(60bk) ECO-Friendly Algae-Based Produced Water Treatment

Produced water (PW) is the largest waste stream generated in oil and gas industries, it contains a mixture of different organic and inorganic components. Qatar is considered one of the top ten oil and gas production countries, so a massive amount of produced water (PW) is expected. Discharging produced water without proper treatment will pollute surface and underground water and soil. One of the identified priority challenges for Qatar vision 2030 is the water security.

The present work develop, for the first time, a sustainable and eco-friendly integrated algae-based treatment system. That algae system utilizes produced water, natural solar light, and CO₂ in an engineered or closed system (photo-bioreactor), to produced treated water with a quality suitable for reuse in different applications such as cooling system. On other hand, the produced algae biomass can be used as a source of animal feed, bio-fertilizer, and alternative feedstock for biofuel. The work was carried out at pilot scale under natural conditions of temperature and solar irradiation.

The results identified the types and concentrations of the potentially toxic compounds and micro and macro nutrients present in the produced water for proper algae growth. Key parameters of light, CO₂ loading, and temperature for the selected microalgae species to establish optimal growth conditions were optimized. Chemical composition of the produced algal biomass were tested and the potential for value-added product development or as a source of animal feed, bio-fertilizer and alternative feedstock for biofuel was evaluated. Results showed that native algae species Mychonastes, Chlorella, Chlorophyta, Desmodesmus, and Scenedesmus can be used successfully for the treatment of PW, organic matter and nutrients removals in the range 88-93% and 80-89% were achieved. Pre-treatment process for the removal of suspended solids and oil content was essential to produce treated water that can be used as in cooling application. Algal feedstock showed high oil content and a potential as a sustainable and eco-friendly fuel source