Aquaculture as an Aesthetic and Waste-Eliminating Food Production System

Jack CochranArchitecture 6232: Systems, Sites, and BuildingProfessor William ShermanDecember 17, 2010

In many ways the world as it exists today can be defined by its hyper- or misuse of resources, a system in which energy rapidly expended remains spent and its by-products unused. The materiality of human civilization thus often operates unidirectionally in an environment that evolved with an opposite sensibility, one in which making and life are impossible without waste and death.

Of exemplary relevance to this issue is the production and consumption of food. At its essence it is the transfer of nutrients and energy, but in many cases the waste generated by human consumption is not available to feed new food growth, both in terms of food scraps sent to landfills and human waste sent to wastewater treatment facilities and rivers as opposed to gardens or farms. The growth of food has become increasingly dependent on alternate sources of nutrients, such as through synthetic or artificial fertilizers and pesticides, and is often transported over great distances. According to the Center for Urban Education About Sustainable Agriculture (CUESA), the average distance food has traveled from farm to plate in the United States is 1,500 miles, which necessitates an expenditure of 10 kilocalories in fossil fuel energy for each kilocalorie gained through food.1 The problems associated with excessive fossil fuel use, runoff of such agricultural products as artificial fertilizers, lack of transparency between consumers and producers of food, and high levels of generated waste has led to a reemerging interest in local food production that uses waste food and plant material as organic fertilizers.

1. Center for Urban Education About Sustainable Agriculture. “Issues in a Nutshell: How Far Does Your Food Travel to Get to Your Plate?” Center for Urban Education About Sustainable Agriculture website (http://www.cuesa.org/sustainable_ag/issues/foodtravel.php), accessed Novem-ber 23, 2010.

With the high levels of world fish and meat consumption, the incorporation of these food sources into a system that utilizes waste as food is a key component of establishing a sustainable agricultural system. To this end, the following essay analyzes three historic and contemporary systems that incorporate to varying extents the production of fish, all of which provide important lessons on how fish growth can contribute not only to the success of the immediate system of which it is a part, but also the economic, social, and ecological well-being of that system’s broader environment. Indeed, the growth of fish in these examples lends insight into how the very concept of waste generated by an urban populace can be returned as food, and in the process of doing so can extend beyond food production to have bearing on the aesthetics and enjoyment of the production systems.

Fish Pond, Pompeii (via James Higginbotham (Modified))

East Kolkata Wetlands (via Google Earth)

Growing Power Aquaculture System (via Michael G. Burlando)

Roman Fishponds

The first and most historic of the three aquaculture examples was less an agricultural act as it was a utilization of fish for aesthetic and social enjoyment, while providing means to convert waste into a food source and, due to their immediate proximity to homes in some cases, a means to cool temperatures in a hot environment. According to James Higginbotham, who has conducted extensive research on the archeological remains of Roman fishponds, or piscinae, both freshwater and saltwater ponds were established and grew to increasing complexity by the beginning of the Roman Empire.2 Some saltwater ponds located on sea edges covered several acres, and freshwater ponds were typically located in greater proximity to residences and decorated gardens.

Although varying in size and in the degree to which they generated food, the piscinae were considered to be emblems of social status, with preference for saltwater fishponds gradually shifting to a preference for the less expensive and easier-to-maintain freshwater variety.3 Aqueducts were employed to bring freshwater from surrounding areas directly into the fishponds, which, through the implementation of outlets at the top of the ponds, provided a continuous flow of clean water that replenished the water used by the fish and helped to continuously aerate it. Freshwater was also important for the saltwater ponds, which helped create a brackish environment through its combination with inundations of waves from surrounding seawater. The circulation of the water enabled through the input from the aqueduct (and sea) also aided in maintaining desired temperatures in the fishponds, as the limited depth of the ponds could expose the fish to extreme temperatures.

2. James Higginbotham, Piscinae: Artificial Fishponds in Roman Italy (Chapel Hill: The University of North Carolina Press, 1997), 1.3. Ibid.

