title: Oilfield water treatment by electrocoagulation-reverse osmosis for agricultural use: effects on germination and early growth characteristics of sunflower.
abstract: This study aims to evaluate the effects of oilfield water (OW), treated by a hybrid process of electrocoagulation and reverse osmosis (EC-RO), on seed germination and early growth characteristics of sunflower (Heliantus annus L.). In the EC step, tests were conducted with 28.6 A m-2current density and 4 min. reaction time. In the RO step, the system was operated with 1 L min-1constant flow and 2 MPa, 2.5 MPa and 3 MPa feed pressures. In all feed pressures, RO polymeric membranes achieved very high removals of chemical oxygen demand (up to 89%) and oils and greases (100%) from EC-treated effluent. In best feed pressure (2.5 MPa), turbidity, total dissolved salts, electrical conductivity, salinity, toxic ions and sodium adsorption ratio values attained internationally recognized standards for irrigation water. Using EC-RO (feed pressure:2.5 MPa) treated OW, germinated sunflower seeds percentage (86 ± 6%), speed of germination (30 ± 2) and biomass production (49 ± 5 mg) were statistically similar to control (distilled water) results. Vigor index average values obtained using OW treated by EC-RO (3871)were higher than that obtained by OW water treated by EC (3300). The results of this study indicate that EC-RO seems to be a promising alternative for treatment of OW aiming sunflower crops irrigation, since the use of this treated effluent did not affect adversely seed germination and seedling development, and improved seedling vigor. Furthermore, OW treatment by EC-RO reduces sodium levels into acceptable standards values avoiding soil degradation.
authors.affiliation: a Environmental Technology Laboratory , State University of Rio de Janeiro , Rio de Janeiro , Brazil.|b Osorio Foundation , Ministry of Defense of Brazil , Rio de Janeiro , Brazil.
authors.forename: Paulo S A
authors.initials: PS
authors.lastname: de Souza
authors.affiliation: a Environmental Technology Laboratory , State University of Rio de Janeiro , Rio de Janeiro , Brazil.
authors.forename: Alexandre A
authors.initials: AA
authors.lastname: Cerqueira
authors.affiliation: a Environmental Technology Laboratory , State University of Rio de Janeiro , Rio de Janeiro , Brazil.
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Rigo
authors.affiliation: a Environmental Technology Laboratory , State University of Rio de Janeiro , Rio de Janeiro , Brazil.
authors.forename: Julieta L
authors.initials: JL
authors.lastname: de Paiva
authors.affiliation: a Environmental Technology Laboratory , State University of Rio de Janeiro , Rio de Janeiro , Brazil.
authors.forename: Rafael S P
authors.initials: RS
authors.lastname: Couto
authors.affiliation: c Department of Biochemical Process Technology , State University of Rio de Janeiro , Rio de Janeiro , Brazil.
authors.forename: Fábio
authors.initials: F
authors.lastname: Merçon
authors.affiliation: d Brazilian Agricultural Research Corporation , Ministry of Agriculture , Rio de Janeiro , Brazil.
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Perez
authors.affiliation: a Environmental Technology Laboratory , State University of Rio de Janeiro , Rio de Janeiro , Brazil.
authors.forename: Monica R C
authors.initials: MR
authors.lastname: Marques
mesh_terms: D000383:Agriculture; D001673:Biodegradation, Environmental; D018525:Germination; D006368:Helianthus / Q000187:drug effects* / Q000254:growth & development*; D009995:Osmosis; D012639:Seeds / Q000254:growth & development; D014865:Waste Disposal, Fluid; D018508:Water Purification
keywords: Electrocoagulation; irrigation; oilfield water; reverse osmosis; sunflower