Phenolic Wastewater Treatment

A simple experimental set-up was used to study the treatability aspect of phenolic wastewater. Three types of systems: i) activated sludge (A.S), ii) granular activated carbon (A.C) and iii) activated sludge plus activated carbon (A.S + A.C) were experimented under different phenol loadings (100, 200 and 300 mg/l) and different flow rates (21.6 and 43.2 l/d) with initial COD concentration 500 mg/l. Phenol toxic effect on biomass was also investigated. The A.S + A.C system gave the highest COD and phenol % removal comparing with the other two systems. Results showed that increasing phenol loading had an adverse effect on treatment efficiency for all cases. Respirometric analysis indicated that, for A.S system, μ^H decreased from 3.20 d at 0.0 mg/l phenol concentration to 2.26 d at 100 mg/l phenol concentration. Increasing phenol load to 300 mg/l results in decreasing μ^H to only 1.21 d. In order to confirm these results, the toxic effect was measured by following the fraction of Specific Oxygen Uptake Rate (SOUR) loss between the sludge with zero phenol and the sludge dosed with phenol. Results obtained indicated an increasing of toxicity factor from 0.325 at phenol concentration of 100 mg/l to 0.63 at phenol concentration of 300 mg/l.