RE: [compost_tea] Vortex Brewer.

From: Stephen Steyn <ssteyn_at_wcaccess.co.za>
Date: Tue, 24 May 2011 18:36:19 +0200

Will;

You seem to write with much authority.

Well, I believe you are absolutely and completely wrong. Its only in a coni=
cal tank that you may get localised dead spots, but generally there is suff=
icient convection in a tank to oxygenate the whole body of fluid. This is e=
specially true if you have a vortex setup or if you have your air source to=
 one side of the tank to create a good current moving up one side and down =
the other. Bob had a setup that had this configuration. Very effective in m=
y opinion. OK?

 

Next the common fallacy that air exchange takes place at the water surface.=
 I believe the interchange of oxygen/co2 takes place more across the surfac=
e of the bubbles than the surface of the body. That’s why we want s=
mall bubbles – to create more surface area for the interaction to t=
ake place. Add to that the fact that we often have a layer of scum or foam =
on the surface of the tank which would prevent fresh oxygenated air from co=
ntacting the water surface – unless you presume the bubbles themsel=
ves to be this source of oxygenated air. OK?

What you might have said is that bubblers tend to clog easily, to harbour a=
naerobic biology and be difficult to clean effectively and that a perforate=
d tube could be a better bet.

As always

SS

 

From: compost_tea_at_yahoogroups.com [mailto:compost_tea_at_yahoogroups.com] On B=
ehalf Of soilfoodweb_at_aol.com
Sent: 24 May 2011 16:39
To: compost_tea_at_yahoogroups.com
Subject: Re: [compost_tea] Vortex Brewer.

 

  

The important factor is mixing of water at the bottom of the tank so you ne=
ed to place the air source at the tank bottom to move water completely in t=
he tank. For aeration it is the action at the water surface that is import=
ant entraining water at the surface. That is where aeration is mostly occu=
rring. Some oxygen will be exchanged as air bubbles pass through the wate=
r column but that is not the most important place for exchange. Ok?

Sent via DROID on Verizon Wireless



-----Original message-----

From: Will Buck <willbuck76_at_yahoo.com>
To: compost_tea_at_yahoogroups.com
Sent: Tue, May 24, 2011 00:19:17 GMT+00:00
Subject: [compost_tea] Vortex Brewer.

  

Hi, I am in the process of building a 240 gallon Vortex brewer.

My first brew went anaerobic almost immediately. Clearly I have undersized =
the air supply and while I would appreciate advise on which pump I should p=
urchase (I used an Eco7 that allegedly provides7 cfm, it appears that I nee=
d to at least double that rate), my question is more about the properties o=
f an air lift pumps so I can maximize the amount of DO.

My design is similar to Bobby Grimes. I purchased a cone bottom tank that I=
 mounted on a stand so the tank is about 4 feet off the ground (ideal for g=
ravity filling the spray rig). The manifold is attached to the base of the =
stand and there are three 2 inch pipes that return water over the top of th=
e tank via air lift from a 17 inch air stones.

My question is at what depth should I put the air stones in the pipes? If I=
 put the stones near the bottom of the pipe I thought this would be ideal b=
ecause the air bubbles would be in contact with the water for a longer peri=
od of time as they rose up the pipe thus increasing DO. But of course the d=
eeper the air stone the lower the performance of the air pump because the r=
esistance pressure is greater. In other words, is there any rule of thumb r=
egarding the depth of the air stone?

This question becomes very important as I look at purchasing a new pump as =
regenerative blowers loose performance very quickly the more pressure they =
are working under.

I would really appreciate any help or ideas, thanks in advance.







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Received on Tue May 24 2011 - 18:48:21 EDT

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