Red Wrigglers Rock

There is a horrible tendency of people with limited understanding of engineering to make things complicated to show how clever they are. Aquaponics tends to be a field (or tank) populated by such people - a limited understanding of engineering causes over-complicated solutions to be built into systems - these solutions don't work well, are unreliable, and cost money. They make the consultant rich and the farmer poor and frustrated.

Good engineers believe that the best part is no part. Good biochemical engineers believe that the best part is a living part. If you can harness a biological system to work with you, it will always yield better than enslaving a biological system to work against itself using technology.

Red wrigglers, or Eisenia fetida, are a type of earthworm adapted to living in low-oxygen conditions. The sludge that forms in aquaponics systems typically comprises fish faeces and various salt precipitates (and snails) that accumulate over time. Aquaculture systems often incorporate complex bioreactors to trap this sludge and release some of the nutrients into the water. These systems are invariably complex, energy-intensive, and prone to failure. The only person who makes money with these systems is the person who sells them to you.

A red wriggler is an autonomous bioreactor!! The red pigment in the worm is haemoglobin - the same pigment that allows our red blood cells to bind oxygen and carry it around. In the case of the red wriggler, this red pigment allows the worm to accumulate oxygen in areas where it is relatively abundant and then go to areas where the oxygen is absent (such as in the sludge) and eat. In a flood and drain system that accumulates sludge, the red wrigglers will move anaerobic sludge and convert it into a mixture of earthworm and bioavailable nutrients. The worms themselves are excellent fish food if they get too plentiful, and the soluble "worm wee" they produce is excellent plant fertilizer.

So next time somebody tries to sell you some complicated energy-intensive bioreactor with lots of moving parts, say no and employ nature's own little desludgers—the red wriggler—a perfectly self-maintaining, food-finding, fertilizer-making, natural bioreactor.