Saturday, June 1, 2013

Anoxic Biocenosis-pots and Cat Clays?

           Question from overseas:

        I write to you from Singapore, on the other side of the world.  I have a 20-year old 50 metric ton koi pond. This volume includes two 4.30 tons aerobic biological filters fed separately by two 6-inch bottom drainpipes from the main pond. The 50 tons of water is turned over every hour.

    I wish to convert one of the filters to provide anoxic filtration. The biocenosis basket it is said to contain “cat litter”, a material I am not familiar with. What is its chemical composition? Is it made from burnt clay comprising mainly calcium carbonate?

    It is said that the anoxic filter will not clog. However I presume there will be a bed of fine sediment at the bottom of the filter, which will have anaerobic reaction if not flushed on a regular basis. Both the filters have pre-settlement chambers to remove the larger solid waste.  In the biocenosis basket please advise what volume of cat litter against what volume of Laterite. Can you email me a sketch to illustrate the construction?
   I shall be pleased if you would advise if my proposal is feasible.

           Thank you
      Keen Wong
          Dr. Novak's reply:  

                 I thought this E-mail that I received today would be great ice breaker because it looks like he uses a bog filter of some sort. He has 13,300 US GAL that’s what 50 metric tons comes up to, and I may be reading this wrong but also he’s using 8600 lbs of aerobic biological filter medium of some sort. With that much weight I would assume its pea-gravel and not just K-1.
     When I talk about cat litter or Oil-Dri (that’s used for it capillary action in picking up liquids) you wouldn’t think I’m talking about nuclear waste or some other esoteric material. In the USA cat litter from Wal-Mart is very easy to buy and it’s cheap, but in other countries I have found that plain old baked, low dust cat clays that are the non-clumping form are not so easy to find. 

         Dr. Franco, he did the Anoxic Filter test from Italy, had to travel to the UK and buy tons of the stuff because in Italy they had none or not the right kind that would suffice for the biocenosis baskets. Because I’m not an expert in cat litter from all over the world I can only tell you what I know. 

Finding alternative brands outside the US like Kitty Litter by Wal-Mart will take some experimenting on your part because very few makers of cat litter will display the ingredients on the outside of the bags or boxes that it comes in. Look for cat litter clays that have been fired at high temperatures because unfired clay granules swell and clump together when wet and crumble when dried, they will surely state it on the box or bag. It is very important that any cat litter clay granules you use keep their structure indefinitely. I show photos of 20-year old cat litter that still holds it structural integrity even when cleaned. Testing clay product for its ability to retain its structure, first soak some of it in a glass of water for 24-hours and check that the granules do not break down.

                                  The photo above is of 20-year old cat litter.

 Bentonite: Do not use
          • Clumping cat litters are made of Bentonite clay, which sticks together when wet. The bentoniteis usually mixed with quartz and diatomaceous earth, which are absorbent.

             Other Clays:
         • Various types of clays are used for non-clumping cat litters. Zeolite, diatomaceous earth and sepiolite are common.

        • (Only use clay –Attapulgite-that has been mined from the earth, clean, baked, and pulverized such as Kitty litter.)

         Making up biocenosis-pots for filtration and plants is really quite simple. The supplies you will need are large planting baskets (11" x 11" x 7" or 14" x 14" x 10"), kitty litter (with no additives just plain clay), and Laterite that will be for the substrate. Laterite is a highly weathered remnant of volcanic rock (weathering implies exposure to tropical temperatures, precipitation, and forest derived humic acids over geologic time). Very rich in iron, and Manganese (iron is needed for plants to make chlorophyll). Taking a plant basket as shown in illustration #1 then filling it with Kitty litter, make sure you leave a small impression in the center of the basket. Take about half cup for smaller baskets and one and a half cups for larger baskets of Laterite and pouring it into the center of the basket then mixing the Kitty litter and the Laterite in the center of the basket.
   Now place only one layer of pond pebbles on top, this is to keep the Kitty litter from floating up after submerging it into the pond. Instead of using pond pebbles, you can also use a black craft screen on top and wire-tie it to the basket. The Laterite will help the bacteria grow in its early stages, once the bacteria becomes established, it will be less dependent upon the iron in the Laterite for growth. The good thing about the planted basket is it will take years before clogging with organic matter (it may take 20 years or longer). You will use the same procedure for the planted biocenosis-baskets, but you will not use the black craft screen on top of this basket only the pond pebbles.
     I hope this helps,   

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