Figura Nº 1. Instalación de Tuberías PEAD
Fuente: BLOGPLASTICS

The treated wastewater is normally leads to the discharge area of the receiving environment at a certain depth and distance from the coast. An output of deep water provide excellent dilution of wastewater. The depth will vary output in a range of 10-60 m, depending on the self-purification capacity of the receiving environment. The receiver means may be a river, lake or sea.

The emissary usually starts in the discharge chamber of the coastal zone, to where the wastewater is lead by gravity or pumping. It is unusual to resort to pumping directly into the outlet pipe and is not recommended. If necessary pump, the best solution is to pump wastewater to the discharge chamber and lead by gravity to the receiving environment.

The main task of the discharge chamber is to prevent air from entering the pipe. The air can cause flotation of the pipe due to the pushing force. It should also take into account the variations of the high and low tides when the discharge chamber is designed.

Issues Relating to the Project

Figura Nº 2. Diseño de Instalación de Tuberías PEAD,
Fuente: BLOGPLASTICS

In general, the specific issues that an outfall character is based are:

– Estructural
– Hidráulico
– Sanitario

La ejecución de un proyecto de emisario submarino deberá ser precedida de una búsqueda de información base por intermedio de tareas oceanográficas de amplia duración y extensión. Dichas tareas abarcan las áreas biológica, física, geológica, química y meteorológica, para la obtención de datos sobre vientos, corrientes marítimas, oleajes, mareas, batimetría y naturaleza de los fondos marinos.

El conocimiento de la naturaleza de los fondos marinos es uno de los aspectos mas importantes por lo que respecta a tuberías en zanja, directamente apoyadas en el fondo marino o una solución compuesta de las dos anteriores, en general la mas usual.

Cuestiones Estructurales

Figura Nº 3. Hundimiento de Tuberías PEAD,
Fuente: BLOGPLASTICS

Las principales fuerzas actuantes en conducciones subacuáticas son las resultantes de oleajes y de corrientes marítimas. Tuberías instaladas a lo largo de los bordes o cruces de ríos, sufren el efecto de las corrientes. En el caso de un emisario submarino, además de los efectos de oleaje y corrientes marítimas, también habrá que tener en cuenta las fuerzas resultantes de la inestabilidad de los fondos.

La evaluación de las distintas fuerzas actuantes es particularmente difícil y muchas veces poco rigurosa.

Se tendrá que obtener respuesta a los siguientes aspectos;

– Resistencia en la zona de rompientes.
– Resistencia en la zona de corrientes.
– Resistencia a la inestabilidad de los fondos marinos.
– Definición de la longitud de los tramos, de acuerdo con las características de implantación.
– Capacidad de utilización de uniones mecánicas para conectar los distintos tramos y mantener la continuidad estructural del emisario en la dirección longitudinal.
– Capacidad de adaptar “lastres” según la profundidad y las características del lecho submarino.

Cuestiones Hidráulicas

En resumen, se identifican las siguientes:

– Definición de caudales y velocidades.
– Determinación de pérdidas de carga.
– Disposición y cálculo de los órganos hidráulicos.

 Cuestiones sanitarias

Figura Nº 4. Hundimiento de Tuberías PEAD,
Fuente: SAMASA

La componente biológica en los estudios oceanográficos se subdivide en distintas partes. Una de ellas consiste en determinar el parámetro T90 (decaimiento bacteriano), con base a lo cual – tomando en consideración los efectos de corrientes, oleaje y vientos – se calcula la longitud de un emisario submarino de residuales.

También estudios de oceanografía química (calidad del agua) permiten caracterizar el medio receptor antes de iniciar el proceso de vertido o de toma. Todos los datos de base obtenidos constituyen referencias para evaluar impactos medioambientales con el funcionamiento del sistema y su control por monitorización, a saber:

– Interacción de corrientes marítimas.
– Vientos.
– Fauna marítima.
– Conocimiento de los perfiles de temperatura y salinidad en el punto de vertido / toma.
– Coeficiente de dispersión y de auto depuración.
– Capacidad del medio receptor, entre otros, para permitir definir la longitud del emisario y características del difusor.

Lastres de Hormigón

Figura Nº 4. Diseño de Hormigon de Concreto.
Fuente: BLOGPLASTICS

Pueden ser de distintas formas geométricas, de acuerdo con el tipo de instalación, recomendándose utilizar lastres excéntricos, para garantizar mayor estabilidad de la tubería.

