less water for flushing than a manual pump a plus when the holding tank is being used. Disadvantages: Require electrical power for operation. Motor, shaft seal and/or impeller may burn up if pump is run dry. AdditivesA variety of additives are available to treat toilet and marine sewage odors and/or to help break down solid wastes. These are typically injected at the toilet intake line, at the toilet itself, or at an inline sewage treatment device. The use of additives in conjunction with holding tank systems is not required. Deodorants may be desired to control odors produced by anaerobic bacteria in holding tanks. However, caution must be used while tanks and system fittings may deteriorate from exposure to certain additives (household bleach, caustic cleaners, etc.). It is important to make sure only additives that are recommended for the particular marine sewage system are used and that they are environmentally friendly as well. Also… as an aside, we (Charles and Mike) took a guided tour with a close navy officer on the nuclear powered USS Olympia to see and understand their waste disposal system. He told us that they also, abiding by law, have to go out pass the 3 miles offshore limit to dump sewage. Also, they have to go 25 miles offshore to dump regular waste products such as plastics and common household rubbish. For the regular trash, the submarine has an onboard system in which the trash is super compacted into a metal cylinder approximately 4 feet tall and 1 foot wide. Then weights are placed in the bottom to ensure it stays at the bottom (25 miles out at sea on the Pacific is around 3 miles deep, and on the Atlantic, much less than a mile) and does not cause any immediate environmental repercussions. This is still harming wildlife, but it could be a lot worse if they just dumped raw trash out at sea. The tour of the submarine was a very interesting and cramped one, and one that has opened our e...
