Leaching continues at Mount Trashmore

Trash tech years away

Sean McGinn, manager of the George Town Dump has confirmed that a planned waste-to-energy – also known as landfill mining – plant at the Mt. Trashmore site, now holding steady at the 55 foot mark, will not be in place for at least 4 years.

This comes amid concerns expressed by Communications and Works Minister Arden McLean that the dump is without a doubt leaching harmful substances into the surrounding soil and water.

Still growing

While the four-year implementation timeline fits within Minister McLean’s commitment to deal with the waste problem during his term, it also means that the trash pile, which takes up much of the 71 acre site, is going to keep on growing until the waste to energy plant begins operations.

The current annual rate of trash added to the 900,000 ton dump is 167,170 tons, based on a daily rate of 458 tons.

While the landfill mining project is under development, Mr. McGinn hopes that the rollout of the Department’s new recycling program will successfully divert 30 per cent of the recyclable aluminium, glass, paper, organic and plastic waste destined for the dump within 3 years.

Construction has already begun on the four recycling depot bins which will soon be placed in high-traffic locations across Grand Cayman.

At the moment, dumpers are being asked to begin separating their waste on-site. In addition, because of the Pink Hibiscus Mealybug problem, all organic waste is now being disposed of at the site in an air-curtained incinerator.

Mr. McGinn has also received a positive response from local bars and restaurants in support of a glass waste separation program to aid the recycling efforts.

‘With reasonable participation of the public and local businesses, in three years, our daily intake of trash should be reduced to around 3 tons,’ he said.

Citing a successful plant he recently visited in Massachusetts, which converts over 400 tons of trash into 9.4 megawatts of electricity per day, he foresees using three tons of ‘fresh’ garbage, plus one ton of ‘old’ garbage to fuel the new power plant and deplete the dump.

Many uses

The combustion by-product is an ash that can be subsequently used to make such products as bricks and paving.

‘We are confident that once we start, we will be able to get rid of all of the garbage that is presently at the site,’ said Mr. McGinn.

The eventual removal of the dump is a good start, says Tim Austin, Assistant Director of Research and Assessment for the Department of Environment. However, but he says the leachates will continue to have an impact long after the dump is gone.

The Department has a North Sound water testing site near the dump’s leachate outflow, where they monitor nitrates, phosphates, and limited temperature.

‘While it is difficult to say whether the nearby sewage treatment facility is having a significant impact on our results,’ said Mr. Austin, ‘we have major concerns about the water quality in that area.’

Mr. Austin says that the coral reefs that sustain much of Grand Cayman’s tourism are highly sensitive to changes in water clarity and temperatures that nitrates and phosphates impact.

‘The North Sound coral reefs are already under stress, and increased phosphates, for example, promote algae growth which, aside from disease, is their number one enemy. Poor water quality is certainly a factor in affecting the North Sound’s aquatic environment,’ he said.

The Department of Environmental Health has been monitoring the groundwater in the dump’s vicinity,

Ground water (water below the ground’s surface) is tested because it can easily be sampled for various leachates.

Monitoring water

Antoinette Johnson is the Department’s Senior Research Officer in charge of the groundwater testing for the dump.

Ms Johnson’s team monitord the groundwater in approximately 10 strategically located testing wells and six to eight surface water sites around the dump for what are known as Appendix One contaminants.

These include heavy metals like lead, nickel and mercury, the volatile organic compounds found in paints, cleaning supplies and fuels, and some other chemicals.

The team uses landfill-monitoring techniques approved by the US Environmental Protection Agency.

‘It is not only a matter of whether the results are below recommended limits,’ said Ms. Johnson. ‘Any changes over time in our results can indicate potential problems.’

So far, Ms. Johnson’s testing has not revealed levels exceeding EPA recommendations.

‘It seems that the high levels of sediments made up of organic matter in the dump are doing a relatively good job of holding in the worst culprits,’ she said.

Jeff Lombardo of Dart Realty concurs. “We have engaged a company to do a comprehensive environmental assessment of the area adjacent to the landfill, which includes water, sediment, soil air and soil testing for a number of chemicals, which may be possibly present at the landfill,’ he said.

‘Based on our results to date, there is no indication of significant impacts to the water, soil and sediment.”

However, the eventual mining of the landfill will disturb the compacted layers inside, which could possibly cause further pollution.

‘Any waste to energy facility that is commissioned there will have to address these considerations,’ said Ms. Johnson.

She also remarked that controlling the increased leachate once the inside of the dump is exposed to the elements, and controlling the methane to prevent explosions are also very big concerns.

Ms Johnson said the one message the Cayman public should be getting from this ongoing situation is that there is no question that current dumping practices cannot continue.

‘It is up to the Cayman public to look at their current attitudes with regards to waste,’ she said.

‘We need to look at ways to minimize waste, to watch what kind of products you buy, and to dispose of them properly. The current dialogue surrounding the dump problem is a great way to begin examining the way our consumer practices affect our Island.’

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