Agricultural Structures-BIOGAS PLANT

Question 1

Used to process animal wastes or manure to produce biogas and sludge.

Answer 1

Biogas plant

Question 2

Consisting of an

inlet/mixing tank, digester, gas chamber and outlet/sludge tank.

Answer 2

Biogas plant

Question 3

Biogas plant where the digester and gas chamber form one unit.

Answer 3

Integrated plant

Question 4

Digester and gas chamber form separate units.

Answer 4

Split-type Plant

Question 5

Plant with series of digesters.

Answer 5

Multi-digester plant

Question 6

Plant consisting of digester and a moving, floating gasholder that either float directly in the
fermenting slurry or in a separate water jacket.

Answer 6

Floating type

Question 7

Closed digester with an immovable, rigid gas chamber and a displacement pit.

Answer 7

Fixed type

Question 8

Plant consisting of a heat-sealed plastic or rubber bag, combining digester and
gasholder.

Answer 8

Balloon type

Question 9

Chamber where manure and water are collected, stored and separated from heavy and non-
biodegradable materials before feeding them into the digester.

Answer 9

Collecting tank

Question 10

Serves as conveyor of the manure-water mixture or slurry from the mixing tank to the digester.

Answer 10

Inlet pipe

Question 11

Any water and air tight container designed for the process of anaerobic microbiological degradation of organic matter into which the slurry is introduced for digestion and methanization.

Answer 11

digester
biodigester
bio-reactor
anaerobic reactor

Question 12

Division in the digester that prevent the slurry from premature exit into the sludge/outlet tank.

Answer 12

Baffle board

Question 13

Mechanical device inside the digester used to stir the slurry.

Answer 13

stirrer
mixer
agitator

Question 14

Space inside or outside the digester for the collection and storage of biogas.

Answer 14

Gas chamber

Question 15

Cantilever beam that holds the gasholder/movable cover in position at the desired biogas
pressure.

Answer 15

Gasholder retainer

Question 16

Serves as conveyor where the effluent or the slurry is forced out.

Answer 16

Outlet pipe

Question 17

Layer of compacted soil and gravel to support the digester wall.

Answer 17

Backfill

Question 18

Amount of slurry fed per unit volume of digester capacity per day.

Answer 18

Loading rate

Question 19

organic material used to produce biogas

Answer 19

Substrate

Question 20

adding or introducing anaerobic bacteria to the digester

Answer 20

Seeding

Question 21

mixture of manure and water

Answer 21

Slurry

Question 22

difference in height between the digester wall and the filling line

Answer 22

Freeboard

Question 23

level of slurry when the digesters is at full load

Answer 23

Filling line

Question 24

average period that a given quantity of slurry is retained in the digester for digestion

Answer 24

Retention time

Question 25

materials that inhibit the normal growth of pathogens in the digester such as mineral ions, heavy metals and detergents

Answer 25

Toxic materials

Question 26

materials that inhibit the normal growth of pathogens in the digester such as mineral ions, heavy metals and detergents

Answer 26

Toxic materials

Question 27

various processes that take place among the methanogens, non-methanogens and substrates fed into the digester as inputs

Answer 27

methanization | digestion

Question 28

anaerobic bacteria that act upon organic materials and in the process, produce biogas

Answer 28

Methanogens

Question 29

temperature range of 20 oC – 40 oC where mesophilic bacteria operates

Answer 29

Mesophilic temperature rage

Question 30

amount of biogas produced per day per cubic meter of slurry

Answer 30

Gas production rate

Question 31

mixture of gas (composed of 50 to 70 percent methane and 30 to 40 percent carbon dioxide) produced by methanogenic bacteria

Answer 31

Biogas

Question 32

layer of floating material (mainly fibrous) on the slurry

Answer 32

Scum

Question 33

settled portion or precipitate of the slurry; a mud-like, semi-solid mass

Answer 33

Sludge

Question 34

residue that comes out at the outlet after the substrate is digested/processed inside the digester

Answer 34

Effluent

Question 35

The minimum diameter of the inlet pipe shall be

Answer 35

0.2m

Question 36

Retention time for liquid pig manure

Answer 36

15 to 25 days

Question 37

Retention time for liquid cow or carabao manure

Answer 37

20 to 30 days

Question 38

Retention time for liquid chicken manure

Answer 38

20 to 40 days

Question 39

Retention time for animal manure mixed with plant materials

Answer 39

50 to 80 days

Question 40

For Balloon Type: | The digester volume is ___% of the total digester volume is occupied by the slurry.

Answer 40

80%

Question 41

The minimum diameter of the outlet pipe shall be ___.

Answer 41

0.2m

Question 42

For fixed type, the volume of the outlet tank shall be ____ of digester volume occupied by the slurry.

Answer 42

1/3

Question 43

The tank should be concreted and a ______ should be provided to control or allow the proper mixture of water and manure.

Answer 43

Sluice gate

Question 44

The floor of the mixing tank should be inclined from ______ toward the inlet pipe and it should be elevated at least ___ from the filling line.

Answer 44

8.5% to 17.5% ; 0.2m

Question 45

Concrete pipe (prefabricated RC pipe) should be used and it should be inclined ____ with digester wall.

Answer 45

58%

Question 46

Lower end of inlet pipe should be positioned below the gasholder retainer for floating type. If there is no retainer, the lower end should be located ____ from the floor of the digester.

Answer 46

100mm

Question 47

Manhole cover should be _____ in | diameter and _____ thick.

Answer 47

0.65m ; 0.125m

Question 48

The floor shall have a slope of about ____ from the inlet to the outlet

Answer 48

2.5%

Question 49

The gas drum should consist of ____ mild steel sheets for the sides and ____ sheets for the top.

Answer 49

2.5 mm ; 2mm

Question 50

The gas drum should have a sloping roof of _____ and it should be provided with guide frame.

Answer 50

16.5%