Lecture 38 - Bioremediation and Wastewater Treatment

Question 1

Name two functions of a wastewater treatment plant?

Answer 1

1. Elimination of human pathogens
2. Reduce organic load

Question 2

What is BOD?

Answer 2

biochemical oxygen demand, the amount of oxygen needed fo microorganisms to breakdown organic materials

Question 3

What are the consequences of high BOD in an ecosystem

Answer 3

1. BOD allows bacterial growth
2. Bacteria use up oxygen
3. Bacteria produce nitrate, phosphate, and ammonia
4. Algae and cyanobacteria increase

Question 4

What is the process of eutrophication

Question 5

What are the three stages of wastewater treatment?

Answer 5

1. Physical settling and sludge removal
2. Microbial degradation and floc formation
3. Chemical treatment to kill pathogens and precipitate phosphates

Question 6

What is activated sludge? How is it produced?

Answer 6

chemoheterotrophs catabolize the biopolymers in wastewater by converting them to intermediates of central metabolic pathways

Question 7

How is a wastewater treatment wetland constructed?

Answer 7

1. wastewater flows into pond with aerators
2. water is aerated
3. Effluent flows into marsh

Question 8

Name two steps of water quality control testing. Name one method for each step

Answer 8

1. Presumptive test (use lactose broth with Durham tube)
2. Membrane filtration (incubate filter)

Question 9

What organism is commonly used as a fecal indicator in water?

Answer 9

E. coli

Question 10

What is the typical groundwater bioremediation program?

Answer 10

in situ treatment where contaminated water is pumped to the surface and mixed with nutrients, upgradient injected

Question 11

What is the principle of microbial infallibility

Answer 11

bacteria can degrade all organic substances

Question 12

What three features render a contaminant recalcitrant to bioremediation

Answer 12

1. the environment (other nutrients available, wrong oxygen conditions, toxic chemicals present)
2. the microbes (cannot degrade/no pathway)
3. the chemical (low solubility, highly branched, highly chlorinated)

Question 13

How do recalcitrant molecules biomagnify in the food chain?

Answer 13

hydrophobic molecules get concentrated in lipid of organisms

Question 14

What is an example of environmental modification to enhance bioremediation?

Answer 14

DDT highly concentrated in merganser (fish-eating duck)

Question 15

Where do natural bioremediation pathways evolve?

Question 16

How can natural pathways be modified to bioremediate a novel (non-natural) chemical?

Answer 16

1. Metabolic pathway engineering - introduce genes into cells for metabolism of a specific product
2. Bioaugmentation - introduce organisms bred to degrade specific contaminants

Question 17

What are three major methods of horizontal gene transfer? What environments are they associated with?

Answer 17

1. Transduction
2. Conjugation
   3.