On-board zero-discharge water treatment unit for well-boats: Arctic char as a case study

ABSTRACT

An onboard zero-discharge water treatment process, aimed at the well-boat industry, is described and demonstrated as an alternative to current techniques. Two live-fish holding trials were carried out with Arctic char for 8 days (84 kg/m³) and 6 days (154 kg/m³). The trials were conducted in a zero-discharge pilot system with a unique water treatment unit relying on electrochemical water-treatment for oxidizing ammonia into N_2(g), disinfecting the water, removing fine particles/organic matter and chlorine-species via activated-carbon filtration. No professional skills are required to operate the system. The TAN excretion rate of adult Arctic char under starvation at 5°C amounted to ~22 mgN/(kg·d). Sensory evaluation showed that Arctic char could be successfully held in a system based on the suggested technology without adverse effects relating to mortality and product quality. The costs of operating the system were assessed at 0.30 USD per one ton of standing stock per 24-h journey.

KEYWORDS:

• Well-boat
• closed transport
• ammonia removal
• arctic char
• disinfection
• live seafood transportation

Acknowledgments

This work was supported by EIT FOOD, Activity 19060. The authors wish to thank Biofishency LTD., for the help in constructing the experimental system.

Disclosure statement

There are no relevant financial or non-financial competing interests to report

Additional information

Funding

This work was supported by the EIT Food [19060].