Effluent generated from oil and gas industries as a result of extraction and exploitation of these industries contains a high concentration of pollutants such as organic carbon, heavy metals, hydrocarbons, aromatic compounds, nitrogen, phosphorus and many mineral salts. The discharge of wastewater containing high amounts of these compounds into the environment has many negative effects on the environment and the lives of humans and other living organisms. Therefore, removing these pollutants from wastewater is essential.
Various systems and methods have been designed for wastewater treatment, each of which has its own advantages and disadvantages. Along with existing methods, microalgae cultivation systems can play a valuable role in wastewater treatment as a new and environmentally friendly technology; Because some microalgae have a high ability to reduce and remove mineral compounds, heavy metals, organic substances and other pollutants in wastewater.
In the present study, the potential of microalgae as bioabsorbers in the removal of metals in Parsian Gas Refinery effluent, has been investigated using two methods, bioaccumulation and biosorption. After initial screening, 2 species of microalgae strains of Chlorella vulgaris and Donalilla salina were selected for bioaccumulation test and 4 species of microalgae strains of Chlorella vulgaris, Donalilla salina, Spirulina platensis and Haematococcus pluvialis were selected for biosorption. In the end, a comparison was made between the results of bioaccumulation and biosorption methods and activated carbon adsorbent. The pH value of the effluent at the time of the experiments was equal to 5.6. The ambient temperature of the laboratory was considered to be 25 degrees Celsius.
In the bioaccumulation method, the maximum removal rate of metals from wastewater was obtained by Chlorella vulgaris microalgae under optimal conditions. In the biosorption method, the maximum removal rate of metals was obtained by Donalilla salina