Grantee Research Project Results
Final Report: Development of Sustainable Integrated Aquaculture Systems With Assessment of Environmental, Social, and Economic Implications
EPA Grant Number: SU833908Title: Development of Sustainable Integrated Aquaculture Systems With Assessment of Environmental, Social, and Economic Implications
Investigators: Fitzsimmons, Kevin , LaBrent, Chrite , Giocamelli, Gene , Silvertooth, Jeff
Institution: University of Arizona
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2008 through August 14, 2009
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2008) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Sustainable and Healthy Communities , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
The treatment and discharge of aquaculture effluent and resulting negative impacts on the environment remains a critical issue that is threatening the sustainable growth of the aquaculture industry. Concentrated aquatic animal production (CAAP) facilities are regulated under the Clean Water Act, Section 104, 33 U.S.C. Yet, even heavily concentrated aquaculture effluent can be reduced to levels acceptable under effluent limitation guidelines (ELGs) through the use of heavy dilutions. As a result, the discharging of mass amounts of diluted aquaculture effluent, even though it satisfies ELGs, is particularly problematic. The resulting negative effects on the environment will continue to intensify in the future if sustainable practices are not developed in commercial scale.
Progress has been made in the development of sustainable agriculture systems. Hydroponics systems, for example, combine agriculture and aquaculture practices to produce both fish and plants. These systems are particularly advantageous because the nutrients contained in the effluent are utilized by the plants for growth, thus reducing the potential discharge into open waters. Relatively few plant species, however, are able to tolerate the stress of growing with their roots submerged in aqueous mediums. Most plants require a soil based foundation for proper root growth. Additional methods of sustainable aquaculture are needed to ensure the continued growth of the aquaculture industry. Moreover, before sustainable practices are implemented in the industry, proof of concept must be demonstrated. To date, few studies have been conducted on integrated systems, which assess the feasibility of adopting economically viable, and environmentally sound integrated systems capable of functioning in large-scale. As a result, the benefits of integrated aquaculture systems have not been realized.
To promote sustainable aquaculture practices at local and international levels; three goals were identified and completed with P3 Phase I support; (1) develop novel Re-circulating Integrated Agriculture-Aquaculture (RIAA) systems, (2) perform several successive food production experiments to determine the conditions that promote economically viable and environmentally sound food production, and (3) evaluate and disseminate results to meet the needs of local and international agriculture industries.
As in hydroponics systems, RIAA systems combine fish and plant production techniques in which the nutrient laden aquaculture effluent is used as a form of fertilizer to stimulate plant growth. The RIAA system in Phase I project was novel however, as it uses soil based plant production with an advanced surface drip irrigation system. Because more plants can be grown in soil based mediums compared to hydroponics systems, RIAA technology offers the advantage of diversifying the product for improved income as well as providing a more diverse diet to local communities.
Summary/Accomplishments (Outputs/Outcomes):
The successful completion of this project was achieved using a multi-disciplinary approach in the design, testing, and implementation of a re-circulating integrated aquaculture production system. Graduate students were individually selected for this project based on their expertise in soil, water, and the environment, and their ability to carry out research and planning towards the solution of environmental and resource use problems.
The first objective was completed by developing a large-scale re-circulating integrated aquaculture system in which aquaculture effluent was used to irrigate individually potted plants (Fig. 1). Three independent RIAA systems were set up to allow for experimental testing. In each system, water from a 5000 L doughboy swimming pool was delivered to 300 individually potted plants using a surface drip irrigation system. The pots were placed into 30 meter long aluminum metal channels which were built at a negative 2° slope. Thus, after being delivered to each pot, water percolated through the soil, migrated down the channels of the plant troughs, where it was collected in basins located at the terminal end. From there, water was pumped back into the fish tanks.
