Sequential and continuous processes of coalescence and adsorption in produced water treatment by coupling a vegetal fiber coalescer and a fixed bed with biochar produced by vacuum pyrolysis of ouricury palm (Syagrus coronata)

• Published in: Journal of water process engineering Vol. 66; p. 106034
• Main Authors: da Silva Almeida, Flávia Bartira Pedro, Esquerre, Karla Patrícia Santos Oliveira Rodriguez, Soletti, João Inácio, de Farias Silva, Carlos Eduardo, da Silva, Ithalo José, da Gama, Brígida Maria Villar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-09-2024
• Subjects: Coalescer bed; Fixed-bed column; Oil industry; Pyrolysis process; Pyrolysis process; Coalescer bed; Oil industry; Fixed-bed column
• DOI: 10.1016/j.jwpe.2024.106034
• EISSN: 2214-7144

Produced water (PW) is considered the largest wastewater stream, and its volume is a major concern for the oil industry. PW has a complex composition consisting of several chemical components, the most important of which is the oil and grease content, making it difficult to biologically treat and dispose of this wastewater for reuse or discharge into water bodies. The present paper aimed to study the treatment of PW through the sequential and continuous processes of coalescence (using vegetal fibers from coconut (FC) and loofah) and fixed-bed adsorption (using biochar from ouricury palm (OP)). For the study, a steady-state horizontal bed coalescer was constructed to study operating parameters (flow rate: 40–80 L/h; time: 10–30 min), and a fixed-bed column using biochar and activated charcoal produced by vacuum pyrolysis, evaluating variables (particle diameter: 0.15–0.5 mm; flow rate: 2.2–4.4 L/h; adsorbent: OP without modifications and activated with NaOH). The innovation of this research is by the sequential treatment of PW using coalescence and fixed-bed adsorption associated to the application of these biomasses (FC, loofah and OP). The results showed that the bed coalescer operated under stable conditions achieved an average oil and grease removal efficiency of 83 ± 7.6 % (at 60 min) and FC demonstrated better performance than loofah. On the other hand, the fixed-bed column presented a maximum efficiency of 84 % using biochar or activated charcoal being the particle diameter and the interaction between flow rate and type of biochar with significative effects on the performance. The results indicated that the treated effluent met regulatory requirements for discharge to water, making it suitable for reinjection or reuse systems.
•Continuous coalescence process applying vegetal fibers was efficient.•Coconut fibers exhibited better performance than loofah.•Flow rate and time influenced continuous coalescence process.•Biochar and activated charcoal with NaOH were applied in adsorption process.•Particle diameter, flow rate and biochar type influenced adsorption performance.