Fish Pond, Tivoli (via James Higginbotham (Modified))

Fish Pond, Baiae (via James Higginbotham (Modified))

Various architectural devices, including vaulted domes that stretched over the length of some fishponds, were employed to provide the fish with shaded areas in addition to surrounding trees.4

In addition to helping preserve the health of the fish, the vaults over the fishponds provided a space from which to observe the fishponds, an important aspect of the incorporation of piscinae at Roman villas. In several cases, ponds were located adjacent to porticoes and vine arbors (pergulae), which in addition to shading portions of the ponds served as areas for visitors and residents to observe the fish. In fact, the substantial majority of fishponds documented by Higginbotham demonstrated a connection with private dwellings, with various platforms providing views of the fishponds and opportunities to dine and perform other activities adjacent to the ponds.5 As evident in the images of piscinae in Baiae and Pompeii, the fishponds served not only as areas to enjoy at various locations around a villa’s grounds, but as a central, focal piece of its site planning and architecture.

In addition to the sensory enjoyment gained through fishponds – both climatically due to the evaporation caused by the presence of water and in terms of light, sound, and smell of the water and the fish – the consumption of the fish and their growth had elements of a cyclical relationship between waste and food. According to Higginbotham, assorted fruit, milk curds, decaying fish parts, dried figs, and small fish were used to feed the harvested fish. Further, the transfer occurred at limited distances, as the fish grown were often consumed on site until shipping practices and sales at local markets became more common.6 As a result, the piscinae formed an early example of the incorporation of

4. Ibid., 26.5. Ibid., 31.6. Ibid., 34.

ORGANIC WASTE FEEDS FISH

FISH GROWTH FEEDS RESIDENTS

EVAPORATION FROM PONDSCOOLS SURROUNDING AIR

FISHPONDS SERVEDAS SOCIAL STATUS MARKERS

Fish Pond, Pompeii (via James Higginbotham (Modified))

artificial fish growth into a residential or urban setting, and doing so in a manner that grew food partially through the use of waste and other harvested plants and animals – all the while creating a setting that was aesthetically pleasing and enjoyable enough to merit fishponds as markers of social status.

East Kolkata Wetlands

Moving forward roughly two millennia to the turn of the 19th century, the utilization of waste to generate food while maintaining aesthetics and highlighting sensory experience erupts in complexity and scale. Outside of Kolkata, formerly Calcutta, a city expected to reach 14 million in population by 2015, are the East Kolkata Wetlands (EKW), a series of small-scale vegetable farms, sewage-fed fisheries, solid waste farms, and development set in between the wetlands and farms. The EKW is considered to be the largest wastewater-fed aquaculture system in the world, as it receives 600 million liters of sewage and 2500 metric tons of solid waste on a daily basis.7 While many initial reactions may be wary of the use of human and solid waste in the production of food, scientists such as Nitai Kundu who have studied the wetlands claim that not only can such a system return substantial amounts of healthy food to the city, the area has developed aspects of an eco-tourist economy due to the diverse flora and fauna found living in the wetlands. In fact, the wetlands are considered to be of international importance by the Ramsar Bureau while utilizing waste to generate 150 tons of vegetables per day and 13,000 tons of fish yearly, which constitutes one-third of the city’s entire fish consumption.8

7. Tarasankar Bandyopadhaya et al., Preliminary Study on Biodiversity of Sewage EFD Fisheries of East Kolkata Wetland Ecosystem (Kolkata: Institute of Wetland Management and Ecological Design, 2004), 5.8. Nitai Kundu et al., “East Kolkata Wetlands: A Resource Recovery Sys-tem Through Productive Activities,” in Proceedings of Taal2007: The 12th

East Kolkata Wetlands (via Flickr user paddy)

The utility of the wetlands, which comprise over 12,000 hectares, is made possible through a combination of human and natural processes. Sewage from Kolkata is sent into the fisheries, where instead of attempting to dispose of the waste, fishermen detain it, allowing for aerobic biodegradation of the organic matter in the sewage. Following this stage, the organic material is capable of being absorbed by plants and plankton, which in turn feed the fish that are grown in the wetlands. As a result the EKW become a means to stabilize waste and filter it through aquaculture, discharging cleaner water downstream, where traditional farms are located and use water from the wetlands further to the east of the city.9

