All over the world, people and governments are spending billions of dollars to manage wastes. The oldest and most common way is a landfill system whose life span governments and environmental groups are trying to prolong by recycling biodegradable waste. Incineration is considered the main alternative.
In the CNMI, solid waste is managed through the landfill system in Marpi and recycling at the transfer station in Lower Base.
The original cost of Saipan’s solid waste management program was $15.1 million when the landfill and transfer station were built seven years ago.
But in eight years of its operation, approximately $18 million has already been spent on the program. By next year, it will need $2 million more for heavy equipment and other operational expenses. And since existing cells will deplete soon, it is also anticipated to require an additional $10 million for expansion.
The cash-strapped CNMI government is consistently challenged by these solid waste issues.
Aside from the ongoing efforts to comply with the U.S. Environmental Protection Agency’s order regarding the old Puerto Rico dump site, the CNMI government also has to deal with the high cost of operating the Marpi landfill, which involves the safety of workers, the devaluation of surrounding properties and the possible emission of toxic gases and other environmental contaminants.
Last week, CNMI-Eco Tech showed lawmakers a new technology that can dispose of the island’s waste.
According to Eco Tech vice president Herman P. Sablan, the technology will help the CNMI save money in operating its landfill.
It will also reduce the need for federal intervention, he said.
And because it disposes waste, the landfill will not be expanded, he added.
This will help preserve the surrounding public lands for homesteads and tourism-oriented projects, or for their natural inhabitants such as birds.
The technology that will be used in the waste treatment system is called pyrolysis, melting vitrification method.
This involves the use of a low voltage direct current high temperature system. It can also treat middle and low level radioactive wastes.
This technology, Sablan said, can turn wastes into energy. The by-products of the system, called crystals, can be used for construction.
How it works
The waste is broken down to create gas, solid and liquid residues through thermal processes. The gas can be burned in the next process. The pysolysis process thermally degrades waste in the absence of air.
In the gasification process, the temperatures are usually above 750 degrees Celsius. The main product of gasification and pyrolysis is syngas which is composed mainly of carbon monoxide and hydrogen with smaller amounts of carbon dioxide, nitrogen, methane and various other hydrocarbon gases. Syngas has a calorific value that can be used as fuel to generate an electricity stream. The calorific value of syngas will depend on the composition of wastes entering the gasifier.
Pyrolysis and gasification rely on feedstock rich in paper, kitchen and garden wastes as well as plastics.
Although these processes are not 100 percent capable of producing renewable energy, they can make a landfill system work better compared to incineration.
Landfills, Sablan said, are costly to develop and maintain, yet have a relatively short lifespan. Landfills also expose contaminants to air and soil. The necessary expansion will also deny future generation the use of nearby lands.
Looking from the top of Suicide Cliff, he also noted that Marpi Landfill is an “un-inviting” sight.
Eco-Tech’s waste disposal system will use solar panels to run the processing plant that can receive 20 metric tons of wastes every day. It can also accommodate the wastes from Tinian so that the municipal government does not have to build its own landfill.
Eco-Tech also plans to build a processing plant on Rota.
