UWE Bristol Engineering showcase 2015

Zac Eddie
BEng Mechanical Engineering
Project Supervisor
Dr. Rohitha Weerasinghe
Urban Farming: An Aquaponic Solution for Food Production
The Problem
In the 40 years between 1959 and 1999 the world population increased from
3 billion to 6 billion people. By the year 2050 it is estimated that this
population will have grown to almost 9 billion and although the annual
growth is slowing down long-range predictions show that the world
population may continue to balloon to 36 billion by 2300. Alongside this
continued growth, the percentage of people living in urban areas has also
been steadily increasing and by 2030 the United Nations forecast that of the
8 billion people living on the planet over 5 billion will be living in urban
centres. To facilitate this growth world food production needs to increase
between 70-100% between now and 2050 despite the available arable land
on the planet slowly running out.
Project summary
With the world population steadily increasing and
available arable land decreasing, this project was
centered around finding a viable solution to urban
farming. Moving agriculture to city hubs could greatly
reduce carbon emissions through eliminating food
miles and make use of currently wasted space.
Project Objectives
• Review current research into urban farming
• Design an aquaponic system that is:
• Modular
• Carbon Neutral
• Self-sustaining
Figure 7 – Side View
Uses
As a single module the system could be placed in the garden, it was designed
to only fill 50% of the average UK garden space. In this configuration it would
sustain 62.5kf of mature trout and 1200 heads of lettuce although any
species of vegetable or fruit could be grown. When connected together the
system could provide for entire apartment blocks in city centers or provide
local produce to local businesses. The system could also be employed in
developing countries to offer a reliable and simple to use food source. Each
system contains removable panels that allow the connection of three other
fish tanks to the main tank which allows the system to grow infinitely big
when the space available allows.
The Solution
An aquaponic system is one in which a symbiotic between plants and fish is
used to produce edible plants and fish. The waste products from the fish is
broken down by bacteria in the water to the nutrients required by the plants.
The plants are grown in a soilless grow bed medium and absorb the nutrients
provided by the fish which would otherwise be harmful to fish. The fish
provide nutrients for the plants, and the plants filter the system for the fish.
This method of agriculture uses over 90% less water than traditional farming
practices at the system is sealed. Once water is in the system it never needs
to be replace apart from losses due to evaporation. The system designed in
this project relies on gravity to draw water from the fish tank into the grow
beds and from the grow beds into the secondary fish tanks. The only moving
parts are four pumps to move the water back into the main tank,. These are
powered by 6 solar panels that provide enough energy in 5 hours of sunlight
to power the pumps continuously.
Project Conclusion
A system was designed that powered entirely by solar
power and is capable of sustaining 62.5kg of mature
trout and 1200 heads of lettuce. As a single module
this system could fit in the average UK garden and
when joined together could be used to fill any space.
It was also found that the system could be used in
developing countries where access to fresh water is
limited.