aquaponics

169 Pages·2017·1.94 MB·English

by  Hadi Harb

AQUAPONICS – A PROCESS CONTROL APPROACH

A Dissertation
Presented to
The Engineering Institute of Technology

by

Noel Scattini

In Partial Fulfillment
of the Requirements for the Degree
Master of Engineering in
INDUSTRIAL AUTOMATION

SEPTEMBER 2017

COPYRIGHT © 2017 BY NOEL SCATTINI

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TABLE OF CONTENTS
List of Figures ................................................................................................................ 5
List of Tables ................................................................................................................. 7
Chapter 1. Abstract ........................................................................................................ 8
Chapter 2. Motivation .................................................................................................. 10
Chapter 3. Literature Review ....................................................................................... 14
3.1 Process Ranges................................................................................................ 21
3.1.1 Plants ........................................................................................................ 19
3.1.2 Bacteria .................................................................................................... 22
3.1.3 Dissolved Oxygen .................................................................................... 25
3.1.4 pH ............................................................................................................. 27
3.1.5 Control pH ............................................................................................... 28
3.1.6 Sodium Control ........................................................................................ 29
3.2 Design Components ........................................................................................ 30
3.2.1 Baffles – Solids Separation ...................................................................... 31
3.2.2 Swirl – Solids Separation ......................................................................... 32
3.2.3 Mineralisation .......................................................................................... 34
3.2.4 Nitrification .............................................................................................. 35
3.3 Nutrient Removal ............................................................................................ 39
3.3.1 Reverse Osmosis ...................................................................................... 41
3.3.2 Electro dialysis ......................................................................................... 42
3.3.3 Selective Electro Dialysis ........................................................................ 42
3.4 Systems Selection Discussion ......................................................................... 43
3.4.1 Recycling Nutrients ................................................................................. 43
3.4.2 Nutrient Redistribution ............................................................................ 46
3.5 Typical Process Ranges .................................................................................. 49
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3.6 Additional Component Research .................................................................... 50
3.7 Discussion ....................................................................................................... 53
Chapter 4. Proposed Control Solutions Using Standard Design Methods .................. 54
4.1 Component Selection ...................................................................................... 55
4.2 Design ............................................................................................................. 57
4.2.1 Process Flow Diagram ............................................................................. 57
4.2.2 Failure Mode Effect Analysis (FMEA) ................................................... 58
4.2.3 Failure Mode and Effect Analysis in Aquaponics ................................... 59
4.2.4 Failure Mode and Effect Analysis on an Aquaponics Process ................ 62
4.2.5 Failure Mode and Effect Analysis Automation and Aeration Control
Strategies .................................................................................................. 64
4.2.6 Failure Mode and Effect Analysis Instrumentation Adaptation .............. 66
4.2.7 Failure Mode and Effect Analysis Discussion ......................................... 68
4.2.8 Piping and Instrumentation Diagrams ..................................................... 69
4.3 HMI Screenshots ............................................................................................. 71
4.3.1 Tank Area ................................................................................................. 71
4.3.2 Mineralization .......................................................................................... 74
4.3.3 Nitrification .............................................................................................. 76
4.3.4 Degassing ................................................................................................. 77
4.3.5 Aquaponics .............................................................................................. 78
4.3.6 Hydroponic .............................................................................................. 79
Chapter 5. Results and Discussions ............................................................................. 82
5.1 Discussions of Design ..................................................................................... 82
5.1.1 Aquaponics Automation by Decoupling Requirements........................... 82
5.1.2 Aquaponics Subsystems ........................................................................... 83
5.1.3 Viability of Process Control Automation in Aquaponics ........................ 84
5.1.4 Process Control Equipment used for Optimization.................................. 85
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5.2 Results for Process Control ............................................................................. 86
5.2.1 Process Configuration .............................................................................. 87
5.2.2 Results of Integrating Process Control Functions .................................... 88
5.2.3 Software Data Analysis ............................................................................ 89
5.2.4 Hardware Data Analysis .......................................................................... 91
5.3 Discussion and Future Work ........................................................................... 92
Chapter 6. Conclusion .................................................................................................. 94
Chapter 7. References .................................................................................................. 97
Chapter 8. Appendix .................................................................................................. 114
8.1 Instrumentation and Alarm List .................................................................... 114

