1. Heidi Emmons, Martin Wosnik, Ian Gagnon, Kaelin Chancey
Protocol for Testing Different Coatings to Minimize Biofouling on Probe Monitoring Instruments and Turbine Blades at the Platform Under the Living Bridge
Heidi Emmons, Martin Wosnik, Ian Gagnon, Kaelin Chancey
Sanborn Regional Middle School and UNH College of Engineering and Physical Sciences
Abstract
Discussion
The Living Bridge project is the Memorial Bridge in Portsmouth that crosses over the Piscataqua River, a tidal estuary. The bridge is instrumented with sensors to measure stressors, traffic patterns, etc. This data is ongoing and available to the public.
Under the Living Bridge is a turbine deployment platform designed to use the tidal energy of the Piscataqua River to produce electricity for the Living Bridge. There are also sensors in the water to measure turbidity, salinity, pH, and water temperature. This data is also available to the public.
Biofouling on the turbine deployment platform is a big problem. Seaweed gets caught on the platform as it goes by, and barnacles and mussels attach to the platform and equipment.
This project will test two types of antifouling paints that both claim to be ecofriendly, but use different ingredients. Twelve hard anodized 6061 aluminum coupons coated with the two antifouling paints, epaint and Sea Nine 211N will be submerged off the platform under the Memorial Bridge to test for the prevention of biofouling. The results of this experiment will hopefully provide a solution to minimize biofouling of the probes and other monitoring instruments, and the tidal energy conversion system turbine blades at the turbine deployment platform under the Memorial Living Bridge.
Most underwater monitoring equipment is made of several different plastics, metals, glass, and rubber. Marine organisms can attach to any surface, especially if there is a crevice or an opening.
These probes and other equipment have to be cleaned and sometimes taken apart to remove the biofouling. This takes time and great effort. It also means they are not able to collect data when out of the water for routine cleaning.
Biofouling is the biggest problem to the proper functioning of marine equipment.
A view of the platform from the boat.
Ian Gagnon removing seaweed from the probes on the platform.
Next Steps
Methods
Continue the ongoing experiment using the coupons.
Analyze the data, then test on the equipment at the platform.
This biofouling test will compare epaint, which uses a soy based polymer that uses the sunlight, to Sea Nine 211N, a new biofouling paint that contains bacteria extracted from Sargassum muticum, common name Japanese wireweed, found to naturally deter marine organisms from attaching to it. These extracts (ethanol fraction from S. muticum) are very efficient settlement inhibitors and have no long term effects on marine organisms.
Introduction
Biofouling of probe monitoring instruments is a big problem. The turbine deployment platform is part of the Living Bridge Project and has several probes submerged in the seawater for long periods of time in order to measure turbidity, salinity, temperature, etc. of the water. Biofouling affects the performance of these probes because they have windows or small openings for the sensors. Barnacles, mussels, seaweed, and algae attach and cover these sensitive areas.
There are many commercial antifouling paints available but most contain metals such as copper which have long term affects on marine life and have been found in sediment.
Results of a previous biofouling test performed by Matt Rowell, at the UNH-CORE test Tidal Energy site in the Great Bay Estuary showed that epaint significantly reduced the amount of biofouling.
Literature Cited
Step 1: Twelve uniform, rectangular coupons were cut from 1/8” thick hard anodized 6-61 aluminum with the dimensions of 8” x 2”.
Step 2: a hole was drilled in each coupon 1/8” from the top to attach to the mount.
Step 3: PVC pipe was cut to 2’ for the mount.
Step 4: 4 coupons were left bare with no coating as the controls, 4 coupons were coated with epaint, and 4 coupons were coated with Sea Nine 211N.
Step 5: all coupons were zip tied to the PVC pipe and hung appoximately 18” under the surface of the water off the platform.
Step 6: After one week, all coupon surfaces are checked for slime layer.
Step 7: Every 3 months, one of each surface coating and one control are removed from the platform, weighed, and scraped of all biofouling material.
Step 8: Identification, classification and quantitative data are collected on all organisms scraped from the coupons.
Armstrong, E. , Boyd, KG, Burgess, JG, Prevention of marine biofouling using natural compounds from marine organisms
Bazes, A., Silkina, A., Mouget, J., Bourgougnon, N., Comparative efficiency of macroalgal extracts and booster biocides as antifouling agents to control growth of three diatom species
Lobe, H., Recent Advances in Biofouling Protection for Oceanographic Instrumentation
Mouget, J., Silkina, A., Vouve, F., Tilly, V., Douzenel, P., Bourgougnon, N., Antifouling activity of macroalgal extracts on Fragilaria pinnata (Bacillariophyceae): A comparison with Diuron
Rowell, Matthew, Experimental Evaluation of a Mixer-ejector Hydrokinetic
Turbine at two Open-water Test Sites and in a Tow Tank Masters Thesis UNH 2012
Wang, K., Wu, ZH., Wang, Y., Wang, CY., Xu, Y., Antifouling Natural Products from Marine Microorganisms and Their Synthetic Analogs
Acknowledgements – This research was supported with funding from the National Science Foundation’s Research Experience for Teachers in Engineering Grant (ENG ). Special thanks to Dr. Stephen Hale, Allison Wasiewski, for their help and support. Thank you to Dr. Martin Wosnik, Dr. Erin Bell, Ian Gagnon, and Kaelin Chancey, and Lee Leon for their help with this project.
Biofouling of the probes from summer Mussels attached inside all openings.