Como los tubos de PE flotan , incluso llenos de agua, para hundirlos habrá que incorporar lastres de hormigón, en general, constituidos por dos piezas de hormigón armado, con dimensiones y formas geométricas distintas, y que se abrazan a la tubería por medio de tornillos y tuercas. En su parte interior disponen normalmente de dos gomas sintéticas tipo EPDM para impedir daños de los lastres de hormigón a las tuberías.

La protección de los elementos metálicos, así como de las bridas para conexión de tramos de tubería, se garantiza con ánodos de sacrificio, en principio de zinc ó de aluminio.

Los lastres deberán disponerse con intervalos equidistantes – no más de 10 veces el diámetro nominal de la tubería, sin exceder 5 metros – para que se alcancen coeficientes de esbeltez bajos.

Por “cargamento” se puede definir como el cociente, representado en porcentaje, entre la suma de todas las cargas de hundimiento y las fuerzas de empuje del sistema, considerando la tubería llena de aire.

Durante la operación de hundimiento la tubería no deberá cargarse más del 65% de la capacidad de flotación, disminuyendo este porcentaje en función de las características del tubo (espesor) y de la profundidad del mar.

El cemento utilizado en el hormigón deberá resistir a la agresividad química del agua y el acero empleado deberá estar recubierto con un mínimo de 40 mm. La superficie de contacto de los lastres con los tubos deberá estar revestida con bandas de elastómero en EPDM o Neopreno de 5 á 10 mm de espesor como mínimo.

El lastre inferior y el superior están unidos con tornillos de acero galvanizado y protegidos con ánodos de sacrificio.

Relación de artículos sobre emisarios submarinos

• Emisario submarino en (PE)
• ¿Cómo funciona un emisario submarino?
• Sistema de Depuración por Emisarios Submarino (SIDES)
• 100 Años de Vida Útil del Polietileno

Fuente:  Vegas, Rodolfo “Construcción de emisarios submarinos con tuberías de polietileno (PE)”.Blogplastic.com. 05 de  agosto del 2014 http://blogplastics.com/construccion-de-emisarios-submarinos-con-tuberias-de-polietileno-pe/.
Adaptado por: Maidee Falcon (Ingeniero Industrial)

Figura Nº1. Lecho Marino
Fuente: Elinsubca C.A

A new study, the prestigious independent Institute for Technological Research of Flanders (VITO), funded by the European plastic pipes industry is conclusive in its results: the plastic pipes are more sustainable than alternative materials.

The results indicate that, on average, plastic pipes have an environmental footprint that is two-thirds less than that of the piping systems materials such as concrete, copper or ductile iron.

Smaller footprint, higher profits

Figura Nº 2. Difusor de Polietileno.
Fuente: Elinsubca C..A

To make a fair comparison between different types of materials and determine the environmental impact of different products, it is necessary to evaluate and analyze every stage of its life cycle.

For each specific application, comparisons have been made according to ISO 14040 and 14044 standards in force, using the same functional unit for different materials compared.

“Environmental footprints” may be adverse or beneficial. Adverse effects such as the emission of greenhouse gases can be generated in the manufacturing stage or at the end of product life; the beneficial effects help to reduce emissions of greenhouse gases by saving energy while the product is in use. Regarding plastic pipes, the life-cycle assessment has shown that the environmental impact of plastic piping systems is significantly less than traditional materials systems.

Determining the environmental impact of a product

Figura Nº 3. Instalaciòn de Tuberias PEAD.
Fuente: Elinsubca

A life-cycle assessment (LCA) complete and scientific is the standard method for an objective comparison of the environmental impacts of different products or services. This type of evaluation involves the systematic collection and evaluation of quantitative data on inputs and outputs of material, energy flows and associated waste product throughout its entire life cycle. Therefore, to calculate global impacts, assess the full range of processes, starting with the production of raw materials, their transformation into products and continuing with the transportation and installation of the products, the use of the product during its life useful, and finally disposal or reprocessing product at the end of his life.
The results of the evaluation of LCA are generally published in the form of Environmental Product Declarations (EPDs) in accordance with prEN 15942, to communicate the overall environmental impact of a product.

The European Association of Plastic Pipes and Fittings (TEPPFA) is an industry association representing European-wide leading manufacturer of plastic pipes and their national associations. TEPPFA has commissioned a series of Environmental Product Declarations, which cover the main types of plastic piping systems, based on updated data ACL.

These life-cycle assessment (LCA) have been performed by internationally renowned Flanders Institute for Technological Research (VITO), following the methodology of ISO 14040 and 14044. The results obtained by VITO were validated independently by other recognized institute sustainable development, Denkstatt GmbH in Austria, following the methodology of ISO standards.

