The primary treatment of the raw sewage, Lozier said, involves putting it in a basin and allowing the heavy matter to settle out. The water then is disinfected with chlorine to kill bacteria and viruses. Nitrogen, which can cause algae growth in a river, is removed. The product then resembles drinking water and is ready to blend with raw water from the Rio Grande. Lozier said unplanned potable reuse happens every day.
Wastewater is treated, then released into the river and ends up in a downstream water supply.
Hines, the city utility manager, is aware of a negative public perception. Many municipalities in Mexico dump untreated sewage into the Rio Grande, which is where McAllen gets its raw water, Hines said. But Nuevo Laredo city engineer Cesar de la Cruz said Nuevo Laredo has a wastewater treatment plant and treats 99 percent of its sewage before putting it into the Rio Grande. Hines said numerous safeguards would be put in place to assure the safety of the reclaimed water. After Phase II of the research, the Texas Natural Resource Conservation Commission would have to approve a reclamation project.