Water. Desalination + reuse
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REGIONS Figure 1: Operator next to one of the early BWRO plants built by Perenne in the interior of the State of Bahia, Brazil This is particularly evident in a country like Brazil, which is a country of nearly 200 million people, roughly the size of the USA and Australia, which alone enjoys 17% of the total world availability of fresh water. Despite the challenges, the majority of the desalination plants apparently have been and are operating satisfactorily. The first was installed in the town of Uaua, which is in the interior of the wonderful but poor state of Bahia, in the 1980s (see Figure 1, taken in 1991). Another dry region is the western coastal strip of Patagonia in Argentina. Some of the cities here bring water from the Andes with pipelines hundred of kilometers long for relatively small populations. Seawater desalination has to be a more economical and environmentally friendly way to provide fresh water to people and industry, and indeed several SWRO plants are being talked about. It is no coincidence that while finalizing this article, I have received news about a oneday seminar on Desalination and Water Reuse in Commodoro Rivadavia, the capital of the Patagonian state of Chubut. The event, sponsored by the local government, also hosted international participants. SIGNIfIcaNcE Of StatIStIcS Looking at the Latin American plants contracted from 2007 in the IDA Desalting Plants Inventory by Desaldata.com and GWI, the overall numbers are not insignificant. Of about 800 plants listed, some 300 are for Mexico and 120 each for Brazil and Chile. Argentina has about 70, Peru and Venezuela 50 each, and Colombia and Ecuador 25 each. Belize, Bolivia, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama, Paraguay, Suriname and Uruguay also have single-digit numbers of desalination plants. There is definitely new attention to the Latin American region, and this is linked to the increasing number of applications and in particular to the fact that larger installations REGIONS have been built all over Latin America. Latin America is also coming out of its shell to share its particular experience. At the latest biannual conference of the Caribbean Desalination Association in Aruba in June 2012, the recipient of the best paper award was Victoria Vasini from Argentina. She presented the paper Results of Ultrafiltration (UF) Compared to Conventional Pretreatment, reporting on over a year of experience at a plant built by Unitek in Chile. The performance of two parallel lines of pretreatment for SWRO, one conventional and one UF, are compared. In particular, the test aimed to compare performance under red-tide conditions, a problem faced by several plants worldwide and particularly severe in Chile. ExpaNdEd dEmaNd fOR ���lOOSE��� mEmbRaNES The Latin American region seems to be increasing its demand from membrane manufacturers for ���loose��� RO and nanofiltration (NF) membranes, as their use is ever-expanding in mining, and also offshore oil extraction operations. Already Brazilian energy giant Petrobras has hundreds of thousands of m3/d of installed capacity using tens of thousands of the patented Dow SR90 elements in order to remove sulphates from seawater. As the Dow patent has now expired, this area of application is attracting the attention of membrane manufacturers. This is heightened by significant new investments by Petrobras, with others expected in the next few years while developing new fields, in particular those of the new so-called Pre-Sal area in Brazil, In addition, oil companies like BP have been publishing papers saying that desalting seawater further, down to a total dissolved solids (TDS) of around 1,000-1,500 ppm, may be the way to go in the future to recover more oil. This would open a huge market for the application of ���loose��� seawater RO membranes, not only in Latin America. country guide are becoming familiar names in the industry. The BHP Billiton SWRO at Minera Escondida is the best known. It was built by Degremont in 2004 with a capacity of about 45,000 m3/d and required TDS of less than 1,300 ppm. The expected construction of a new plant, based on an environmental impact statement (EIS) approved for 360,000 m3/d, has been the holy grail of Chilean desalination for OEMs and manufacturers for a number of years. Economic slowdown permitting, the construction of a plant of about half the approved capacity appears now closer to realization. Among recent plants, the one at the port of Punta Totorarillo, negotiated by Acciona with iron and steel company CAP, will have an initial capacity of 17,000 m3/d, which can be stepped up to a maximum of 52,000 m3/d, and includes operation for 20 years. The plant will serve several CAP mining operations in the Copiapo Valley, all around 100 km from the plant and located at much higher altitudes. These Chilean projects have attracted the interest of all major global OEMs, with the Spanish at the forefront. This is due to the cultural advantage they enjoy in the region and the drying up of the Spanish local market. KEy pROjEct fEatuRES Two key features of these projects, which are evident in the two examples of El Coloso and Punta Totorarillo, are that: l Seawater is desalted at sea-level, but water produced is pumped several thousands of meters up the Andes, where the mines are, so that more energy is normally spent in the transport of water than the desalting process itself l most of the water is used as process As water, little stress is put on the quality of water produced, emphasis being on low energy to minimize the overall energy requirement, already very high. While the mining sector shows the largest potential in Chile, it is an The simplest way to look at the region in more detail is country by country. cHIlE As it was at the end of the 19th century, Chile is again in the desalination spotlight due to some already built, ongoing and planned SWRO plants in the mining sector. Minera Escondida, Candelaria, Mantoverde, Punta Totorarillo, El Morro, El Tesoro and many others, all plants featuring RO technology, | 26 | Desalination & Water Reuse | November-December 2012 Figure 2: