| Maurice, I've been curious as to why you did not line the bottom of the ponds and put clay back on top of the plastic. Doesn't the plastic on the sides sort of billow up if the water level is higher in adjacent ponds? You must have really tight clay that does not allow any water to move horizontally.
I guess everyone has problems with air stones clogging. I run the smallest regenerative blower possible to minimize electrical costs so the air flow drops off sharply if the diffuser starts to clog. I am always battling iron precipitate and iron bacteria. The higher the iron, the faster the stones clog. I started looking into your birm (sorry, not brim) filter but doubt I can afford the equipment or the energy to operate it.
I'm glad to hear you say you run the air line without a diffuser stone. I have been slowly getting rid of my stones too but won't switch over completely until doing some tests to see if it is really more efficient. Reportedly, the oxygenation in shallow ponds is enhanced more by creating surface disturbance to maximize oxygen transfer through the surface than by trying to create small bubbles and transfer oxygen from the bubble to the water.
Ranskye, the prototype paddlewheel was really great. I found a little 50 rpm gear motor for $35 US which only draws 13 watts! The shaft, paddles, bearing and float were all fabricated from PVC pipe or sheet. I had it loaded to the max, and it was moving the water around pretty well in a little 50 ton pond. There was no doubt that it was more energy efficient than the air stones. However, before I could do the definitive test, a branch fell out of a tree and lodged in the paddlewheel, stripping the gears. I was pissed, but will repair it and install a cage over the top to keep debris out of the paddles.
The next step is to start runnig oxygen transfer tests. There is a standard test protocol developed by the sewage treatment engineers. You use sodium sulfite catalized by cobalt chloride to remove all the oxygen from the water, turn on the aeration equipment, and plot the dissolved oxygen level as it increases. The results are boiled down to the weight (kg or lbs) of oxygen transferred to the water per kilowatt of electricity consumed by the aeration equipment. I finally have all the chemicals, O2 meter and test tank together, but won't have time to do the tests until June or July. Will let you guys know if anything useful comes out of it.
KFG, put an elbow and a short vertical nipple on the end of the horizontal pipes so no water can flow through until the level reaches the desired height.
-steve hopkins |