Closed-loop RAS allows for efficient solid waste capture and collection. However, the intensive nature of the process also results in the production of a concentrated waste stream. With the increasing use of large-scale RAS, more waste is being produced in land-based systems and agricultural use of liquid waste becomes non-viable in many locations. Waste treatment and disposal leads to additional costs for farmers. A biosolids waste management strategy is required to ensure a sustainable expansion of the industry. The aim of this paper is to offer a concrete contribution to the development of an economically and ecologically sustainable biosolids waste strategy for the RAS industry.
This involves the use of solids/liquid separation technologies that are efficient in human resource (operations and maintenance) and consumables (water, energy, conditioning). An innovative technology has been developed by Fournier Industries to achieve such a goal. The Fournier Rotary PressTM has been recently introduced in the RAS industry both in North America and in Norway. We use empirical data drawn from Fournier’s experience in North America and in Scandinavian countries to outline lessons learned. Process data (dryness, capture rates, water, energy and chemical conditioning consumption) collected from Rotary Press operations are presented.
We also examine the contribution of this technological innovation to other land farming waste management operations, such as dairy and swine manure used in renewable natural gas (RNG) generation, to open perspectives for the future of RAS.
From this operational experience, we draw conclusions on technical and commercial strategies that will be key for the successful transitioning of the RAS community to a more circular and low-carbon economy.