ABSTRACT
Aerobic heterotrophic Gram-negative bacteria are highly active in the aerobic wastewater treatment and biodegradation of xenobiotics. The genera important in the aerobic treatment of wastewater are Pseudomonas, Acinetobacter, Zoogloea, Flavobacterium, and Alcaligenes. Some of them are opportunistic bacteria and can cause diseases in immunosuppressive, young, or old people. Therefore, all treatments of water and soil infected by these bacteria must be performed avoiding the dispersion of these bacteria to environment. Aerobic heterotrophic Gram-positive bacteria, for example from the genus Bacillus, are important in environmental biotechnology. Some of them form spores. Bacillus spp. are dominant bacteria in the aerobic treatment of wastewater or solid waste rich in such polymers as starch or protein. Some species of the genus Bacillus, for example Bacillus anthrax, are pathogenic. Actinomycetes are aerobic heterotrophic Gram-positive filamentous bacteria which are active degraders of natural biopolymers and are used in the aerobic composting of solid wastes. Nitrifying bacteria comprise two groups of aerobic bacteria: ammonia-oxidizers and nitrite-oxidizers. Sulfur-oxidizing chemolitotrophic bacteria oxidize reduced sulfur compounds and are used for the bioremoval of toxic H2S from water and wastewater. Iron-oxidizing bacteria are capable of oxidizing Fe(II) in acid or neutral environments. They remove iron from drinking water. The precipitation of biogenic iron hydroxide can clog pipelines. Cyanobacteria are oxygenic prokaryotic phototrophs. Algae are eukaryotic phototrophic organisms that carry out oxygenic photosynthesis with water serving as the electron donor. Phototrophs are used for the removal of nitrogen and phosphorus from food processing wastewater. However, the blooming of cyanobacteria or algae in water polluted by ammonium or phosphate is a reason of bad odor and taste of water. A tutorial with solutions and a quiz bank are added to this chapter.
