Design tips for keeping your RAS facility disease free

Guy Alon | Customer Operation and Service Manager

10.06.2021

With some forethought and forward planning, your RAS (Recirculating Aquaculture System) facility can deliver two important requirements: avoiding the risk of disease-induced mortality, and eliminating the use of antibiotics and chemicals treatments. The key is to consider from the outset how to create and maintain a closed, bio-secure production environment, that is free of pathogens. From the earliest planning and design stages, layers of biosecurity must be built-in throughout the facility, from the ground up.

Here we review some key design recommendations that will assist you in achieving a pathogen-free RAS facility.

Dressing rooms

One design feature that is important for maintaining biosecurity in a RAS facility, and should be considered for every building on the premises, is staff dressing rooms. These should include a locker area for storing the day clothes that personnel arrives in, beyond which personal items and equipment should not be allowed. The locker area should lead to showers and another separate changing room, where clean work clothes are stored, for dressing. Once dressed, workers should walk through a sluice for boot disinfection, and thoroughly wash their hands before entering the facility itself. On the way out of the facility, they should go straight to the locker room, from where their work clothes can be collected for washing.

Machine rooms

There are likely to be machine rooms in every building of the RAS facility. They may contain a range of systems, for example, oxygen generator, air compressor, air dryer, cooling system, etc. It is highly recommended to locate machine rooms so that personnel may enter them from within the production halls, and to fumigate them during startup. When maintenance personnel is required to enter these rooms, they should be made off-limits for personnel working inside production until they have been re-fumigated after maintenance has been completed.

Disinfection room

All new equipment to be used in the production hall should be thoroughly disinfected in a designated disinfection room prior to use, to prevent pathogens entering from outside of the facility. The room should have a separate entrance and exit doors, to prevent contact between personnel, and to ensure that any equipment leaving the disinfection room is not re-contaminated on its way out.

Utility rooms

It’s important to locate utility rooms, accommodating a range of systems such as HVAC, water heating, feed storage, fuel storage, electric generators, etc., outside of the biosecure area, to prevent access from within the production hall which could lead to contamination. Sewerage lines, air ducts, electrical cabling, etc., should also all be designed with biosecurity in mind.

Quarantine area

Eggs, fingerlings, and PLs (post-larval shrimp) need to be contained in a quarantined area when they arrive at the facility, in order to verify that they do not carry any disease. They should only be allowed to leave quarantine once they have safely passed a veterinary exam.

The highest risk of biosecurity breach, is in the quarantine/hatchery area, as it may harbor undetected pathogens arriving from various sources of genetics. It is therefore located in a separate room within the quarantine area, with its own distinct access control, and should be designed so that there is no transfer of water, equipment, or personnel between the hatchery, the nursery, and grow-out building.

Egg or larvae de-boxing room

As eggs or larvae arriving at the facility may be contaminated, it is recommended to designate a de-boxing room, where they can be removed from the boxes, washed and disinfected. They should then be transferred directly to the hatchery, without any equipment or personnel transfer between the areas.

Denitrification System (DNS)

The DNS should have a separate biosecurity regime to the production hall, as it receives water from several sources, increasing the chance of contamination. It is advised that any person entering the DNS from within the production hall first go through a disinfection room and change their clothes, before passing through a sluice and washing their hands. Maintenance workers entering the DNS from the outside, must also pass through a disinfection room and wear suitable protective clothing.

Vermin control

It is very important that the RAS facility buildings are designed to prevent access by vermin – such as birds, rodents, wildlife, and large insects – as they may carry pathogens into the facility. The facility should be completely sealed, including fixing nets around fans and double electric doors that prevent animals from entering the facility.

There is a lot to think about when setting up your RAS facility, and biosecurity is certainly one of the major issues to consider from the outset. By building it into the technology design as well as the facility layout, it will play an important role in maintaining a disease-free environment, enabling consistent, uninterrupted production of fresh, healthy fish.