Fossil Energy Environmental Research Including Innovative Concepts for Wastewater, Sludge, and Product Treatment

摘要

Some of the components of the waste stream, including hydrogen sulfide, ammonia, and phenol, may be present in sufficiently high concentrations to be recoverable by stripping processes or solvent extraction. However, the dephenolated liquors may require further treatment before the aqueous stream can be released or recycled. Biooxidation processes are under development for this application. At first, activated sludge systems with large, stirred-tank reactors were used. However, this method required many hours of residence time, and thus large tanks, to achieve the very low phenol levels that were required. More efficient fluidized-bed bioreactor systems, using microorganisms immobilized as a fixed film on suspended particles, seem to be much more appropriate for this application. Typically, microorganisms such as the commercial preparation PHENOBAC (Polybac Corporation, Berlin, NJ), are used to initiate the active bioreactor system. This immobilized biocatalyst is effectively retained in the bioreactor at high microbial concentration, and when oxygen or air is also introduced in sufficient quantities, the bioreactor system is much more efficient than the conventional stirred tank. For example, phenol degradation in the fluidized bed generally ranged from 10 to 50 kg/(m sup 3 . d) with inlet phenol concentrations of 20 to 200 g/m sup 3 . This rate is 10 to 50 times higher than conventional activated sludge systems in stirred-tank bioreactors. Effluent phenol levels as low as 25 mg/m sup 3 were observed and other hazardous organic chemicals were also oxidized, including thiocyanates which were removed at a rate about 0.1 that of phenol. This type of bioreactor has exhibited stable biological activity for periods of several months with few operating problems. 9 refs. (ERA citation 12:044822)