COD reduction of textile effluent in three-phase fluidized bed bioreactor using Pseudomonas aureofaciens and Escherichia coli

Abstract

This paper investigated the effect of mixed cultures of Pseudomonas aureofaciens and Escherichia coli and air as gas on degradation of chemical oxygen demand (COD) in three-phase inverse fluidized beds (TPIFBs) for textile effluents with initial COD of 1200 ppm (effluent 1) and 640 ppm (effluent 2). Investigators focused on the importance of different design of gas spargers of the TPIFB for checking its effect on COD reduction performance. For this purpose, four different gas spargers were fabricated for gas flow entry into bioreactor with different % open area: Gas sparger 1 (18% open area), sparger 2 (10.42% open area), sparger 3 (8.077% open area) and sparger 4 (1.53% open area). These percentage open area decided the amount of gas flow in a unit time in batch studies, which in turn rely mainly on superficial gas velocity. The reduction in COD was measured at two different superficial gas velocity (0.00343 and 0.004068 m/s) and at two ratio of static bed height to diameter (H/D) of 0.5 and 0.25 in an aerobic mode. Textile effluent 1 resulted in 98.07% COD reduction with sparger 3 and discharged at 23.14 ppm in 28 h. Textile effluent 2 resulted in 96.5% COD reduction with sparger 2 and discharged at 22.4 ppm in 22 h. The resulting COD values of Effluent 1 and effluent 2 were in range of discharge limit and resulted at a low gas velocity of 0.00343 m/s and low H/D ratio of 0.25. The gas holdup correlation was found to be e g = 0.0064 U g 0.98 .

Industrial Water Demand and Wastewater Generation: Challenges for Bangladesh’s Water Industry

“…TDS and TSS levels in textile wastewater depend on initial water turbidity, dyes, and a high level of salt use. 31,32 The median value of TDS (2015 mg L −1 ) in Bangladesh textile wastewater was comparatively higher than the median values in China (1145 mg L −1 ) and Turkey (1800 mg L −1 ) but similar to that in Vietnam (2087 mg L −1 ), and European countries (2100 mg L −1 ) (Figure S4). The median TSS value in Bangladesh textile effluents is comparatively higher than those of China, Turkey, Vietnam, and European countries (Figure S4).…”

Process parametric study for COD removal of electroplating industry effluent

“…The raw untreated electroplating effluent (initial COD of 1140 mg/l) was collected from a nearby area of Rajkot city. It was treated in a bioreactor fabricated from acrylic (Sur and Mukhopadhyay 2017a), and solid media particles were made up of polypropylene (Online resources: ESM: Table S1). Electroplating effluent (composition: Cr = 19.4 ppm; Ni = 9.4 ppm; Fe = 0.9 ppm; conductivity = 68mS/cm; pH 4.1) was treated to investigate the performance of gas sparger in a batch mode i.e., zero liquid velocity.…”

“…Recent developments in three-phase inverse fluidized beds have encouraged its applications in various industries, viz. biotechnological (Sur and Mukhopadhyay 2017a) and environmental (Haribabu and Sivasubramanian 2014) and chemical (Rajasimman and Karthikeyan 2007).…”

“…This fact encourages the present work. Moreover, the quantum of research for effluent treatment in the batch mode, using TPIFB, is limited (Sur and Mukhopadhyay 2017a). Therefore, the current research specifically investigates the parameters and their correlations responsible for the reduction in COD of the electroplating effluent through a single representation for the full TPIFB operation, carried out in the batch mode.…”