Low Cost Strategy for Treating and Reusing Wastewater on the U.S. - Mexican Border

1. Purpose and Objectives: The purpose of this study is to examine the feasibility of linking several “natural” treatment systems to treat and recharge effluent. The objective is to benefit Nogales, AZ, and other border communities that need low-cost, low-technology, environmentally sound alternatives for sewage treatment and sustainable water supplies.

2. Funding: $140,000

3. Partners: Arizona State University (ASU) and the Southwest Center for Environmental Research and Policy (SCERP).

4. Description and Methodology: The lack of adequate wastewater treatment facilities is a major problem for communities along the U.S./Mexico border. Hence, this project will seek to alleviate part of the problem by using three natural components—A lagoon, a wetland, and a groundwater recharge basin. The study site is Nogales, AZ, where a lagoon treatment system already exists. A pilot-scale wetland treatment system will be built in a collaborative effort between the U.S. Bureau of Reclamation and the City of Nogales. ASU will build pilot-scale percolation basins using soils collected from three potential recharge sites to simulate groundwater recharge of treated effluent. This may very well be the first lagoon-wetland-recharge system in the Southwest. ASU will analyze the performance of the entire treatment system with respect to water quality standards for effluent-dominated streams (lagoon-wetland system) and municipal drinking water (lagoon-wetland-recharge system). Practical design and operational criteria for wetland treatment systems and recharge basins will be developed or modified for arid border cities. ASU will also study hydrologic and ecosystem impacts of several options for discharging or recharging effluent from the Nogales wastewater treatment plant.

5. Status: Project will be complete in 1999.