Question 194General Subjects - 1st Asst/Chief

The correct answer is C) Type III. A Type III MSD is used solely for the storage of sewage and flush water at ambient air pressure and temperature. It does not treat the sewage, but simply holds it until it can be properly disposed of. The other types of MSDs (Type I and Type II) actively treat the sewage to meet certain water quality standards before discharge, while Type IV systems utilize incineration or other methods to eliminate the sewage. The regulations governing marine sanitation devices are set forth in 33 CFR Part 159, which define the different types of MSDs and their requirements. Type III systems are the simplest design, relying on storage rather than treatment to manage the vessel's sewage.