Microbiological aspects of sewage odor problems in the urban environment - a review

Growing human population and increasing urbanization call for the need for proper wastewater treatment to reduce environmental pollution and reduce the excess use of natural resources. During the collection of municipal wastewater, the rapid aerobic respiration often causes oxygen depletion and anaerobic conditions in the sewer system resulting in the production of malodorous compounds. The odor problems may lead to public complaints, or in the case of the sewage workers the released volatile compounds even cause serious health hazards. Therefore, microbes have a dual contribution in the urban water cycle, since they have a decisive role in wastewater treatment and the removal of pollutants, but they can also cause problems in the artificial environment. In this review, I would like to summarize the processes underlying the generation of the bad smell associated with sewage and wastewater or with the collection and treatment infrastructure, tracking the way from the households to the plants, including the discussion of processes and possible mitigation related to the released hydrogen sulfide, volatile organics and other compounds.