Things are looking up for the heavily polluted Santiago River, as the first of two large water-treatment plants in the Guadalajara metro area opened last weekend.
Tlajomulco’s energy efficient El Ahogado plant will treat approximately 17 percent of Guadalajara’s sewage, produced by around 820,000 inhabitants of the southern metropolitan zone. El Ahogado has the capacity to clean 2,250 liters per second, although at first it will only take in 1,600 liters per second, while the facilities are being stabilized.
At the inauguration on Saturday, President Felipe Calderon said the government has built 653 plants during his administration, fulfilling the goal of cleaning up 60 percent of Mexico’s sewage.
Work began on El Ahogado in November 2009. Built with 3,000 metric tons of steel and 20,000 cubic meters of concrete, it covers an area of ten hectares. There is an adjacent land reserve of another ten hectares in case population growth means the plant needs to be expanded.The plant treats water through various processes, including sedimentation, use of bacteria to kill off pollutants and ultraviolet light disinfection. The latter eliminates unwanted microorganisms without using chemicals that could affect the structure of the water or generate harmful by-products.
The four containers where decaying organic matter is treated are completely closed off to prevent the escape of unpleasant smells, while the plant also has systems to prevent noise pollution.
By treating the sewage in an environment devoid of oxygen, the plant will generate methane gas, which can be exploited to produce some of the power supply. The plant will generate around 1.6 million kilowatt hours per month, almost 60 percent of the electricity it consumes.
This will bring annual savings of around 25 million pesos. The State Water Commission (CEA) says treating one cubic meter of contaminated water will cost just 64 centavos, while in comparison it would normally cost from six to ten pesos per cubic meter in a small treatment plant.
Once clean, the water from the plant will be used in industrial processes, agricultural irrigation and refilling the El Ahogado dam.
The treatment plant will also contribute to the recovery of the Rio Santiago, which begins life at Lake Chapala and weaves east of Guadalajara through the Huentitan Canyon, before eventually flowing into neighboring Nayarit and out into the Pacific Ocean. Picking up a lot of sewage in the industrial area of El Salto and again from Guadalajara, it is one of the most polluted rivers in the country according to the National Water Commission (Conagua).
Construction is also well underway on Guadalajara’s Agua Prieta treatment plant. Scheduled for completion in October 2013, it will be the biggest plant in Mexico and the third largest in Latin America. Built at a cost of 2.18 billion pesos, it will treat between 75 and 80 percent of the metropolitan area’s sewage, at a rate of 8,500 liters per second. The plant, situated to the north of the city on the highway to Saltillo, will return most of its treated water to the Rio Santiago.