Hazardous Waste Treatment Technologies

Abstract

This review focuses on hazardous waste treatment technologies published in 2001 and consists of two main parts: (1) biological treatment and (2) physical and chemical treatment. BIOLOGICAL TREATMENT Aerobic Processes. Substrate interactions in benzene, toluene, ethyl benzene, and xylene (BTEX) and methyl tert-butyl ether (MTBE) mixtures by an MTBE-degrading isolate, PM1 were studied (Deeb et al., 2001). BTEX and MTBE degradation occurred primarily via two independent and inducible pathways. Severe inhibition of MTBE degradation by ethylbenzene and the xylenes and the partial inhibition by benzene and toluene were observed. Hatzinger et al. (2001) evaluated biodegradation of MTBE by the hydrogen-oxidizing bacterium Hydrogenophaga flava ENV735. Growth of ENV735 on MTBE or tert-butyl alcohol (TBA) as sole sources of carbon and energy was greatly enhanced by the addition of a small amount of yeast extract while the supplement of hydrogen gas (H 2 ) did not affect MTBE degradation by the strain. MTBE degradation activity was constitutively expressed in ENV735 and was not greatly affected by formaldehyde, carbon monoxide, allyl thiourea, or acetylene but was inhibited by 1amino benzotriazole and butadiene monoepoxide. Kane et al. (2001) studied the potential for aerobic MTBE degradation with microcosms containing aquifer sediment and groundwater from four MTBE-contaminated sites characterized by oxygen-limited in situ conditions. The effects of oxygen and water-soluble gasoline components on in situ MTBE degradation varied from site to site and phylogenetic analysis might be a promising predictor of MTBE biodegradation potential. Liu et al. (2001a) reported that Arthrobacter bacteria demonstrated MTBE degradation activity when grown on butane but not when grown on glucose, butanol, or tryptose phosphate broth. The presence of butane, tert-butyl alcohol, or acetylene had an adverse impact on the MTBE degradation rate. Neither Methylosinus trichosporium OB3b nor Streptomyces griseus was able to cometabolize MTBE. Pruden et al. (2001) developed five aerobic Literature Review 2002 3 examined (Fava and Di Gioia, 2001). A substantial decrease of soil ecotoxicity was observed in SL-supplemented microcosms and SL was found to be a good carbon source for both indigenous and ECO3 bacteria, as well as a product capable of enhancing the PCB bioavailability in the microcosms. Kim and Picardal (2001) isolated bacterial strains, SK-3 and SK-4, capable of aerobic growth on ortho-substituted dichlorobiphenyls as sole carbon and energy sources. During growth on 2,2'dichlorobiphenyl and 2,4'-dichlorobiphenyl strain SK-4 produced stoichiometric amounts of 2-chlorobenzoate and 4-chlorobenzoate which were not formed when strain SK-3 was grown on 2,4'-dichlorobiphenyl. Zhoa and Ward (2001) studied substrate selectivity of a 3-nitrophenol-induced metabolic system in Pseudomonas putida 2NP8 transforming nitroaromatic compounds into ammonia under aerobic conditions. All of the 30 monoor dinitroaromatic substrates except 4-nitrophenol, 2,4-dinit...

Competitive Adsorption of Methylene Blue and Cu2+ onto Citric Acid Modified Pine Sawdust

“…In order to minimize the environmental effects, these pollutants must be removed from wastewater before discharging. The removal of heavy metals and dyes from wastewater can be achieved by several techniques such as precipitation, flocculation, adsorption, and ion exchange and so on [3]. Among these, adsorption has been proved to be effective and attractive process [4].…”