This is a 250 word (approx) summary of a chapter
from my water gardens book pictured to the left.
For a complete list of summaries see the right hand column
Concepts: This chapter explains how biofilters work and how to get the
most out of them in a very easy to understand way. Just sit back and get
yourself a cup of coffee and let me explain .......
sugar, coffee, dissolve, mass, stir, surface area, brown, biofilter,
liquid, stirring, particles, temperature, teaspoons, granule, principles.
Summary:
- The performance of a biofilter no matter what its design is greatly
influenced by the principles described below.
- I hope you take sugar with your coffee because this will help you to
understand what is important in assessing and improving performance of any
biofilter.
- I think I have forgotten to put sugar in so I put another 2 teaspoons
in and then stir the coffee.
- On another occasion I go to a fancy restaurant and have a cup of coffee
and put 2 teaspoons of that fancy brown crystal sugar in my coffee - looks
like small lumps of light brown coal.
- In case 2 it took much longer to get the sugar to dissolve because it
was much lumpier and in the third case it took longer to dissolve because
the temperature of the coffee was cooler than normal before we stirred the
coffee.
- In the world of chemical engineering we talk of "Mass Transfer
Processes."
- In technical terms we exposed each granule of sugar to a new bit of
liquid containing only a little dissolved sugar and we did this repeatedly
until the stirring stopped.
- Before I started stirring my cup of coffee very little sugar was in
contact with the hot liquid because it was sitting in a heap at the bottom
of the cup.
- AT THE INTERFACE BETWEEN TWO COMPONENTS TRANSFER (sugar and water in
this case) BETWEEN THE TWO IS LIMITED BY THE CONCENTRATION DIFFERENCE.
- The reason was that the larger particles of brown sugar had a much
lower surface area in contact with the hot liquid.
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Full details of this important biofilter article in my book.
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