The study said the data collection systems of plastic pipes companies representing more than 50% of the European market. Data piping systems of alternative materials (concrete, ductile iron and copper) were obtained from publicly available information.

Environmental impact criteria

The environmental impact of each pipe material has been evaluated throughout its entire life cycle, according to six different criteria:

Figure No. 4. Sinking of polyethylene pipe to the seabed Source: ELINSUBCA C.A.

1) Potential of “abiotic” destruction: the over-extraction of mineral, fossil fuels and other inert and non-renewable materials, can lead to depletion of natural resources.

2) Potential “acidification” emissions, such as sulfur dioxide and nitrogen oxides, due to manufacturing processes, leading to acid rain that damages the soil, water resources, human and animal organisms and the ecosystem.

3) Potential ‘Eutrophication': arising from the over-fertilization of water or soil nutrients such as nitrogen and phosphorus. This accelerates the growth of plants and kill animal life in lakes and waterways.

4) Potential contribution to “global warming” (carbon footprint): the greenhouse gases (CO2 and methane) in the atmosphere is one of the biggest contributors to global warming, affecting both human health and the ecosystem in which we live.

5) Damage Potential Ozone: reduction of the ozone layer in the atmosphere caused by the emission of chemical foaming agents and cleaning allows the passage of higher levels of UV radiation from the sun, causing skin cancer and decreasing performance the crops.

6) Potential “oxidation photo-chemistry” chemical photocatalytic reaction of sunlight with primary air pollutants such as volatile organic compounds and nitrogen oxides, causes chemical mists (smog) affecting human health, crops and the ecosystem in general.

Comparison of different piping systems

Figure No. 5. Installation of subsea pipelines
Source: Elinsubca C.A

Different types of piping systems typically offer different benefits. These are provided by a range of alternative materials and different kinds of plastic. In this study we have made direct comparisons between plastic pipes Polypropylene or PVC and ductile pipes for evacuation casting systems; polyethylene or PVC pipes and ductile iron pipes in water supply systems under pressure; Three different types of PVC pipes or concrete pipes Polypropylene and sanitation systems without pressure; and crosslinked polyethylene pipes (PE-X) or multilayer PE-PEX / AI / PE-PEX and copper piping systems hot and cold water.

The study was conclusive in favor of plastic piping systems. Throughout the full range of applications evaluated, it has been shown that on average, the use of plastic piping systems reduced by two thirds the environmental footprint compared to alternative materials.

More detailed information about the EPD’s for each class of plastic pipe can be obtained by contacting www.teppfa.eu or TEPPFA: info@teppfa.org

Author’s note:

TEPPFA is the European association of plastic pipes and fittings, which groups 15 national associations and 11 direct member companies. TEPPFA represented by industry directly employs 40.00 people, annually produces 3 million tons of plastic pipe with an annual turnover of 12 billion euros

Source: ASETUB (Spanish Association of Manufacturers of Plastic Pipes and Fittings) http://asetub.es/medio-ambiente/declaraciones-medioambientales/articulo-de-prensa

Adapted by: Maidee Falcon (Industrial Engineering)

Figure No.1 Venezuelan coast.
Source: Elinsubca C.A

Waste of human origin have come to the seas for thousands of years, where there has been the assimilation of this organic load through the purification capacity of the ocean. In the past, when we lived in settlements with small populations could live in balance with the environment without waste represent a pollution problem because it came through rivers and runoffs in concentrations they remained below the purifying capacity these natural areas. However, today we have adopted a lifestyle that has led to the creation of highly populated cities, being necessary to continue taking advantage of the immense purification capacity that provides oceans but requiring a device to help transport wastewater to remote areas of shorelines.

Technology that harmonizes with the planet:

The outfall is a system designed to harmonize with the natural process of self-purification which establishes the planet. This should ensure through processes of dilution, dispersion and bacterial decay, that sewage from cities and coastal villages are degraded naturally by the purification capacity of the oceans.

How does an outfall:

• The residual water is discharged through several openings in the diffuser (nozzle) as a series of jets, horizontal, round and high speed that produces turbulence and mixing.

• Dilution occurs during the first few minutes, quickly seawater mixes with sewage and pen tends to rise by the difference in density of the two media.

• 

  Figura Nº 2. Instalación del Emisario              Fuente: Elinsubca C.A

  Dilutions reached within that region, known as near field (or mixing zone) are typically in the order of hundreds (minimum 1: 100) and could reach losmiles (1: 2000 for example). Therefore, concentrations of pollutants are reduced quickly and substantially.

