A modified constructed wetland system for greywater treatment and reuse

Jhonatan B. da Silva, Paulo J.A. Oliveira, Marc Á. BonczPaula L. Paulo

Contains chemicals and hardly any nutrients

High solids concentration (even light gw (hair and lint)

Due to (among others):

• dynamics and behaviour of individuals, sanitary standards, age, lifestyle, eating habits, water use and availability, choice on personal care and household products

2

Composition and volume /person highly variable

BackgroundGreywater (gw)

choice – some points to be considered

• required quality of the effluent (reuse applicable?)

• Sustainability of household or small scale system:• Cost• Operation and maintenance requirements• Odour nuisance• Health risks

BackgroundGreywater treatment (small scale)

3

Natural treatment systems

• Good visual impact• Landscaping: total integration with ndividual gardens

or common areas (condominial)• May promote water conservation by the direct reuse of

GW• Increase of green sites in urban areas – expected

contribution to an improvement of microclimate.

Background Greywater treatment

4

Constructed wetlands

• Most common system for small scale greywater treatment (peri-urban, rural areas)

• Simplified and low-cost treatment system • Clog easily depending on substrate type and influent

characteristics• Requires a pre-treatment unit (e.g. septic or sed tank)

How to adapt for the use in urban area?

Background Greywater treatment

5

high variationComposition and volume

High impactHousehold or swws

soil and plants based system

• Inbuilt AnC (car tires)• Layers of different substrates• Fast growing, high water

consumption plants• Effluent percolates upwards

through the layers

BackgroundEvapotranspiration tank (Tevap)

6

• AnC replaces a pre-treatment unit• retaining solids • equalising the inflows

• avoiding clogging• improving the stability of the

system • low maintenance

BackgroundHypothesis

7

CEvaTAnC

• Combination of CEvaT + HSSF-CW• Main focus: direct reuse of gw for

gardening using the system itself

BackgroundEvaTAC

8

CEvaTHSSF-CW

EVaTAC

greywater

BackgroundEvaTAC

9

CEvaTZero discharge

HSSF-CW

Combination of units: depends on final use (if any)

CEvaT + HSSF-CWTreated GW

GW

CEvaT

CEvaTCEvaT

• To propose a modified design of a cw system for GW - EvaTAC

• To better understand the capacity of the AnC to equalise the daily variation of flow and organic load in the EvaTAC.

• real scale EvaTAC system

• 24 hours and 8 days monitoring profiles

10

Objectives

Dimensions

CEvaT: 2.0 m × 1 m × 1.05 m (level exit - 0.74 m)

HSSF-CW: 2.0 m × 1 m × 0.60 m (level exit - 0.4 m)

Material

Masonry, lined with Fiberglass

Full scale - 3 persons household

3 years in operation, Light greywater

Ornamental Plants

White ginger, Caladium, Canna x generalis

(beri), heliconia pisittacorum (parrot´s peak)11

Material & MethodsExperimental setup - EvaTAC

Material & MethodsExperimental setup - EvaTAC

12

gravel n 4

gravel n 2

soil

fine gravel

grav

el n

2

grav

el n

2

HSSF-CW

CEvaTAnC

piezometersFiberglassD=0.5 m

• Filtering material

• Gravel (different particle sizes)

• Soil

• Geotextile blanket

• Bottom slope: 1%

13

Material & Methodsmonitoring profiles

.

P1P2

P3

P4

Profile A24 h, sinks and showersProfile B24h , sinks, showers and laundry (washingmachine)Profile C 8 days, same as B

PZ

• Greywater characterisation (routine simulation)

• Interviews• Questionnaires (filled during the profiles)

Material & MethodsMonitoring profiles

Quantitativecharacterisation

• Flow meters (generationpoints)

• P4 - Ultrasonic flow meter

• Levellogers (piezometers– closest to the exit in both units)

• Meteorological station(hidrological conditions)

Qualitativecharacterisation

• grab or composite samples - depending on situation

• Parameters

• CODtotal, CODsoluble, Solids, turbidity, pH

• Sensors: temperature, conductivity, redox potential.

14

ResultsProfile B - Flow patterns and level

15

0

2

4

6

8

10

12

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Time (d)

Q (

L.m

in-1

)

Q - P1 Q - P3 Q - P4

bath 1 bath 2 washing

rinsing

73

74

75

76

77

78

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Time (d)

Lev

el C

Ev

aT

(cm

)

35

36

37

38

39

40

Lev

el H

SS

F-C

W (

cm)

Level CEvaT Level HSSF-CW

DAYNIGHT NIGHT

ResultsProfile B - Flow patterns and level

16

0

2

4

6

8

10

12

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Time (d)

Q (

L.m

in-1

)

Q - P1 Q - P3 Q - P4

bath 1 bath 2 washing

rinsing

73

74

75

76

77

78

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Time (d)

Lev

el C

Ev

aT

(cm

)

35

36

37

38

39

40

Lev

el H

SS

F-C

W (

cm)

Level CEvaT Level HSSF-CW

DAYNIGHT NIGHT

ResultsProfile B - Flow patterns and level

17

0

2

4

6

8

10

12

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Time (d)

Q (

L.m

in-1

)

Q - P1 Q - P3 Q - P4

bath 1 bath 2 washing

rinsing

73

74

75

76

77

78

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Time (d)

