Effect of nitrate on anaerobic azo dye reduction

• Published in: Bioprocess and biosystems engineering Vol. 36; no. 1; pp. 69 - 79
• Main Authors: Cirik, Kevser, Kitiş, Mehmet, Çinar, Özer
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.01.2013; Springer Nature B.V
• Subjects: Amines; Azo dyes; Bacteria, Anaerobic - metabolism; Batch processes; Batch reactors; Biodiversity; Biotechnology; Chemical oxygen demand; Chemistry; Chemistry and Materials Science; Color; Color removal; Dyes; Environmental Engineering/Biotechnology; Enzymes; Food Science; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Industrial Waste - prevention & control; Microorganisms; Naphthalenesulfonates - isolation & purification; Naphthalenesulfonates - metabolism; Nitrates; Nitrates - metabolism; Nutrient removal; Original Paper; Oxidation-Reduction; Oxygen - metabolism; Population dynamics; Reactors; Textile Industry; Textile industry wastes; Textile industry wastewaters; Water Pollutants, Chemical - isolation & purification; Water Pollutants, Chemical - metabolism; Water Purification - methods; Anaerobic color removal; Denaturing gradient gel electrophoresis; Nitrate; Remazol Brilliant Violet 5R; Sequencing batch reactor
• DOI: 10.1007/s00449-012-0762-9
• ISSN: 1615-7591

The aim of the study was to investigate the effect of nitrate on anaerobic color removal efficiencies. For this aim, anaerobic–aerobic sequencing batch reactor (SBR) fed with a simulated textile effluent including Remazol Brilliant Violet 5R azo dye was operated with a total cycle time of 12 h, including anaerobic (6 h) and aerobic cycles (6 h). Microorganism grown under anaerobic phase of the reactor was exposed to different amounts of competitive electron acceptor (nitrate) and performance of the system was determined by monitoring color removal efficiency, nitrate removal, nitrite formation and removal, oxidation reduction potential, color removal rate, chemical oxygen demand (COD), specific anaerobic enzyme (azo reductase) and aerobic enzyme (catechol 1,2 dioxygenase), and formation and removal of aromatic amines. Variations of population dynamics of microorganisms exposed to various amount of nitrate were identified by denaturing gradient gel electrophoresis (DGGE). It was found that nitrate has adverse effect on anaerobic color removal efficiency and color removal was achieved after denitrification process was completed. It was found that nitrate stimulates the COD removal efficiency and accelerates the COD removal in the first hour of anaerobic phase. About 90 % total COD removal efficiencies were achieved in which microorganism exposed to increasing amount of nitrate. Population dynamics of microorganisms exposed to various amount of nitrate were changed and diversity was increased.