In addition to the sewage-fed fisheries, the EKW also contain a portion of farms that utilize solid waste from the city. Organic and other solid waste forms are transported to the wetlands via trucks and are sorted through by local residents, who utilize organic waste on vegetable gardens and sort through other forms of trash for recycling and resale. According to Tony Juniper, the combination of workers in the fisheries, on vegetable farms, and in garbage sorting contributes to the livelihood of 50,000 residents, some of whom are also involved in maintaining the canals that direct sewage to the fisheries.10 The workers, further, have developed the use of sewage in fish farming to such an extent that the yield-cost ratio in the EKW is far greater than in any other fish farm in India, an important economic accomplishment while organic pollution in the wetlands has been reduced by 80 percent.11

World Lake Conference, edited by M. Sengupta and R. Dalwani (2008): 868-77.9. Ibid., 876.10. Tony Juniper, “Kolkata: Wonders of the Waste Land,” Guardian Weekly (UK), August 6, 2004 (http://www.mindfully.org/water/2004/kolka-ta-wetlands6aug04.htm) (accessed September 19, 2010).11. Kundu, 877.Four Stages at East Kolkata Wetlands (via Google Earth)

East Kolkata Wetland System

As a result, workers in the EKW have managed to close to a considerable extent the food-waste cycle, utilizing the waste from the city in order to generate new food – and in the process of doing so, have created a healthy ecosystem of diverse animal and plant life. Sewage and trash become resources and are utilized, as opposed to being sent downstream where others might be incapable of using them and thus consider them waste or pollution. And, to stress the scale again, this has occurred for nearly a century for a city now approaching 14 million.

Growing Power, Milwaukee

In what might be termed a combination of the first two examples but what also presents entirely new components to the question of aquaculture, Growing Power of Milwaukee has been at the forefront of urban farming since its founding in 1993. Formed by Will Allen, Growing Power consists of fourteen greenhouses on two acres, inside of which occurs a network of vermiculture, aquaculture, water filtration systems, and organic gardening, all of which is capable of providing enough food for 10,000 people due to the highly rich soil used in the farms.12

According to Eli Rogosa, the way in which the aquaculture system operates at Growing Power is through providing tilapia, the main fish product, with food in the form of duckweed, and the water in which both the tilapia and duckweed grow is sent to other plants for their growth and filtration.13 Duckweed, first of all, is a plant that converts

12. Elizabeth Royte, “Street Farmer,” New York Times, September 5, 2009 (http://www.nytimes.com/2009/07/05/magazine/05allen-t.html), ac-cessed December 2, 2010.13. Eli Rogosa, “Organic Aquaculture,” Heritage Wheat Conservancy website (http://www.growseed.org/growingpower.html), accessed De-

Tilapia Tank

Plants Filter and Utilize Nutrients in Water through Microorganisms

Plant Growth with Soil in Aquaponics (all images via Michael G. Burlando)

ammonia in fish waste into a biomass edible for fish, which is capable of sustaining the growth of tilapia without additional feed.14 Water containing fish waste is then sent through a filtration system comprised of wetland plants, which contain microorganisms primarily on their root structures that also convert remaining ammonia into nitrate, which is then absorbed by the plants. Following this filtration, the cleaner water is sent to vegetable crops in troughs, and the clean water is then returned to the fish tank, where it falls from above to help aerate and circulate the water in the tank for the health of the fish.15

An essential component of the system, however, is the growing medium for the vegetable plants: rich soil created through vermicomposting. By feeding food scraps and other organic waste to worms, rich compost is created – in the range of 100,000 pounds generated each four month period. This compost is applied to some 25,000 potted plants in Growing Power, which generate $30 per square foot.16 As a result, Growing Power has set up a system in which the various components are able to perform beneficial actions for the other components in the process of aiding themselves. The fish waste fuels the growth of various plants throughout the aquaponics system, which in turn provide food for the fish and filtered water for the health of the fish. The plants thus grow and generate vegetables for local residents to consume, and the additional biomass waste of the unused parts of the plants are turned into compost, which helps provide nutrients for other plants in the system. Further, as Growing Power has numerous contacts with surrounding businesses and restaurants, they are able to turn others’ organic waste into compost through vermiculture, thereby preventing that waste from going to

cember 1, 2010.14. Ibid.15. Ibid.16. Royte.

