iAVs/DWC Comparison

Inspired by a study undertaken at the American University in Cairo, I’m preparing for my own iAVs/DWC comparison.

The obvious question that arises is..”If the AUC already did such a comparison, what’s the point of repeating it?”  The answer is simple.  While the AUC study found that iAVs was the better method for Egypt, the methodology was flawed to the point where neither system was able to perform as it should.

The project requires that I build two systems – side-by-side – so that they are, as near as practically possible, operating in the same environmental conditions.

The fish tanks have a capacity of 1,000 litres.  The DWC grow tank also has a capacity of 1,000 litres.  The sand biofilter will contain around one cubic metre of sand…equal to a 1,000 litres in volume terms.  Each of the filtration modules is 200 litres.

With the iAVs, all of the fish wastes will go to the sand biofilter.  In the DWC, all fish wastes will flow through the filtration modules with a view to capturing them, processing them (out of the water flowpath) and returning them to the system – less the sludge.

I’m currently gathering the hardware to build these systems and I hope to commence their construction in the coming week.

Organic Hydroponics

A few weeks ago, I built a little biofilter/brewer to enable me to learn more about cost-effectively turning organic substances into plant-available nutrients.    

The biofilter consists of a 20-litre plastic drum into which I’ve placed a 750-litre/hr pond pump.

The 20-litre bucket is fitted with a lid into which I’ve drilled some small holes.  A 10-litre bucket sits on top of the 20-litre drum – supported by the lid with the holes.  I’ve placed a coir garden pot liner inside of the 10-litre…and part-filled it with coarse sand.

The sand will filter out any solid materials and will serve as bio-media…housing the nitrifying bacteria and other microbes that will convert the organic substances that I want to decompose so that they become plant-available.

The simple plumbing arrangement allows me to adjust the rate of flow through the top bucket while also stirring – and aerating – the contents of the 20-litre bucket.

I’ve just started it up and my first trial will involve one of the most accessible organic substances of all – human urine.  

Notwithstanding, it’s alleged ‘yuk’ factor, urine is very interesting stuff.  It contains valuable nutrients which are wasted by flushing it down the toilet.  But its role in the waste cycle doesn’t end there.  We waste millions of megalitres of potable water – using billions of dollars of infrastructure – flushing it into waterways where it (along with the other substances in wastewater) harms the aquatic and marine environments.

Stick with me – and we’ll both learn more about making – and using – ‘pee tea’ from urine.