Aquaponics

Aquaponics is the simultaneous farming of fish and plants, leveraging their mutual syngergies in a closed loop system. The waste of one becomes the food for the other. Such circular, cradle-to-cradle systems are being recognized for leveraging nature’s efficiencies to naturally reduce our carbon footprint and effectively grow protein and plant nutrient sources at the same time.

Aquaponics UK is a social enterprise in the UK that champions Urban Food Production using an Aquaponic model which leverages the symbiosis of fish farming with hydroponics.

TEDx Warwick: Charlie Price from Aquaponics UK, explores the role aquaponics can play in the future of our collective food supply

Time Lapse of Building a Aquaponic Greenhouse

Time Lapse over 9 days of building a flood and drain, system with a timed short circuit to control flood and drain cycles

WHAT

  • A sustainable way of farming food using very few inputs to produce a wide range of healthy and high value foods all year round.
  • The growing of fish, or other aquatic organisms with plants in a controlled environment, optimising energy, water and nutrient use to produce the maximum amount of protein and vegetables in a given area.
  • Fish wastes provide nutrients for the plants which in turn act as a harvestable filter system, cleaning the water so it can be continuously recycled. Off-cuts from plants are composted and the worms fed to the fish creating a completely closed-loop production system.

WHY

  • 90% less water use than conventional agriculture.
  • Combined technologies minimise energy use & systems often incorporate renewable energy technologies.
  • Closeness to markets: freshest food with minimal transport emissions.
  • No fertilisers or herbicides required & pesticides are replaced with biological control.
  • Fish meal replaced with worms and insects from composting of plant off-cuts.
  • Maximum plant densities and year round growing = huge yields.

WHERE

Aquaponics can be described as ‘closed-loop’ production in that it has the capacity to provide all  inputs to the system within the system itself and to recycle its own wastes. For this reason the applications of aquaponics are almost endless… it does not require fertile soil or large water inputs and so can be practiced almost anywhere. The ecosystem approach to farming lends itself well to conservation and development projects and also to education. Systems provide interactive hands-on learning environments and offer a wide range of activities for learning and teaching in multiple subjects, carrying with it important principles about natural cycles, farming and recycling.

Why Do Aquaponic Systems Require An Additional Energy Input?

Aquaponics can be described as an energy efficient method of producing food particularly in comparison to conventional hydroponics and recirculating aquaculture systems. This is is partly due to conscious design choices which minimise energy requirements but predominately because the combination of the two techniques allow the energy costs to be shared. Two crops are effectively produced for the price of one.

Aquaponics systems on the whole operate within a controlled environment for year round production and this does necessitate an energy input of some kind particularly in temperate climates. Essential components such as the pump and aerators may be mechanically powered via a non-electrical means e.g. via foot , gravity or even play! (see:www.ideorg.org). This may not be possible however in larger systems or where a level of automation is required and so at Aquaponics Uk we strive to integrate renewable energy technologies with our systems wherever possible.  We are currently seeing rapid improvements in the efficiency and affordability of renewables which can easily be engineered into an aquaponics system.

(Source: AquaponicsUK)

The Plant is an innovative Urban Vertical Farm in Chicago. It applies the closed loop principles of Urban Farming that feature: symbiosis and the cradle-to-cradle concept of  Waste=Food.


Figure 1: The Plant Urban Vertical Farming System Diagram (Source: The Plant and Matt Bergstrom)



The Plant is the brainstorm of John Edel.  It is a refurbished Meat Plant which is being revitalized into a modern urban farming facility. Edel  has a vision of an integrated farm model of the future that includes:

  • net zero energy vertical farm
  • food-business incubator
  • research and education space
  • 1/3 of The Plant will hold aquaponic growing systems
  • 2/3 of The Plant willl incubate sustainable food businesses via low rent, low energy costs, and a licensed shared kitchen
  • The Plant will create 125 jobs in Chicago’s economically distressed Back of the Yards neighborhood
  • The Plant will operate on a Combined Heat and Power (CHP) system that will eventually divert over 10,000 tons of food waste from landfills each year to meet all of its internal heat and power needs.

 

The following information is based on information excerpted from The Plant’s FAQ page and explains all the components of this urban food growing ecosystem:

What is a vertical farm?

The Plant prefers the following definition:

  1. Farming in multiple stories of a building, and
  2. Farming from floor to ceiling in a room.

The main point of vertical farming  is the increased crop density: you are planting more layers of crops per square acre than you would on a single flat farming surface.

What is aquaponics?

