Lecture 40 Flashcards
What are the main recyclers of biomass on earth?
microorganisms.
What are the goals of wastewater treatment?
Kill and pathogens that may be present and reduce the organic load and nitrogen and phosphorous in the water.
What is biochemical oxygen demand?
The relative amount of dissolved oxygen consumed by microbes to aerobically decompose all organic and inorganic material in a water sample. Polluted water will have a higher value of this than pure water. The oxygen is used to convert pollutants (organic) into CO2.
What are marine dead zones? How do they form?
These are areas where oxygen concentrations in water have fallen so low that animals cannot survive. Nitrogen and phosphorous from fertilizer and sewage in the freshwater layer cause huge algae blooms, when these algae die they sink into the salty water below and decompose, using up oxygen in the deep water below due to bacteria utilising it. Animals cannot survive in these zones as the oxygen levels have gotten too low.
What is the objective of sewage treatment?
To produce a disposable effluent without causing harm to the surrounding environment and also prevent pollution.
What is primary waste treatment? How effective is it?
The wastewater is screened, removing indestructibles in the sedimentation tanks and is incinerated, the liquid and remaining organic material is disposed of in the sea. This process is physical only and removes 60% of contaminants but only 34% of biochemical oxygen demand.
What is a coliform?
Bacterial indicator of sanitary quality of foods and water. The presence indicates that other pathogenic organisms of fecal origin may be present.
What is secondary waste water treatment?
Utilisation of microorganisms and oxygen on the liquid from primary treatment, contains an aeration tank with the microorganisms and a settling tank which difficult sludge settles in and is sent to an anoxic sludge digestor (anoxygenic bacteria), the clear effluent leaves from the settling tank. Any sludge that can’t be digested by the anoxygenic bacteria is incinerated.
What is tertiary wastewater treatment?
Anything more than primary and secondary treatment e.g filtration, disinfection (e.g with UV, chlorine or ozone).
What is produced by Anoxic sludge bacteria and methanogens in humans which can be used as fuel?
Biogas (methanol) can provide fuel for cooking and light and is relatively clean burning. Could also help resolve the global energy crisis.
What is clostridia acetobutylicum?
A bacteria which produces ethanol, butanol and acetone from pyruvate (among other things) which is produced during cellular respiration.
How are biofuels produced by bacteria?
Large polymers like starch, sucrose or lactose are broken down through solubilise and hydrolyse, the bacteria then fermentate this and this can be distilled to form ethanol. A possible biofuel.
What is clostridium magnum?
A bacteria that is able to metabolize gaseous substrates includes hydrogen, carbon monoxide and carbon dioxide.
What are designer microbes?
Microbes designed for a specific purpose e.g degrading difficult to degrade pollutants or for bioremediation (cleaning up toxic waste).
