Environment: Managing waste becoming more than reduce, reuse, recycle

Each year, Cayman adds about 90,000 tonnes of waste to a single landfill site that already contains 1.5 million tonnes of garbage. In an area of 37 acres, this means the trash piles nearly 90 feet high.

Each man, woman and child in Cayman generates 2,775 pounds of waste during the course of a year. Once Cayman’s tourist population is factored in – tourists raise Cayman’s full-time population by about 8,600 – that figure is 2,442 pounds per year, about the same weight as a compact car.

“That is quite high,” says Martin Edelenbos, Engineering Coordinator, Waste Management, Dart Realty (Cayman) Ltd., who presented the above statistics at the Royal Institution of Chartered Surveyors conference in Grand Cayman last month.

The landfill is managed mostly as an open dump with large exposed areas of waste in close proximity to the most densely populated and developed part of the island. The 70-acre area is not lined or engineered and the dump which makes up just over half of the site, grows by 8,000 cubic yards per month.

But this is about to change.

In 2017, government picked a consortium led by Dart as the preferred bidder for an integrated solid waste management system that is going to replace the current landfill which is nearing the end of its life.

The new system will include a waste-to-energy facility and operate as a public-private partnership on a contracted ‘design, build, finance, operate and maintain’ basis. Talks with the government to resolve the remaining contractual issues have been ongoing since October 2017.

But, speaking at the RICS conference, Edelenbos, said, “I don’t think that the time that has been spent is abnormal for this type of project.”

The waste management expert for Dart Realty and DECCO, Dart’s construction arm, said that the 25-year programme is complex and he predicted it will take until late spring or summer this year for the government contract to be finalised.

A global problem …

Aside from population growth, income is a major driver of waste generation globally, and high-income countries are the biggest waste producers per capita. The U.S., for instance, produces nearly as much waste as China, even though it only has about a third of the population.

Cayman is no different. International Solid Waste Association data shows a correlation between income and waste generation in the Caribbean, where Cayman is the largest waste producer on a per-capita basis. Plastic garbage, which often washes onto Cayman’s shores, is only part of the waste disposal problem, even though it is the most visible example as plastics travel great distances across the world’s oceans.

Globally, about 30 percent of waste remains uncollected, and out of 7.7 billion people worldwide, only 3.5 billion have access to a managed waste system. Because eight of the world’s 10 major rivers flow through poor and developing countries, where historically rivers have been used to dispose of waste, the problem does not remain localised.

… managed locally

However, it is at the local level that waste must be managed, and the list of problems associated with Grand Cayman’s landfill is long.

The landfill is managed as an open dump near a school and residential areas. The lack of regular soil cover, which technically differentiates a landfill from a dump, attracts rats, dogs, birds and insects and risks supporting the spreading of diseases.

While in the U.S. and Canada it is a requirement that waste is covered with a minimum of six inches of soil at the end of every day, Edelenbos noted, there are no environmental controls in place here for leachate or landfill gas. And storm water is an issue in the former mangrove area as it can get contaminated.

“Fortunately, as a matter of circumstance, groundwater contamination does not appear to be much of a problem at the site. What’s worse is that there is very little control over storm water. So, any leachate that leaks out of the landfill gets washed into the North Sound,” Edelenbos said. “That will all be resolved once the site is remediated.”

This will also happen very quickly, once DECCO has a contract with government, he added.

Fires are probably the most serious contamination aspect in the landfill, Edelenbos said, given that the smoke from dump fires is quite toxic.

Only last month, a small fire occurred in the landfill, but it was put out quickly.

Although there is a certain degree of control over the waste, with special waste, like acid batteries, being managed, a recycling programme in its infancy, stockpiles of scrap metal and much reduced stockpiles of tyres, several consultant reports commissioned by government have confirmed that the current situation is unsustainable and poses a potential environmental threat.

The reports called for an integrated waste management solution, which simply means that different types of waste are managed in different ways.

The solution pursued by the public private partnership project aims to reduce the amount of waste that goes into the landfill by up to 95 percent.

The scheme will add a couple of steps to the often quoted ‘reduce, reuse, recycle’ approach to dealing with waste. In Cayman, the fourth ‘R’ will be ‘recover’, which refers to the recovery of energy from waste that cannot be managed in any other way. Only the ash that is left over after the waste-to-energy process will be deposited into a landfill.

The waste-to-energy facility is the most expensive part of the programme and is expected to cost in excess of $100 million.

In the waste-to-energy facility, waste is collected in a hopper that feeds into a furnace, which burns the waste and produces heat that is used in a boiler to generate steam, which in turn powers the turbine that produces electricity. Exhaust gases are treated and scrubbed of contaminants before they are released through a chimney.

The fly ash, which is the air pollution control residue, is processed and tipped into the landfill.

The bottom ash from the furnace makes up between 20 and 25 percent of the total weight that is going into the landfill. Edelenbos explained that, to achieve a reduction of 95 percent of waste that goes into the landfill, it must be stripped of metal and other materials that can be reused as aggregate.

The only comparable waste-to-energy facilities in the region are in Bermuda and in St. Barths, Martinique.

At full capacity, the Cayman plant will generate 7.5 megawatts of electricity which will be sold to CUC. This represents about 8 percent of the island’s electricity consumption.