Aquaponics is the combination of:

  1. aquaculture (growing fish in a farm setting) and
  2. hydroponics(growing plants in water and without soil)

Aquaponics is an almost fully-closed cradle-to-cradle ecosystem. It requires very little input:

  • some fish food
  • some micronutrients
  • some energy
  • and generates almost no waste

Symbiosis of Aquaponics closed loop system

Aquaculture is generally bad for the environment because the fish farms release tons of polluting fish waste into nearby lakes, rivers and seashores. That waste has nutrients in it that algae use to grow, so when there’s a big influx of nutrients, algal blooms result. The algae release toxic chemicals into the water and also absorb dissolved oxygen in the water, killing other sea life. (Notably, fertilizer that runs off conventional farms causes the same problems.)

Hydroponics requires the addition of nutrients (usually in the form of expensive chemicals). Fish waste is very high in ammonia, which is a form of nitrogen. If there’s too much ammonia in the water, it will kill the fish (and plants!). But nitrifying bacteria can break ammonia down into nitrites, which the plants can absorb. So, in aquaponics, the fish, bacteria, and plants all rely on each other to thrive.

Why tilapia and not some other kind of fish?

Tilapia is often used in Urban Food Production because they are eminently suited for this environment:

  1. They are fresh-water fish and a salt-water system is far less suitable for growing vegetables
  2. They grow quickly; they can be harvested after about 10 months
  3. They naturally thrive in a crowded tank and can easily tolerate a range of temperatures and water qualities
  4. The Plant is crossing two different breeds that, together, produce only male babies. (Kind of like breeding a horse and a donkey to get a sterile mule.) By keeping only male fish in our growing tanks, this will prevent breeding, which keep all fish of the same size. This helps to keep the Plant’s system in balance and to prevents the problem of bigger fish eating the smaller ones.
  5. It is also possible to grow perch, freshwater shrimp, and other kinds of fish.

Why mushrooms?

Mushrooms are one of nature’s decomposers, so they’re great for making further use of “spent” material like brewery mash (mash is grain that’s been heated in water to make the beer).

What is kombucha?

Kombucha is tea that has been fermented with a combination of bacteria and yeast. Like all fermenting things (including the beer that will also be brewed at The Plant), Kombucha emits carbon dioxide and absorbs oxygen. Conversely, plants absorb carbon dioxide and release oxygen. The growing rooms will be connected to the fermenting rooms (both beer and kombucha) and circulate the air between them. Doing so will improve plant growth—some estimates suggest up to 20%.

Will the Plant raise chickens or bees ?

Yes, they are looking into what’s allowed under the City of Chicago’s new Urban Agriculture ordinance.

What does it mean to be net-zero energy?

The Plant will produce all of its own electricity and heat on site and using proven technologies:

anaerobic digester will take in food waste (everything from spent distillers grains to vegetable produce waste to beef-fat sludge), digest it, and release methane into a combined heat and power (CHP) system. This system will supply the building with heat and electricity. The Plant will remain connected to the public electrical grid and natural gas pipeline, providing us not only with a backup power source but also the possibility of feeding surplus electricity back to the public grid.

What is an anaerobic digester and how does it work?

All organic matter breaks down over time, eaten by bacteria that’s all around us—it’s nature’s way of recycling matter and redistributing nutrients. This process can happen in two ways:

  1. Aerobic digestion happens in the presence of oxygen. It generates carbon dioxide, solid compost, and liquid compost (also known as compost tea, a great fertilizer for gardens).
  2. Anaerobic digestion happens in the absence of oxygen. It generates methane gas, digested solids (sometimes called digestate), and digested liquids (sometimes called a liquor).

The Plant is installing an anaerobic digester that takes in food scraps, digests them and releases methane into a covered storage tank. The methane will be pumped into a combined heat and power system, which will it will be burned in a generator. That combined heat and power system will produce:

  • Electricity, which will power the building;
  • Heat, which will run through a absorption chiller, which is used to regulate the temperature of the building;
  • Carbon dioxide; and
  • Water.

(Little known fact: most industrial buildings generate so much heat as a byproduct of industrial processes that they actually need to be cooled year-round. This is particularly true of The Plant, which is both very well-insulated and will produce heat from food manufacturing, beer-brewing, and grow lights.)

Why not do regular aerobic composting?

Regular composting produces only carbon dioxide – unless it doesn’t get enough oxygen, in which case it produces methane. (This is a bad sign in regular composting because the methane from the compost pile, when not captured and burned, is released into the atmosphere where it acts as a highly potent greenhouse gas.)

Carbon dioxide is a very stable molecule, which means it’s hard to break apart the bonds. (Breaking the bonds of molecules releases energy.) Methane, on the other hand, is relatively unstable; the bonds can be broken at a lower temperature – low enough that it’s a great source of fuel for running a turbine.

