Dewatering Aquaculture Effluent For The Hydroponic Production of Pak Choi (Brassica rapa chinensis) and Production of Vegetable Seedlings

Project Overview

GS11-098
Project Type: Graduate Student
Funds awarded in 2011: $9,932.00
Projected End Date: 12/31/2013
Grant Recipient: Auburn University
Region: Southern
State: Alabama
Graduate Student:
Major Professor:
Dr. Jesse Chappell
Auburn University

Annual Reports

Commodities

  • Animals: fish

Practices

  • Crop Production: irrigation, organic fertilizers, tissue analysis
  • Production Systems: general crop production

    Abstract:

    The aquaculture industry will continue to grow in order to meet the consumer’s demand for aquatic animal protein. Recirculating aquaculture systems will help to intensify production on the producer’s farm, but waste water treatment technologies will be required to ensure the discharged waste does not have a socio-economic impact on limited, natural resources. Geotextile technology aides in the capture and treatment of discharged wastes on the producer’s farm, but finding ways to utilize the solid and liquid component created by the geotextile technology will be required. Using the solid and liquid components for horticulture plant production may provide farmers with a method for additional on-site waste remediation while diversifying production. The experimental trials using the solid component suggest incorporating low levels of dewatered aquaculture effluent into commercial substrates may provide a means of redirecting aquaculture waste into a resource for horticulture production. The plant growth response was dependent on the substrate and water source. The benefits of the leachate exiting the geotextile bag were dependent on the source of aquaculture effluent and the management of the production system. Nonetheless, the high pH level of the leachate will need to be managed to ensure optimal levels are maintained for plant production. Acid injection is commonly used by the horticulture industry to mitigate sub-optimal pH of irrigation water. Appropriate choice of acid and its injection could provide supplemental nutrients and lower pH in circumstances where the leachate exiting the geotextile bag is deficient in dissolved macronutrients. The cost associated with acid injection will be dependent on the chemical parameters of leachate (i.e. alkalinity). Using the leachate as a plant nutrient source will be important in regions where quantities of commercial, inorganic fertilizers are difficult to obtain and freshwater resources are depleted.

    Introduction

    The aquaculture industry will continue to grow in order to meet the consumer’s demand for aquatic animal protein. Recirculating aquaculture systems will help to intensify production on the producer’s farm, but waste water treatment technologies will be required to ensure the discharged waste does not have a socio-economic impact on limited, natural resources. Geotextile technology aides in the capture and treatment of discharged wastes on the producer’s farm, but finding ways to utilize the solid and liquid component created by the geotextile technology will be required. Using the solid and liquid components for horticulture plant production may provide farmers with a method for additional on-site waste remediation while diversifying production. The experimental trials using the solid component suggest incorporating low levels of dewatered aquaculture effluent into commercial substrates may provide a means of redirecting aquaculture waste into a resource for horticulture production. The plant growth response was dependent on the substrate and water source. The benefits of the leachate exiting the geotextile bag were dependent on the source of aquaculture effluent and the management of the production system. Nonetheless, the high pH level of the leachate will need to be managed to ensure optimal levels are maintained for plant production. Acid injection is commonly used by the horticulture industry to mitigate sub-optimal pH of irrigation water. Appropriate choice of acid and its injection could provide supplemental nutrients and lower pH in circumstances where the leachate exiting the geotextile bag is deficient in dissolved macronutrients. The cost associated with acid injection will be dependent on the chemical parameters of leachate (i.e. alkalinity). Using the leachate as a plant nutrient source will be important in regions where quantities of commercial, inorganic fertilizers are difficult to obtain and freshwater resources are depleted.

    Project objectives:

    The objectives of the proposed project were: 1) Use filtrate exiting the geotextile bag as a nutrient source for a cultivar trial of hydroponically produced pak choi at Auburn University and evaluate plant growth parameters and health. 2) Repeat objective one with the two best pak-choi cultivars at a moderate-sized aquaculture farm utilizing RAS technology in Browns, Alabama and evaluate plant growth parameters and health. 3) Evaluate the dewatered solids as an element of soilless media and nutrient source for the production of vegetable seedlings. Plant growth parameters and health of transplants were assessed.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.