Biodegradation potential of immobilized bacteria in the treatment of Tannery Industrial effluents from industrial estates in Kano State, Nigeria

Abstract

Industrial Effluents Samples from Gashash Tanneries (TAN1) in Bompai Industrial estate, Larabee Tannery Industry (TAN2) in Sharada Industrial estate and Z Tannery Industries (TAN3) in Challawa Industrial estate, Kano State, Nigeria were collected over a period of six months (August 2017 to January 2018) for assessing the biodegradation potentials of bacteria in the treatment of organic pollutants within the effluents. Bacteria were isolated from the effluents and immobilized on agar-agar. Different masses (5 g, 10 g, 15g, 20 g, and 25 g) of the bacteria were used in the treatment of 250 ml of the effluents for ten days in a shaker incubator (Gallenkamp-OC-4364-L) at the temperature 30 °C and speed of 60 rpm. Pre-treatment analysis of the effluents for Temperature, pH, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Suspended Solid (SS) and Total Dissolved Solids (TDS) gives the following results; temperature (ºC) ranged (26.38±3.81-30.33±3.79); pH (5.35±1.57-9.00±0.78); BOD (13.85±6.42-38.75±16.20); COD (1406±208-3532±1373); SS (208±235-780±739) and TDS (266±253-5276±2971). No statistical differences (p ≤ 0.05) was observed for all the results among the different industries. The bacterial isolates were identified as Neisseria spp, Bacillus cereus, and Staphylococcus aureus, in TAN1, TAN2, and TAN3, respectively. After treatment of the effluent with the different masses of the isolated bacteria, the mean level of BOD was found to range as (0.55±0.36-6.92±5.49); COD (ND-3134±1595); SS (18±022-898±672) and TDS (4±002-83±078). The results of Post-treatment analysis showed that there is overall decrease in the levels of the parameters determined when compared with that of the pre-treatment. The overall percentage reduction of the immobilised bacteria in the treatment of the respective effluents was in the order TAN2 (72%)>TAN1 (70%)>TAN3 (62%). Hence, the immobilized bacteria are having higher biodegradation potential for the treatment of the tannery effluents.