Don’t you release carbon dioxide when you burn methane? Doesn’t that contribute to global warming?

Yes, we will release carbon dioxide by burning methane, but no, our methane will not contribute to global warming. There are basically two sources of carbon dioxide in the atmosphere:

  1. The carbon cycle is the age-old process through which the Earth circulates carbon between the atmosphere and plants. Plants absorb carbon dioxide and use it to make sugars internally, which helps them grow. After those plants die, they decompose and the sugars break back down into carbon dioxide – the same amount of carbon dioxide they took out when they were alive. While there are sometimes fluctuations, the carbon cycle by itself creates relatively stable levels of carbon dioxide in the atmosphere.
  2. Global warming is the result of extra carbon dioxide emitted into the atmosphere in addition to what’s moving around in the carbon cycle. Burning fossil fuels releases carbon dioxide that was trapped underground millions of years ago. It comes from plants that decomposed underground and were turned into oil, coal, or natural gas. This long-lost carbon dioxide is much more than the Earth is currently adapted to use. The increased CO2 levels are creating what is known as the “greenhouse effect.” This happens because the Earth reflects back into space some of the heat from the sun, but every carbon dioxide molecule acts as a tiny mirror, re-reflecting that heat back to the Earth rather than allowing it to escape into space. By adding enough extra carbon dioxide to the atmosphere, we are heating up the global climate and changing weather patterns around the world.

So, back to our original question: why isn’t The Plant contributing to global warming? Because we’re using food scraps that are already a part of the current carbon cycle: those plants would grow, die, and release carbon dioxide regardless of whether or not we harnessed their energy.

What is a combined heat and power (CHP) system?

A CHP system is an engine attached to both a turbine and a heat recovery unit. The turbine creates electricity and the heat recovery unit captures the heat released from the engine. The heat released in our system will be in the form of steam at about 800º F and will be sent to an onsite brewery for their brewing process. The steam will return at about 200º F and will be sent through an absorption chiller, which will chill (or heat, if needed) water running through tubes throughout the building. That water will cool or heat the building as needed.

Absorption chilling is a complex process explained in greater depth here.

Also, it’s important to note that if we powered the CHP system with natural gas (as many factories do), we would enjoy the efficiency of jointly producing heat and electricity (it’s about double that of pulling using electricity off the grid and creating heat in a boiler), but we would still be using a non-renewable energy source. That’s why we’re putting in the anaerobic digester: to create a renewable source of methane (the main component of natural gas).

How did the team come up with all of these ideas?

John Edel, the Executive Director, has been thinking about growing plants in buildings since his childhood visits to the Garfield Park Conservatory, with its towering palms and lush gardens all growing indoors. He also knows a lot about manufacturing and has spent a lot of time researching the industrial history of Chicago.
He wanted to create a space where manufacturing and indoor growing could happen together. Both processes use a lot of energy. The CHP system produces both the heat needed for manufacturing and the electricity needed to run the grow lights.

To develop these ideas, John has worked closely with students from the Illinois Institute of Technology, as well as friends from the community (many who have come through on building tours) with suggestions about other possibilities for symbiosis.

Why does the team focus so much on food? Can’t this be done with any kind of manufacturing?

Absolutely. In fact, that’s the message of this whole building: manufacturing and growing – both of which use a lot of energy – can happen in a sustainable way. The Plant is focused on small-scale food production as their main focus of manufacturing because John et al. happened to find a building with a lot of valuable food-grade materials.  These materials allowed the team to create space safe for food preparation. Had  the team chosen a different building they could have combined growing with some other type of manufacturing.

All kinds of industrial buildings can be repurposed to house manufacturing and growing systems powered by renewable energy and to create jobs. This is the point The Plant is trying to make! You can do this anywhere to great benefit to society.

What does it mean to be food-grade?

“Food-grade” means that a space is safe for food preparation, according to very strict government health and safety standards. When the former owners, Peer Foods, were processing meat in the building, they had to meet standards set by the U.S. Department of Agriculture that required most of the building to be made out of materials like FRP (fiber-reinforced polymer) on the walls and sanitary brick or a rubberized concrete on the floors. There’s also lots of high-grade stainless steel throughout the building that will be reused as kitchen spaces. These materials prevent mold and bacteria growth, they’re easy to clean, and stainless steel doesn’t corrode. Notably, the USDA required meatpacking plants to get rid of asbestos and lead piping a long time ago, and there’s none in The Plant.

How much work was required to renovate this building for urban food production?

