Corrosion protection in water treatment

The problem of drinking water and sewage in the world, threatens the planet with the possibility that the next World War will not be for oil or energy; nothing could be further from the truth: it will be because of the control of drinking water sources, which become scarcer with each passing day.

The excessive increase in the world population, climatic changes and the destruction of forests and green areas that are the origin of large sources of white water, lead countries to take corrective actions to protect drinking water sources and in turn, the regeneration of used or sewage.

The industrialized countries of America, Europe and Asia, have begun processes of collection, treatment and return of wastewater to its sources of origin. This allows the used waters to be regenerated and returned to the rivers, lakes and seas from which they were taken, so as to compensate for the high consumption that is made daily.

But population growth not only brings problems of deforestation, it also brings a high consumption of water in the manufacturing processes of goods and services, as well as the food we eat, which require clean water for its manufacture.

In Venezuela, in 1998, the state company Hidroven and its different subsidiaries had several plans for the recovery of wastewater at the national level, which were equated with the projects that at that time had in execution the countries of the first world.

The joint plan PDVSA and Hidroven, proposed the collection of wastewater in the cities near the facilities of the subsidiaries of the state oil company, in order to treat the waters and use them in the cooling processes of the different plants, thus reducing the use of white water for such purposes.

Two of the most ambitious projects of that time, had José in the East and Maracaibo in the West, as pilot plans for the collection of wastewater, its transfer to treatment plants adjacent to the refineries; water regeneration and its use in the cooling process. This led to significant savings in white water consumption. These plans have not yet been carried out.

This is a constant in America, and in interviews held with several mayors of different cities in the region, after presenting the situation and the possible solutions to them, the response has always been very grim and sincere: "What you propose to me is excellent and necessary, but since the people do not see it, it does not generate votes, so this has no life."

With the right plans in place, the waters of the Guaire River and El Valle, in Caracas, could soon cease to be black to become white waters that would improve the standard of living of Caracas.

The composition of the effluents, the level of flow, the speed of their movement, the turbulence, the geographical features between the collection area and the treatment plants create a situation where the generation of these bacteria increases and destroys the installations in a very short time. The topography and environmental conditions of Mexico City, San Salvador, San José, Tegucigalpa, Caracas, Bogotaá, Quito, Lima, La Paz, San Juan, Oranjestad, Santiago, Santo Domingo, as well as other important cities such as Santa Cruz, Guayaquil, Medellín, Maracaibo and Monterrey, in our area, makes them ideal for the generation of these bacteria.

The different structures that make up the system of collection, transport and treatment of the serividal waters, are exposed to attack by these bacteria and the acid that condenses. The solution to the problem is the application of anticorrosive and anti-abrasive coatings that protect both steel and concrete from such a harmful and destructive attack.

Today lifting stations, interconnectors, collection lines, treatment plants, aeration tanks, separators, decanters, reactors and other facilities, are at the mercy of bacteria, particulate matter and acid, which gradually deteriorate them, to the point that it is necessary to demolish them and make them again. It is here, where anticorrosive coatings come into the picture.

Protection, the key
One of the alternatives offered today to the different water authorities is the application of protective coatings on equipment and structures, at the time of manufacture. This guarantees the user, in this case the cities, a service life that can easily exceed 35 to 40 years, on an ongoing basis.

This does not indicate that the structures in service cannot be protected, nothing further from reality, but it seeks to convince the mayors, municipalities, cities and regional, state and federal authorities, as the case may be, that any new project of collection and treatment of effluents, must be fully coated, before entering into service. And the structures that are in service today can be recovered, repaired and proteguidas, thus gaining at least another 25 years of service, without the need to demolish and rebuild them again.

There is a very wide range of products for this process. Cementitious products for the recovery of concrete that cure in three to five hours, materials for sealing joints, materials to stop infiltration, fissure sealants, substrate recuperators, fault sealants; in short, a range of products that allow engineers to plan repair and maintenance processes that are carried out in a short time, returning the structures to service, significantly reducing downtime, and inconvenience to the inhabitants of the areas in question.

The development of 100% solid epoxy technologies helps to extend the service life of coated installations, since they do not contain solvents, problems related to trapped solvent, bubbles and delaminations, are minimized and / or disappear, leaving a coating completely immune to chemical attack. On the other hand, technologies formulated precisely for wastewater environments, with moisture-tolerant materials, easy and quick application and curing much faster than conventional products, allow to reduce application costs and labor and make the works are done in less time, creating little inconvenience for people who live near the areas involved in repairs.

On the other hand, in residual effluents, aggregate loads, as well as the topography of the area, make the flow highly abrasive. These coatings provide a high resistance to abrasion, impact and wear, which together with its high impermeability and chemical resistance, gives us a long service life.

Colombia embarked on this process and installed a large effluent treatment plant in the beautiful city of Cartagena de Indias, in the north of the country. Puerto Rico has initiated recovery plans for structures exposed to damage by these bacteria and began a process of recovery of collection lines and lifting stations, as well as treatment plants. St. Croix, USVI, is another island that is in the process of recovering and protecting its entire effluent collection system and Hess Oil (Hovensa) itself is working on the recovery of effluent collection systems for the refinery it owns on the island.

Mexico City, famous for its history and its high population level, (more than 20 million inhabitants), has embarked on a process of recovery of effluent collection lines and is planning to build new treatment plants, to treat and recover wastewater. And the city of Monterrey, (Nuevo León, Mexico), could not be less, so today it is one of the cities that collects and treats more wastewater, reaching almost 90% of its effluents.

The cities that settle in the basin of the Rio Grande (on the American side) and the Rio Grande (on the Mexican side), are obliged to return the largest amount of wastewater, after being treated, to the source of origin; that is, to the river, in order to maintain the water level, so that the populations located downstream, continue to receive water for their irrigation processes, cultivation and other uses.

Panama City, in Panama, is another city with a huge wastewater management project. The city's water authority is working to recover and coat the manholes as well as the other structures of the collection and treatment system, in order to recover the wastewater and return it to its sources.

Conclusion
In short, with each passing day, more and more countries are focusing their eyes on recovery and coating technologies for wastewater environments. Sewage ceased to be a waste product, to become a renewable and reusable product.

The more scarce drinking water, the more wastewater is abundant and if we start from this premise, its recovery, return to the causes and its reuse, it becomes more attractive and more necessary.

* International Sales Manager, Sauereisen, Inc.
[email protected]