Issue 103: Sustainable Aquaponics

November/December – 2008
Author: Dr Brett R. Roe and Prof David J. Midmore

Is aquaponics technology a viable option for potential investors? In this critical assessment the authors highlight issues constraining the development of a sustainable commercial aquaponics industry. They also report on their investigation of linking vermiculture with aquaponics.

By Dr Brett R. Roe and Prof David J. Midmore

First vermiponic NFT trial growing Pak Choi (Brassica rapa, var chinensis).

There are valid arguments as to why aquaponics may be an ecologically-minded and economically viable option for potential investors. However, at this time, the vast majority of aquaponic systems are simply not sustainable. Furthermore, there are other issues that must be considered by anyone contemplating aquaponics, such as the current climate of the Australian industry, hurdles regarding organic certification, and the lack of data that could be used to accurately model aquaponic systems. We propose that the foremost issue regarding the future of the aquaponic industry is the necessity for the continued development of sustainable aquaculture (fish) feeds. Finally, we suggest for those contemplating aquaponics, that they first consider what consultation services, system design, management tools, operating methods and economic structure best suit their needs, skills and budgets.

The Integrated Waste Reclamation and Animal-Plant Production Systems project is undertaking an investigation of vermiponic and vaquaponic methods that aim to generate vermiculture liquor and castings, chemical-free hydroponic plant produce, and live earthworms from abattoir paunch and aquaculture waste via the use of food web conversions and physical linkages. Both vermiponics and vaquaponics represent theoretical and technical progress toward sustainable primary production, which if practised widely, could impart substantial decentralised effects upon waste management, chemical-free food production, soil development and other associated aspects of resource management, environmental stewardship, economics and community health.

Replicated vermiculture conversion pits.

Mr. William ‘Brock’ McDonald, CQ University Vermiponic/Vaquaponic Technician, quantification of earthworms.

Beef cattle paunch waste.

Close up of beef cattle paunch waste.

Ms. Elena Tchurilova, CQUniversity Hydroponic Researcher and M.Sc. degree candidate.

NFT Pak Choi (Brassica rapa, var chinensis).

Aquaponics

There are several arguments as to why aquaponics may be an ecologically minded and economically viable option for potential investors (especially for backyard, hobby or micro-commercial scale systems). These include, but are not limited to, increased efficiency of water usage and treatment, the potential for branding diversified products as organic (or chemical-free), and supply of niche markets. There are a host of aquaponic publications and other sources of information, in most instances generated by a relatively limited number of experts, that discuss the positive aspects of aquaponics in-depth and therefore this article will not further reiterate those viewpoints.

The reality is that the vast majority of aquaponic and aquaculture systems are, at this point in time, simply not sustainable. This is due to the fact that these systems utilise commercially available aquaculture feed (fish meal pellets – fish oil supplements), of which many are partially or mostly composed of fish harvested from wild habitats in volumes and at rates that outstrip the capacity for population recovery.

Of course, aquaponic practitioners cannot be faulted for using such feeds for obvious reasons: the product is affordable, widely available and is readily consumed by fish; the product is high quality in terms of composition and shelf life; there is consistency and ease of application; and most importantly (from the perspective of aquaponics), the composition of the resulting fish metabolic wastes require minimal (if any) fortification and/or enrichment of macro and micronutrients to grow a broad range of plant species.

We suggest that the foremost issue concerning the future of both the aquaponic and aquaculture industries is the necessity of the continued development of sustainable aquaculture (fish) feeds. Leaders of, and experts within, these industries must increase investment in the development of sustainable feeds in order to avoid further damage to natural fisheries and the hastening of the decline of aquaculture-based industries on a global scale.

Commendable efforts by a number of companies, research groups and individuals around the world are underway to further develop aquaculture feeds that are composed of renewable plant and insect ingredients or developed from organic waste sources and/or that are more assailable (e.g. less metabolic nutrient waste by-product). The latter of which may occur to the detriment of aquaponics as the technology, as practised in many configurations, is dependent upon fish metabolic by-products to support plant growth.

