Development of a De-watering System and Cost Analysis to Transform Fish Waste from Recirculating Aquaculture Systems into Value Added Garden Compost

Project Overview

Project Type: Farmer
Funds awarded in 2021: $14,963.00
Projected End Date: 01/31/2022
Grant Recipient: Aroostook Band of Micmacs
Region: Northeast
State: Maine
Project Leader:
Cara ODonnell
Aroostook Band of Micmacs


  • Animals: fish


  • Animal Production: aquaculture
  • Education and Training: demonstration
  • Farm Business Management: budgets/cost and returns, value added
  • Natural Resources/Environment: other

    Proposal summary:

    Recirculating Aquaculture is an innovative, environmentally friendly and highly productive way of fish farming. Overfishing, pollution, climate impacts and dams have reduced the ability to harvest fish from the wild, however the demand for fish as a food staple remains high. Aquaculture remains one of the world’s fastest growing agri-food production systems, with a constant market demand for high quality fish. Stringent environmental restrictions in Europe prompted development of recirculating technology that has the added benefits of less disease and more stable production, that is both cost effectiveness and environmentally sustainable. Recirculating Aquaculture Systems, known as RAS, produce less waste than alternative methods. However, for small scale fish farms, utilizing this waste as a value-added compost product can be important to their bottom line, or even critical to sustaining their business. 

    This project will document how to create a dewatering structure for the high liquid content produced by RAS waste, and outline the cost benefit of the process. We will outline the process of estimating the amount of total solids produced by a system in a given year,  as well as how to determine the appropriate nutrient concentrate values for a competitive, marketable product. We hope to inspire others who are considering RAS technology by demonstrating the additional environmental and economic benefits. We will share our results with key RAS and aquaculture websites in the United States.

    Project objectives from proposal:

    This project seeks to accomplish the following objectives:

    Objective 1: create a prototype for a dewatering system that addresses the unique composition of RAS waste.  We will demonstrate how to efficiently build a dewatering bed and canopy, with discussion on optional materials that can be used. We will discuss weather conditions that may accelerate or hamper successful evaporation. Ideally, we will model how simple, flexible and affordable the process can be. The hatchery has a USDA MET meteorological station on site that takes continuous readings. 

    Objective 2:  Provide a cost benefit analysis. Demonstrate the economic cost and revenue of creating a value-added liquid fertilizer product to be sold as a garden supplement. We will document all costs associated with developing a dewatering system, Percent Solids analysis, nutrient content analysis bottling, marketing, etc. with developing fish waste as a value added liquid fertilizer product. We aim to demonstrate how to boost profit margin for this product

    Upon successful completion of this project a press release will be routed to RAS colleagues to share the cost benefit, to inspire prospective operators to choose RAS technology. 


    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.