• Dilution pen still drifting with the ocean currents and is spread by oceanic turbulence, causing the transport of this and dispersal at sea. this happens biological treatment of wastewater in the area of ​​dilution and dispersion due to the assimilative capacity of the sea.

• Another important process is the bacterial decay, is the death of these microorganisms because the sea destroys most terrestrial organisms thanks to the action of high salinity, temperature and ultraviolet radiation from sunlight.

• The rapid uptake of substances by the marine environment and the bacterial decay ensures that dilution outfall is perfectly compatible with the most restrictive applications including use for swimming, fishing, recreation and sports.

Sanitation in Latin America beaches waiting:

Figure No. 3 hydraulic pressure test in pipes HDPE. Source: Elinsubca C.A

The situation reflects the Pan American Health Organization (PAHO) in its publication entitled “Disposal of sewage in coastal cities, applying outfalls,” states the following:

“It is common practice in coastal cities discharge their wastewater untreated into the nearest body of water or more convenient and usually neglected its environmental consequences and health, mainly due to lack of financial resources. In most coastal cities in Latin America and the Caribbean, raw sewage discharges occurring on or very near bathing beaches. Geometric mean total coliform levels above 100,000 MPN / 100 ml has been frequently observed in public bathing beaches with individual measurements at times approaching levels of raw sewage. Wastewater discharges near the coastline cause aesthetic problems, pose potential risks to the ecology and public health and sometimes involve restricting tourism negative economic consequences. “

Figure No. 4.Lanzamiento HDPE pipe from shore sea. Source: Elinsubca C.A.

PAHO report concludes, as a strategy that:

“The economic situation in Latin America does not allow the adaptation of control techniques water quality used in developed countries. For example, the secondary treatment applied to wastewater in developed countries represents a cost that may not be feasible for the countries of the region and unnecessary to achieve water quality goals. On the other hand, outfalls provide an efficient, safe and relatively inexpensive technology for the disposal of sewage and when they are designed appropriately and combined with preliminary or primary treatment, can achieve the objectives of water quality and minimize adverse impacts environment / ecology and public health. The coastal population and living near estuaries, potentially served by outfalls, was estimated at 110 million in 2000, with a consequent wastewater flow of about 250 m3 / s. The proper disposal of this wastewater is critical for the future development and environmental welfare of the region. “

Source: (PAHO) Pan American Health Organization.

Adapted by: Sergio Elena (Mechanical Engineer).

Figure No. 1. Sinking Pipe HDPE Source: Elinsubca C.A

A purification system for outfall – SIDES (term used by ELINSUBCA) is an intelligent solution for the treatment of both industrial wastewater and domestic, which uses the purifying capacity of the ocean to degrade the organic load contained in municipal effluents, in balance with the marine ecosystem.

Its operation can be explained by separating it into 6 main stages:

1. DESIGN SYSTEM (BASIC RESEARCH AND ENGINEERING):

Figure No. 2. purification system by Submarine
Source: Elinsubca C.A

SIDES design should be unique to each project, at this stage you should be considered oceanic studies: bathymetry, current dynamics, composition of the seabed and environmental studies. Consideration should be given health study of various domestic and industrial sources that produce wastewater; their wealth and their physicochemical and biological composition. Counting on these inputs is in the ability to perform hydraulic, structural and sanitary sizing calculations that will enable Debugging System for Submarine.

2. CONTROL IN THE FOUNTAIN (households and industry):

Figure No. 3. Purification System for residential and industrial areas. Source: Elinsubca C.A

This stage includes the control should be practiced in the producing sources of wastewater which is connected to the network of municipal collectors, also the constant monitoring of the effluent before the entrance to the outfall.

In the case of domestic sources, it would be advisable to implement educational awareness campaigns network user to avoid throwing solid, oil or other toxic waste into drains, so that energy savings occur during stage pre-treatment of the effluent, which improves the efficiency of the cleaning system. Other control measures can be applied at home connections, to prevent the passage of solid network of collectors, as well as incentives for recycling campaigns that help improve the quality of domestic effluents.

In the case of industrial effluents, it should be stricter control that covers from the detailed description of the production processes in order to practice the necessary improvements to avoid the issuance of non-biodegradable waste, especially toxic or persistent elements that may cause damage marine organisms (eg heavy metals, radioactive substances, hydrocarbons, persistent organic compounds, etc.). In other words, the processes must be adequate to ensure a free effluent from non-biodegradable agents, a removal of coarse solids and fats.

