Cleaning and disinfection are essential to minimize the risk of disease outbreaks in RAS facilities. Tests carried out in Marineholmen RASLab show that VESOS cleaning and disinfecting agents from CID Lines are very effective in ensuring high biosecurity.

The vast majority of new land-based aquaculture facilities built in Norway today are recycling facilities (RAS). In addition, many of the old through-flow facilities are being converted to RAS. Land-based facilities have many advantages, but also significant infection hygiene challenges. Regular cleaning of installations and production units is an essential safety measure to prevent the build-up of pathogens.

VESO holds the agency pre-washing and disinfectants from CIDLines. Now Marineholmen RASLab has tested the products in the RAS Laboratory in Bergen. The analyzes from the RAS facility show that CID Lines' products are very effective for both cleaning and disinfection, and provide good user safety.

It is important to wash down between batches in the RAS Plant

- We get a lot of questions about RAS systems from breeders, says Andreas Pedersen, technical salesperson for VESO's hygiene products.

- The RAS system is built around the biofilter that cleans the water. The point is that the filter should take care of biological diversity. It's almost like a separate ecosystem, but it also means that you take care of both friendly and disease-causing bacteria. If there is an accumulation of pathogenic bacteria, it can lead to problems, he points out.

According to Pedersen, it is very important in such systems to wash down the fish-carrying part of the system between stockings, as well as to wash down contamination if there has been an outbreak of disease. This will help maintain good infection hygiene and fish welfare, she says.

Trials with CID Line's products in the lab

VESO has extensive experience with the use of cleaning and disinfecting agents from CID Lines in both agriculture and water systems.

- We have seen that these products work very well in normal hatcheries and well boats and had great faith that the products would also give good results in full-scale RAS facilities. We therefore wanted to evaluate the performance in experiments in the lab to see if our experiences were confirmed. Now Marineholmen RASLab has tested the products and I am proud to say that they delivered very well, says Andreas.

Same starting point as for large scale

Marineholmen RASLab AS is a research and innovation facility that contains twelve independent RAS units from Alpha Aqua AS.

In this project, the researchers did three analyzes with CID Line's cleaning and disinfection products: ATP measurements for hygiene control, which is an indirect measure of how many cells remain on a surface, as well as two types of KIM analyzes (colony forming units). Samples were taken from various locations and surfaces within the RAS system, in addition to free water samples after the system had circulated.

Each unit in the lab consists of a fish tank of 1m3 and remaining cubicles of 1.5m3, with a total water volume of 2.5m3.

- Although these units are small compared to RAS on a commercial scale, all the elements for water purification and fish houses are the same, points out Erna Heggland, operations operator at Marineholmen RASLab.

Heggland explains that the RAS system is very complex and has a significant surface area that needs to be cleaned and disinfected.

-Since there are many suitable products available on the market, the aim of this project was to evaluate the performance of different cleaning and disinfection products distributed by VESO.

Different concentrations

- We used different concentrations of the different products and solutions were tested to develop effective and economical cleaning procedures for RAS. We also established a cleaning and disinfectant protocol in collaboration with VESO, explains Heggland

Before cleaning, all units had Atlantic salmon smolt for almost 4 months, which is comparable to rearing cycles in commercial RAS salmon smolt production.

The products were tested in all units in water at 15 ppt salinity. The RAS units (8 out of 12) were treated with several soap combinations and/or disinfectants in different solutions and with different working times to establish an optimal cleaning protocol for the RAS.

The effect of three different cleaning agents was evaluated. The chemicals supplied by VESO were:

Kick-Start - an acidic disinfectant chemical consisting of a mixture of hydrogen peroxide and peroxyacetic acid. Kick-Start can be used for both cleaning and disinfection.

Dm Cid Pro is an alkaline cleaner made from potassium hydroxide and sodium hypochlorite.

Dm Clean Super is an alkaline cleaner made from potassium hydroxide and sodium hydroxide.

We are very pleased with the products. They have delivered optimally and are as good as we thought

Will use the products

All the products used for cleaning or disinfection in the RAS units gave very satisfactory results.

- The products were also easy to handle and work with, although personal protective equipment was strongly recommended, says Heggland.

When cleaning with Dm Clean Super and Kickstart, the stronger application solutions gave the best results, but for Dm Cid Pro, the weakest application solution gave comparable results to the stronger application solutions, explains the researcher.

- Based on the results, we at the RASLab will probably use the Kickstart product ourselves for both cleaning and disinfection of the RAS units. It gave excellent results even at low concentrations and limits the amount of chemicals that have to be handled by the staff, points out the operations manager.

VESO is very pleased that the products gave such good results:

- We are very pleased with the products. They have delivered optimally and are as good as we thought, concludes Pedersen.