Compared efficiency of sustainable and conventional treatments of saline oily wastewater rejected by petroleum industry in Algerian Sahara

Abstract

In recent years, petroleum and gas industries are singled out because considered to be extremely polluting. Consequently, the sustainability of this sector constitutes a challenge for oil and gas companies. As a solution to this problematic, the study suggests the use of solar energy to treat saline oily wastewater by evaporation/condensation process. It evaluates the treatment reliability and validity in term of efficiency that is also compared to a conventional treatment by coagulation/flocculation. In laboratory scale, the experiments conducted in a single treatment step obtained significant pollutants removing by reaching 98.6% of hydrocarbons, 84.3% of BOD, 78.8% of COD, 99% of total suspended solids and until 97% of metallic pollution. In real conditions of use, after one year test duration, results confirmed solar wastewater treatment (SOWAT) reproducibility of efficiency facing significant variability of pollutants concentration. Hydrocarbon ranged from 1 to 7 mg/l after a treatment of raw wastewater containing between 10.5 and 518 mg/l. Total suspended solids evolved from 1 to 200 mg/l facing a raw wastewater concentration that ranged from 100 to 880 mg/l. Comparatively to conventional treatment, SOWAT recorded close efficiency. Better yet; it stood out in its ability to remove high salinity for oil wells reinjection.