Ozone is very unstable so it quickly bubbles out of the water inside the degas chambers. Because of this, ozone must be removed from the water. In extreme cases ozone can even cause death. Ozone, however, can be dangerous to marine creatures, causing the burning of the gills of fish and the delicate tissues of invertebrates. As the ozone breaks down in the water it reacts with dissolved organics as well as bacteria and parasites. Ozone is introduced into the water by passing air through an electrical discharge just before injection into the water. The hydrophobic end is attracted to the interface and attaches to the surface of the bubble as it rises to the surface.Īnother type of chemical filtration that we employ at the Aquarium is ozone. Because some complex compounds or organic compounds have hydrophobic (“disliking water”) and hydrophilic (“loving water”) ends, these dissolved organics are attracted to the interface between a gas and a liquid. The foamy solution then rises to the surface where it is skimmed off. Protein skimming takes advantage of the polar nature of organic molecules, attracting them to the surface of air bubbles shot into a column of water. One method of chemical filtration is protein skimming or foam fractionation. Chemical filtration in a way is mechanical filtration on a molecular level. These dissolved products are ones that can no longer be removed by mechanical filters. This type of filtration removes wastes (proteins and organics) from the water before they have a chance to decompose. A good mechanical filter is one that traps many solids, keeping the water clear, without clogging up too often.Ĭhemical filtration is the second type of filtration. Mechanical filter media can be in the form of sponges, loose bonded floss, foam, or even sand. Coarse filters capture fewer particles but clog more slowly. Fine filters can capture very small particles but clog easily and must be cleaned regularly in order to maintain good water flow. The composition of the media within the filter is directly related to the type and size of particle the filter can remove. Mechanical filters catch and hold particles by physically trapping them within the filter. It can, however, remove solid waste particles from the water before they have a chance to break down into ammonia. Unfortunately, mechanical filtration cannot remove dissolved ammonia from the water. Mechanical filtration is the removal or straining of solid particles from the water. The Aquarium uses three main types of filtration: mechanical, chemical, and biological. Fortunately, nature has provided us with bacteria that can perform this process for us! These bacteria will convert ammonia into nitrite and then eventually to nitrate, which is relatively harmless to the animals in our exhibits as long as regular water changes are performed. The nitrogen cycle (or nitrification cycle) converts toxic ammonia into other less harmful nitrogen compounds. At the Aquarium, we take advantage of something called the “nitrogen cycle” to prevent ammonia levels from becoming too high in our exhibits. In an aquarium environment, however, it would not take long for concentrations of ammonia to reach highly toxic levels. In nature, the ocean is so large that the waste can be diluted into very low concentrations. These waste products will eventually break down into ammonia, which can be highly toxic to marine animals. Like all living creatures, marine animals give off waste products. Why is filtration necessary? Fortunately, Liz Keenan with the Education Department provided me with a wealth of information on filtration practices in effect at the Aquarium of the Pacific that I would love to share with you! Recently, I mentioned that the Aquarium filters approximately 1,000,000 gallons of salt water per hour to support over 12,000 marine residents. Whether you’re maintaining an exhibit that holds 200 gallons or 200,000 gallons, filtration is an integral part of any successful man-made marine habitat.
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