Monday, October 8, 2012

Aquaponic Food Production for Long Term Survival

This article does a nice job sumarizing several basic points worth knowing about aquaponics.  It is also helpful to us as we start-up a small scale system, since it is designed for survival situations. We are focused on commerical aquaponics and so need to do many things different, but see if you can gleen a few helpful ideas like I did..

Here is the link, please read the whole article, I am thinking that a future quiz will cover some of its points:

Here is a quote:

"A working "biofilter" is the key ingredient to a good aquaponics system, as the bacteria in the biofilter keeps the fish water clean, and changes ammonia into nitrogen for the plants. The bacteria need to reside in a wet environment that has plenty of oxygen, and little or no light. A gravel bed that is alternately flooded and drained, is perfect for this type of bacteria to thrive in. Other aquaponic solutions, such as Nutrient Film Technique (NFT) and Deep Water Raft Technique, use a large amount of netting submerged in the water to give a place for the bacteria to reside. We chose a grow-bed filled with 1 foot of gravel as our biofilter, as it is simpler to build.

The bacteria in the gravel biofilter changes the ammonia into nitrogen in two steps. The first step is performed by the Nitrosomonas bacteria, which changes the total fish ammonia (NH3 and NH4+) into nitrite (NO2). The next process is accomplished by the Nitrobacter bacteria that changes the nitrite (NO2) into nitrate (NO3), which the plants use as fertilizer. The ammonia and nitrites are very toxic to fish, while the nitrates are fairly harmless, so it is important to monitor the bacteria by testing the water quality using the inexpensive aquarium test strips sold at any pet store. As long as you have a large amount of gravel or other media for the bacteria to colonize, your water quality won't be an issue. If you are using sterile media, you won't have any bacteria to start with, and you will need to purchase the bacteria from an aquarium shop or from Fritz-Zyme. We used gravel from a creek, as the Nitrosomonas and Nitrobacter bacteria is always abundant in river gravel. Since these two types of bacteria work in tandem and do not reproduce quickly, it may take anywhere from 2 to 4 weeks to ramp up the bacteria to full production. So, it may important not to add a large number of fish at the same time unless you already have a good supply of bacteria at work in your system.   Our first step in construction of our Aquaponic system was to lay an 8' x 8' "carpet" of around 40 concrete blocks for the foundation of the fish tank. It took a long time to get the blocks level using a spirit level and a long 2x4, but this is probably the most crucial part of the construction. The next step was to build the fish tank out of wood, that would ultimately be fitted with a rubber liner. I created a square box out of 2x12 lumber standing on their edges, that was a little less than 8' x 8' and held together by wood screws. I designed it so that the 2x12's had an extra 3.5" overlap or "flap" on each of the corners, so I could drill holes and put carriage bolts through the 4x4 posts and 2x12 sides from two different directions on each of the outside corners. This holds the wood seams together. It is very important to "overbuild" the tank seams on a wooden fish tank with carriage bolts, wood screws, etc. as the water pressure is very great. Once I had my square box built, I made sure it was perfectly "square" by measuring the distances diagonally across from each corner. When these two distances were the same, I knew it was square. Then I covered what was to be the bottom of the tank with 8' long 2x4s, nailed into the 2x12s with a 2" gap between each 2x4. When I turned the 8'x8' box over and placed it on the concrete block foundation, the gaps between the 2x4s allowed me to put shims between the blocks and the 2x4s, so that each concrete block was helping to evenly support the 2x4s that held up the fish tank. "