In addition to unsustainable aspects of aquaculture feeds, there are other issues that must be considered by anyone contemplating aquaponics as an enterprise, which include but are not limited to the points listed below:

Methodology: A widely accepted aquaponic method requires that aquaculture and hydroponic systems are to be hydrologically linked via in-line recirculation in real-time, and managed primarily for plant production because the plants represent the product from which the bulk of revenue can be generated (Lennard, 2007). The goal of the method is to closely match fish metabolic outputs (the only source of plant nutrients utilised other than carbon) to the plant nutrient requirements, resulting in a near-zero nutrient waste stream; a worthy goal indeed. Therefore, aquaculture enterprises opting to move into aquaponics following that method must prepare for a shift in market focus away from selling fish as the primary product to selling plant produce as the primary product.

Competition with the many dedicated commercial aquaculture and hydroponic producers aside, that method (as far as we are aware) has yet to be successful at any substantial commercial size (e.g. product sales ≥ $200,000 per year) over periods of time that lend stability to the business within the marketplace (e.g. ≥ 5 years). However, it is certainly possible (as some reports suggest) that aquaponic systems are achieving levels of commercial success following the widely accepted method. We urge owners of those systems to allow accurate and detailed documentation of the inner workings of those systems for the benefit of the industry as a whole.

Furthermore, hydroponic linkages to aquaculture businesses that do not aspire to the widely accepted method, but focus on aquaculture as the primary enterprise without focusing on near-zero nutrient waste streams, have been operating successfully at commercial capacities for some time.

Fish as Bio-converters: Rarely is the decision to integrate fish culture into commercial hydroponic systems based on the desire to expand product range. This is particularly true when considering the widely accepted aquaponic method described previously. The fact is that fish within aquaponic systems are primarily viewed as bio-converters used to process fish feed into soluble plant nutrients. The rationale supporting this view commonly centres on the desire to avoid using petrol-chemical derived inorganic hydroponic nutrients because of (1) the environmental impacts associated with their production, use and disposal, (2) the rising cost of inorganic hydroponic nutrient solutions, (3) the ‘chemical’ stereotype that may tarnish the perception of inorganic hydroponic produce, and (4) the inability to potentially market hydroponic produce as chemical-free or organic if grown using inorganic nutrient sources.

In response, we suggest that it is very difficult to accurately determine which source of hydroponic nutrients (i.e. petrol-chemical derived or bio-converted fish feed) causes more or less environmental damage when considering their production, use and disposal from a global ‘cradle to grave’ perspective. For hydroponic practitioners who produce excess nutrient waste streams, it may be possible to implement low-tech methods of managing those waste streams with the added benefits of enhancing local biodiversity and possibly generating a secondary agri-product (e.g. constructed wetlands).

With regard to rising costs of inorganic hydroponic nutrients, we again suggest it is difficult to accurately determine the long-term economic trends of the hydroponic nutrient industry as opposed to aquaculture feed industry. Additionally, when applied to hydroponic systems, the true costs of nutrient use become site-specific due to specific system designs, management and production methods, environmental aspects and other unique factors.

As for negative perceptions, we believe the hydroponic industry has, for the most part, successfully overcome this issue, and that most consumers are now accepting of inorganic hydroponic produce. Furthermore, the issue of organic or chemical-free hydroponic and/or aquaponic produce is not only a question of definition and methods of production, but more important is the state of competition with traditional agriculture and aquaculture industries and the influences those industries have upon collateral organisational and governmental policy and regulation.

Hence, given these and other arguments presented in this discussion (e.g. technical challenges of adding aquaculture to hydroponics), whether or not it makes sense to integrate fish as bio-converters into commercial hydroponics is a debatable issue. We suggest as an alternative that the hydroponic industry invest in the development of hydroponic nutrient solutions that are generated from renewable resources and/or organic waste sources.

