Demolition / Recycling of Materials
The (non-polluting) waste resulting from the demolitions allowed the local adoption, in the Park of Nations, of simple recycling mechanisms which led the contractors to absorb the demolition debris, reusing it as a raw material in future construction works, avoiding the use of places for the dumping of materials with its environmental consequences. For this purpose a large scale recycling system was installed in the Park of Nations which served to process the materials left over from the demolition work. This recycling process involved about 812,000 tonnes of concrete materials, with the addition of all the masonry made up from tiles, blocks and stone to the amount of 190,000 tonnes and the pavements in concrete or bituminous materials to a total of 60,000 tonnes. The quantity of steel resulting from the separation of concrete came to about 5,000 tonnes which were taken to the foundry for its appropriate transformation. The recycling of ferrous materials and of others which was not possible in the installations in the Park of Nations were processed in outside units.

Petrol Industry Land / Beirolas Waste Landfill
The diagnostical studies carried out on the southern part of the Park of Nations, where the petrol companies have been installed since the forties, led to the discovery of the presence in places of levels of hydrocarbons well above acceptable limits for the residential use of the land, as was planned in the approved Urbanisation Plan. However, the results of these studies were encouraging, given that they allowed the confirmation that the geological characteristics of the place (a layer of clay of low permeability was identified) acted as a natural barrier to the deeper migration of contaminants. The depth to which contamination of the soil was detected did not exceed, as a rule, two metres, with an estimate of about 250,000 m³ of soil which required treatment. The Beirolas Waste Landfill is situated to the far north of the Park of Nations, between the river Trancão and the Beirolas Waste Water Treatment Plant. In the period from 1985 to 1990, this landfill was the favourite place for the dumping of solid waste coming out of Lisbon. It was used for a greater period than that initially intended, which resulted in its excessive use and consequent functional failures in terms of its systems for the drainage of lixiviums and bio-gas which had been planned, as well as a degree of instability in the embankments of the landfill, something which was detected during the visits made to the location when the diagnostical studies were being carried out. The work carried out for the environmental recovery of the landfill included: (1) smoothing out of the embankments of the landfill, in order to ensure their stability; (2) the extraction of lixiviums which had accumulated on the interior of the landfill and its treatment in an appropriate place; (3) the extraction of bio-gas and its treatment (burning or use for the production of energy); (4) isolation of waste deposits by means of the application of an impermeable membrane; (5) installation of a drainage system for surface waters; (6) emplacement of a layer of earth which would allow the installation of vegetation planned for the Tagus Park, the 80 hectare park which occupies the northern part of the Park of Nations. The need to quickly clean up the land around the petrol industry installations in order to move onto the general modelling of the terrain and to smooth out the embankments of the Waste Landfill using filling materials to guarantee its stability, were determining factors in the choice of a technical solution to clean up the petrol companies’ lands. Thus, the excavation and transportation of the soil contaminated with hydrocarbons to the Beirolas Waste Landfill, where it was deposited in a confined unit so as to guarantee its isolation, was considered the most appropriate solution in view of the deadlines imposed for the cleaning process of the land around the petrol industry installations, given that any of the other of the solutions studied (thermic treatment or bio-correction) would imply much longer periods of time than those available for the development periods for the EXPO`98 project. On the other hand, this solution allowed the use of the petroleum-contaminated soils as a necessary landfill material for the smoothing out and stabilisation of the embankments of the Waste Landfill. The installation of a mobile Waste Water Treatment Plant during the soil excavation works enabled the cleansing of the subterranean waters and the recovery of free products (diverse types of petroleum-based products), which, after separation by aqueous fractionation, was led off to be re-used in accordance with its characteristics.

Waste Landfill / Beirolas Waste Waters Treatment Plant
In the context of the recovery of the Beirolas Waste Landfill it was necessary to extract the lixiviums produced by the degradation of the rubbish, ensuring its adequate treatment, given that we were dealing with aggressive fluids which pollute the environment. The proximity of the Beirolas Waste Waters Treatment Plant facilitated the treatment of these fluids which were pumped through the elevation system installed in Waste Landfill and duly treated in the Waste Waters Treatment Plant. On the other hand, the improvement works of the Beirolas Waste Waters Treatment Plant, which was the responsibility of the Lisbon Town Council, required the introduction of tertiary treatment, which would allow the water treated in the Waste Waters Treatment Plant to be used to irrigate the green areas of the Park of Nations, namely those which are in the area of the Waste Landfill. This was one of the cases in which, taking advantage of the presence of two environmentally unpleasant infrastructures from the perspective of urban development, the Urbanisation Plan of the Parque EXPO made possible an integrated improvement of tremendous environmental value.

Transplantation
About 500 trees which were previously growing on the land of the Park of Nations form part of the green areas created by the Urbanisation Plan of the Parque EXPO. Resorting to the use of German technology – the best system – these trees were transplanted from the places they were growing to a provisional zone before going to their definitive location. This transplantation allowed these trees to be preserved, and which, otherwise, would certainly have been destroyed in the process of the works. Although they are only a small part of the 10,000 planned for in the Urbanisation Plan, these 500 trees in the terrain also represent the effort of Parque EXPO to search for integrated solutions for the success of the project. Besides these trees, around one hundred trees from Lisbon and surrounding areas were transplanted to the Park of Nations, some already to their definitive locations, by means of the traditional method of transplantation.

Preparation of the Mould
As an alternative to the importation of the mould to receive the plantations planned for in the Urbanisation Plan, the Parque EXPO prepared, inside the Park of Nations, the mould which it used in the green areas. The preparation of this mould resorted to the use of materials originating in the Park of Nations itself, including the mud from the Waste Water Treatment Plant and the compost arising out of the treatment of waste from the Beirolas Solid Waste Treatment Plant. The detailed characterisation of the various types of soil existing in the Park of Nations allowed the identification of the appropriate proportions in which, mixed together with the materials previously mentioned, the best agronomic conditions were arrived at to receive the mould covering planned in each of the green areas of the Urbanisation Plan.

The Parque EXPO prepared about 150,000 m³ of mould on its lands, which was applied in the green areas it prepared.