Saipan Integrated Waste Management System

Planning, Design, and Construction Management (1999 – 2004)

The island of Saipan is the capital of the US Commonwealth of the Northern Mariana Islands (CNMI), a 14-island archipelago in the North Pacific Ocean, about three-quarters of the way from Hawaii to the Philippines. CNMI is under the jurisdiction of the US Environmental Protection Agency (EPA), Region 9.

In the early 1990s, the EPA issued a compliance order to CNMI to close Saipan’s Puerto Rico Dump, which was plagued with flies and landfill fires, near areas frequented by tourists, and visible from the main highway. Although the dump had begun as a military dump site, it had become the island’s only municipal solid waste disposal site.

By the late 1990s, daily soil cover was being placed over the refuse. This helped control the flies and fires, but the site drew increasing negative publicity from the media and became a sensitive topic with the local tourism industry. Clearly, a new landfill was needed so the dump could be closed. CNMI’s goal for a new waste management system was not only to comply with federal regulations, but also to implement state-of-the-art waste reduction and diversion (i.e., recycling or composting) technologies.

In 1999, CNMI awarded MACTEC a contract for solid waste planning and design services. CNMI also hired a Solid Waste Program Manager and formed a Solid Waste Task Force led by the lieutenant governor to oversee planning and to establish policies for implementing new solid waste programs. In 2002, after successful completion of the project’s planning and design phases, CNMI awarded MACTEC another contract for construction management services for the new solid waste facilities.

Community Education and Public Involvement

Initially, MACTEC developed a community education and public involvement program to inform stakeholders (government, businesses, and residents) of solid waste problems and potential solutions, to raise environmental sustainability awareness, to encourage participation in the decision-making process, to gain feedback about preferred solutions, and to complete site selection processes started earlier by CNMI. This program carried through the entire project, involving the public in initial planning, decision making, groundbreaking, and ribbon cutting ceremonies.

Implementing a Waste Management Plan

$4.3 million Lower Base Refuse Transfer Station

8,000-square-foot solid waste transfer building

$9.4 million Marpi Solid Waste Facility

The sources, composition and quantities of waste going to the Puerto Rico Dump were evaluated and used to develop twenty-year projections. It was discovered that 33 percent of Saipan’s solid waste stream was garment waste (garment manufacturing is the island’s primary industry) and other easily divertible products.

Because of Saipan’s remoteness and the associated difficulties with operations and maintenance, it was necessary to develop technologically simple solid waste diversion and disposal systems. This eventually included implementation of diversion programs, a new solid waste transfer station and materials recovery facility, and a new municipal solid waste landfill. Longer-term implementations included neighborhood convenience centers, revisions to collection programs, additional recycling and reuse programs, and provisions for a waste-to-energy incineration system.

All planning and design efforts were coordinated with the EPA, CNMI’s Department of Environmental Quality, CNMI’s Division of Solid Waste Management, and CNMI’s Solid Waste Task Force to secure the required construction and operation permits.

Lower Base Refuse Transfer Station

MACTEC designed the $4.3 million Lower Base Refuse Transfer Station to enable residential and commercial vehicles to drop off solid waste at a central, easily accessible location for bulk transport to the landfill. The station includes all utilities (water, sewer, power and communication), a truck weighing station, a 10,000-square-foot materials recovery building, and an 8,000-square-foot solid waste transfer building.

Offsite, a wetlands area was constructed for stormwater treatment, and improvements were made to a nearby highway intersection.

A New Landfill

The $9.4 million Marpi Solid Waste Facility includes site-support facilities, a diesel electrical power generation facility, fuel storage systems, a small-hauler drop-off area, a twelve-acre lined waste management unit, a five-million-gallon leachate storage pond, water and wastewater systems, stormwater control systems, site access roads, and parking. The initial twelve-acre lined area is designed to be expandable as needed to handle future solid waste disposal needs. The facility is fully compliant with the Resource Conservation and Recovery Act’s Subtitle D, which covers municipal solid waste.

The new landfill is used only for disposal of municipal solid waste or other non-hazardous wastes. It is constructed of multiple refuse lifts, each composed of numerous refuse cells. The lifts are sloped to facilitate drainage and to minimize cover material requirements. Daily waste placement areas are kept to the smallest area practical for the waste volumes received.

There are numerous environmental safeguards in place, including stringent load inspection requirements (waste designated as prohibited is not accepted) and quarterly testing of four groundwater-monitoring wells. Other safeguards include…

• A daily six-inch soil cover controls odors, reduces windblown litter, minimizes infiltration of water into the refuse, and provides support for vehicles. Soil cover material is stockpiled adjacent to the landfill.
• The landfill liner system includes a geosynthetic clay liner, a welded 60-mil high-density polyethylene (HDPE) geombrane, a geocomposite drainage layer, and overlying soil operations layers.
• A leachate collection system was installed to facilitate detection, sampling and removal of any leachate in the landfill. Collection begins at a rock drainage layer with six-inch-diameter HDPE lateral pipes. Drainage from the lateral pipes flows into an HDPE main pipe and on to the leachate sumps. The leachate is removed by pumps installed in 18-inch-diameter HDPE sump riser pipes. The sump riser pipes and main pipes extend above the landfill surface to allow service cleanout.

The Benefits

The Marpi Solid Waste Facility opened on schedule in February 2003. Between January and June 2004, the facility received and managed 19,564 tons of materials. About 12,542 tons were sent to the landfill, while 36 percent was diverted for recycling or composting. The most common wastes diverted during this six-month period were garment waste, green waste, soil, concrete, cardboard, large appliances, used tires, glass, office paper, aluminum, old newsprint, and plastic bottles.

During the design process, MACTEC was able to incorporate many sustainable design features to help conserve natural resources and protect the environment:

• Applying pollution prevention and temporary erosion control measures
• Preserving existing shade trees
• Preserving existing wetlands and constructing additional wetlands for stormwater discharge treatment
• Specifying energy-efficient equipment, solar water heating, natural lighting, and natural ventilation in covered work areas to reduce energy consumption
• Specifying slope stabilization, mulching, and vegetation of non-traffic areas to control erosion
• Specifying vegetation that does not require irrigation, and specifying rainwater catchment systems for domestic water, to reduce community water consumption
• Using compacted coral in place of blacktop to reduce heat islands
• Using subsurface infiltration and sedimentation basins in stormwater management systems

The Future

Throughout this effort, CNMI has made great strides in addressing its solid waste management concerns, and nearby islands have expressed an interest in learning more. CNMI recently hosted a training session in Saipan that drew attendees—both operators and regulators—from American Samoa, Federated States of Micronesia, Guam, Palau, and Yap.

The session, funded by the US Department of the Interior’s Office of Insular Affairs, covered the basic concepts of solid waste management, including development of a reasonable waste generation estimate, environmental compliance, financing, and daily operations.

Saipan now has an efficient, cost-effective waste management system that has been lauded by the EPA and was recognized by the Solid Waste Association of North America (SWANA). SWANA, which is North America’s leading professional solid waste association, awarded CNMI a Silver Solid Waste Management System Award in 2004.