Can Treated Wastewater Reestablish Aquatic Communities in Desert Rivers?

Authors: Drew Eppehime, Hamdhani Hamdhani, Michael Bogan

Year: 2017 (xlix)

Abstract

In arid climates, increasing water consumption associated with human population growth has resulted in the loss of surface water resources For example, much of the Santa Cruz River in southern Arizona and northern Sonora lost perennial flow in the mid-1900s due to extensive groundwater pumping However, portions of the river have been artificially reborn through effluent discharge from wastewater treatment plants: Nogales International Wastewater Treatment Plant (Rio Rico, AZ) and the Agua Nueva and Tres Rios Water Reclamation Facilities (Tucson, AZ) This effluent discharge has created aquatic habitat, but it is not known how taxa have responded to the artificial flow regime and water quality dynamics We collect monthly samples along the lower Santa Cruz River at six reaches near Tucson This monthly collection includes benthic multihabitat and drift net sampling Our sampling efforts have revealed a surprisingly diverse community yielding >40 aquatic macroinvertebrate species and 4 species of fish within the effluent dominated lower Santa Cruz River Our sampling has also revealed the presence of microplastics (such as micro beads from personal care products) in this treated wastewater The Santa Cruz River illustrates the potential for water reuse to restore aquatic and riparian habitat, but it also demonstrates some of the remaining challenges of wastewater use (eg microplastic pollution) As urban development continues, discharge of effluent into rivers and streams will become more common Continued research is needed to determine the viability of treated wastewater to augment or replace natural flows and to incorporate ecosystem services into effluent management