FOULING PROTECTION FOR MARINE OPTICAL SYSTEMS
Biofilm and Biofouling growth on marine in situ sensors is a well-known bottleneck when autonomous in situ monitoring is performed in seawater. Technological solutions have been under investigations for many years now. Still new improvements are studied.
This project consist to test in the Mediterranean sea environment an innovative technique to protect optical windows that are part of optical oceanographic sensors or more generally part of optical devices like underwater cameras and lights. The biofouling protection is achieved by a conductive layer that coats the optical window and is used to generate very low quantity of hypochlorous acid by controlled in situ chlorination of seawater.
Moreover, this innovative low power demand and very efficient biofouling protection technique can be controlled by a loop system based on a biofilm sensor (Collaboration with ISMAR-CNR,Marco Faimali (Italy) and ALVIM Srl Giovanni Pavanello (Italy)) that can trigger the active biofouling protection device only when biofilm formation is detected. The final purpose of such arrangement is to save energy by controlling the operation of active biofouling protection systems (wipers, bleach, localized chlorination, etc.) and then to lower as much as possible the energy demand and/or biocide release.
Our biofouling protection technology has been fully integrated to TriOS commercial optical sensors and an HD camera. The deployment at sea is performed on an underwater-cabled structure equipped with an EMSO COSTOF II junction box, and an ALVIM biofilm sensor for the antifouling protection control system loop.
Marine fouling is very specific to the location where it is considered. The OBSEA Mediterranean location would be very profitable to complete efficiency test of our antifouling system that has been carried out, up to now in Atlantic sea at Ifremer Brest. The OBSEA real time connexion to shore is mandatory to show in real time the performance of the system during the DEMO phase of the EU NEXOS project that is happening at end of 2017. The shallow water of the OBSEA observatory is very adapted to get high fouling development during this period of the year. Finally, the OBSEA observatory is fully compatible with the junction box used on our fouling protection system since the JB is a COSTOF II that is used on the EMSO EGIM module that has been already managed by OBSEA few months earlier.