Lev

el C

Ev

aT

(cm

)

35

36

37

38

39

40

Lev

el H

SS

F-C

W (

cm)

Level CEvaT Level HSSF-CW

DAYNIGHT NIGHT

Level CW

Level CEvaT

ResultsProfile B - Flow patterns and level

18

0

2

4

6

8

10

12

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Time (d)

Q (

L.m

in-1

)

Q - P1 Q - P3 Q - P4

bath 1 bath 2 washing

rinsing

73

74

75

76

77

78

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Time (d)

Lev

el C

Ev

aT

(cm

)

35

36

37

38

39

40

Lev

el H

SS

F-C

W (

cm)

Level CEvaT Level HSSF-CW

DAYNIGHT NIGHT

Level CW

Level CEvaT

evapotranspiration

19

A

ResultsProfiles A, B and C

Inflow volume and Evapotranspiration

B C A B C

20

A

ResultsEvapotranspiration – Profiles A, B and C

B C A B C

CEvAT HSSF-CW

21

CEvaT – higher potential for evapotranspiration (soil, plants density)

About 4 times the Evap in the HSSF-CW

A

ResultsEvapotranspiration – Profiles A, B and C

B C A B C

CEvAT HSSF-CW

22

Profile B (1 d) Profile C (8 d)

QP1 = 8.3 L.min-1 QP1 = 6.6 ± 2.2(36) L.min-1

sampling

pointP1 P2 P3 P4 P1 P2 P3 P4

CODt(mg.L-1)

290 113 55 41 307 ± 190(8) 147 ± 67(8) 118 ± 21(8) 73 ± 16(8)

T(NTU)

60 35 40 9.3 56 ± 17(8) 45 ± 17(8) 43 ± 12(8) 10 ± 1.5(8)

Resultsqualitative - Profiles B and C

COD and Turbidity to illustrate behaviour

No means to assess removal efficiency

23

Profile B (1 d) Profile C (8 d)

QP1 = 8.3 L.min-1 QP1 = 6.6 ± 2.2(36) L.min-1

sampling

pointP1 P2 P3 P4 P1 P2 P3 P4

CODt(mg.L-1)

290 113 55 41 307 ± 190(8) 147 ± 67(8) 118 ± 21(8) 73 ± 16(8)

T(NTU)

60 35 40 9.3 56 ± 17(8) 45 ± 17(8) 43 ± 12(8) 10 ± 1.5(8)

Resultsqualitative - Profiles B and C

Turbidity

Low variation between AnC and CevAT (P2 - P3)

Most retained in HSSF-CW (P4)

24

Profile B (1 d) Profile C (8 d)

QP1 = 8.3 L.min-1 QP1 = 6.6 ± 2.2(36) L.min-1

sampling

pointP1 P2 P3 P4 P1 P2 P3 P4

CODt(mg.L-1)

290 113 55 41 307 ± 190(8) 147 ± 67(8) 118 ± 21(8) 73 ± 16(8)

T(NTU)

60 35 40 9.3 56 ± 17(8) 45 ± 17(8) 43 ± 12(8) 10 ± 1.5(8)

Resultsqualitative - Profiles B and C

Profiles B and C higher variation than Profile AP1 - CODtotal as high as 900 mg.L-1

HRT (average)CEvaT – 3 to 6 daysHSSF-CW – 1.8 to 2 days

EVaTAC - 5 to 8 days

Does not reflect in final effluent (Profile C – 8d)

Resultsqualitative - Profile B

25

0

100

200

300

400

500

600

700

P1-1 P1-2 P1-3 P2-1 P2-2 P2-3 P2-4 P3-1 P3-2 P3-3 P4-1 P4-2 P4-3

CO

D (

mg

.L-1

)

CODtotal CODdissolved

Variation of COD (total and dissolved) along P1 to P4

Inlet

AnC

outletCEvaT

Resultsqualitative - Profile B

26

0

100

200

300

400

500

600

700

P1-1 P1-2 P1-3 P2-1 P2-2 P2-3 P2-4 P3-1 P3-2 P3-3 P4-1 P4-2 P4-3

CO

D (

mg

.L-1

)

CODtotal CODdissolvedAnaerobic chamber

Indicates mixture in the AnC –mixed flow reator?

Variation of COD (total and dissolved) along P1 to P4W

ash

ing

mac

hin

e

sho

we

r

Bef

ore

wm

Aft

er

wm

Stable valuesfor COD in P4 along Profiles

B and C

outlet

Conclusions

• Monitoring profiles - appropriate tool to better understand the capacity of the AnC to equalise the daily variation of flow and organic load in the EvaTAC .

• For low flows (sinks and showers) no mixing observed in the. For higher flows (e.g. washing machine) the AnC attenuates the peak load and stabilises the system.

27

• AnC replaces a pre-treatment unit.

• The HSSF-CW operates as an efficient polishing unit.

• CEvaT and HSSF-CW complement each other.

• 3 years of operation: no sludge withdrawal, no maintenance in the distribution pipe (inlet) of the HSSF-CW.

• householders routine undisturbed, rendering a green site totally integrated into the garden, without the use of potable water for irrigation.

28

Conclusions

29

During the experiments (2015)

Present days (2016)

Thanks for the attention!

AcknowledgmentsFINEP – project nº.01.10.0507.00

Fundect- MS – project nº 021/11 and PhD grant