Hello everyone
I am an expat in my wifes native country of Poland looking to start a DWC on our land behind our house. Let me be clear I am going into this with the intention of aiming for profit from the start. I am not an idealist out to save the world, but it would be great to get a large amount of organic produce to market using sustainable methods. I would love it if anyone could weigh in with pointers as I am in the planning stage.
The Plan (in progress):
The land is a strip running approx N-S for 80m long and 16m wide. There is a gentle slope on the land of 1.7 degrees running south downhill (I might dig a trench at the southern end of the slope for water catchment into a tank to supplement water loss in the system).
Here are pictures of the land looking south from the northern corner as it stands now:
https://ibb.co/jLdbKdhttps://ibb.co/hEUoXySeeing as I want to raise brown trout I feel it best to build a separate insulated construction of around 13m width x 15m length to house the tanks, with possible partitions to keep things quiet and manageable for the fish away from anything else (maintenance, storage and management etc) and to regulate their climate and water.
The greenhouse will be a single span 13m width construction with built-in climate controls. I have in mind 4 x 2m wide channels where floating poly rafts will grow herbs and greens as a starter crop. Already thinking of heating in mind, I reckon a boiler could sit in the tank room and flow out into the greenhouse, in which case it will be warmer closer to the tank room, the northern end, allowing for tighter temp control for the trout (obviously heating water and system water are separate). This means if the tanks sit higher already, the water from the fish could flow downhill above the plants in the greenhouse to the far southern end, then flow back north along the channels to buried sumps and then pumped back to the fish. To my mind it seems better to have the pumps, sump and valve controls all near to one another in case of catstrophy or maintenance. Running to one end then the other would get stressful.
There are so many factors now to consider, I thought it best to open up the idea to you guys. Bear in mind this is not a BYAP system, and for sure it will require much market research. Crops we had considered and will aim for are basil (first and foremost), chives, rucola, lettuce, maybe kale and tomatoes (if the nutrient levels and rafts will allow) and possibly even flowers (both hanging from overhead and perhaps others in the channels).
Some challenges/questions I have highlighted in my mind are:
1. Trout needs / sensitivities / water flow / filtration systems.
- As the hinge factor in the system, the fish are obviously crucial. I know very little of aquaculture, but there is a strong network in this country and I am keen to get up to speed and input what is necessary to take care of my fish. I will design the system around their survival. Stocking densities are something that I feel I will come to understand as it goes forward, as every system is different, but naturally the basics can be grappled with before designing, as there will be details upon which everything hangs in the balance.
- What tank sizes would be prudent for such an enterprise, and from what material? The grow channels will initially total between 400-440m2 (4300-4700 sf). Several tanks seem to be necessary to separate fish sizes and when spawning. There is space in the tank room but the configuration needs thought.
- I lean also towards one or two channels taking the smaller fish’s water, and other channels handling the bigger requirements via larger plants. This might require a sluice-type arrangement for when things go wrong and flow needs to be cut off to one channel and diverted to another, to save the fish and plants. Perhaps the filtration system itself could handle it, I am not sure at this stage. If this is the case some very stringent monitoring of levels in the system might need to be in place from the get-go.
- Flow-wise, I aim to create a centrifuge in my tanks with pumps entering from low down through the wall at opposite angles and creating a gentle spin homemade-style. Tell me if this is a bad idea.
2. Supplementary lighting / solar power.
- To meet the power needs I want to slant the roof of the tank room to accommodate solar panels that face south. It could help to supplement costs on lighting out of season (through overhead LED panels) and run the pumps. This in itself is an entire project, I feel, and might have to come once production is up and running.
3. Local climate / greenhouse control.
- The central european climate (much like the people) is volatile and can cause issues, but checking Denver where I know AP is up and running, they have a similar climate and seem to make it work fine. Perhaps a solar greenhouse would be a prudent option but sadly the layout of our land robs us of that decision.
- The sunlight is good so it should be no problem to grow around the year as long as we can keep temps up. I feel flattening out the ground and laying insulation underneath concrete would help things a lot, at an extra cost obviously, but that would be offset by the off season organic produce we could grow. With LEDs it would be cheaper. Temps do get deep though… the first winter I was here it hit -30C in january for a day. The locals say it is warming up year by year but for me thats a warm day on Mars.
- At the design stage, I feel to warm the greenhouse with hot water might be cheaper than induction heaters, and to insulate and embed these somehow would be best, but where to put them is the question. The floor? In insulation around the channels? Under the channels, along the walls?
4. Business plan.
- Finally the most important part: making the money. This is where I need input from the experienced and successful AP people here, if they feel willing to share. I want to get my ducks in a row before everything reaches its final stages, as my wife will be the one handling the sales and I want a stable marriage as well as a successful business (yeah, yeah - call me crazy).
- In terms of the market, it will really come down to us making headway into it, but as I found in previous businesses, it really helps to be the one the customer comes to, not the other way around. Deliveries, negotiations, customers etc will take time away from running the system, and if there is any way to solidify the process and keep it running smoothly I would appreciate tips in that vein.
Before signing off I should say that I have a talent for designing and configuring systems of this kind of thing. My previous project was a shiitake farm (similar in some ways with balancing multiple system factors) and my experience was that no matter how much you plan and prep beforehand, a system with many integrated areas will always require calibration on-the-go due to the scale factor as it builds up. Entropy too is a bitch, all those niggling problems with weird things you can’t plan for when energy increases in the system. This is the kind of challenge that I love, however. I realise from the start that I/we will have to become experts in testing water quality; levels of pH, oxygen, ammonia, bacteria, fish stress and disease, filtration methods and all sorts of other things, as well as pest control and greenhouse management methods.
Please feel free to attack my idea savagely and pick it apart. Thanks in advance
