Treated Wastewater for Agricultural Irrigation

Anton (Tony) G. Callery, Treatment Process Business Development Manager for Latin American Operations within ITT's Water and Wastewater business: "Peru has a critical need for biologically treated wastewater because its supply of extracted freshwater is dwindling, and 80 percent of that is currently being used for agricultural purposes," said Callery. "As a result, the country enacted new regulations in July 2008 for the reuse of wastewater, including effluent that is applied toward animal care and crop cultivation. Those regulations in turn prompted SEDAPAL, the water resources agency for Lima, to decide that ITT Water & Wastewater should collaborate on the new wastewater treatment plant with Abengoa, the project contractor. ITT was assigned responsibility for not only the facility's process design and engineering, equipment supply, and electro-mechanical installation, but also its start-up and first six months of operation."

The modified SBR process that is central to the new technology is an Intermittent Cycle Extended Aeration System (ICEAS) that has two compartments - a pre-react zone and a main-react zone - for treating the wastewater. At the end of the eight-hour ICEAS process, the wastewater will then undergo tertiary filtration to ensure removal of Helminth Ova, a parasite generally resistant to current forms of oxidizers and disinfectant technologies, at which point it will meet all the quality requirements for usage.

In addition to generating the treated wastewater, the plant will ultimately produce each day about 900kg of dried biosolids extracted from the wastewater. These will also have agricultural application as they can be used for soil pH stabilization and to add nutrients to the soil.

"This project represents an important addition to the strong emerging economy of Peru, which is home to 30 million people, yet is so mountainous and arid that only three percent of the country's land is considered arable," said Callery. "The plant should prove especially beneficial in serving the needs of up to 70,000 residents of Manchay."