A thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 1989

Ethylene hollow fiber membranes of 0.2 æm pore size were used as direct solid/liquid separation device in laboratory-scale aeration tanks for the treatment of phenol, 2-chlorophenol, 2,4,6-trichlorophenol and pentachlorophenol. Phenol-adapted sludge was used. The biodegradability of the chlorinated phenols was dependent on the acclimation period and the chemical properties of the compounds. 2-chlorophenol and 2,4,6-trichlorophenol were readily degraded after 13 days acclimation, while pentachlorophenol required an acclimation period of 20 days. The removal efficiency of the chlorophenols increased with a longer adaptation period and higher volumetric organic loading. Removal rate of phenol and 2-chlorophenol was much faster than 2,4,6- trichlorophenol and pentachlorophenol. Utilization rates of phenol and 2-chlorophenol (kg phenols/(kg MLSS.d)) were over 0.04 and 0.004 d -t respectively, while that of 2,4,6-trichlorophenol and pentachlorophenol wer e around the range of 2.2 x 10 -J d - 1 {u2022} The direct membrane separation activated sludge system was shown to be very stable against shock loadings due to a high MLSS concentration achieved by membrane separation. Good effluent quality was attained as well, owing to the membranes' ability to retain macromolecules from cell lysis.