Usually industries must have a permanent control of the quality of its wastewater by the competent state body, this control will determine whether the effluent produced meets the parameters established in the environmental regulations and with the variables set in the design scrubber system.

3. PRE-TREATMENT (ELIMINATION OF SOLID AND FATS):

Figure 3. Transportation Outfall
Source:. Elinsubca C.A.

In the pre-treatment should include a large removal of coarse solids, settleable and suspended, as well as fats effluent, in order to reduce the undesirable aesthetic impact on the receiving environment, by the appearance of floating solids, stains fat and accumulations of sediment on the seabed.

4. TRANSPORT OF EFFLUENT (OUTFALL):

Figura 3. Tuberías de Polietileno de Alta Densidad
Fuente: Elinsubca C.A

The suitably treated waste water, with partial elimination of fats and solids, are conducted to the mixing zone in the receiving environment (sea, river or lake) through a pipe or outfall.

This line pipe should be designed to prevent the occurrence of failures effluent leaks that could represent a source of contamination in nearshore areas. The pipeline can be constructed in various materials, however, it is recommended to run these facilities with pipe High Density Polyethylene (HDPE acronym in English); as it provides a system capable of operating for a long time (over 60 years), economic, free from faults and without maintenance costs when it is designed correctly.

5. MIX IN THE MIDDLE RECEIVER (DIFUSOR):

At this stage effluent treatment is completed by means of natural purification capacity of the aquatic environment. Since the ocean has a steady source of energy (from the rotation of the earth) that produces continuous ocean currents and oxygenation of the huge volume of the aquatic environment. It has the ability to incorporate the effluent to this medium to be part of (or food chain) of the marine ecosystem, becoming a food source decomposers and detritus trophic organisms cycle.

Figure 6. diffuser
Source: Elinsubca C.A

Through three physical-biological processes debugging is achieved:

• Initial dilution: effluent is conducted to the so-called mixing zone, where a mixture will occur through the discharge diffuser, which is designed to achieve high dilution in the receiving means, achieving lower effluent concentration at least 100 times (dilution of 100: 1) sustained (for example: if you have an effluent with a BOD value of 200, is will fall at least to a value of 2), and in many cases can reach higher dilutions 2000 times (2000 dilution: 1). This initial dilution through diffuser gives rise to the so-called “pen dilution”, being important for design variables: depth, density and temperature of the receiving environment.
• Dispersal: then transport this pen will occur by the action of ocean currents that produce unadispersión effluent (or dilution far field) in an increasing water volume, achieving full integration of the food load to the aquatic environment.

   

• Bacterial decay: bacterial decay refers to the death of typical wastewater effluent (causing gastrointestinal illness in swimmers who use the beaches or spas) pathogenic bacteria. This decay or bacterial death occurs from transportation effluent through the outfall and achieves greater efficiency in the aquatic environment due to the action of several factors: the ultra violet rays, salinity, heat shock and the action of organisms predators existing in the medium.

6. ENVIRONMENTAL MONITORING:

Figure 7. Inspection on the seabed.
Source: Elinsubca C.A.

Environmental monitoring in a primary factor purification system, since it is intended to do a survey of the initial environmental conditions of the receiving environment (baseline) in the area near the mixing zone and in human use ( as beaches, spas or shellfish farming). This baseline will serve as a standard of comparison with respect to subsequent sampling, once the system is put into operation debugging. It will determine its proper functioning, discard as undesirable accumulations of sediment on the seabed and the water quality values ​​specified in the standard for human use areas are achieved.

This monitoring provides other advantages, as it serves as an experimental source that generates valuable information for calculating future projects also could easily detect one

system malfunction, allowing the necessary demanding those responsible for the project, improvements for its smooth operation.

In conclusion, the purification system by Outfall – SIDES, is an intelligent system using the purifying capacity of the aquatic environment, incorporating the effluent as a food load in the food cycle of this ecosystem. Is a reliable, robust and economic system; able to debug large wastewater flows continuously, with an inexhaustible source of free energy that provides a dynamic current and a convenient constant oxygenation of the receiving environment.

Figure 1. Pipe Factory
Polyethylene.
Source: Pipelife Norge AS

Systems polyolefin sewer pipes have a life expectancy of at least 100 years. This is the conclusion of a recent two-year project commissioned by TEPPFA (Trade association Representing manufacturers and national associations of plastic pipe systems in Europe) and independently analyzed by Professor Heinz Dragaun of the School of Higher Education (TGM) in Vienna . The project involved the excavation of many samples of pipe networks in service were tested and evaluated under laboratory conditions meticulous. It is expected that the results of the analysis and conclusions of this work have a favorable influence on those sewer operators facing large capital investments in new or replacement networks.

