Rapid removal of bacterial endotoxin and natural organic matter in water by dielectric barrier discharge plasma: Efficiency and toxicity assessment

• Published in: Journal of hazardous materials Vol. 318; pp. 15 - 23
• Main Authors: Zhang, Can, Fang, Zhendong, Liu, Wenjun, Tian, Fang, Bai, Miao
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.11.2016
• Subjects: Acute toxin; Bacillus subtilis; Bacteria; Bacterial endotoxin; Dielectric barrier discharge; Dielectric barrier discharge (DBD) plasma; Endotoxins; Escherichia coli; Freshwater; Inactivation; Natural organic matter (NOM); Staphylococcus aureus; Sterilization effects; Toxicity; Water; Water; Acute toxin; Bacterial endotoxin; Dielectric barrier discharge (DBD) plasma; Natural organic matter (NOM)
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2016.06.036

•DBD plasma inactivated the bacteria (Bacillus subtilis, Escherichia coli, Staphylococcus aureus and HPC) in water.•‘Activated’ water treated by DBD has delayed bacteria inactivation effect.•DBD plasma removed the endotoxin released by Escherichia coli, as well as artificially simulated endotoxin in a control solution.•The NOM in filtration effluent of a WTP was well removed by DBD plasma.•DBD plasma contributed to decreasing of pH value and improvement of acute toxicity in water. Low-temperature plasma was used to control bacteria, endotoxins and natural organic matter (NOM) in water by a dielectric barrier discharge (DBD) device. Results indicate that DBD plasma has an obvious inactivation effect on various bacteria in water. The degree of inactivation from difficult to easy is as follows: Bacillus subtilis>Escherichia coli>Staphylococcus aureus. Activated ultrapure water treated using DBD plasma exhibited a sustained sterilization effect, but this sterilization effect decreased gradually after 1h. The total-endotoxin (free-endotoxin and bound-endotoxin) released by Escherichia coli during inactivation, as well as artificially simulated endotoxin in a control solution, was significantly controlled by DBD plasma. Both the metabolites that appeared after inactivation of microorganisms by plasma treatment, and the NOM in filtration effluent of a water treatment plant were well removed by DBD plasma if the treatment duration was sufficiently long. However, the acute toxicity increased significantly, and persisted for at least 2h, indicating that some long-life active substances were generated during the DBD process. Therefore, the removal of bacteria, endotoxins or NOM does not mean a safe water is produced. It is also important to eliminate the toxicity and byproducts produced during water treatment for the continuous promotion and industrial application of DBD plasma.