BIOL 223 Topic 4: Bioremediation and Wastewater Treatment Lecture Notes

Flashcards covering bioremediation, redox reactions, uranium cleanup, and wastewater treatment processes.

__ involves bringing foreign microbes into an environment to remove contaminants.

Bioaugmentation

__ involves feeding or helping preexisting microbes in an area to remove contaminants.

Biostimulation

A __ reaction involves the transfer of an electron.

Redox

__ is the gaining of an electron, making the molecule an electron acceptor.

Reduction

__ is the losing of an electron, making the molecule an electron donor.

Oxidation

What does the mnemonic OIL RIG stand for, and what does it help remember?

OIL RIG stands for 'Oxidation Is Losing' (electrons) and 'Reduction Is Gaining' (electrons). It is a mnemonic device used to remember the definitions of oxidation and reduction in redox reactions, clarifying which process involves the loss or gain of electrons.

The goal of uranium bioremediation is to convert water soluble U6+ to __.

U4+ in uraninite (not water soluble)

U6+ is water soluble, while U4+ in __ is not.

uraninite

Microbes like Shewanella, Geobacter, and Desulfovibrio species can be used in the bioremediation of __.

Uranium

For uranium bioremediation, organic matter or H2 serves as the __.

electron donor

__ is unique because of the way its pili transfers electrons.

Geobacter

The C:N:P ratio is important for __.

Biostimulation

Xenobiotics are challenging to degrade because they are __ to microbes.

unnatural

A key advantage of bioremediation is that it is often the __ method for pollutant removal.

cheapest

A disadvantage of bioremediation is that it can have __ results and may take a long time.

unpredictable

The main aim of wastewater treatment is to reduce __ and the amount of organics, not destroy all bacteria.

BOD (Biological Oxygen Demand)

Activated sludge is composed of slimy masses called __ where microbes attach.

flocs

Anaerobic wastewater treatment is useful for very high __ wastewater from industrial sources.

BOD (Biological Oxygen Demand)

In anaerobic digesters, remaining organics are converted to or .

CO2; CH4

Advanced wastewater treatment aims to remove remaining organics, inorganic nutrients like N and P, and __.

toxins

Phosphorus can be removed in advanced wastewater treatment by __ (PAOs) that make polyphosphate.

phosphorus-accumulating organisms

__ bacteria can remove nitrogen by converting NH3 directly to N2.

Anammox

What is bioremediation?

Using biological agents, like microbes, to remove or neutralize pollutants from contaminated environments.

Why are redox reactions crucial in bioremediation processes?

They facilitate the transfer of electrons, which is essential for microbes to break down or transform contaminants, often by changing their solubility or toxicity.

In uranium bioremediation, what is the function of organic matter or \text{H}_2 ?

They serve as electron donors, providing the electrons needed by microbes to reduce soluble \text{U}^{6+} to insoluble \text{U}^{4+} (uraninite).

Why are xenobiotics challenging for microbes to degrade?

They are often synthetic and structurally unfamiliar to microbial enzymes, meaning microbes may lack the specific metabolic pathways to break them down efficiently.

What is the primary goal of conventional wastewater treatment?

To reduce Biological Oxygen Demand (BOD) and the concentration of organic matter, rather than eliminate all microorganisms.

In activated sludge systems, what are 'flocs'?

Slimy masses composed of microbial communities where bacteria attach and grow, crucial for consuming organic pollutants.

When is anaerobic wastewater treatment particularly advantageous?

For treating wastewater with very high Biological Oxygen Demand (BOD), typically from industrial sources, due to its ability to handle high organic loads without oxygen.

What are the main gaseous products formed when organics are converted in anaerobic digesters?

\text{CO}2 (carbon dioxide) and \text{CH}4 (methane).

Besides organics, what other types of contaminants does advanced wastewater treatment aim to remove?

Inorganic nutrients such as nitrogen (N) and phosphorus (P), as well as various toxins.

How do Phosphorus-Accumulating Organisms (PAOs) contribute to phosphorus removal in advanced wastewater treatment?

PAOs accumulate excess phosphorus intracellularly as polyphosphate, which can then be removed when the microbial biomass is separated from the treated water.

What is the role of Anammox bacteria in advanced nitrogen removal from wastewater?

Anammox bacteria directly convert ammonia ( \text{NH}3 ) and nitrite into nitrogen gas ( \text{N}2 ), reducing the need for oxygen in the nitrogen removal process.