Industry Experts: It may be difficult to obtain unbiased opinions and recommendations regarding the design and operation of aquaponic systems as profitable and stable businesses of commercial scale because conflicts of interest may exist with aquaponic experts (e.g. researchers, consultants, system designers and aquaculture/hydroponic distributors), who profit from selling aquaponics in one way or another. The majority of experts who sell aquaponics have not, do not, and possibly could not make an exclusive living by managing aquaponic systems or otherwise selling animal and plant products produced in aquaponic systems they themselves own or operate. To obtain overtly cautionary or negative consultation with respect to investing in an aquaponic system is unlikely, even if expert consultants have never achieved commercial success over periods of time that lend credibility to their skills and the aquaponic methods they endorse.

Counterbalancing that, those who champion aquaponics are necessary if the industry is to improve, evolve, gain credibility and proliferate. Therefore, until unequivocal, reproducible and transparent evidence (biological, economical, geographical, and methodological) proves validity beyond a doubt, we suggest that consultation grounded in commercial success and factual information (both positive and negative) must be the goal for any reputable aquaponic expert. Furthermore, performance bonds linked with consultancies and design services (which are standard practice in many industries) would most certainly give credibility to consultancies confident enough in their skills and aquaponic technology to bond their services and products. Consultancies would then take a fiscal responsibility for the outcomes of the systems they are involved with from a design, operational and production standpoint.

Industry Representation: In Australia, ongoing attempts to form organisations that aim to represent a unified aquaponics industry have achieved limited success. Loosely defined factions and individuals within the Australian aquaponics community have emerged and maintained degrees of separation between themselves. It is our view that this has occurred due to differing opinions and conflicting experiences regarding aquaponics and aquaponic methodology, and the ever-present lure of profit to be had by those who aspire to dominate the fledgling industry. Problems such as these are not confined to the aquaponics industry, as similar problems exist in most primary production industries.

Such a lack of cohesiveness among experts and practitioners imparts an embarrassing weakness to the Australian aquaponic industry that can only be rectified when all those involved exercise humility and work together towards the progression of the industry in a professional and altruistic manner. To begin with, we suggest that the most commonly referred to definitions of aquaponics (which underpin the widely accepted method of aquaponics described earlier) be broadened to include integrations that practise any method of aquaculture linkage to hydroponics. This shift in philosophy stands to embrace practitioners currently alienated by narrow definitions that only recognise methods of in-line recirculation (i.e. hydrologically real-time linkage between the aquaculture and hydroponic enterprises). Also, if standard aquaponic methods (SAM) come to form through suitable channels of industry consensus, we suggest they include as a primary tenet the use of sustainable feed sources in applications where it is technically and economically feasible.

Furthermore, any individuals that comprise a representative organisation must not aspire to make a profit from the aquaponic industry directly, indirectly, collaterally or otherwise. Individuals given the honour to represent the industry from apex positions of authority and influence must not accept substantial payment in any way, shape or form, but serve the industry for the good of the industry itself without prejudice or ulterior motive. This condition may be difficult for some to accept, but nevertheless it would most certainly alleviate many conflicts apparent at the national organisational level.

Of course, there are other tenets by which any representative organisation must abide; the subject of which could embody a protracted discussion paper.

Certification: Government agencies and certification organisations have yet to legislatively embrace aquaponics in a way that would allow the industry to capitalise on aspects of aquaponics (e.g. chemical-free or organic branding/certification) that could make those businesses more competitive with stand-alone aquaculture and agriculture operations. Hence, a unified aquaponic association that took on the role of organic certification of aquaponic products could fill a position where a void currently exists. Whether or not any future certification body would fall victim to the organisational pitfalls discussed earlier is unknown, but we remain optimistic.

