2. Methods

2.1 Equipment

We require the following materials for the construction of the automated Aquaponics system:

Sensors

Ammonia sensor x1

Nitrate sensor x1
Dissolved Oxygen sensor x1
pH sensor x1
Salinity levels x1
Temperature sensor x1
Chloride sensor x1
Calcium chloride sensor (hardness of water) x1
Data loggers x3

Breeding system

Food timer x1
Abalone fish food x1
Fish tank x1 (0.5m x 0.35m x 0.8m)
Water pump x1
Air pump x1
Air tubes x2
Bacteria life solution x1
Abalone x7


Hydroponics

Hydroponics tray x1 
Board x1
Net pots x8
Peppermint seedlings x9
Filter system

1.25 litre plastic bottle x1
Small pebbles x7
Filtering medium x1
Bio-filtration filter x1
Automation
Arduino UNO x1
Relay system x1
Chiller (Fan) x1
Light bulbs (red- 6 and below, green- 7 (neutral),  blue- 8 and above x3
Battery x2
Wires x8
Rainbow cable x1
Soldering iron x1
Soldering wire x1
Equipment for safety precautions

Safety goggles (pairs) x4
Woollen gloves (pairs) x4
Bin for disposal of sharp objects x1
Lab coats x4


2.2 Diagram





Figure 2.2.1 - Water pump

Fig 2.2.2 - Sketchup model of the tank


2.3 Procedures

Fish tank

  1. Pour tap water into the fish tank and fill in 3/4 full.
  2. Submerge the water pump into the fish tank.
  3. Connect the water pump with the connectors using a water hose.
  4. Connect the connectors to the 1.25 litre bottle using a water hose.
  5. Switch on the water pump.
  6. Connect the oxygen pump to the fish tank using air pipes.
  7. Switch on the oxygen pump and turn the air pressure to high.



Hydroponics 

  1. Measure the diameter of each net pot (7.5cm), and cut 10 holes from the foam board accordingly.
  2. Put the 9 net pots into the holes that were cut out in the foam board and leave one empty.
  3. Place the foam board with the pots on top of a container.
  4. Drill a hole at a height of 7cm from the bottom of the container. (overflow method)
  5. Pour water into the container until it is 3/4 full.
  6. Tape a piece of string below the hole to guide the water into the fish tank.
  7. Wash away the soil from the peppermint seedlings’ roots.
  8. Put the peppermint into the net pots.
  9. Fill up the net pots that have the peppermint with Leca beads to support it. 

Breeding system

  1. Put 7 abalone into the fish tank.
  2. Feed the abalone with the fish food. (feeding times to be advised)
Filter system
  1. Cut the bottom of a 1.25 litre bottle.
  2. Turn the bottle upside down.
  3. Poke two holes through the cap and cap the bottle.
  4. Pour the bacteria cultivating balls into the bottle.
  5. Pour pebbles on top of the bacteria cultivating balls.
  6. Place a filter medium on top of the pebbles.
  7. Poke a hole at the height of 14 cm from the bottom of the cap. (overflow method)
  8. Place the filter bottle above the empty hole in the foam board.
  9. Connect a water hose to the hole for the water to flow out into the tank.

Sensor system
  1. Place the chloride sensor into 1/2 of the depth of water to check the chlorine level. 
  2. Turn on a data logger.
  3. Connect the chloride sensor to the data logger and observe the chlorine levels of the tap water in the fish tank over a few days. Fishes cannot survive in waters of high chlorine levels, therefore the water should have a chlorine level as low as possible before we put in the fishes.
  4. Put the nitrate and ammonia sensors into 1/2 of the depth of water in the fish tank.
  5. Connect the sensors to the data logger.
  6. We will not feed the fish for two days and observe for any changes in the ammonia level and nitrate level. 

For Ammonia, Nitrate, Calcium chloride, pH sensors
  1. Recalibrate the sensors. 
  2. Insert the tip of the sensor into the water.
  3. Connect the sensors to the data loggers for data collection. 
For Temperature Probe (does not require calibration)
  1. Insert the tip of the sensor into the water. 
For Dissolved Oxygen Sensor
  1. Remove the membrane cap from the tip of the probe. 
  2. Using the pipet, pour 1 ml of the DO Electrode Filling Solution into the membrane cap. 
  3. Carefully screw the cap back into the electrode. 
  4. It is necessary to warm up the probe for 10 minutes before taking readings. To warm up the probe, leave it in the water and connect it to the data logger, and leave it running for 10 minutes.

