Marburg Commercial System

[GaryD]

Hi,

Several weeks ago, Martin O'Dee and I were approached to take over the establishment of a small commercial project in the Brisbane Valley.

Another party had commenced the project but the clients elected to discontinue the relationship. We were asked to do what was required to move the project (as it existed) to an operational footing.

Martin and I have worked together a number of times.

I assisted him during the very successful 2009 Commercial Aquaponics Seminar that brought Dr James Rakocy to Australia and he reciprocated when I ran my first aquaponics seminar at Creek Street. We subsequently collaborated in the upgrade of Martin's Rush Creek aquaponics system.

This is the second commercial aquaponics system that Martin has put together - his first being at Mildura in Victoria.

The Marburg Project comprises a large greenhouse which will house all of the growing systems and an insulated shed (love that shed) which will accommodate the fish side of the operation.

At the time we took over the project, the frame for the large greenhouse had been erected and the shed had been completed. Some of the aquaponics equipment had been delivered.


Gary

[GaryD]

Hi,

I thought it might be time for a few update photos of the Marburg project.

Photo 1 - The greenhouse with its cladding on.
Photo 2 - Inside shot of the greenhouse.
Photo 3 - Evidence of the greenhouse at work - it was quite mild outside.


Gary

[GaryD]

Hi,

Some more on the site preparation. These photos were taken weeks ago but, since I'm limited to 5 images per post, I'm just adding them a few at a time.

Photo 1 - Grow tanks positioned for marking out purposes.
Photo 2 - Marking out for the pipe work
Photo 3 - Fat bloke counting out the fittings. There are hundreds of them.
Photo 4 - Martin assembling an air manifold for the grow tanks.
Photo 5 - Trenching completed. The white fabric is GeoTextile - inhibits weed growth.

Gary

[GaryD]

Hi,

Photo 1 - the excavation for the sump tank.
Photo 2 - the sump tank is positioned in the hole. This tank was originally supplied as a fish tank but we've resolved that it will serve a more useful purpose as a sump tank. The system has been re-configured to enable easy disconnection of the aquaculture system from the growing systems - particularly important in the case of a commercial system.

Gary

[GaryD]

Hi,

The Marburg project is plodding along quietly.

Our client (a busy engineer) is largely assembling the system himself with the assistance of family members.

Martin and myself revised the original project specification and provided technical advice on putting the system together.

Some recent photos:

• The first row of raft tanks in place
• A 500 litre mineralisation tank
• A 7,500 litre clarifier tank - designed to provide a retention time of at least 20 minutes.
• One of two 5,000 litre aquaculture tanks

A quarantine system, comprising two 1,000 litre tanks, is operating and water is circulating through the first bank of grow tanks.

I'll post more photos as they come to hand.

Gary

[aquapoolman]

Thank you for sharing this with us!!

so 2700 gallons of fish tank wate and 2000 gallons for the clarifier?
Is it normal to refer to the clarifier in terms of its volume as compared with the volume of the fish tank?

If so, 75% ratio seems very fail safe. Is this to account for future addition of fish tanks?

Im very curious, how many rafts are there? and how much does each raft hold?

You mentioned that being able to keep aquaculture and hydroponic water separate are important for commercial system. Why?

Also do the fish tanks operate using CHOP method?

Sorry for so many questions, thanks again for posting these pictures and detailing this setup!

-Jacob M. Brettler AKA Aquapoolman

[GaryD]

Hi Jacob,

so 2700 gallons of fish tank wate and 2000 gallons for the clarifier?
Is it normal to refer to the clarifier in terms of its volume as compared with the volume of the fish tank?

The fish tanks total 10,000 litres and the clarifier is 7,500 litres......and there's a 2300 litre sump tank.

If so, 75% ratio seems very fail safe. Is this to account for future addition of fish tanks?

The clarifier has to be able to contain at least 20 minutes of water flow......to enable the solids to settle out. The system has been designed to allow for expansion......more fish tanks and more grow beds.

Im very curious, how many rafts are there? and how much does each raft hold?

There are six raft tanks (each 6 metres by 1.2 metres) and a similar number of smaller flood and drain grow beds (each about 2m x 1m). The size of the Styrofoam rafts......and the number of plants that can be grown in each raft......is determined by the type of plants being grown.

You mentioned that being able to keep aquaculture and hydroponic water separate are important for commercial system. Why?

In normal operating circumstances, the aquaculture and hydroponic elements are fully integrated. Being able to separate them is important in the event that the operators contract a fish disease....or a plant infestation.....so that either system can be isolated and the problem treated without doing harm to the other.

Also do the fish tanks operate using CHOP method?

Yes.......the system is a CHOP system.


Gary

[Crusty]

Interesting layout.

What fish species was selected and at what density?

What sort of nitrifying filtration, what size, what media etc?

Any particular reason for burying the pipe work?

[GaryD]

Hi Paul,

What fish species was selected and at what density?

The system was designed around barramundi. Because the focus is on plant production, the fish are stocked at a relatively low density......enough to meet the needs of the plants.

What sort of nitrifying filtration, what size, what media etc?

The system relies on the surfaces of the rafts, tanks, pipework and plan roots to accommodate the nitrifying bacteria. There is also a substantial volume of water in the system.

This system was largely modelled on the UVI system.

Any particular reason for burying the pipe work?

To avoid having to work around it and to avoid UV degradation of the pipework.

The original layout was proposed by the contractor that we replaced. Our involvement was simply to resolve the obvious design issues and to assist the owner-operator to get it up and going with the least expense.

This required, among other things, replacement of the original fish tanks (one of which we turned into a sump tank) with 5,000 litre aquaculture tanks and the incorporation of a large clarifier and a mineralisation tank.

The system is a work-in-progress for the owner who is undertaking most of the set up work himself.

Gary

[Crusty]

The system was designed around barramundi. Because the focus is on plant production, the fish are stocked at a relatively low density......enough to meet the needs of the plants.

The system relies on the surfaces of the rafts, tanks, pipework and plan roots to accommodate the nitrifying bacteria. There is also a substantial volume of water in the system.

This system was largely modelled on the UVI system.

Utilizing the UVI model it is suggested that a feed rate of 60 to 100grams of feed per day per m2 of raft area. I am not sure if this is for nitrifying or for nutrient as other docs from the same UVI system suggest a feed of 3.2grams per m2 per m3. I can not be bothered to calculate the TAN removal rate/day of styrofoam but it can be worked out from the UVI figures.

Using just the main rafts alone (6 x 6 x 1.2m) provides 43.2 m2 of raft. 43.2m2 x 100grams = 4.32kg of feed per day. At a guess the feed rate will be roughly 2% of the mass per day. This will allow for the fish bio mass to be 216kg which in your 2x 5000liter tanks equates to 21.6kg/m3 there about. Not taking into account that the protein content of a barra compared to a tilapia are vastly higher I would adjust this number to half that capacity. Take for example the tilapia protein content in the UVI is 36% which is much lower than protein in barra (55%) specific feed which will vastly change the TAN removal.

Only guessing really but isn't 20 odd kg (if that can be achieved) is a little low for Barra from an economical stand point, don't you think?
What happens if he wants to double his density to achieve profitability?
Does he have to then add the additional cost of growbeds and infrastructure to accomodate an upscale?
What happens when the feed rates are increased?
If it is costs you more to grow the fish than it does to simply operate a hydroponic system what is the point?
What redundancy is in place when you have to disturb the rafts or replace rafts or isolate either system when at peak density and feed rates?

I think it is great people are having a go at commercial aquaponics. Every time I inquire about the input and output calculations, I am met with vague generalizations. To this day, I can not figure out why...