The second objective was completed by performing successive experiments to identify the conditions which promote economically viable and environmentally sound food production. Data were analyzed to determine which systems generated high plant and animal yield production, maximum nutrient utilization, and high benefit to cost to ratios. A total of three plant species were grown using aquaculture effluent as nutrient laden water source; barley (Hordeum vulgare), basil (Ocimum basilicum), and soybean (Glycine max). Each of these plant species was supplied with aquaculture effluent from pools containing Tilapia at densities of 3 kg/m3, 6 kg/m3, and 9 kg/m3 respectively. Total fish feed and fish density was kept constant over the course of each experiment to ensure the same nutrient load was being delivered to each system over time. The number of plants was maintained the same for all experiments at 300 plants for each system. 150 plants were grown in ½ gallon pots and 150 in 1 gallon pots to evaluate amount of soil needed for efficient growth. The efficiency of nutrient utilization and net nutrient uptake in each integrated aquaculture system were determined. Water samples were extracted for water quality analysis both before it enters and after it exits the plant beds. Nitrate, ammonia, total nitrogen, phosphate and orthophosphate concentrations were determined from each of water samples. Temperature and dissolved oxygen were also monitored in each system. Nutrient uptake efficiency was calculated as the difference between nutrient concentrations contained in the influent and effluent water samples. Water quality and plant growth rates were compared over time to determine the conditions which maximized plant and animal biomass production through nutrient utilization.
One of the key findings in part of the second object was that all plant species were able to grow readily using aquaculture effluent as a form of fertilizer. However, the growth rates of barley, basil, and soybeans, were dependent upon the nutrient concentrations in the water as well as the size of the pots in which the plants were grown. Moreover, the nutrient concentrations in the aquaculture effluent were proportional to the density of fish in the 5000 L pools (i.e. higher densities of fish correlated to higher nutrient concentrations). Total plant height was consecutively higher from treatments with 3, 6, and 9 kg of Tilapia per m3. In terms of rapid plant growth, the best results were obtained by irrigating plants with aquaculture effluent from the pools with 9 kg of fish per m3. This was the highest density of fish used in this project studies and it is reasonable to assume that higher plant yields would be generated using irrigation water from aquaculture tanks with densities of fish greater than 9 kg per m3. Similar results were found for each plant species was collected from each experiment.
Approximately 80% of the total nutrients were removed through the irrigation process, irrespective of the initial concentrations, as the effluent migrated through the potted soil. The hypothesis prior to the start of the experiment was that a reduction in nutrient concentration would be observed over time in correlation to plant growth. However, in the experiment, no such correlation was observed. In contrast, the soil was observed to act as a physical filter which 80% of the organic nutrient load (presumably bound to algae and other micro biological species) was captured as the irrigation water migrated through the soil. The final significant result observed in this project was that approximately 90% of the aquaculture effluent was recaptured and pumped back into the pools. 10% was presumably lost primarily through evaporation. System leaks were occasionally found and fixed on site and the associated water loss was not considered significant.
The final objective of the P3 Phase I project was completed by disseminating results to the local community, the academic community, NGOs, and farmers both in the United States and several countries around the world including Uganda, Mexico, and Paraguay. In support of the RIAA project, a study was completed on the potential economic impacts of aquaculture development in rural communities. This work, titled “The Use of Multipliers to predict the effect of growth of aquaculture on rural Arizona Communities,” was presented at the World Aquaculture Society Conference in Busan, Korea in May of 2008. Results from the project will also be presented at an upcoming conference in May, 2009. The title of this up-coming presentation is “Utilizing aquaculture effluent from Tilapia to grow Barley (Hordeum vulgare) using RIAA systems.” A manuscript is also is being generated in combination with this presentation and will be submitted to the Journal of Aquaculture in the summer of 2009.
Students from the project developed partnerships with three high schools in Tucson, Arizona. The graduate students traveled to the local schools and held public seminars and class room discussions emphasizing sustainable agriculture methods. Students from the high schools also traveled to the Environmental Research Lab (ERL), where development of the RIAA systems took place, as part of class room field trips.
Conclusions:
P3 Phase I project provided proof of concept that RIAA technology provides significant environmental and economic benefits. Successive experiments in part of the Phase I project revealed the broad capabilities of RIAA systems to grow multiple plant species. Two significant benefits to the environment were also demonstrated; 1) approximately 80% of the nutrient load was removed as the effluent migrated through the potted soil, and 2) approximately 90% of the water was recaptured and pumped back into the aquaculture tanks.
Before being discharged into the environment, nutrient levels in aquaculture effluent must be reduced to levels acceptable by the EPA. The treatment of the aquaculture effluent represents one of largest operational costs in aquaculture industry. However, the present study demonstrated that nutrient concentrations in aquaculture effluent may be cost-effectively reduced by irrigating potted plants and re-capturing the water. The re-capture of 90% of the aquaculture water also demonstrates the efficiency of resource use in RIAA systems. As water availability is often scarce, especially in arid regions around the world, efficient water use is essential for the continued growth of the aquaculture industry.
