Reclaiming Agricultural Drainage Water with Nanofiltration Membranes: Imperial Valley, California, USA

摘要

We conducted pilot-scale field experiments using nanofiltration membranes to lower the salinity and remove Se, As and other toxic contaminants from saline agricultural wastewater in the Imperial Valley, California, USA. Farmlands in the desert climate(rainfall ～7.4 cm/a) of Imperial Valley cover ～200,000 ha that are irrigated with water (～1.7 km{sup}3 annually) imported from the Colorado River. The Salinity(～850 mg/L) and concentration of Se (～2.5μg/L) in the Colorado River water are high and evapotranpiration further concentrates salts in irrigation drainage water, reaching salinities of 3,000-15,000 mg/L TDS and a median Se value of ～30μg/L. Experiments were conducted with two commercially available nanofiltration membrabes, using drainage water of varying composition, and with or without the addition of organic precipitation inhibitors.