Dear Friends:

Dr. Michael O. Agho [moagho@cyberspace.net.ng] asked
> In the section on Discussion, you wrote,
> >4. Time of outflow: 1 month after loading into a digester. Keep slurry
> >outflow directly into fishponds to avoid ammonia nitrogen volatile.
> >However, shallow basins are needed as sedimentation pond,
> >oxygenation pond and algae pond to further reduce the BOD of
> >slurry by 30% according to George Chan.
>
> Could you please explain why shallow basins favour low slurry BOD
> compared to deeper basins.

In China we don't practice shallow basins to reduce BOD of the effluents
from a digester. Maybe there are not enough land for shallow basins, but we
adjust the input of the effluents into fishponds.

According to George Chan, it needs shallow basins to reduce BOD further. It
is supposed to be 30% reduction of BOD. I have not seen the exact figures
measured on his claim !

Li Kangmin