In summary, RIAA technology improves the conversion of fish feed input to plant and animal biomass, over traditionally used land based farming and aquaculture techniques, thus reducing the potential discharge of nutrients to open waters. Because RIAA systems offer the ability to grow multiple plant species, species may be selected for production in rural communities which are expected to generate high return on investments (ROI) based on high local demand. Generated revenues would be sufficient to recoup initial start-up costs in a relatively short time period as well as to cover operational and maintenance costs necessary for sustainable food generating purposes.
Proposed Phase II Objectives and Strategies
The aim of the P3 Phase II is to build upon the work completed in the Phase I project and to establish sustainable food production practices in Tabasco, Mexico. To accomplish this, the multi-discipline team in the Phase I project has formed strategic partnerships with experts from the Universidad Juárez Autónoma de Tabasco (UJAT) and the Universidad Autonoma de Tamaulipas (UAT). Project team members were individually selected for the proposed project for their expertise in soil, water, economics, knowledge of Mexican indigenous cultures and language, and their ability to carry out collaborative research and planning towards the solution of environmental and resource use problems. Together, the research project members will integrate their research expertise to implement RIAA systems to satisfy the agriculture needs in rural communities. The successful transfer of RIAA technology in Tabasco, Mexico will provide an environmentally friendly means of sustainable food production with the potential to mitigate poverty and malnutrition. Furthermore, the successful transfer of RIAA technology will warrant the continued expansion of sustainable food production systems across local and international regions.
Three objectives have been identified for the completion of the proposed project;
I. Development of RIAA system at the Universidad Juárez Autónoma de Tabasco (UJAT)
II. Transfer of knowledge and starting materials to rural communities
III. Facilitate development of RIAA systems in rural communities of Southern Tabasco
The first objective will be completed by developing a closed re-circulating integrated aquaculture (RIAA) system at UJAT where an aquaculture facility has been operating successfully for over 10 years. The fish species, Oreochromis niloticus, commonly referred to as the Nile Tilapia, will be used in all production systems. Plants will be compared based on price, locally available quantity and quality, demand, and rate of growth. The plants with the fastest rate of biomass production and highest expected return on investment will be grown in order to generate high food reserves and sufficient revenues to cover short and long term costs.
The second objective of the proposed project is to utilize the developed RIAA system to 1) educate several indigenous tribes including Lacandon, Mayan, and other groups native to Tabasco, on the uses and benefits of integrated production and 2) provide start-up materials necessary for indigenous tribes to begin establishing their own RIAA systems. Indigenous tribe members will be brought to the University for one-day educational Seminars in which the system and its benefits will be explained in detail. Informational packets will also be made and given to the tribe members. Such information will included how to build, what materials to use for development and maintenance, how to mange production yields (i.e. how to generate consistent production results etc.), and how to fix and avoid common problems. Secondly, animals (Tilapia fingerlings) and plants (seeds or seedlings) grown in the RIAA system at UJAT will be made available to the tribes for starting their own RIAA systems.
The third objective will be completed as an outreach project from UJAT. Dr. Contreras-Sanchez, the director of the UJAT aquaculture program, 2 of his graduate funded students, and 2 students from the University of Arizona will go out to the indigenous rural communities to help establish RIAA technology. Dr. Contreras-Sanchez has already traveled to several of these communities and has stated that the transfer of necessary equipment for RIAA development will not be overly difficult. In addition, suitable materials and methods have been identified which will be instrumental to the successful implementation of RIAA systems in these rural communities. The materials are inexpensive and easy to obtain and maintain.
Implementation of integrated agriculture-aquaculture systems in Tabasco, Mexico will benefit individuals, communities, and societies through the creation of a sustainable food supply. The likely completion of Phase II will demonstrate how RIAA technology integrates and sustains environmental protection, economic prosperity, and social benefits in rural communities. Through the demonstrated benefits to people, prosperity, and the planet, this technology will be expanded in future years across scales in both developed and developing worlds.
P3 Phase II:
Development of Sustainable Aquaculture Practices in Tabasco, Mexico Using Novel RIAA TechnologyThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.