A modified constructed wetland system for greywater treatment and reuse Jhonatan B. da Silva, Paulo J.A. Oliveira, Marc Á. Boncz Paula L. Paulo
Background Greywater (gw) Composition and volume /person highly variable Due to (among others): • dynamics and Contains chemicals and behaviour of hardly any nutrients individuals, sanitary High solids concentration standards, age, (even light gw (hair and lifestyle, eating habits, lint) water use and availability, choice on personal care and household products 2
Background Greywater treatment (small scale) 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 3
Background Greywater treatment 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. 4
Background Greywater treatment 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? high variation High impact Composition and volume Household or swws 5
Background Evapotranspiration tank (Tevap) 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 6
Background Hypothesis • AnC replaces a pre-treatment unit • retaining solids • equalising the inflows • avoiding clogging • improving the stability of the system • low maintenance AnC CEvaT 7
Background EvaTAC • Combination of CEvaT + HSSF-CW • Main focus: direct reuse of gw for gardening using the system itself EVaTAC greywater HSSF-CW CEvaT 8
Background EvaTAC Combination of units: depends on final use (if any) CEvaT Zero discharge CEvaT CEvaT CEvaT + HSSF-CW Treated GW GW CEvaT HSSF-CW 9
Objectives • 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
Material & Methods Experimental setup - EvaTAC 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 & Methods Experimental setup - EvaTAC CEvaT AnC soil gravel n 2 Fiberglass piezometers D=0.5 m gravel n 4 • Filtering material HSSF-CW • Gravel (different particle sizes) • Soil gravel n 2 gravel n 2 fine gravel • Geotextile blanket • Bottom slope: 1% 12
Material & Methods monitoring profiles Profile A . 24 h, sinks and showers Profile B 24h , sinks, P3 P3 showers and P1 P1 P2 P2 P4 P4 laundry (washing PZ PZ machine) Profile C • Greywater characterisation (routine 8 days, same as B simulation) • Interviews • Questionnaires (filled during the profiles) 13
Material & Methods Monitoring profiles Quantitative Qualitative characterisation characterisation • Flow meters (generation • grab or composite points) samples - depending on situation • P4 - Ultrasonic flow meter • Parameters • Levellogers (piezometers • COD total , COD soluble , – closest to the exit in Solids, turbidity, pH both units) • Sensors: temperature, • Meteorological station conductivity, redox (hidrological conditions) potential. 14
Results Profile B - Flow patterns and level NIGHT NIGHT DAY 12 washing bath 1 bath 2 10 rinsing Q (L.min-1) 8 6 4 2 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Time (d) Q - P1 Q - P3 Q - P4 78 40 Level HSSF-CW (cm) Level CEvaT (cm) 77 39 76 38 75 37 74 36 73 35 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Time (d) Level CEvaT Level HSSF-CW 15
Results Profile B - Flow patterns and level NIGHT NIGHT DAY 12 washing bath 1 bath 2 10 rinsing Q (L.min-1) 8 6 4 2 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Time (d) Q - P1 Q - P3 Q - P4 78 40 Level HSSF-CW (cm) Level CEvaT (cm) 77 39 76 38 75 37 74 36 73 35 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Time (d) Level CEvaT Level HSSF-CW 16
Results Profile B - Flow patterns and level NIGHT NIGHT DAY 12 washing bath 1 bath 2 10 rinsing Q (L.min-1) 8 6 4 2 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Time (d) Q - P1 Q - P3 Q - P4 78 40 Level HSSF-CW (cm) Level CEvaT (cm) 77 39 76 38 Level CW 75 37 Level CEvaT 74 36 73 35 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Time (d) Level CEvaT Level HSSF-CW 17
Results Profile B - Flow patterns and level NIGHT NIGHT DAY 12 washing bath 1 bath 2 10 rinsing Q (L.min-1) 8 6 4 2 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Time (d) Q - P1 Q - P3 Q - P4 78 40 Level HSSF-CW (cm) Level CEvaT (cm) 77 39 76 38 Level CW 75 37 Level CEvaT 74 36 73 35 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 evapotranspiration Time (d) Level CEvaT Level HSSF-CW 18
Results Profiles A, B and C Inflow volume and Evapotranspiration A B C A B C 19
Results Evapotranspiration – Profiles A, B and C CEvAT HSSF-CW A B C A B C 20
Results Evapotranspiration – Profiles A, B and C CEvAT HSSF-CW A B C A B C CEvaT – higher potential for evapotranspiration (soil, plants density) About 4 times the Evap in the HSSF-CW 21
Results qualitative - Profiles B and C Profile B (1 d) Profile C (8 d) Q P1 = 6.6 ± 2.2 (36) L.min -1 Q P1 = 8.3 L.min -1 sampling P1 P2 P3 P4 P1 P2 P3 P4 point COD t 41 307 ± 190 (8) 147 ± 67 (8) 118 ± 21 (8) 73 ± 16 (8) 290 113 55 (mg.L -1 ) T 43 ± 12 (8) 10 ± 1.5 (8) 60 35 40 9.3 56 ± 17 (8) 45 ± 17 ( 8) (NTU) COD and Turbidity to illustrate behaviour No means to assess removal efficiency 22
Results qualitative - Profiles B and C Profile B (1 d) Profile C (8 d) Q P1 = 6.6 ± 2.2 (36) L.min -1 Q P1 = 8.3 L.min -1 sampling P1 P2 P3 P4 P1 P2 P3 P4 point COD t 41 307 ± 190 (8) 147 ± 67 (8) 118 ± 21 (8) 73 ± 16 (8) 290 113 55 (mg.L -1 ) T 43 ± 12 (8) 10 ± 1.5 (8) 60 35 40 9.3 56 ± 17 (8) 45 ± 17 ( 8) (NTU) Turbidity Low variation between AnC and CevAT (P2 - P3) Most retained in HSSF-CW (P4) 23
Results qualitative - Profiles B and C Profile B (1 d) Profile C (8 d) Q P1 = 6.6 ± 2.2 (36) L.min -1 Q P1 = 8.3 L.min -1 sampling P1 P2 P3 P4 P1 P2 P3 P4 point COD t 41 307 ± 190 (8) 147 ± 67 (8) 118 ± 21 (8) 73 ± 16 (8) 290 113 55 (mg.L -1 ) T 43 ± 12 (8) 10 ± 1.5 (8) 60 35 40 9.3 56 ± 17 (8) 45 ± 17 ( 8) Profiles B and C Does not reflect in final (NTU) higher variation than Profile A effluent (Profile C – 8d) P1 - COD total as high as 900 mg.L -1 HRT (average) CEvaT – 3 to 6 days HSSF-CW – 1.8 to 2 days EVaTAC - 5 to 8 days 24
Results qualitative - Profile B Variation of COD (total and dissolved) along P1 to P4 700 Inlet CODtotal CODdissolved 600 500 COD (mg.L -1 ) AnC 400 CEvaT 300 200 outlet 100 0 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 25
Results qualitative - Profile B Washing machine Variation of COD (total and dissolved) along P1 to P4 700 Anaerobic chamber CODtotal CODdissolved 600 After wm 500 shower COD (mg.L -1 ) Before wm 400 300 200 outlet 100 0 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 Indicates mixture in the AnC – mixed flow reator? Stable values for COD in P4 along Profiles B and C 26
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
Conclusions • 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
During the experiments (2015) Present days (2016) 29
Thanks for the attention! Acknowledgments FINEP – project nº.01.10.0507.00 Fundect- MS – project nº 021/11 and PhD grant
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