A lot! – estimates range about 15,000 working hours between July 2010 and February 2012.

Who is doing all the work?

The Plant staff and a huge pack of volunteers. There are two full-time staff members, three part-timers, four long-term, very dedicated volunteers, and a few interns in and out. There have been up to 1,500 volunteers help, some for just a day, some who come back regularly.

What is deconstruction?

Deconstruction is the opposite of construction: it’s the careful removal of materials from a building with the intention of reuse. Demolition, on the other hand, is the destruction of a building without much regard for keeping building materials intact.

Can you really reuse 80% of the existing building materials?

Given that they were found them in such good shape, yes. Keep in mind that much of this figure refers to the building’s physical structure – the brick walls and concrete floors. But the team is going to great lengths to remove other materials in a functional state so they can be reused.

Isn’t that a lot of trouble?

Yes, but the Plant believe that there is both monetary and intrinsic value in doing so. Tearing down buildings anywhere leaves gaping holes in the fabric of the city, especially in neighborhoods like Back of the Yards. To the north and east there are huge factories, but to the south and west there are homes. Leaving a building vacant makes people wary of it because it invites criminal activity. Tearing a building down puts a big hole in the area. And a recent study suggests that even if you tear down a warehouse building and replace it with an office building that’s 30% more efficient, it will still take 12 years to recover the energy spent in actually constructing the new office building. By making use of the energy embedded in this building, you will save the energy that would be spent building a new one.

Does it save money?

  • Absolutely. To construct a new industrial building in Chicago costs roughly $70 to $85 per square foot
  • To construct a glass building that would let light in could be upwards of $200 per square good
  • The Plant team estimates spending well under half of that when the project is done
  • The Plant team will eventually publish a business case study when  finished to show the details

What is the difference between “The Plant” and “Plant Chicago”?

  • “The Plant” is the name of the building we’re in at 1400 W. 46th St. It is owned by Bubbly Dynamics, L.L.C. (which is in turn owned by John Edel, the Plant’s Executive Director.)
  • “Plant Chicago” is the name of the non-profit that owns and operates most of the vertical farming space in the building (some is operated by other tenants).
  • It will also own and operate the shared kitchen planned to be built out by roughly 2014, and will conduct research and educational programming in the building. Plant Chicago is technically a tenant of The Plant.

How much of the business at The Plant will be for-profit and how much nonprofit?

Nearly all of the businesses will be for profit by virtue of the fact that they deal with raising and preparing food, which is generally a private enterprise.

The major exception is Plant Chicago, NFP, which is an Illinois-registered not-for-profit corporation and is seeking federal tax-exempt 501(c)(3) status. Plant Chicago will conduct research and educate the public on sustainable food production, job creation, renewable energy use, and green building renovation. To that end, it will own and operate about 22,000 of the 30,000 s.f. of growing space (where the research will take place) as well as the shared kitchen (where the job creation will take place). It will also host extensive educational programming to teach adults and children about The Plant.

This sounds like a complicated business. How many different kinds of permits and licenses do you need to put it together?

Lots, and more to come:

  • The renewable energy system will likely require at least 8 separate city- or state-based permits or approvals for air, water, waste, and zoning
  • The building itself requires all of the standard construction permits

Green Sky Growers is a rooftop farm located on top of the Garden Building in Winter Garden, Florida. It is the first Certified Green building in the world with commercial-scale, Aqua-Dynamic farming on the rooftop. Green Sky Growers produces tons of fresh vegetables and fish on an annual basis without the use of harmful pesticides.

  • Environmentally friendly growing practices include the harvesting of rainwater that is recycled in the Aqua-Dynamic growing systems
  • All the growing systems continuously recycle 100% of the nutrients and water
  • The majority of food produced is available to the local Winter Garden community, thus providing healthy, locally grown and low carbon-footprint food

Green Sky Growers Closed Loop Process

Tilapia fish tanks are the key component to Aqua-Dynamic farming. Each tank is home to 500 – 600 Nile tilapia. By controlling temperature, diet and water quality we can produce a 1.5 lb – 2 lb tilapia in 12 – 18 months from a 1” fry. Our rooftop system produces healthy fish that are locally grown and free of harmful chemicals. Fish waste is filtered from each tank and then digested into minerals that the plants will use. Living biological filters will convert harmful ammonia to a nitrate form of nitrogen, which will be absorbed by the food crops above. After the fish water has passed through the filters and the digesting equipment, it is then delivered to the hydroponics growing systems above. The plants absorb the minerals from the water and the excess water drains from the hydroponics system back into the fish tanks. This completes the Aqua-Dynamic loop.