Most European countries have outdated sewage systems. They not only leaks and poor performance; also they require replaced or simply be modernized. Life expectancy is a key factor in any investment decision. Systems polyolefin (polypropylene and polyethylene) have been widely used for over 40 years, and compared with non-plastic materials of pipes, consistent solutions have provided longer term. However, while life expectancy polyolefin pipes has been debated for many years, it has never been given a definitive conclusion. Until now.

Greater confidence.

Figura 3. Traslado de Tubería
Fuente: Saneamiento marítimo S.A

Tony Dalton, General Manager TEPPFA is delighted with the results of the project: “The designers, owners and operators of sewer networks can now be sure that these sewerage systems have a service life of at least a hundred years, when materials, products and installation practices meet the appropriate requirements.

The results are also of vital importance for suppliers of materials, pipe manufacturers and contractors working closely with market sewage system. Obviously it will create more attractive for sewage pipes and allow polyolefin applied with greater confidence, as their yields are consistent throughout his long life as an installed capital. The conditions set by the project team were rigorous and based on real-time data long term. For example, the tests included excavation of pipes that have already been in use for up to 40 percent of their service life offered. These tests showed that there has been a deterioration or excessive degradation during this time.

Tony Calton notes that “although the excavated pipes were manufactured using formulas of first-generation materials, their residual life was estimated at more than 50 years. We should note that current formulations offer performance greater useful life than previous materials “.cien years when materials, products and installation practices meet the appropriate requirements.

Figura 2. Hundimiento de la tubería hacia el lecho marino.
Fuente: Elinsubca C.A

The results are also of vital importance for suppliers of materials, pipe manufacturers and contractors working closely with market sewage system. Obviously it will create a greater appeal to the sewer pipes of polyolefin and allow applied with greater confidence, as their yields are consistent throughout his long life as instalado.Otros the capital key factors were investigated during this project, but found that no adversely affected life expectancy. These include the chemical composition of sewage aguae, the temperature profile of sewage flows and changes in installation practices used. the influence of high concentrations of waste water that is typically associated with pipeline systems structured wall was also examined.

The full technical report and a technical summary are available on the website of TEPPFA. A four-page brochure that describes the project scope is also available through the company members TEPPFA and / or members of national associations. It is also important to note that this project was coordinated by TEPPFA together with LyondellBasell, Borealis and TGM (Austria).

Source: TEPPFA. Tony Calton

Translation and Adapted by: Stefan Balabanoff (Consultant Economist)

Take pumping pit Seawater

Systems water intake built in high density polyethylene ((HDPE acronym in English) are intended for the abstraction of water from a natural source such as:. Seas, lakes or rivers These systems are used for supplying water for various purposes such as providing drinking water or process water, for desalination of water for cooling systems for air conditioning systems and for the production of clean energy.

Various water intake constructions have been built around the world with pipes High Density Polyethylene, given the extraordinary advantages of the material and technological advances in this type of construction with HDPE. Thanks to the properties of HDPE, these systems can be designed to achieve longer life (over 60 years) with the goodness of being maintenance-free, because it does not suffer the effects of corrosion that attacks other traditional materials. The experience of the last five decades, several projects around the globe, leads to the conclusion that “when systems submerged pipe it is, is the HDPE option more advantages,” because you can count on a cost curve vs lowest since the initial investment, with shorter project execution and technology involving the marine environment amiably time.

Communicating Vessels System:

A water works simply, an example can be seen in the model of “Taking Seawater System Vessels by Comunicantes”. It consists of a pit built on land below sea level, which is connected to the marine environment through a HDPE pipe and a filter that prevents the entry of particularly thick; on the grave of communicating vessels is a pump that sucks the salt water to be stored in a tank or to be directly used in the application to which it is intended.

For the calculation of the pipe must have studies bathymetry and marine currents in the area to be installed, in order to calculate the stability of the pipeline on the seabed and ensuring water quality at the point of uptake (low suspended particles). This is installed with reinforced concrete counterweights that are attached to the pipe; They are built in several long stretches (eg 300 m in length) which are flanged at sea to interconnect; finally ditched the pipe to remain buried in the seabed, especially at depths less than 10 m is required.

Specific applications:

They are diverse applications model “Taking seawater Comunicantes System Vessels” and can be found mainly in:

• Desalination plants supply.
• Cooling thermoelectric plants.
• Power complexes saltwater pools.
• Aerates conditioning systems cooled water (SWAC acronym in English).
• Production systems ocean thermal energy (OTEC acronym in English).

