1. Introduction

1.1 Engineering Problem 

As the world population is increasing daily, (Just in Singapore, it has hit up to a population 
of 6.9 million!), more space is used for residential areas, factories or even for recreation! (i.e. shopping malls etc). Agriculture and aquaculture take up a lot of space and its quality is dropping even more. Just like the oil palm cultivation in Malaysia, they have poor farming practices, such as monoculture where one single crop is planted over again and again. This reduces soil fertility and causes soil leaching and severe soil erosion. Agriculture and aquaculture is thus becoming more expensive as the product requires heavy transport and preservation in order to deliver them into the urban areas where the consumers are. Agriculture has shaped society and without it, we would not have food to survive. Thus, this project aims to solve this problem on a smaller scale. 

1.2 Engineering Goal 

Development of an automated aquaponics system for the production of abalone, as well as the production of mint. Mint has many uses and it could benefit the people, it includes reducing the symptoms related to digestion, clear sinuses, fight infection, act as an insect repellent, quick and effective remedy to nausea, clears up congestion of nose, throat or lungs and many more. Other than that, the automation of the system will give us the convenience as it will monitor the temperature and pH levels; in this way, we are able to change the following factors according, saving time and benefitting the abalone’ growth. 

1.3 Specific Requirements 

Our engineering requirements include the following: 
1. In modern world context (so that not only urban residents will be able to utilise it, but also the people living in the city etc) 
2. Automated system (able to tell temperature of the water) 
3. Easy to maintain the temperature of the water at 24.8 degrees Celcius. 


1.4 Alternative solutions 


1.4.1 Aquaponics 
Aquaponics is a sustainable food production system that consists of conventional aquaculture of breeding aquatic animals and hydroponics, which is a water-based method of cultivating plants. Effluents which are gases and slightly polluted water from the waste of the aquatic animals will accumulate in the water, and increase the toxicity level for the fish. As such, these by-products will be broken down by nitrogen-fixing bacteria, then filtered out by the hydroponics plants. Finally, the clean water will then be recirculated back to the fish and this cycle will repeat itself (Rakocy, Bailey, Shultz & Thoman, 2013). The advantage is that this system produces protein (fish) and vegetables in one system and it produces 4 to 10 times more vegetables than the conventional urban agriculture. Other than that, it is uses up to 90% less than conventional agriculture and furthermore, as water is constantly being recirculated back to the fish, water usage is minimal and reuse of water is highly efficient. They are also naturally organic, with no chemicals (Jed Davis, Lucas Davis, David Buckley & Ruth, 2014). 

Unfortunately, a major disadvantage would be that it is usually expensive to set up, inclusive of the cost wirings, housing, tank plumbing and budget for the fish and plants. 

Tubes and water supply needs constant monitoring to see if they are still functioning properly (Leah Moore, 2012). Water pH level will also have to be monitored closely, as one faulty component can cause the whole system to break down easily. It is also not advised to grow root crops. Leafy vegetables are advised instead. The water needs to be free of toxins such as ammonia and nitrates and have sufficient oxygen levels for aquatic organisms to survive (McCarthy, 2013).


Fig 1.4.1.1


1.4.2 Hydroponics 
Hydroponics is a method of crop cultivation which uses the method of soilless growth of plants. The nutrients that are normally found in soil are dissolved into water, creating nutrient solutions. Roots are usually submerged or suspended to be able to absorb the nutrients found in the solution. Since arable land is on the decline, hydroponics is seen as a solution where plants can be cultivated using water which is abundant, hence it is versatile (Turner, 2008). Hydroponics has several advantages. It has almost no pollution as most of the nutrients are all absorbed by the plants. Soil is not required for hydroponics and there is no need for huge farming as it allows the crops to be produced in greenhouses, even in the desert sands. It is a stable technology for growth of plants and ensures high yields. Other than that, desired nutrient environment can be easily provided for plant growth and since water stays in the system, reusing of water is efficient. Lastly, there is no chemicals involved (Sharmila Saheed, 2013). However, everything has its advantages and disadvantages. It has a high set-up cost as it requires meticulous planning when designing and constructing (Hydroponics Center, 2011). Hydroponic conditions, especially the presence of high humidity, would create a hot bed for salmonella growth (Department of Agriculture, Forestry and Fisheries, 2011). Salmonella can then be transmitted through human consumption and cause food poisoning. Since hydroponics are soilless, diseases are able to spread quicker as they are not contained (Black, 2009).


Fig 1.4.2.1


1.4.3 Aeroponics 
Aeroponics is a method where plants are grown in a humid environment without the use of any growing medium, making it suitable for indoor gardening or greenhouses. (True AeroponicsTM, 2013) It stimulates rapid plant growth as the plants will rapidly develop root 
systems (D’Gardener, 2008). The plants are suspended in a growing chamber. A pulsed sprayer will release a fine, high pressure mist which consists a mixture of water, nutrients and growth hormones into the enclosed environment of the growing chamber at a time interval and duration for the plants (True AeroponicsTM, 2013). Aeroponics, when compared to the traditional method allow plants to grow faster, as the roots are exposed to more oxygen, and thus obtain higher yields from the plants. It has been proven that it can aid growers to optimize rooting on most plants. Aeroponics is beneficial to the environment in a sense that the water used in aeroponics can be reused. The water loss of an aeroponics system is cut by 99% when compared to the traditional farming methods. When compared to hydroponics, aeroponics offers more control over the root system as the roots aren’t immersed in any liquid (True AeroponicsTM, 2013). If needed, the aeroponics system can be moved around easily. A main drawback of the aeroponics system is that the root chamber, the one containing the dangling roots, attract lots of bacterial growth due to its semi-moist environment, so it has to be cleaned regularly. The entire system depends on the pumps, sprinklers and timers, so if any one of these break down and are not fixed in time, the plants can wither and maybe even die. One must also be proficient in knowledge about plants, such as nutrition amount as there would be no soil to soak up excess nutrition (D’Gardener, 2008). All these may make the system a meticulous one that requires time and effort.


Fig 1.4.3.1


1.4.4 Final Solution 
Our best solution would be to incorporate modified passive aquaponics into an automated aquaponics system. By having an automated aquaponics system, one can save time measuring the variables and allowing the system to thrive and having a high productivity rate. One would also be able to ensure the health of the plants and the abalone easily, producing high yield and benefitting them. Aquaponics create harvests of good quality and nutritional value, essential for healthy consumption. Since water from aquaponics system can be collected and recycled, there would be less runoff and lesser chances of water bodies being polluted. They also help to improve air quality, replacing carbon dioxide with oxygen and acting as a natural filter, providing cleaner air (Fitzgerald, 2011). Harvesting would reduce strain as one would not be needed to dig or tile the land, making harvesting a more efficient and easy job with no expensive equipment (Bardot, 2012). This would also mean less fossil fuel used and less carbon emissions.Aquaponics uses only a fraction of the water used in conventional farming and can use even less if you collect rain water to add to your system. Aquaponic farmers are not dependent on huge amounts of water as are conventional in-ground farmers and it does not have the same environmental impact of tremendous water consumption and waste. Aquaponics also can grow more produce compared to produce grown conventionally in the ground. Vegetables usually grow significantly faster, and at three to four times the density, without ever depleting the nutrients. Its soil counterpart depletes nutrients with every planting and farmers struggle to replace them with synthetic fertilizers. This way of growing food means the aquaponics farm does not require farmland with fertile soil, or even land with soil at for that matter. Hence, having an automated Aquaponics system is chosen as the best solution. Its advantages make it a feasible concept due to its versatility and productivity.

Fig 1.4.4.1

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