Backyard Aquaponics
A place to discuss aquaponics

I thought worms would be able to live totally underwater, saves a lot of hassle there...

you have a good stuart, I suspect I'll do a bit of reading on what sort of conditions caused clogged gravel and which have succeeded.

1 data point: I have continuous flow, no worms, clogged gravel (in two systems). I'm planning on adding worms, but life has other priorities. *grin*

I think that continuous flow drives them out (although folks with more experience may disagree (see above posts)), so intermittent flow would be better.

I think DO is the issue. I think a totally flooded bed could support worms, but I see many many drawbacks.

So FD on the gravel filters it is. Plenty of aeration for fish and worms. Anybody seen industrial size auto siphons?

I've made some out of 32mm pipe

monya's is a 90mm 'loop' style syphon...I think...
dumps 4kl in a couple of minutes

This is one of the things that we do have good data on. Someone, I think they were in the UK (info is on the forum somewhere) did a study on plant growth and nutrient levels in AP after it had been through a long flow. From memory they found no difference in nutrient levels after AP water had run through 60m of NFT channel. From this they conlcuded that a plants growth (and by inference nutrient availability) was indepent of position in a GB or NFT channel. Therefore there should be no problem, from a nutrient availability point of view, seperating the media from the plants.

Great post Steem!

The sides of the building could also be planted walls watered by returning AP water from the roof if the sun reaches the sides.

No big deal on the long post, good stuff in there.

Mixed use, hoping for a fairly consistient three story deal dominated by commercial on the bottom floor with residential on the top. Industrial on part of the site as well.


Idea I'm currently trying to run with is to divide public activity into three sections: a sub level for goods and high density transit (trains, busses), a street level for commercial activity, and a roof level for recreation, relaxation and farming. Glass walls won't do too well since building will be very close to one another and street widths will be kept to a min. Also, southern exposure on the site is small. There are lots of people (especially out of NYC) that are looking into these vertical concepts, cool stuff, but I think for the scale of this site, might be limited to vines growing up or down on building sides.


Nutrient cycle through BSF composting (non-fecal) for fish ingestion. Water cycle by using grey water (very advanced treatment) or rainwater for AP systems. Not gonna close the cycle, just bring the ends a bit close together.


Very cool idea, lots of landscaped space on roofs for parks+rec, really neat to use useful plants for that purpose, plus take some grey/rain water.


Working on it, probably anaerobic digestion separate from the city utilities. Need to figure out costs...


Hmmm, likely to incorporate district cooling, perhaps heating as well with waste power from nearby steel operations. Sunlight is free, but so is waste heat from big utilities. Might make more sense economically.


Plants not much of an issue on building walls for the structures sake, but they just wouldn't get a lot of light there. Solar is nice, but wind is the most likely option for this development, preliminary studies for offshore turbines already paid for by the developer and results look promising.


Sacrifice in this development was light. Trying to maximize light for plant growth, not indoor lighting. Truth of the matter is that lighting efficiencies will increase while impact of power generation will decrease. Not saying it's not a tough trade off, but in the long term, I think it's a good decision.

Thanks for all the thoughts, I really appreciate them.

-Jon

Here is one aspect I have not seen discussed on this project idea yet.
Humidity issues with the basement fish systems. Please do some research into methods to control humidity, moisture damage, and mold. These issues are of great concern to greenhouse growers and there is lots of into on that side for venting and such to minimize problems from excessive humidity and many ways to keep humidity high enough to keep plants happy too. As for fish tanks and gravel beds in the basement, please make sure you won't be making the building sick by creating an excessively humid environment where moisture will collect on surfaces and grow mold. This might be as simple as sealing the fish area off from the rest of the air space in the building and providing separate ventilation while also making sure the walls for the fish space are insulated and won't be so cold that condensation will collect on them.

I mention these things because I live in a sub tropical climate and have suffered from needing to battle mold and humidity issues as a fact of life in this climate.

Reading all the comments about worms dealing with solids.
Do keep in mind that worms poop too. The materials that come out of worms are closer to mineralization than before going through the worms but there are still solids there. So worms might not make a bio-filter indefinitely able to cope with over stocking but they will help some. Same with plants, they use up minerals and turn them into plant mass which gets periodically removed from the system. There has been some discussion that certain minerals might be more easily accessed by plants in close proximity to the solids. I would like to note that a bio-filter that is properly sized to a purpose, does not necessarily ever clog up. Clogging and excessive solids build up are totally a function of too much feed input or stocking density or other solids for the system to cope with. (No blame just people having to cope with the limitations of their situations and yet manage a system in one way or another.)

