How big should an iAVs biofilter be?

Question

533 views1 January 2025biofilter construction

2

anonymous 5 February 2022 0 Comments

Admin Changed status to publish 1 January 2025

2 Answers

score 2 · Answer 1 · 2022-02-05T00:27:29+00:00

If you are building a backyard iAVs…or even a small commercial unit…beds that are up to six meters long are easy to level and will (all other things being equal) drain in a timely manner.

Beds that are much longer than that will be more complicated when it comes to levelling…and you’ll reach a point where you have to think about different drainage arrangements…to ensure that complete and timely drainage occurs. This is the realm of the more experienced horticulturist…probably working in a controlled-environment cropping greenhouse.

We recommend a fall of 1:50. Short beds…up to 3 meters long…will drain well enough if they are flat. Up to 6 meters long, and they will need a slight fall…and upwards of 6 meters, ensuring adequate fall gets more complicated.

The other consideration is the logistics of working with the beds. Shorter beds are easier to get around for day-to-day operations…like seeding/planting, plant culturing/trellising, harvesting – and maintenance.

Shorter bed lengths – up to 6 meters – is also consistent with our recommendation to have a series of smaller tank/bed modules rather than one large fish tank and longer sand biofilters.

The width of beds should be not more than 1.2 meters…so that operators can reach into the middle of the bed with undue stretching.

The depth of a biofilter will depend on the type of plants being grown, but 300 – 400mm is suitable for most purposes.

score 0 · Answer 2 · 2025-01-01T01:49:28+00:00

This is covered in Chapter 8 and Chapter 12 of the iAVs Handbook.

Here’s a breakdown of the recommended biofilter sizing guidelines:

Fish Tank to Biofilter Volume Ratio (V:V): The recommended volume ratio between the fish tank and the biofilter (sand bed) is 1:2. This means that for every unit of water volume in the fish tank, the biofilter must have twice the volume.
Fish Tank to Biofilter Area Ratio (V:A): The recommended ratio between the fish tank volume and the biofilter surface area is 1:6. This means that for every liter of water in the fish tank, there should be six times as much surface area in the biofilter.

Example:

If your fish tank has a volume of 500 liters, your biofilter should have a volume of 1000 liters and a surface area of 3000 square meters.

Flexibility in System Design:

While adhering to these ratios is crucial, iAVs offers flexibility in layout and configuration. The biofilter can be designed in various shapes and arrangements as long as the fundamental volume and area ratios are maintained. This adaptability allows users to tailor the system to their specific needs, space constraints, and available resources.