Municipal wastewater treatment process alternatives

Another example of the application of fermentation is the removal of organic compounds from exhaust air. Such biofilters are often trickle-bed reactors, in which the microorganisms grow on a solid support, such as wood chips or porous stones. Water is trickled through the reactor, whereas the exhaust air flows in the opposite direction. The bacteria digest the organic components and destroy odor-causing chemicals. Biofilters are applied in municipal wastewater treatment, food production, paint, paper, and timber industries or soil remediation. They provide an attractive alternative to thermal, chemical, and adsorptive processes for cost-effective treatment of air pollutants. 

Among the different wastewater streams, the amount of effluents from municipal wastewater treatment plants (WWTPs) has increased during the last decades. Since more stringent regulations on environment protection are adopted worldwide, the quality of WWTP effluents must be improved before discharge, to preserve natural water resources from contamination at the same time, the generation of these huge quantities of wastewaters to be processed, has raised questions on the opportunity to consider them as a potential alternative water resource for some human activities [18]. Therefore, wastewater purification and reuse have twofold major impacts... 

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