For Calcium sensors

1. Wash the tip of the sensor thoroughly with tap water/deionised water.
2. Dry the sensor with a paper towel.
3. Connect the sensor to the data logger.
4. Switch to the calibration mode.  
5. Dip the sensor into the 1000 mg/L chloride/calcium solution.
6. Make sure that the ISE is not resting on the bottom of the container containing the solution.
7. Wait for 30 secs for the live voltage to stabilise.
8. Take out the sensor.
9. Wash the tip of the sensor with tap water/deionised water.
10. Wipe it dry with a paper towel. 
11. Enter the calibration route on the data logger. 
12. Dip the tip of the sensor into the 10 mg/L chloride/calcium solution.
13. Make sure that the ISE is not resting on the bottom of the container containing the solution.
14. Wait for 30 secs for the voltage to stabilise. 
15. Take out the sensor.
16. Wash the tip of the sensor with tap water/deionised water.
17. Wipe it dry with a paper towel. 

For Ammonium and Nitrate sensors

1. Wash the tip of the sensor thoroughly with tap water/deionised water.
2. Dry the sensor with a paper towel.
3. Connect the sensor to the data logger.
4. Enter the calibration route on the data logger.  
5. Dip the sensor into the 100 mg/L ammonium/nitrate solution.
6. Make sure that the ISE is not resting on the bottom of the container containing the solution.
7. Wait for 30 secs for the live voltage to stabilise.
8. Take out the sensor.
9. Wash the tip of the sensor with tap water/deionised water.
10. Wipe it dry with a paper towel. 
11. Switch it to the calibration mode again. 
12. Dip the tip of the sensor into the 1 mg/L ammonium/nitrate solution.
13. Make sure that the ISE is not resting on the bottom of the container containing the solution.
14. Wait for 30 secs for the voltage to stabilise. 
15. Take out the sensor.
16. Wash the tip of the sensor with tap water/deionised water.
17. Wipe it dry with a paper towel.           
    
For pH sensor

1. Wash the tip of the sensor thoroughly with tap water/deionised water.
2. Dry the sensor with a paper towel.
3. Connect the sensor to the data logger.
4. Enter the calibration route on the data logger.  
5. Dip the sensor into the pH 4 solution.
6. Make sure that the ISE is not resting on the bottom of the container containing the solution.
7. Wait for 30 secs for the live voltage to stabilise.
8. Take out the sensor.
9. Wash the tip of the sensor with tap water/deionised water.
10. Wipe it dry with a paper towel. 
11. Switch it to the calibration mode again. 
12. Dip the tip of the sensor into the pH 7 solution
13. Make sure that the ISE is not resting on the bottom of the container containing the solution.
14. Wait for 30 secs for the voltage to stabilise. 
15. Take out the sensor.
16. Wash the tip of the sensor with tap water/deionised water.
17. Wipe it dry with a paper towel. 

Arduino automation

1.  Launch the ‘Arduino’ application (you can search spotlight)
2.  Use the Arduino Leonardo and connect it to your Macbook
3.  Once you have connected, you would be able to program the Arduino Leonardo (using the codes etc)
4. You then connect the system such that it will create a circuit between the battery, relay system and chiller.
5. From the battery, connect 3 wires. 
6. At the end of each wire, connect one bulb. (red, blue and green)
7. Once you have set up the system, you need to put the pH sensors and temperature sensors halfway through the waters. 
8. Connect the sensors to the Arduino too! 
9. As you can see it is all linked together; the temperature sensor will activate the relay system and in turn, the relay system will activate the chiller; which would be able to turn the temperature down. 
10. For the pH sensor, it will be connected to the Arduino which will be connected with the battery and the battery is connected the the 3 bulbs so if it is neutral (7), green bulb will blink, if it has a pH level of more than 8, it will blink blue and if it has a pH level of less than 7 then it will turn red.
11. This way, we would be able to change the necessary variables accordingly. 

Approximate Calibration Voltages 
  1. Ammonia sensor has a 2.1 voltage for high solution (100 mg/L) and 1.3 voltage for the low solution (1 mg/L)
  2. Calcium sensor has a voltage of 1.9 voltage for high solution (1000 mg/L) and 1.5 voltage for low solution (10 mg/L) 
  3. Chloride sensor has a voltage of 2.0 for high solution (1000 mg/L) and 2.8 voltage for low solution (10 mg/L)
  4. Nitrate sensor has a voltage of 1.6 for high solution (100 mg/L) and 2.4 voltage for low solution (1 mg/L)
2.4 Risk Assessment and Management

List/identify the hazardous chemicals, activities, or devices that will be used.
We will be using the Arduino Leonardo device that will be connected to our Macbooks and then that will be connected to the aquaponics system that connects the relay, chiller and the bulbs together. In the process, we might experience a short-circuit, resulting in us getting electrocuted. 



Other that that, we would be using the temperature sensors, calcium sensors, ammonium nitrate sensors etc. Through this process, we need to work with chemicals (calcium solution, ammonia nitrate solution- high and low), thus, we might get burnt or harmed.



