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Date November 2018 Marks available 1 Reference code 18N.3.HL.TZ0.10
Level Higher level Paper Paper 3 Time zone TZ0 / no time zone
Command term Deduce Question number 10 Adapted from N/A

Question

The diagram shows an overview of the Henriksdal wastewater treatment process in Stockholm, Sweden.

State a group of organisms that will be active in the fermenter labelled X. 

[1]
a.

Deduce, with a reason, whether X is a continuous fermenter or a batch fermenter.

[1]
b.

Probes are used to monitor significant variables within the fermenter. List three significant variables that should be monitored in the fermenter.

[3]
c.

State the main component of biogas.

[1]
d.

Inside Y there are rotating paddles. Outline two reasons for these paddles being needed.

[2]
e.

Markscheme

bacteria
OR
archaeans
OR
methanogens ✔

Accept a named bacterium

a.

continuous because there is a constant input of raw materials ✔

b.

a. pH/acidity/alkalinity ✔

b. foam ✔

c. metabolites ✔

d. substrate ✔

e. oxygen ✔

f. carbon dioxide ✔

g. temperature ✔

h. pressure ✔

Accept other valid condition

c.

methane ✔

d.

a. mixing substrate to increase contact with bacteria
OR
preventing sedimentation ✔

b. avoids formation of biofilms ✔

c. aeration for aerobic bacteria ✔

e.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.
[N/A]
d.
[N/A]
e.

Syllabus sections

Option B: Biotechnology and bioinformatics » Option B: Biotechnology and bioinformatics (Core topics) » B.1 Microbiology: organisms in industry
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Option B: Biotechnology and bioinformatics » Option B: Biotechnology and bioinformatics (Core topics)
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