The Relationship of Genus Bacillus, Sulfate Reducing Bacteria

and Sulfur Oxidation Bacteria in the Activated Sludge

Sui KanazawaAdvanced Environmental Engineering Course

Gunma National College of Technology

2012 Japan-Taiwan Symposium on intelligent Green and Orange (iGO) Technology

2/12

1. Background the corrosion of sewer pipe, B.Subtilis,

Sulfate Reducing and Sulfur Oxidation bacteria (SRB and SOB)

2. Purpose of this research

3. Materials and Method

4. Result and Discussion

5. Summary

1. Presentation Outline

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Corrosion of sewer pipe due to sulfuric acid

• Lifespan : 50 years 　　 only 10~20 　years

• Protection : the sheet covering method△ unworkable

1. Back ground (1/3)

http://www.mcon.co.jp/kasens.htmlhttp://blog.livedoor.jp/tetsu1982/archives

before after

the corrosion of concreteCa(OH)₂ + H₂SO₄ →CaSO₄+2H₂O 4/12

The mechanism of the corrosion due to SRB

1. Back ground (2/3)

H₂O

SO₄²⁻H₂S

H₂S

the occurrence of H₂S by SRBSO₄²⁻ + 2C + 2H₂O→2HCO₃+H₂S

the diffusion of H₂S

the formation of sulfuric acid by SOB H₂S + 2H₂O→H₂SO₄ +4H₂

SRB : Sulfate Reducing BacteriaSOB : Sulfur Oxidation Bacteria

• rod-shaped, gram-positive bacteria• exists widely in nature

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　1. Back ground (3/3)

Bacillus. subtilis

the inhibition of sewer odor

the limitation of activity of Escherichia coli

limitation of SRB?

6/12

　2. Purpose

To prove the interaction between B. subtilis, SRB and SOB

To develop the technique for corrosion protection of concrete

　3. Materials and Method (1/4)

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the activated sludge

Okutone Amenity Park• the night soil treatment plant in Gunma• membrane separation method• the activated sludge of a B. subtilis-dominated

• wet sample• freeze-dried sample

a biological floc composed of bacteria

　3. Materials and Method (2/4)

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Measurement of the Bacillus. subtilis

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• dilution at 10³ to10⁷ times• cultivation for 2 days

Measurement of the colonies

　3. Materials and Method (3/4)

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Measurement of the SRB

Measurement of the number of SRB which turn black

• cultivation for 10 days• MPN method

　3. Materials and Method (4/4)

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Measurement of the SOB

• Starkey medium• shaking culture for a week• MPN method

Measurement of the number of SOB which was below

4.5 pH

　6. Result and discussion

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The number of the colonies

B. subtilis(cells/ g ) SRB(cells/ g ) SOB(cells/ g )freeze- dried sample 6.6× 10⁷ 7.9× 10⁷

liquid sample 5.0× 10⁷ 9.2× 10⁷ 6.1× 10⁴ 8.9× 10⁷ ～ 0.5× 10⁷ ～

5.43× 10⁸ [1] 33.6× 10⁷ [2]data from preceding study

Okutone Amenity Park

[1] data of the night soil treatment plant[2] data of municipal wastewater disposal plant

• the number of SRB is not small in the activated sludge of a B. subtilis- dominated

• the sludge was odorless

The activity of SRB was inhibited by some factor ?

　7. Summary

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The number of SRB was not small especially in the activated sludge of B. subtilis-dominated.

We need to research to examine others waste water

treatment plant to examine the activated sludge of

laboratory scale reactor