Aquaponic Modelling: We believe there is a lack of aquaponic data which meet the scientific standards required to be useful in modelling (i.e. predicting) within acceptable ranges of accuracy the inputs, outputs and variability of aquaponic systems operating under a variety of abiotic and biotic conditions (e.g. climate, water quality, species used, economic circumstances). Virtual or ‘soft’ models, as opposed to quantitative models, are highly theoretical and are constructed with either minimal or without quantitative data and therefore rely primarily on assumptions and questionable numerical values to drive decision frameworks. Although virtual models are easier to construct than their mathematically derived counterparts, this benefit comes at the expense of robustness and accuracy of the modelling tool because models are only as good as the quantity and quality of data used to build them. If investors choose to use modelling tools to aid in the development or management of aquaponic systems, we believe it is imperative to evaluate the underlying data sources from which the model is constructed (if any) to assess their usefulness prior to investment.

Skill Sets: Most potential aquaponic investors are not highly skilled in both aquaculture and hydroponics and the integration of the technologies. Hydrologically linking aquaculture to hydroponics introduces a host of biological, physical and chemical dynamics which constantly interact (synergistically and antagonistically) at various system levels. Because of this, standard pitfalls associated within stand-alone aquaculture and hydroponics now become more complicated, which invokes further demand upon the practitioner to increase skill level and possibly investment (by way of training, and ongoing consultation), or suffer the possible consequences of reduced productivity or system failure.

Commercial Viability: A number of commercial aquaponic systems (of differing designs) we have visited and/or have first-hand knowledge of in Australia and abroad are not commercially viable as stand-alone businesses, but are supported by collateral commercial ventures, federal-state-community grants, and/or volunteer or subsidised labour. Currently, the inability of commercial aquaponic enterprises to become and remain independently financially viable appears to be the rule rather than the exception.

Aquaculture Feeds: The price of commercial fish feed containing high percentages of fish product is increasing due to the depletion of natural resources and rising costs associated with manufacture and distribution. If this trend continues, profit margins of aquaponic and aquaculture businesses could suffer as long as they remain dependent on those commercial feeds.

Parasites: Control of parasitic infestation in plants and infection in fish using proven treatments and medications can cross-contaminate between fish and plant components in systems that follow an in-line recirculation design. Aside from issues of plant and animal toxicity, the loss of an organic certification (or chemical-free brand) could result. However, it should be noted that it is normal for parasites to be present in diverse ecosystems, and reside within their hosts, in numbers that cause nominal impacts. Also, biodiversity within systems may help guard against explosions in parasite populations through bio-control mechanisms, although this aspect of parasitology has yet to be evaluated sufficiently within aquaponic systems.

Kit Systems: Purchasing small-scale, ready-made aquaponic kit systems from reputable distributors may be a practical choice because kit systems are fast, easy, and can circumvent common design pit-falls and wasting money and time ‘re-inventing the wheel’. However, on the down-side, aquaponic kits are more expensive than DIY systems, may be designed to keep customers dependent on collateral support products and services, and most importantly, detract from the critical knowledge that can be gained from building and managing aquaponic systems designed to custom specifications. For those with the skill and knowledge required to build aquaponic systems, the essential hardware is readily available from a range of local hardware stores to specialist aquaculture, hydroponic and aquaponic distributors. Furthermore, most of what is known about building and managing aquaponic systems can be accessed via aquaculture, hydroponic, aquaponic and collateral information sources (e.g. academic journals, trade magazines, training courses, and internet forums). Hence, for those wishing to design and construct small-scale systems, there are ample resources available to them without having to pay consultant fees or for ready-made aquaponic systems to support their efforts.

Rooftop Systems: Recently, the potential for rooftop aquaponic systems has been given attention by several media sources, although the authors of this discussion are not aware of any existing rooftop aquaponic systems, or for that matter, the existence of rooftop hydroponic systems of commercial scale that are economically viable. Investigations undertaken by the authors (2007) regarding constructing an aquaponic/hydroponic system upon a Brisbane shopping centre rooftop suggested that, at that time, the rooftop application did not make economic sense as a stand-alone business when applying a standard investment/return curve over a 5-year period. This was primarily due to the costs of retrofitting the existing rooftop structure to enable the support of production systems.