Here are a few notes that could help keep maintenance easier.
1-CHIFT pump in sump or basement tank. Have a media bed between the fish tank and pump so as to keep the pump cleaner. If you have enough solids filtration happening before the pump, then the only buildup on/in the pump will be bio-slime which is far better than the chunky stuff that clogs trap baskets or food and poo that might make it through and be pureed and tend to murk up the system a bit. (My biggest gripe about my system is that I didn't do CHIFT PIST and I need to clean out my pump trap too often.)
2-Perhaps you could arrange for your basement media beds to grow some low light demand plants that would only need minimal supplemental light. House plants that help clean the air or something like aloe that might actually suffer in a sunny greenhouse (yes Aloe does fine in flood and drain gravel beds.)
3-For media beds on the roof, you can reduce weight by using alternative media. The expanded clay balls are much lighter than gravel. Coco coir is also lighter though it will hold much more moisture and could turn your water tea color

Very important point. Most folks who have tried to put systems indoors have had major problems. Moisture, mold, etc. There are various ways to deal with this, such as a covered system (for his FT and worms beds). One could bubble air into the FT, let it pass by the worms and vent the exhaust air outdoors, with a condenser/heat exchanger* to recover heat.

*I'm not an expert, but know these things exist. I just don't know the exact current terminology and technology. *sigh*

tcl-
very good point on the humidity. i think this makes fish selection a much easier issue, cold water all the way. probably looking at trout or perhaps cold water tilapia. i think as long as the water is cold enough, a bit of air pass through will be sufficient to keep the moisture down.

probably need some fancy equipment to warm up the water a bit before it hits the gh on the roof or cool it back down on it's way back. good argument for rare water transfers between FT/Gravel Filters and NFT/Gravel Beds.

This sounds like a fun project.

I have been in the greenhouse industry for 20 plus years and teach greenhouse design.

Your greenhouse in Detroit on the roof will be exposed to incredible heat loss in the winter, The fuel bill will be astronomical, with little protection from the wind your heat will be pulled out so fast you won't know what hit you. Not to mention the summer energy required to cool it (use a retractable roof if you must be on the roof)

So, for a far-out urban how about considering something truly urban, INside.

there are new LED lights that can be used that use a fraction of the energy. I was just looking at one that uses 15 watts and is the same output as a 150 watt HPS.

they are not perfect yet, they seem to be best at a very specific distance from the crop, so things like tomatoes might not work but basil, lettuce etc would be perfect.

they do not provide the heat that HID's do, so you might actually have to add a few metal halides for vertical growing crops. But then again you dont have to exhaust the excess heat.

this would limit your need to push water up 2 stories, again cutting your energy

put solar panels on the roof where they belong.

you can still catch all the water and recycle it clean it or what ever you want to do with it.

you can use solar hot water heating on the exterior building walls to warm the water and the growing room.

Using all available space in the cities is key,

keep it up!

you have seen vertical farm? http://www.verticalfarm.com/

cheers

peter

peter- thanks for the thoughtful post, I certainly agree with you that using all available space in cities is key. Solar power is an excellent solution in many places, but this development is likely destined for wind turbines instead (it's sort of a dreary place). Water going up a bit isn't too big of a deal, that head can be recaptured on the way back down.

I would be very interested to pick your brain about greenhouses. It would seem that in the winter you would certainly need to transition to crops that take colder weather better, at least in most of the installations (not ruling out some small tropical sections...). Plus if you cover the entire roof, you capture much of the escaping heat out of buildings. I was thinking the roof would be plastic, but these places are supposed to double for green space, so I'm not sure if the aesthetic will be there. Perhaps some glass that opens and closes?

What about solar greenhouses that have double or triple layers and enormous thermal buffering?

As for the folks over at vertical farm, I think their effort is admirable and their heart is in the right place but that they need to bring some more agricultural people in so they can get some accurate estimates of what reasonable goals they should be shooting for.

-jon