Author: Ing Sergio Elena.
www.elinsubca.com

Take Seawater System Vessels by Comunicantes

Prelaunch sea outfall.

Outfalls have been used with excellent results in different parts of the world for handling wastewater from cities and towns coastal, by which is put into use the natural ability of the ocean to clean up the pollution load of municipal effluents.

This system provides debugging great advantages in handling the wastewater, being very efficient, reliable and robust in performance; low investment cost compared to other technologies and maintenance free to be constructed with pipes High Density Polyethylene (HDPE acronym in English).

How do they work:

This system works using natural purification capacity of the oceans through three-biological physical mechanisms: dilution, dispersion and Bacterial decay. The waters from residential collectors and collectors from industrial leading to a primary treatment plant for removal of coarse solids and fats that may cause undesirable aesthetic effect on the marine environment; then the water is carried to an area in the sea where sea conditions provide the dynamics needed to produce a large dilution of the pollutant load in a very large volume of water flow, where the death of pathogenic bacteria eventually produce and the organic load is evenly integrated into the food chain of aquatic environment.

Debugging system by Outfall:

Why HDPE:

In recent decades they have achieved very satisfactory results in the construction of outfalls with Pipe High Density Polyethylene (HDPE) for the great benefit of this material oak traditional technologies, being able to achieve a system with investment costs more low, with the longest service life (over 60 years) and virtually maintenance free as it will not corrode or produce scale on the inner walls of the pipe. This pipe is installed on the seabed by counterweights reinforced concrete uniformly distributed over the pipe and is buried to protect it from the action of currents and shock anchors mainly in the area of shallow (less than 10 m ).

Author: Ing. Sergio Elena 

www.elinsubca.com

Debugging system Outfall – SIDES

Long underwater pipe sections PEAD

Aqueducts submarines are used to transport drinking water or raw water through seas, rivers or lakes, in order to serve populations that are isolated by these aquatic environments.

Several submarines aqueducts are currently installed in different parts of the world, carrying water to islands from the mainland, crossing gulfs and passing rivers and lakes found in the most feasible route to bring the service to towns that need it for not having own resource of water in amounts sufficient for its development.

An example of underwater aqueducts in operation can be found in Venezuela, currently serving the islands of Margarita and Coche, in the state of Nueva Esparta, carrying water from reservoirs and Clavellino Turimiquire, both located in the Sucre State. These aqueducts total more than 120 km of pipe of various diameters (from 200-900 mm) and carry a total of 3200 l / s, to attend a population of approximately 490,000 inhabitants, totaling nearly 700,000 people in seasons of rest with the influx of vacationers (estimated figures for 2012).

Why HDPE:

There are many advantages provided by the construction of these aqueducts pipes HDPE High Density Polyethylene (DHPE acronym in English). Today it can be considered that the HDPE is the most reliable and economical choice when submerged systems it is because it can have the benefits of a material that is not attacked by corrosion of the marine environment, achieving a system with greater life (over 60 years) being maintenance free; with great flexibility to absorb the irregularities of the seabed and earthquakes; and large hydraulic advantages to drive higher flows with lower friction losses, due to the low fouling the inner walls of the pipe.

How are built:

The transport is usually carried out from a reservoir located on the mainland, through an aquatic area, which is constructed with a HDPE pipe system with reinforced concrete counterweights that are installed in solidarity along the pipeline. These submarines aqueducts must be built through long stretches of welded pipes continues its flanged ends, approximate lengths between 300 and 500 m, which are prepared on the ground and then are taken floated to the installation area to sink so on the seabed.

The long stretches are interconnected by means of flanges, bolts and gaskets stainless steel high pressure, allowing seal the system. To ensure adequate protection of the aqueduct is necessary to make an underwater trenching to bury the pipe and leave it out of the reach of ocean currents and possible clashes with anchors or trailers with fishing nets, especially at lower depths of 10 m where reach higher magnitudes of currents that can affect system stability.

For the design of a submarine pipeline should be available with current studies and bathymetry that reveal in detail the necessary variables to make structural calculations and choose the best route to position the pipe on the underwater bed. Particularly in submarine aqueducts (unlike outfalls) should have systems of dampers, which are part of the counterweights concrete to limit the efforts that may result from the expansion of the pipe to the internal pressure increased system .

