Unit 2–Lecture 12 (Microbiology of the Built Environment) Flashcards
Mining with Microorganisms
Pyrite (FeS2)
Sulfides also form insoluble minerals with metals
Economically feasible to mine low-grade ores only if the metal can be concentrated
Microbial leaching
—-the removal of valuable metals, such as copper, from sulfide ores by microbial activities
Bioremediation of Uranium-Contaminated Environments
Uranium contamination of groundwater has occurred where uranium has been processed or stored
Some bacteria can convert U6+ to U4+
—-U6+ is water soluble
—-U4+ is not water soluble
Uranium is contained, not removed
Bioremediation of Organic Pollutants: Pesticides and Plastics
Some xenobiotics can be degraded partially or completely if another organic material is present as a primary energy source for a microbe
The microbe breaks down the xenobiotic and the organic molecule (co-metabolism)
Pesticides and Plastics
Chlorinated xenobiotics can be degraded
—-anaerobically (reductive dechlorination)
—-aerobically (aerobic dechlorination)
Reductive dechlorination is usually a more important process because anoxic conditions develop quickly in polluted environments
Wastewater
Domestic sewage or liquid industrial waste
“Gray water” is the water resulting from washing, bathing, and cooking
Sewage is water contaminated with human and animal fecal material
Wastewater Treatment
Relies on industrial-scale use of microbes for bioconversion
Following treatment, the discharged treated wastewater (effluent water) is suitable for:
—-release into surface waters
—-release to drinking water purification facilities
Primary Wastewater Treatment
Uses physical separation methods to separate solid and particulate organic and inorganic materials from wastewater
Secondary Wastewater Treatment
Aerobic Secondary Treatment
—-uses digestive reactions carried out by microbes under aerobic conditions to treat wastewater with low levels of organic materials
Activated sludge and the trickling filter are the most common decomposition processes
Advanced Wastewater Treatment (Tertiary)
Any physiochemical or biological treatment process added for the further processing of secondary treatment effluent
Additional removal of organic matter and suspended solids
Reduces the levels of inorganic nutrients
—-phosphate, nitrate, nitrite
Most complete method of treating sewage but, because of costs, is not widely adopted
Advanced Wastewater Treatment
Example of tertiary treatment:
Phosphorus removal
—-Big Rapids uses chemicals (FeCl3)
Contaminants of emerging concern:
New biologically active pollutants are being released in treated or untreated sewage
—-pharmaceuticals
—-personal care products
—-household products
—-sunscreens
Drinking Water Purification and Stabilization
Purification involves many steps
—-Sedimentation to remove particles
—-Coagulation and flocculation form additional aggregates, which settle out
—-Filtration
—-Disinfection (typically with chlorine gas or UV radiation)
The Microbiology of Homes and Public Spaces
The microbiota of a home is very predictive of specific family, and the microbiota changes within days of a change of occupancy
Flushing a toilet can release 100,000 bacteria into the air, which can then transmit enteric bacteria from person to person
Sexually transmitted diseases, however, are unlikely to be transmitted in this way because they are sensitive to drying out and would die before transmission
Biodeterioration of Stone and Concrete
Biodeterioration is the loss of structural integrity of stone or concrete caused by microorganisms
Microorganisms can colonize the surface of stone
Microorganisms can grow within certain stones (endolithic)
—-bacteria
—-archaea
—-fungi
—-algae
—-cyanobacteria
