ito a 50ltr drum. I then add water and mix with a drill and paint stirrer a couple of times, and add the bio that settles to the top to next batch on its second wash.

Water washing can be such a pain in the butt. I used to do it, but decided that dry bubble washing was a much simpler process. Now, I process my bio, drain the by-product, transfer the bio to my wash tank, and dry bubble wash for a few days.

With this method, there is no risk of emulsions and no wash water to dispose of. One advantage of the water wash is that it flushed all the particulates out of the bio, whereas with dry bubble washing I have to filter them out.

Just my 2 cents

Justin