subject: Buying Affordable Marine Sanitation Systems [print this page] Any boat, yacht, ship or vessel that has a toilet installed on board, which is referred to as a marine sanitation system, is required to be equipped with one of three types of MSDs (Type I, Type II or Type III). The three are all designed to meet different needs and have effluent level requirements. Those boaters with vessels that have portable sanitation systems are not required to fulfill this obligation since they can be removed from the boat. Those with portable toilets are not subject to MSD regulations.
Type I marine sanitation systems are flow through devices for maceration and disinfection for vessels that are shorter than 65 feet long. The waste produced can not have a fecal coliform bacteria count that is greater than 1000 per 100 mL, and it cannot have any visible floating solids, either. These types of sanitation systems disinfect the waste prior to it being discharged into the waters.
Type II sewage treatment devices are flow through systems that are designed for vessels that measure more than 65 feet in length. The waste that is in the unit can not have a fecal coliform count that is greater than 200 per 100 mL. With this sanitation device, there can be suspended solids but they cannot be more than 150 milligrams per liter. These are pretty similar to Type I systems, but these have a more advanced micro biological treatment set up and it will discharge waste with lower fecal coliform counts as well as reduced suspended solids. These basically work like a miniature septic system.
Type III devices are not flow through systems, so they are not really working or disinfecting systems for boats, ships and other vessels; in contrast they are holding tanks and are for use with vessels of any length. These Type IIIs are designed to prevent the discharge of untreated sewage by holding the wastes until the tank can be emptied at a marina dock. Since they hold waste instead of passing it through and discharging it, they are not treatment sanitation systems but instead are simple tanks that receive sewage that is flushed from the marine head. The holding tank contains deodorizers and other chemicals. It is these holding tanks that are designed to be pumped out by shore side pump out facilities.
If you are considering purchasing one of the available marine sanitation systems for your vessel, just make sure that whichever one you purchase is approved for use by the United States Coast Guard.