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LIST OF FIGURES
Figure 1 Productive Nitrification Levels ..................................................................... 19
Figure 2 Plant Nutrient Availability ............................................................................ 20
Figure 3 5.5pH to 6.2pH nutrient availability in hydroponic solutions ....................... 22
Figure 4 Nitrogen Cycle Time ..................................................................................... 24
Figure 5 UVI Filter ...................................................................................................... 32
Figure 6 Radial Flow Settling Filter ............................................................................ 34
Figure 7 Increased Surface Area with Plastic Bio-filtering ......................................... 36
Figure 8 Bio Disc Filtering .......................................................................................... 37
Figure 9 Simplified Moving Bed Bioreactors .............................................................. 38
Figure 10 Estimated Additional Nutrients ................................................................... 48
Figure 11 Requirements Overview .............................................................................. 49
Figure 12 Tequatic Filter 100 – 10,000 mg/lt solids .................................................... 52
Figure 13 Skid Mounted Equipment ............................................................................ 52
Figure 14 System Selection ......................................................................................... 55
Figure 15 Process Flow Diagram ................................................................................. 58
Figure 16 Fail Safe Design .......................................................................................... 65
Figure 17 P&ID Sheet 1 ............................................................................................... 70
Figure 18 P&ID Sheet 2 ............................................................................................... 70
Figure 19 Tank HMI Layout ........................................................................................ 71
Figure 20 Typical Ladder Diagram for Tank ............................................................... 72
Figure 21 Main Alarm Indication ................................................................................ 75
Figure 22 Mineralisation Functioning Screenshot ....................................................... 74
Figure 23 Mineralisation Ladder Logic ....................................................................... 75
Figure 24 Nitrification Monitoring .............................................................................. 76
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Figure 25 Nitrification Ladder ..................................................................................... 76
Figure 26 Degassing Monitoring ................................................................................. 77
Figure 27 Aquaponics Monitoring ............................................................................... 78
Figure 28 Aquaponics Nutrient Monitoring and Control ............................................ 79
Figure 29 Hydroponics Nutrient Monitoring and Control ........................................... 79
Figure 30 Hydroponics Pump Sequencer Control ....................................................... 80
Figure 31 Hydroponics Nutrient Measurement & Control .......................................... 80

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LIST OF TABLES
Table 1 Failure Mode Effect Analysis Responses ....................................................... 62
Table 2 Software Functions ......................................................................................... 89
Table 3 Hardware Devices ......................................................................................... 911

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CHAPTER 1. ABSTRACT
Hydroponics technology is a method for growing plants and vegetables of a
commercial value without soil. The plants are either floated or treated with a nutrient
water film, to supply the optimum nutritional requirement for specific plants or
fruiting vegetables. As a closed system, hydroponics results in very insignificant
water loss to the environment. This technology is becoming more popular with
communities and governments as the preservation of water becomes more of an issue.
This is especially important in regions where water is a scarce and hence an expensive
commodity. Hydroponic systems may be located within industrial complexes near to
the point of consumption.
Aquaculture is the science of raising aquatic animals such as fish, prawns etc.
Aquaponics is technology developed from the aquaculture industry that integrates
intensive farming of fish and utilizes plants (integrates hydroponics) in a continuous
closed loop to clean the water for the fish. For aquaponics to work there must be a
symbiotic, closed loop relationship between both subsystems. There are some natural
symbiotic features, for example, fish produce ammonia, which is converted by
bacteria into nitrates. Nitrates are toxic to fish above certain levels; however, nitrates
represent a nutritional requirement of plants thereby reducing nitrate levels in the
shared medium i.e. a symbiotic relationship.
However, aquaponics is a complex system of interacting parameters some of
which are mutually incompatible. For example, the pH range best suited to bacteria
activity differs significantly from that required by plants such as fruiting vegetables.
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In effect whilst there are natural symbiotic relationships in aquaponics, there are also
systems that are antibiotic.
The ideal parameters have been identified for each subsystem and the
challenge has been to optimally control these parameters and address the problems of
antibiotic subsystems. Supplying optimal parameters could increase the number of
viable commercial crop varieties including fruiting vegetables in an aquaponics
system. In order to achieve these goals process control systems have been
investigated. A control solution was developed using standard design methods such as
Process Flow Diagrams (PFDs), Failure Mode Analysis and Piping & Instrumentation
Diagrams (P&IDs) which resulted in instrumentation tag and alarm lists. Work to date
indicates this is the first process control automated approach to aquaponics.
The use of process control and the automation that it incorporates is able to
measure and maintain multiple control loops, having multiple control loops that are
not dependent on others would remove some of the identified limitations by dividing
the process to meet those ranges that have been researched as optimum at particular
stages.

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CHAPTER 2. MOTIVATION
Research carried out by Dr. James Rakocy (Rakocy, 2013) looks at sizing or
controlling the process by the amount of fish feed that is introduced into the system in
comparison to the amount of growing area to control the process by limiting the
amount of nutrients in the system.
Additional Research by Dr. James Rakocy (Rakocy, 2013) has looked at the
nutrients required within the aquaponics system that includes additional items that are
required and quantities to supplement plant nutrient processes to maintain conditions.
These conditions include the addition of essential nutrients for plants that are missing
such as (Rakocy, 2013)calcium, iron, and potassium into aquaponics systems.
This research is relevant when sizing components in the process so it can be
designed to established and trialled parameters from research Rakocy and Lennard
(Wilson Lennard, Aquaponic System Design Parameters) have documented with
expected measurable results. However, some of this data does not take into account
that automation techniques could also be utilised to keep the process within
established parameters, which should provide similar or improved results as with
trialled process ranges. The addition of automation and its associated instrumentation
could introduce better control over some of the inputs, which can control the ranges of
the process, which ultimately controls the outputs of the system. This thesis will look
at some of the known data or techniques along with the adaptation of technologies to
illustrate some of the ways that automation could benefit the processes by monitoring
and controlling the process to assist in optimisation.
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