SWRO plant providing 50% of potable water supply to the city of Antofagasta, Chile application in the municipal sector that is attracting the most immediate interest and is of great significance to the region. The city of Antofagasta for a number of years has been relying on water desalted from the sea with a plant supplied by Spain���s OHL Inima. The plant started operating in 2003 with a capacity of 150 L/s and increased it in stages, finally reaching 600 L/s, ie, about 50,000 m3/d, which in turn means about 50% of Antofagasta���s potable water supply (see Figure 2). The balance comes from the Andes. Now, environmental approval has been granted for the duplication of the Antofagasta plant, which means that the request for qualification to build a second plant is expected to be launched before the end of the year or early next year. When the new plant is operational, Antofagasta, a city of 200,000 inhabitants will be the first city in Latin America relying 100% on fresh water desalted from the sea. The water from the Andes will be freed to be used in mining operations. Add this to the fact that Antofagasta already had a large MED plant in the 19th century, and it is not surprising that Aguas de Antofagasta, which owns and operates the plant, has been at the forefront in launching the first desalination and water reuse association in the region, Asociaci��n Latino Americana de Desalaci��n y Reuso del Agua (ALADyR). At the beginning of October 2012, ALADyR organized and hosted its third biannual international conference in Antofagasta attracting nearly 300 participants from 12 countries. The new board of directors was elected and Luis Curridor of Degremont Chile is the new president. At the conference, the operating arm of Aguas de Antofagasta, Atacama Water Technology Ltd (AWT) surprised participants by announcing that it had been appointed as the commercial representative for NanoH2O���s thin-film nanocomposite QuantumFlux SWRO membranes in northern Chile. AWT had already supplied QuantumFlux membranes to the Taltal I desalination plant, which produces part of the potable water supply for the city of Taltal. While the first plant used Hydranautics membranes, this new agreement appears to imply that the new plant will be built using NanoH2O elements. This development is another sign that Latin America is coming Figure 4: SWRO plant serving the phosphate plant of Brazilian mining company Vale do Rio Doce at Bayovar, Northern Peru. to front stage in desalination technology. MEXICO While Chile has relatively large plants, desalination plants of significant size exist all over Latin America, in particular in Mexico. Even if many of the large plants which have been talked about for many years, like the seawater desalination plant of Hermosillo in Sonora, and the plants planned on the Mexican side of the USA/ Mexico border, have never materialized, many seawater desalination plants have been built in the last 50 years, based on both evaporative technology (multi-stage flash (MSF) and MED) and membrane technology Many brackish-water RO plants have been built. One industrial example worth mentioning is the Santa Cruz SWRO plant. The plant, built by Degremont under a build-operate-transfer (BOT) agreement and serving a plant of national oil company PEMEX, has been in operation from 1999 and has a capacity of 18,000 m3/d. On the municipal side the most recent example is El Salitral, also known as Ensenada, won by OHL/Inima and having a capacity of 21,000 m3/d. Under Mexico, it is impossible not to mention the iconic Yuma Desalting Plant, constructed in the USA under authority of the Colorado River Basin Salinity Control Act of 1974 to treat saline agricultural return treated water intended for inclusion in water deliveries to Mexico. It is worth remembering that, even if seldom used, it constitutes a landmark in development of RO technology. VENEZUELA Venezuela can still boast the largest SWRO plant built on land in Latin America. It has a capacity of 75,000 m3/d, and water produced is for potable and industrial use. The plant was built by Acciona for Petr��leos de Venezuela. (See Figure 3) PERU While working on the possible privatization of Sedapal, the water utility of Lima, Peru, promoted by the World Bank in the early 1990s, the author was very impressed by their main water treatment plant, La Atarjea, built by Degremont in the late 1950s. It was impressively well designed, but also very well operated and maintained, to the credit of both Degremont and Sedapal. While being impressed by the plant, one could not fail to be concerned by the apparent fragility of the water supplies for Lima. La Atarajea relies on water of one river, the Rimac, and during the driest months in the Andes, the full flow of the river is diverted to the plant and treated. Alternative water supplies from wells or rivers both north and south seemed to be rather uncertain. Twenty years later, when the population of Lima has swelled, and climate change has taken its bite on the glaciers feeding the Rimac, it is not surprising that desalination plants have been considered for this beautiful and most ancient city, where it has never rained. (In reality, during the several months of constant fog, the famous neblina, at times one can have a sense of getting wet from the thick water particles of the fog, but it is not rain). So, the fact that a large desalination plant will be built north and/or south of this ever expanding city of around 8 million people, seems a certainty. It is just a matter of time. Everybody in desalination has heard of the project of Lima Sur. Started as an independent private initiative proposal put forward by Mitsui and Doosan several years ago in line with Peruvian legislation, it then migrated to a Mitsui/Veolia initiative. When this initiative was finally rejected by the government, Biwater put forward a new one, still based on a BOT concept, which is understood to be still formally standing and gives Biwater a right of first refusal when the process is put out to tender. The author has recently heard that the process for Lima Sur (now called Provisur) has started again, ��� November-December 2012 | Desalination & Water Reuse | 27 |