Marine sanitation device
Marine sanitation devices
Section 312 of the Clean Water Act seeks to address this gap by prohibiting the dumping of untreated or inadequately treated sewage from vessels into the navigable waters of the United States (defined in the act as within 3 miles (4.8 km) of shore). It is implemented jointly by EPA and the Coast Guard. Under Section 312, commercial and recreational vessels with installed toilets are required to have marine sanitation devices (MSDs), which are designed to prevent the discharge of untreated sewage. EPA is responsible for developing performance standards for MSDs, and the Coast Guard is responsible for MSD design and operation regulations and for certifying MSD compliance with the EPA rules. MSDs are designed either to hold sewage for shore-based disposal or to treat sewage prior to discharge.
The Coast Guard regulations cover three types of MSDs.Large vessels use either Type II or Type III MSDs. In Type II MSDs, the waste is either chemically or biologically treated prior to discharge and must meet limits of no more than 200 fecal coliforms per 100 milliliters and no more than 150 milligrams per liter of suspended solids. Type III MSDs store wastes and do not treat them; the waste is pumped out later and treated in an onshore system or discharged outside U.S. waters. Type I MSDs use chemicals to disinfect the raw sewage prior to discharge and must meet a performance standard for fecal coliform bacteria of not greater than 1,000 per 100 milliliters and no visible floating solids. Type I MSDs are generally only found on recreational vessels or others under 65 feet (20 m) in length. The regulations, which have not been revised since 1976, do not require ship operators to sample, monitor, or report on their effluent discharges.
Critics point out a number of deficiencies with this regulatory structure as it affects large vessels. First, the MSD regulations only cover discharges of bacterial contaminants and suspended solids, while the NPDES permit program for other point sources typically regulates many more pollutants such as chemicals, pesticides, heavy metals, oil, and greasethat may be released by large vessels as well as land-based sources. Second, sources subject to NPDES permits must comply with sampling, monitoring, recordkeeping, and reporting requirements, which do not exist in the MSD rules.
In addition, the Coast Guard, responsible for inspecting vessels for compliance with the MSD rules, has been heavily criticized for poor enforcement of Section 312 requirements. In its 2000 report, the GAO said that Coast Guard inspectors “rarely have time during scheduled ship examinations to inspect sewage treatment equipment or filter systems to see if they are working properly and filtering out potentially harmful contaminants.” GAO reported that a number of factors limit the ability of Coast Guard inspectors to detect violations of environmental law and rules, including the inspectors’ focus on safety, the large size some ships, limited time and staff for inspections, and the lack of an element of surprise concerning inspections.25 The Coast Guard carries out a wide range of responsibilities that encompass both homeland security (ports, waterways, and coastal security, defense readiness, drug and migrant interdiction) and non-homeland security (search and rescue, marine environmental protection, fisheries enforcement, aids to navigation). Since theSeptember 11 terrorist attacks on the United States, the Coast Guard has focused more of its resources on homeland security activities.26 One likely result is that less of the Coast Guard’s time and attention are available for vessel inspections for MSD or other environmental compliance.
Annex IV of MARPOL was drafted to regulate sewage discharges from vessels. It has entered into force internationally and would apply to ships that are flagged in ratifying countries, but because the United States has not ratified Annex IV, it is not mandatory that ships follow it when in U.S. waters. However, its requirements are minimal, even compared with U.S. rules for MSDs. Annex IV requires that vessels be equipped with a certified sewage treatment system or holding tank, but it prescribes no specific performance standards. Within three miles (5 km) of shore, Annex IV requires that sewage discharges be treated by a certified MSD prior to discharge. Between three and 12 miles (19 km) from shore, sewage discharges must be treated by no less than maceration or chlorination; sewage discharges beyond 12 miles (19 km) from shore are unrestricted. Vessels are permitted to meet alternative, less stringent requirements when they are in the jurisdiction of countries where less stringent requirements apply. In U.S. waters, vessels must comply with the regulations implementing Section 312 of the Clean Water Act.
On some ships, especially many of those that travel in Alaskan waters, sewage is treated using Advanced Wastewater Treatment (AWT) systems that generally provide improved screening, treatment, disinfection, and sludge processing as compared with traditional Type II MSDs. AWTs are believed to be very effective in removing pathogens, oxygen demanding substances, suspended solids, oil and grease, and particulate metals from sewage, but only moderately effective in removing dissolved metals and nutrients (ammonia,nitrogen and phosphorus).