What is High Density Polyethylene (HDPE)?
It is a synthetic polymer, thermoplastic polyolefins member obtained from a reaction known as polymerization of polyethylene made from ethane, a component of natural gas. In the high density polyethylene to higher density, lower permeability, due to their nonpolar nature, it absorbs very little moisture and has high quality vapor barrier substance. It is designated as HDPE (High Density Polyethylene)
What are the properties of high density polyethylene?
- Excellent thermal and chemical resistance.
- Very good impact resistance.
- It is solid, colorless, translucent, almost opaque.
- Very good processability, ie can be processed by forming methods used for thermoplastics such as injection molding and extrusion.
- It is flexible even at low temperatures.
- It is tenacious.
- Stiffer than LDPE.
- Presents difficulty printing, paint or paste on it.
- It is very light.
- Its density is equal to or less than 0.952 g / cm3.
- It is not attacked by water resistant to 100 ° C and most ordinary solvents acids.
Why use HDPE in the construction of submarine pipelines?
It is the best alternative for the construction of submerged structures, their advantages which outweigh other conventional materials such as steel, cast iron, fiber or concrete. The most striking benefits of HDPE are:
- Lower frictional losses.
- Easy to transport.
- It is not attacked by corrosion (does not require cathodic protection).
- It prevents the accumulation of sludge and scale within.
- Long life (over 60 years).
- Lower costs of procurement and installation.
- Lower maintenance costs.
- Resistant to earthquakes.
- Elasticity and flexibility to adapt to the topography.
What is an outfall?
It is a system of wastewater treatment that uses a water purifying capacity of the receiving environment by conducting the effluent, raw or pre-processed, from the coast to the bottom of a marine and coastal sector.
What is the main objective of an outfall?
The main objective of the outfalls is to minimize the environmental impact that can have dumping sewage into the sea, or what is the same, ensuring good dilution so that the mixture of wastewater and seawater does not alter in any way the natural appearance and is harmless to the marine ecosystem, to the coast and to the health of humans.
What is the initial dilution or dilution near field?
It is the mechanical process by which the substances are diluted in water by mixing and turbulence, decreasing the concentration uniformly, when it falls to a larger volume of wáter.
What is the dispersion or diffusion far field?
It is a physical process caused by currents caused by the mixture of water leaving the emissary to the great ocean volume surrounding favoring the dilution process.
What is bacterial decay?
It is a measure used to indicate the death of pathogenic bacteria that occurs in the marine environment. This “decay” occurs by several factors: the high salinity that has the sea temperature, U.V. rays solar and action of predators organisms in the marine environment.
What provides the purification capacity in an outfall?
The rapid dilution of substances in the marine environment and the bacterial decay possible to ensure that the action of purification system outfall (SIDES) is perfectly compatible for more restrictive use of environmental standards, including use for bathing, farming, fishing , recreational and sports.
What is Bioaccumulation?
It is a process of progressive accumulation of chemicals in the tissues of living things, as they move up the food chain.
What it is called Mixing Zone?
It is the region located in the coastal marine area around the diffuser discharge delimited for complete mixing of the effluent with the receiving environment, which are restricted the activities of human use.
