Background

In 2001, the community received drinking water services, but did not have access to a sanitary sewer system. Most residents and businesses used on-site systems to manage their wastewater, including septic tanks with leach fields or cesspools. However, many of those on-site systems were failing due to maintenance issues, inadequate sizing, deteriorated tanks, etc., and, in some cases, wastewater was directly discharged to the ground, which posed a risk for groundwater contamination and waterborne diseases. To remedy this situation, Doña Ana County proposed building a wastewater collection system to convey the wastewater nine miles to the West Mesa Santa Teresa Wastewater Treatment Plant (WWTP) (now the West Mesa WWTP).

Project Scope

The project was divided into two phases: 1) the construction of a new wastewater collection and conveyance system for the community of La Union; and 2) the future expansion of the West Mesa WWTP. The components of the wastewater collection and conveyance system included installation of 42,000 linear feet of 8” gravity lines, 46,100 linear feet of force mains of varying diameters, as well as construction of five lift stations. The proposed treatment components included construction of a fourth sequence batch reactor (SBR) train with 150,000 gpd capacity, improvements to laboratory facilities, an effluent pond that would discharge to an irrigated field and an additional sludge drying bed.

Benefits

The project provided first-time wastewater collection and treatment services to residents, thereby significantly reducing public health and safety risks.