conclusion possibly the most complex and critical project ever undertaken by the Bermuda Government.

The magnitude of the project coupled with the perceived detrimental impact on Bermuda resulted in the venture becoming high profile and sensitive -- both environmentally and economically -- from the start.

But it was evident that Bermuda needed to find an alternative waste disposal plan. In the early 1980s with 80,000 tonnes of domestic and commercial waste being generated annually, the Island's only landfill site was nearing capacity and producing unacceptable problems for local residents.

The Government decided to replace landfill as a method for disposal of combustible waste with the provision of a municipal waste-to-energy mass burn incinerator.

So in 1987, Von Roll Ltd. of Switzerland was engaged to design, procure and install the incinerator's mechanical and electrical plant. Objections on environmental grounds delayed planning approval and caused delays in the development of the project.

But in-depth hearings and environmental impact studies were initiated and it was later shown that the impact on the environment would be acceptable.

In 1991, the Ministry of Works & Engineering became faced with the challenge of coordinating the design and the considerable task of bringing together the multi-national workforce to construct the $70 million facility. By October, 1994, the plant was in operation.

Said senior plant manager Mr. Al Keeler: "The plant is still in the commissioning stages and there are some construction deficiencies that need to be remedied. Also some mechanical work needs to be done in various areas of the plant.

"But the incinerator is still receiving about 5,000 tonnes of waste per month,'' he noted, adding that the volume of combustible waste is reduced by 70 percent.

"I'm very impressed with the facility. And I think it was the best option for Bermuda. The problems we are experiencing are no worse or different than those associated with mass burn incinerators in any other country.'' The Tynes Bay facility has two streams each capable of incinerating six tonnes of waste per hour. A single stream can incinerate all of the Island's current combustible waste, while the second acts as a full back up.

Each stream is designed to operate 24 hours a day for 4,000 hours between planned maintenance shutdown, when the alternate stream takes over.

Incoming waste is inspected and weighed prior to discharge into the refuse bunker. It is then mixed to provide a homogeneous material before it goes into the furnace. The temperature of combustion is controlled by the volume of air and the rate of feed through the combustion chamber.

The gases from the combustion process are cooled at various locations by passing them over banks of boiler tubes containing water, which is chemically treated to reduce the possibility of corrosion.

The boiler produces steam superheated to 400 degrees Celsius, which is fed to a steam turbine coupled to an electricity generator. And the turbine generator is connected to the facility's distribution system, which in turn, is interconnected with Belco to enable energy to be either imported from, or exported to the public supply system.

Each stream of the plant has the capacity to produce in excess of 2.5 MW of electricity, approaching five percent of the Island's average need.

Said Mr. Keeler: "The incinerator has generated well over 4,000 mega watt hours of electricity in total. And when the plant gets all the energy it needs, the surplus is exported to Belco.

"In the future, there's no reason why our turbine can't run for about 8,000 hours a year, which could supply Belco with a lot of excess power.'' After driving the turbine, the steam is condensed by sea water and passed back into the boiler system via a de-aerator to ensure water is returned to the boiler free of gases. If the turbine is shut-down, the combustion process will continue by diverting the steam from the boiler to separate dump condensers.

The sea water is returned to the ocean at approximately 10 degrees Celsius above ambient.

Combustion gases are cleaned by passing through electrostatic precipitators which remove in excess of 99 percent of particulate matter. And from there, fans emit the gases to the atmosphere through a chimney, which is 91 metres above sea level or 75 metres above the surrounding ground level.

Monitoring equipment continually measures temperature, oxygen, carbon monoxide, sulphur dioxide, hydrogen chloride and opacity to establish that emissions remain within permitted limits.

Waste water generated by the facility is collected in a large storage tank and is then pumped into the quench tank to be absorbed by hot ash.

Ash that drops off the furnace grate and the particulates removed by the electrostatic precipitators is also transported to the quench tank. The combined wet ash is then conveyed to the ash bunker for storage.

Ash handling equipment near the ash bunker is used to process the ash, which is graded by passing over a 100 millimetre screen, and ferrous material is removed with a magnetic separator.

The ash is weighed and the moisture content is determined prior to mixing with cement to form ash concrete, which is formed into one metre cube blocks, each weighing approximately two tonnes.

The ash-concrete blocks are placed in Castle Harbour where they are being used for shore protection and land reclamation.

TONNES OF TRASH -- The bunker at the Tynes Bay plant stores up to 2,500 tonnes of garbage. Presently, the incinerator receives about 5,000 tonnes of refuse per month.

OCEAN VIEW -- The Tynes Bay Waste Treatment Facility on Palmetto Road, which overlooks the North Shore, reduces Bermuda's combustible waste by 70 percent.

SENIOR PLANT MANAGER -- Having worked in the utility engineering field for the past 24 years, Canadian Mr. Al Keeler brings a lot of management expertise to the Tynes Bay Incinerator.

MINI SUPPLEMENT SUP