The European Parliament Water Framework Directive (WFD), 2000/60/EC, is a standard establishing a common framework for water policy in Europe. Its aim is to ensure the protection of water and promote its sustainable use to ensure the long-term availability of this natural resource. The WFD takes water from being a simple resource to being considered in the European Union as the key to the conservation of living systems associated with it. It represented a milestone in the management of water resources and related ecosystems in Europe and was a reference for most developed countries. Continue reading
Within the construction sector, a wide variety of containment and stabilisation systems for slopes and hillsides have been used over time to address the problems of landslides and collapses of large land masses.
In general, one can consider the stabilisation systems acting on a mass of unstable terrain that would otherwise cause deep landslides, and other containment systems applicable to minor slopes of less unstable ground. The stabilisation systems on hillsides or slopes usually consist of several types combined together. Continue reading
Pile foundations are used in construction to form deep foundations in the search for layers of resistant soil capable of withstanding loads that cannot be properly distributed by a shallow foundation. The component fixed into the ground is the pile, which can take various shapes and sizes and be made of different materials, although they are typically of concrete or steel.
There are basically 4 methods of driving piles: by percussion, vibration, drilling and pressure. Continue reading
An important part of the economic and social development of any country is the construction sector. There are major challenges in all phases of projects, in both civil engineering and in building, to minimise the impact on people and the environment.
In the developed world, environmental issues such as the efficient use of resources and their sustainability, the protection of biodiversity, climate change and the risk of accidents have become very important in all areas, including construction. Continue reading
Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) are two of the most important parameters to characterise (measure the degree of pollution) of wastewater.
BOD, the biological demand for oxygen a source of water has, is the amount of oxygen used by microorganisms to break down organic substances. These are usually bacteria (aerobic or anaerobic), yeasts and plankton contained in the water. It is a measure of the degree of contamination and is expressed in mgO2/L. Continue reading
There is a wide range of commonly used coagulants and flocculants for the clarification of various types of wastewater.
In general, they can be classified into two types: inorganic and organic. The inorganic compounds are usually metal salts, typically aluminium or iron (with the most widely used being aluminium sulfate, iron sulfate and iron chloride); while the organic compounds are polymers (polyelectrolytes), and represent a wide variety of water soluble macromolecular compounds of natural or synthetic origin, which have the property of enhancing the flocculation of suspended particles. Continue reading
Turbidity is an optical property that broadly describes the clarity or cloudiness of water. It is related to colour, but has more to do with the loss of transparency due to the effect of suspended particles and colloidal material.
Turbidity impacts on aquatic ecosystems by dispersing sunlight and reducing the oxygen concentration. It also affects photosynthesis as well as the respiration and reproduction of fish. Suspended particles also contribute to the adhesion of many heavy metals and other toxic compounds. Turbidity is considered a measure of water quality: the more turbid the water, the lower its quality. Continue reading