TREATMENT OF WASTEWATER BY USING COMBINATION OF ADSORPTION AND BIODEGRADATION

Abstract

Phenol and phenolic compounds are the most important constituents of the effluent comes from so many industries like oil refineries, coke oven plants, steel plants, pesticides, insecticides, pulp and paper, plastic, textile, dye, polymeric resin, pharmaceutical industries etc. These wastewaters require careful treatment before being discharged into the receiving stream of water. Treatment of these wastewaters is challenging for a pollution-controlling engineer. Adsorption and Biodegradation are two important techniques for treating wastewaters. Both have significant advantages as well as disadvantages. The combined application of these above two techniques has got an extra edge over the two processes separately. In the present study Phenol and Resorcinol has been biodegraded by using Pseudomonas putida in the presence of GAC. Simultaneous Adsorption and Biodegradation (SAB) has been studied against Adsorption. The effects of initial concentration, pH, adsorbent dose and particle size have been studied for SAB as well as for adsorption and are compared. The values of U.max for Phenol and Resorcinol were found to be 0.452 hr' and 0.219 hr"1. The variation in the rate of removal of Phenol and Resorcinol between SAB and Adsorption for adsorption dose 6 gm/l, is higher among the three adsorbent doses 6 gm/l, 8 gm/l and 10gm/I considered for the study. The higher rate of removal of Phenol has been found at pH 6.24 for SAB, but for Resorcinol it is at pH 5.91. Particles of sizes 1.4-2 mm, 2-4 mm and 4-5 mm have been tested for SAB. It is .found that the variation in the removal of Phenol and Resorcinol between SAB and Adsorption for 4-5 mm particles is higher among the particle sizes considered for the study. It is observed that the rate of removal of Phenol for initial concentration 60 mg/1 is higher than that of 40 mg/l. For resorcinol it is found that the rate of removal for initial concentration 80 mg/I is higher than that of 60 mg/l for SAB. Kinetic parameters have been found out. In the column study breakthrough curves have been found out for adsorption and SA 13 with Pseudomonas putida immobilized on fresh activated carbon. Reactor performance has been 111 calculated. After the bed reached exhaustion it was bioregenerated for 12 hrs .Later breakthrough curves have been found out and reactor performance and percentage regeneration has been determined. The percentage regeneration is observed to be 61.82 % for Phenol and 50.76 % for Resorcinol. Freundlich parameters have been calculated for fresh activated carbon adsorption, SAB and bioregenerated activated carbon (1s` cycle) for both Phenol and Resorcinol.