Author: Ing. Sergio Elena 
www.elinsubca.com

Underwater diagram Aqueduct

Pipes scheme intake and discharge

The thermoelectric plant will provide water for industrial processes through a desalinator system, which will capture seawater through a simple system of communicating vessels. This is composed of a pit as pumping station and HDPE pipe 315 mm in diameter and 906 m length, which connects and continuously feeds the sea during pumping pit water. This design was proposed by the engineering company Vepica C.A. and was approved by the inspection company C.A INELMECA, both Venezuelan companies with great experience in the area of ​​consulting engineering.

One of the challenges presented by this project was the construction of the system of communicating vessels, which had no previous similar experience in the country. ELINSUBCA C.A being selected and a specialist in the construction of submarine pipelines systems HDPE company, presented a coherent constructive design in three stages of development:

1. 

   Fosa de bombeo para Toma de Agua de Mar

   PUMPING PIT: reinforced concrete structure built to receive and store seawater from outlet pipe with dimensions: 4.25 m x 6.50 m x 9.20 m (width x length x height). The complexity in its construction was determined by the excavations below the water table, as being just 300 meters from the shore of the beach, the sea level is 4.5 m above the floor of the pit. This structure suction pumps that carry seawater desalination system will be installed.

2. PIPELINE TAKES: Installation of 906 m of HDPE pipe Ø 315 mm, consisting of a stretch of land 250 m from the pit to the point of entry to the sea (transition zone) and 656 m of pipe weighed down with anchors reinforced concrete and buried in the seabed. This underwater pipeline built into the pump pit, keep the connection to the sea to complete the system of “Feed Comunicantes Vessels”.
3. DISCHARGE PIPING: installation of an outfall in HDPE 1124 m in total length and Ø 315 mm, consisting of a stretch of land of 384 m ranging from a pit of loading to the sea, and a submarine section 740 m anchors weighed down with concrete and buried in the seabed. Through this pipe the water already treated product of industrial processes thermoelectric plant, including the reject water from the desalination plant is returned, discharged through a diffuser built with 6 outlets 75 mm in diameter, each connected to type duck bill valves to improve the initial dilution of the effluent discharged into the sea.
   

   Launch Pipes – Stretches Submarines

The intake and discharge pipes were built in long stretches of approximately 300 m, connected to the sea through a technology developed by Elinsubca that significantly reduces execution times and the risk of industrial accidents. Thanks to this constructive proposal was possible to complete the work within a period of four months, with zero accidents and full operation of the system.

With the development of this work, Venezuela has considerable experience in building power systems seawater communicating vessels, this being evidence of ideal solution for powering desalination plants and cooling systems in power plants by employing of HDPE submarine pipelines.

Marketing Management of Elinsubca C.A

Take Seawater System by Communicating Vessels

Installing outfall Carupano – Venezuela

(*)

Fundamental variables in the design of a outfall.

Submarine discharge diffuser

Dilution capacity of an emissary constitute three main factors:

a).-Distance wing that the effluent is discharged from the coast or to areas of human uses,

b).-Depth of discharge of effluent, and

c).-The efficient design of the diffuser discharge which must be adapted to the specific conditions of the marine area that will receive the effluent.

1.-Marine bathymetry and topography of the coastal zone related area: With this information, you can determine potential suitable for the installation of the outfall routes, providing deep sea area under study, and the approximate length.

2.-Study current, waves, tides and winds: With these results, we can understand the behavior of currents in the study area, in magnitude and direction over time. This allows a simulation of dilution with specialized software, placing an unloading area where the prevailing currents for the longest time of the year allow the effluent away from the coast or areas of human uses.

Of these two aspects it is possible to obtain the information necessary for the design of the diffuser, with which pretend to achieve the highest possible primary dilution for the rest of the work is achieved with the action of ocean currents.

3.-Composition of the seabed: This study seeks to examine in detail the composition of the sea, geologically bed (if rocky, sandy, muddy, clay, etc.) and biologically (as ecosystems: coral reefs, sandy areas, grasslands Thalasia, etc). On the one hand it allows us to design the route emissary intervening as little as possible to the most fragile ecosystems such as coral, and moreover it is possible to design the work of burying the pipeline, according to the hardness of the ground, for proper protection of it.

References:

(*) Study: “OUTFALL VIABLE ALTERNATIVE FOR DISPOSAL OF SEWAGE IN COASTAL CITIES IN LATIN AMERICA AND THE CARIBBEAN”. Author: HENRY J. SALAS (Advisor on Water Pollution Control CEPIS). Original Air Date: 1988 (Updated: September 1995). Lima Peru.

By:  Ing. Freddy Guerra

www.elinsubca.com

Caracas,  March, 4 of 2013