In the drainage of the rain and filtered waters, directed to the inspection boxes, the presence of a high content in ash was noticed, which was conducted directly to the sewage system of the Airport without previous treatment, and this would generate a direct pollution of the water resource. In the construction process of the project, the ash is used to fill and, in suspension in the draining water, affects the quality of the water, which generates a direct pollution of the sewage system, which additionally supposes contractual non-observances with the Civil Aviation, apart from possible fines and sanctions by the Secretariat of Environment, which established the prohibition of pouring industrial waters directly to the sewage system.

In order to mitigate this environmental impact generated by the development of the project, as well as observing the applicable regulation, it is necessary to adopt corrective measure, and the discharge of waters in the conflict point is immediately suspended. Additionally, the need to build a desander of rain and runoff waters, located close to the Resting building (conflict point) is established. As a last resort, it is decided to carry out, additionally, a protection of the drain, which is the final point to which the project’s waste waters arrive, to the sewage system of the El Dorado Airport.

As a result of the implementation of these measures, and to check that the construction of the desander observed the needs for which it had been built, a Monitoring and Follow-up Programme was carried out of the waste and domestic waters derived from the project, where the waste water quality that would be discharged in that point was tested. The obtained results were compared with parameters established by regulation, and it was checked that the project observes the requirements requested in the environmental subject and the desander complied with its function correctly. With all this, the observance of the applicable regulation has been achieved, as well as an important decrease of the pollution levels of the discharged waters.