Hazardous Waste Treatment Technologies

Abstract

This review focuses on hazardous waste treatment technologies published in 2004 and consists of two main parts: (1) biological treatment and (2) physical and chemical treatment. BIOLOGICAL TREATMENT Aerobic Processes. Johnson et al. (2004) investigated the effects of methyl tertiary butyl ether (MTBE) on the MTBE oxidizing activity of Mycobacterium vaccae JOB5. MTBE enhanced MTBE oxidation in cells grown on organic acids, compounds that are commonly found in anaerobic, gasoline-contaminated environments. Maliyekkal et al. (2004) evaluated the performance of benzene, toluene, and xylene degradersunder substrate versatility conditions. The degree of degradation was in the following order: toluene > benzene > xylene. Nicholson and Fathepure (2004) examined the biodegradation of benzene by halophilic and halotolerant bacteria under aerobic conditions. The enrichment, which was dominated by Marinobacter spp., was able to mineralize benzene. Pruden and Suidan (2004) evaluated the effect of benzene, toluene, ethylbenzene, and xylene (BTEX) mixture on biodegradation MTBE and tertbutyl alcohol (TBA) by pure culture UC1. The BTEX mixture did not affect either the rate 2145 or the lag period of MTBE or TBA degradation, except that increases in the TBA degradation rate in the presence of BTEX were occasionally observed. Shi et al. (2004a) examined the biodegradation of natural and synthetic estrogens by nitrifying activated sludge and ammonia-oxidizing bacterium Nitrosomonas europaea. Significant degradation of estrone (E1), 17beta-estradiol (E2), estriol (E3), and ethynylestradiol (EE2) by both cultures was observed. Microbial degradation of estrogens using activated sludge and night soil-composting microorganisms was studied (Shi et al., 2004b). Both cultures almost completely degraded natural estrogens E1, E2, and E3 from initial concentrations of 20-25 mg L -1 , while synthetic estrogen, EE2, was not degraded. Yoshimoto et al. (2004) studied the degradation of estrogens by Rhodococcus zopfii and Rhodococcus equi isolates from activated sludge in wastewater treatment plants. Both isolates completely and rapidly degraded 100 mg of E1, E2, E3, and EE2 L -1 . Chang et al. (2004a) isolated two aerobic phthalic acid ester (PAE) degrading bacteria strains, DK4 and O18 from river sediment and petrochemical sludge, respectively. The two strains rapidly degraded PAE with shorter alkyl-chains while PAE with longer alkyl-chains was poorly degraded. Itrich and Federle (2004) conducted batch activated-sludge die-away studies to determine the effect of ethoxylate number and alkyl chain length on the kinetics of biodegradation of linear alcohol ethoxylates. Ethoxylate number had little effect on the first-order rates for primary biodegradation while alkyl chain length had a larger effect. Aerobic biodegradation of linear alkylbenzene sulfonates (LAS) and their degradation intermediates in seawater was examined (Leon et al., 2004).Fournier et al. (2004) studied the biodegradation of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) ...