Hanging Plants Fed with Soil and Filtered Water

Vermicomposting

Compost Heats and Insulates Buildings (all images via Michael G. Burlando)

DUCKWEED

EARTHWORMS

MICROORGANISMS

TILAPIALETTUCE/SHORT STEM PLANTS

WETLAND PLANTS

AMMONIA

NITRATE

absorbs

produce

eat

through

becomes

use

WATER

and filter

use and filter

use

FOOD SCRAPS

COMPOST

convert

to

become

HUMANS

eat

create

as it falls, aerates

HUMAN WASTE

eat

Diagram of Growing Power System

a landfill and turning it into a resource that helps fuel the entire system. Waste from the consumer and from the fish is recycled and returned to begin the next stage of growth and consumption and waste.

This mutual support and interaction of various components of the Growing Power facility has even been extended to the provision of heat for the facility, as well. The heat generated for fish tanks in the winter is used to heat the greenhouse as a whole, and compost is often piled alongside greenhouses to help provide insulation and a source of heat while creating the soil needed to grow plants inside.

Conclusions

In the interest of establishing an agricultural system that uses waste products as resources, these three models demonstrate to varying extents ways in which various components can work in concert to achieve such an end. Although not all of the systems incorporate as many sources of waste as is possible - such as through Growing Power’s lack of use of human waste - the methods demonstrated provide excellent models for adaptation of existing systems. Of course, it may be incorrect to assume that the United States will eventually follow the lead of Kolkata in utilizing human waste in the production of fish and other food sources. However, the more agreeable uses of waste - such as those demonstrated in piscinae and at Growing Power - can help formulate new, widespread means of food production. These systems, which might include personal aquaculture systems or community-scale farms, can both demonstrate personal or community-based reuse of waste for food production - in a way that also reminds visitors and users of the beauty of a return of/to nature. Either way, it

Mathieu Lehanneur, Local River (via Dezeen)

is through an understanding of such systems as the three studied here that we can begin to be reminded of how to reuse waste as food: by determining what can use the waste of something else in order to eventually return it - directly or indirectly - back to its source.

Bibliography

Bandyopadhaya, Tarasankar, et al. Preliminary Study on Biodiversity of Sewage EFD Fisheries of East Kolkata Wetland Ecosystem. Kolkata: Institute of Wetland Management and Ecological Design, 2004.

Center for Urban Education About Sustainable Agriculture. “Issues in a Nutshell: How Far Does Your Food Travel to Get to Your Plate?” Center for Urban Education About Sustainable Agriculture website (http://www.cuesa.org/sustainable_ag/issues/foodtravel.php), accessed November 23, 2010.

Higginbotham, James. Piscinae: Artificial Fishponds in Roman Italy. Chapel Hill: The University of North Carolina Press, 1997.

Juniper,Tony. “Kolkata: Wonders of the Waste Land.” Guardian Weekly (UK), August 6, 2004 (http://www.mindfully.org/water/2004/kolkata-wetlands6aug04.htm) (accessed September 19, 2010).

Kundu, Nitai, et al. “East Kolkata Wetlands: A Resource Recovery System Through Productive Activities,” in Proceedings of Taal2007: The 12th World Lake Conference. Edited by M. Sengupta and R. Dalwani (2008).

Rogosa, Eli. “Organic Aquaculture,” Heritage Wheat Conservancy website (http://www.growseed.org/growingpower.html), accessed December 1, 2010.

Royte, Elizabeth. “Street Farmer.” New York Times, September 5, 2009 (http://www.nytimes.com/2009/07/05/magazine/05allen-t.html), accessed December 2, 2010.