Lastly, the last hazard would be the glass tank as it is fragile and brittle, thus it can break anytime. As we will be using the tank regularly, if it happens to break at our hands, we will get scarred and possibly cut ourselves (hands etc)



Identify and assess the risks involved



Figure 2.4.1

Source: (Workplace Safety Health Council, 2012)


Figure 2.4.2
Source: (Workplace Safety Health Council, 2012)


Figure 2.4.3
Source: (Workplace Safety Health Council, 2012)


Risks involved

Risk #1: Short circuit can cause electrocution.

Risk #2: The glass tank could break and cause injuries.

Risk #3: If the tank is too heavy it could cause the support to break and destroy the system.

Risk #4: If water spills it can cause people to slip .
Risk #5: Chemicals are used in the sensors and if spilled, it might cause serious consequences.

Risk #6: Error with the Arduino Leonardo could cause error in the systems and cause sparks and maybe fires. 

Risk #7: Usage of Macbook near bay could cause it to short circuit and due to it being so close to user, it can injure him/her.


Figure 2.4.4


Describe the safety precautions and procedures that will be used to reduce the risks.

Risk #1 : Make sure to use insulated tools and rubber gloves when working with the electrical systems.

Risk #2 :  Be cautious when working near the tank and maybe use a plastic tank instead. 

Risk #3: Use stronger or more supports in order to support the weight.

Risk #4: Make sure to clean up water when it spills or wear sandals to avoid slipping.  

Risk #5: Exercise caution when using the sensors and wear a labcoat and gloves in order to avoid getting the solutions/chemicals into your hands.

Risk #6: Program the Arduino Leonardo and connect the relay system and chiller with it so as to avoid fires that may outbreak. 

Risk #7: Place your Macbook further away from the bay to prevent electrocution.


Describe the disposal procedures that will be used (when applicable).

- Chemicals
1. While handling with chemicals, put on safety goggles and gloves to prevent getting the chemical into contact with your bare skin or eyes.
2. After using the chemicals, dispose the chemicals into the sink and wash your hands. 3. If any spillage occurs, do inform the teacher immediately. If the spillage is minor, clean the area up immediately.

- Dead abalone/plants
  1. Take a fishing net and fish out the deceased fish.
  2. Dispose of it by a few different ways:
  • Flush it down the toilet.
  • Seal it in a plastic bag and throw it into a garbage bin.

List the source(s) of safety information.

Hauter,  S. & Hauter, D. (n.d.) How to Dispose of Deceased Fish. Retrived 11 July, 2014, from http://saltaquarium.about.com/od/fisheuthanasia/a/aadeceasedfish.htm
Princeton University (2014) Chemical Spill Procedures. Retrived 10 July, 2014, from http://web.princeton.edu/sites/ehs/emergency/spills.htm
Sharpe, S. (n.d.) Are Aquariums Safe? - Aquarium Safety. Retrived 10 July, 2014, from http://freshaquarium.about.com/od/beginnerfaqs/a/aquariumsafety.htm
Wikihow (n.d.) How to prevent electrical shocks. Retrived 10 July, 2014, from http://www.wikihow.com/Prevent-Electrical-Shock


2.5 Data Analysis

1. Using the sensors, we will record down the water parameters of the water in the fish tank. We will dip all the sensors into the water in the fish tank and then connect them to the dataloggers. The dataloggers will be record down the data of different water parameters over a period of time and then, we will export the data into the Logger Pro 3 application into our learning devices. After that, we will analyse the data and the graphs. Over time, we will find that our ammonia level has decreased and our nitrate levels has increased, which shows a sign of the experiment working well. 

Temperature sensors: 

Powered by Arduino which powers the relay and chiller. From the relay system, we will be able to tell whether the temperature needs cooling or not (since fish lives in a cold environment). We would then lower the temperature if necessary. (until these two sensors are stabilised, we will then use Arduino to automate the rest of the sensors; Ammonium Nitrate etc) 2. Measure the length of the fishes, height of the plants and number of leaves at the start of the experiment. Every Monday, Wednesday and Friday, we will do the same measurements and plot graphs using the data collected. Two separate graphs for fishes and the plants. Graph 1, Y axis will be the length of fishes (cm) and X axis will be the number of days. Graph 2, height of the plants (cm) and number of leaves, while X axis will be the number of days. Looking at the growth and rates of the fishes and plants, and that they survive, then we can determine if the experiment is working well. 3. We also can use video clips to explain our system and to show how it works. (show how the automation of the system will be able to instil convenience and effectiveness at the same time) We can also plot a graph to show the height of water level in the hydroponics tray against the time, with Y axis for the height (cm) and X axis for the time (minutes).

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