The Living Machine & Leachate

By Laura Llewellyn

Hypothesis

The living machine will successful remove contaminants from leachate while remaining a healthy environment itself.

The living machine will remove the contaminants found in leachate but some of the aquatic life will die in the process.

The living machine will not remove a sufficient amount of contaminants found in the leachate.

Step 1- Anaerobic Reactor

- Leachate drains from reactors (left)

- To a septic tank (right)

- Leachate manually transported to tank 1

- Purpose: to reduce concentrations of BOD5 and solids

Step 2- Anoxic Reactor

- promote growth of microorganisms

- Settled bio-solids from clarifier can be recycled back into anoxic reactor

- Aerated - Vented with plant

bio-filter

Step 3- Closed Aerobic Reactor

- reduce BOD5, odors, and stimulate nitrification

- Aerated and mixed by bubble diffuser

- Usually covered with bio-filter

Step 4- Open Aerobic Reactor

- covered by vegetation

- Further reduce BOD5 and nitrification

More Open Aerobic Reactors

- size and number vary according to influent characteristics, effluent requirements, flow conditions and design

- Variety of plants is key

Step 5- Clarifier

-settling tank for remaining solids

-pumped back into closed aerobic reactor or removed

Step 6- Ecological Fluidized Bed

- inner and outer tank with growth medium inside the inner tank

- Water flows in circular motion from the outer to the inner tank

- Circulation periodically reversed by air pump to prevent sludge build up

Water Quality Tests

- over 5 week period

- Week 1 no leachate in system

- Leachate added during week 2 & 3

- System design changed week 4

Temperature

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5

Week

Celc

ius

pH

- concentration of Hydrogen ions

- pH scale

1 (acidic)…

6.5-8.2 (aquatic life flourishes)

14 (alkaline/basic)

Temperature

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5

Week

Ce

lciu

s

pH

6

6.5

7

7.5

8

8.5

9

9.5

1 2 3 4 5

weekly analysis

pH

level

tank 1

tank 2

tank 3

tank 4

tank 5

tank 6

tank 7

Dissolved Oxygen (DO)

- quantity of oxygen being used by water- High DO- slow uptake by microorganisms- Low DO- high demand from microorganisms- DO increases with temperature

Dissolved Oxygen

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5

weekly analysis

DO

lm

g/L

tank 1

tank 2

tank 3

tank 4

tank 5

tank 6

tank 7

Temperature

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5

Week

Ce

lciu

s

Specific Conductance

= measured conductance (uS)

1+.019(field temp. - 25)

- affected by presence of inorganic dissolved solids such as chloride and phosphate

Specific Conductance

0

100

200

300

400

500

600

700

1 2 3 4 5

weekly analysis

Sp

ec.

Co

nd

. le

ve

l

tank 1tank 2tank 3tank 4tank 5tank 6tank 7

Temperature

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5

Week

Ce

lciu

s

Chloride Content

- chloride contents doubled when leachate was added to the system

Chloride

0

1

2

3

4

5

6

7

8

9

10

2 5 6 7

tank

mg

/L

no leachate with leachate

Nitrate Content

- nitrate can stimulate algae growth thus cause low levels DO

- Other Living Machines have goals <5 mg/L

Nitrate

0

0.5

1

1.5

2

2.5

3

2 5 6 7

mg

/L

no leachate with leachate

Sulfate Content

- Potentiometric titration of pure leachate revealed

.6 mg/L sulfide - Sulfide is converted into sulfate - Sulfate decreases around system

Sulfate

0

0.5

1

1.5

2

2.5

2 5 6 7

tank

mg

/L

no leachate with leachate

Conclusion

- The living machine is capable of handling the leachate.

- Improvements on design will increase the machine’s capabilities…- Better flow of water around the system- Less rocks where sludge can collect- More diversity of plant life