Evaluation of potassium as promoter on anaerobic digestion of saline organic wastewater

• Published in: Bioresource technology Vol. 266; pp. 68 - 74
• Main Authors: Li, Jing, Shi, Wansheng, Jiang, Changwang, Bai, Ling, Wang, Tao, Yu, Jiangnan, Ruan, Wenquan
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2018
• Subjects: Anaerobic digestion; Potassium; Saline organic wastewater; Viability of cells; Saline organic wastewater; Potassium; Anaerobic digestion; Viability of cells
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2018.06.066

•Potassium can promote the AD efficiency of saline organic wastewater (2.0% NaCl).•The optimal promoting effect was attained when the KCl dosage was 0.174%.•Potassium addition improved the dehydrogenase activity and bacterial cell viability.•Potassium has a long-term effect on keeping cell morphology in saline wastewater. In this work, the effect of potassium on mesophilic anaerobic digestion (AD) of saline organic wastewater, which consisted of simulated effluents obtained from heparin sodium production, was studied. The results showed that the addition of potassium chloride (KCl) to saline organic wastewater enhanced the AD efficiency. The optimal dosage was found to be 0.174% when the salt (NaCl) content was 2.0%. Under this condition, the chemical oxygen demand (COD) removal efficiency, dehydrogenase activities, and the viability of microorganisms reached 62.7%, 55.7 TF μL−1, and 78.4%, respectively, which were 115.4%, 77.2%, and 20.3% higher than those without the addition of potassium chloride. The consumption of volatile fatty acids (VFAs) was enhanced during the AD process. Moreover, less humic-like and protein-like residues appeared in the wastewater after AD. Potassium could maintain the morphology of anaerobic microorganism under high salinity and showed a long-term effect.