Additionally, because rooftops upon which commercial production would make sense are located in densely populated urbanised zones, a myriad of hurdles would need to be overcome with respect to zoning, town planning and construction, environmental health and waste management, food production, preparation and distribution, and other operational and logistical challenges. Local authorities will in most instances define rooftop systems as intensive agriculture/aquaculture activities, and therefore changes to governmental policies across multiple departments will be a prerequisite to ‘fitting’ any rooftop system into existing urban development and regulatory frameworks.

However, it is certainly possible to construct rooftop aquaponic systems given enough money, time, interest and collateral support, and we applaud any ‘green’ rooftop project as there are undeniable environmental and social benefits associated with green rooftops of any kind.

Aside from these issues, we encourage continued investigations and practical applications of aquaponic systems of any configuration; especially those systems that aspire toward commercial and research applications. However, this discussion questions whether it is wise to invest in aquaponics as a business venture. From a broader perspective, this discussion questions the ability of those historically involved with the organisation of the Australian aquaponic industry at the national level to rise to the challenge and effectively lead the industry into the future via overcoming the obstacles currently apparent, as well as those on the horizon. However, because the Australian aquaponic industry is still very young, now is the time to impart an industrial code of practice to effectively govern and uphold the reputation of the industry as it evolves.

Finally, we suggest as a preliminary step for those considering investing in aquaponics, that they first consider what consultation services, system design, management tools, operating methods and economic structure best suit their needs, skills, budget and other investor specific conditions prior to investment.

Vermiponics and Vaquaponics

Moving beyond aquaponics, the Integrated Waste Reclamation and Animal-Plant Production Systems project that is underway at the Centre for Plant & Water Science (CQUniversity – Rockhampton) is undertaking a step-wise investigation of methods that aim to generate vermiculture liquor and castings, chemical-free plant produce and live earthworms (that could be used as fish feed) from abattoir paunch and aquaculture waste, water, atmospheric carbon dioxide and sunlight (for the most part) via the use of food web conversions and physical linkages that are practical and technologically straightforward.

The first phase of this investigation centres on vermiponics, which is defined as the integration of vermiculture with hydroponics utilising any design, linkage or methodology. The second phase of this investigation centres on vaquaponics, which is defined as the integration of vermiculture, aquaculture and hydroponics utilising any design, linkage or methodology. Both vermiponics and vaquaponics represent theoretical and technical progress towards sustainable primary production, which if practiced widely, could impart substantial decentralised effects upon waste management, chemical-free food production, soil development and other associated aspects of resource management, environmental stewardship, economics and community health.

Since the inception of the project several vermiponic goals have been met; vaquaponic integrations are planned for late 2008. We intend to report our work in respective academic journals at the conclusion of the research project.

Acknowledgements

We would like to express our gratitude to the Rural Industries Research Development Corporation, Vermicrobe International Pty Ltd, and Ell-grow Systems (by Boxsell Hydroponics Pty Ltd) for their generous support of this project. Additionally, a special thanks to both William ‘Brock’ McDonald (Project Technician) and Elena Churilova (MSc. Candidate) for their on-the-ground technical and logistical support.

About the authors

Dr Brett Roe completed a Ph.D. of Applied Science (2005), in part, by successfully integrating fish and crayfish aquaculture with hydroponic plant production (utilising both in-line recirculating and batch-flow aquaponic designs) that resulted in high quality market-sized products. Dr Roe currently serves as an Honorary Research Fellow with the Centre for Plant & Water Science – CQUniversity Australia. Email: b.roe@cqu.edu.au

Professor David Midmore is a trained crop physiologist with research experience on four continents that extends into systems analysis and integrated approaches to solving issues of resource use and food production. Professor Midmore is the Director of the Centre for Plant & Water Science – CQUniversity Australia.

Together, they are supervising (Midmore) and managing (Roe) the Integrated Waste Reclamation and Animal-Plant Production Systems project located at CQUniversity, Rockhampton, Queensland.

References

Lennard, W. (2007). Aquaponics: What’s the Reality?

Proceedings of the Moraitis Australian Hydroponics & Greenhouse Conference, Tasmania, 24-27 June 2007.

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One Response to Issue 103: Sustainable Aquaponics

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