Backyard Aquaponics
A place to discuss aquaponics

Hello, does someone have experience in phosphorus recycling and solubilizing from fish waste by bio-digestion means for example ?

In aquaponic systems where the solid excretions of fish are removed, poor level of phosphorus are found in the water because phosphorus is mainly excreted as organic solid form. Remove the fish sludge out of the system is important to avoid quick clogging issues, right? So, a possibility to recycle the nutrient presents in the sludge, especially P, could be to digest it and solubilize it into a form assimilated by plants. And this in a kind of bioreactor...
Cheers

I think the products of anaerobic digestion need to be really well aerated before they are returned to the system to allow any nasties to off-gas.

If you are running high fish to plant ratios then overloading the gravel beds inherent waste digesting capabilities is a real possibility. Some remove solids and then use various methods to treat them and return them to the system. This is not unusual many people do it.

My preference would be to expand the total growbed to fish ratio (add more growbeds and plants) to a level I would feel comfortable can deal with the fish waste. I would also try ensure even distribution of the solids as well as add solids eating worms to the beds.

I think there is a real possibility that even returning solids or digesting and then returning solids may not provide all the nutrients and minerals needed by plants so, a regime of supplementation might be appropriate.

The experienced system operators here often talk about system maturity and how plant performance improves over time. This makes sense to me as nutients, minerals and beneficial organisms build to abundance in the system.

As we build an appropriate environment, where everything needed by the plant to reach its genetic potential is present, we should see excellent results.

Hey there BorisD,

Welcome to the forum.