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Willow Evapotranspiration Zero Discharge Sanitation

Presentation at Wexford County Ireland November 21th. 2007

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Willow Evapotranspiration Zero Discharge Sanitation

  1. 1. Willow Evapotranspiration Zero Discharge Sanitation Arne Backlund www.BACKLUND.dk
  2. 2. From the first known ”unknown” system in 1991/1992 to best known practice in 2007 recommended by authorities in Denmark for highest demands
  3. 3. BACKLUND Small R&D Consultant Engineering and Lecturing family company established 1986 Located 10 km north of Copenhagen City in Denmark Working in many countries in Europe Main Focus Ecologically Sustainable Sanitary Solutions
  4. 4. Research & Development BACKLUND participation in Sustainable Sanitation projects carried out for the Danish Environmental Protection Agency EPA (funded through the " Action Plan for the Promotion of Ecological Urban Renewal and Wastewater Treatment" and European Union FAIR-Programme
  5. 5. BACKLUND R & D • Short Rotation Willow Biomass Plantations Irrigated and Fertilised with Wastewater in Sweden, Northern Ireland, France and Greece • Willow Evapotranspiration Beds with Zero discharge in Denmark • R & D in Denmark, Sweden and Germany concerning Diverting NoMix Toilets and Waterless Urinals to Enable Reuse of Energy Resources and Nutrients in Humane Urine and Human Faeces
  6. 6. BACKLUND R & D • Vacuum Toilets in Sweden, Denmark and Germany – Reduction in Wastewater production and Treatment of the Collected Material at Biogas Works • Collection, Storage and Irrigation of Human Urine in Agriculture in Denmark and Sweden • Draining and Composting of Collected Black Wastewater in Denmark and Sweden
  7. 7. BACKLUND R & D • Sustainble Handling of Urine, Faeces and Grey Water from Danish Allotment Gardens by means of Diverting (No-Mix) Toilet Systems and Evapotranspiration Willow Beds • Evaluation of Functioning of Alternative Toilet Systems and their Ability to Reduce Pathogens in Denmark and Sweden
  8. 8. Reflex or Reflection • Mixing - Discharge & Dilution – best solution to polution? • Problems are not automaticly solved with more of the same thinking (Paradigm) that created the problem in the first place.
  9. 9. EU Water Framework Directive from Year 2000 • Before 2015 • Good conditions in: • Surface water (streams, lakes, coast) • Ground water
  10. 10. Flow or Stream of Material • Urine • Faeces • Toilet paper • Flush water • Grey water
  11. 11. Flow or Stream of Material • We almost excrete the same amount of nutrients as we consume • Human urine contributes with only 1 % of the volume of household wastewater but contains 80 % of N, 55 % of P and 60 % of K in household wastewater and less than 0.6 % of cadmium and 0.06 % of lead
  12. 12. Selected Components • Waterless urinals • No-Mix/Diverting toilet stools • Collection and composting units • Anaerobic fermentation • Willow evapotranspiration bed • Willow plantation
  13. 13. Wastewater Fractions from households • Type Content • Classic Toilet, bath, kitchen, wash • Black Toilet • Grey Bath, kitchen, wash • Light grey Bath, wash • Yellow Urine • Brown Faeces
  14. 14. Elements in Alternative Handling of Wastewater • Source control • Collection • Storage • Transport • Treatment • Discharge / recycling
  15. 15. Water consumption Today With savings Toilet 50 25 Bath 40 25 Kitchen 50 25 Wash 10 5 Total 150 80 Fractionated water consumption, l/(cap·d)
  16. 16. No-Mix flushing toilets
  17. 17. Removal processes in constructed wetlands Particulates settle Degradation of organic matter Little nitrification Denitrification Plant-uptake (N and P) P is filtrated/adsorbed Degradation of organic matter
  18. 18. Proces NH4 + -N (%) Total-N Total-P Organic matte (as BOD) (%) Septic tanks ~ 0 10 10 30 Biological sandfilters* 80-90 25-30 50 97 Constructed wetlands* 30-50 50 50 95 Willow plants* ~ 100 ~ 100 ~ 100 ~ 100 *all includes pretreatment in septic tanks Removal rates in alternative wastewater management
  19. 19. Drip Irrigation
  20. 20. Drip Irrigation
  21. 21. Drip Irrigation
  22. 22. Short-Rotation Willow Biomass Plantations Irrigated and Fertilised with Wastewaters
  23. 23. Short-rotation Willow biomas Plantations Irrigated and Fertilised with Wastewaters • Results from a 4-year multidisciplinary field project in Sweden, France, Northern Ireland and Greece • Results www.BACKLUND.dk
  24. 24. Willow Zero Discharge System Components in Denmark • Household Sanitary Installations • Flushing Tank • Settling Tank • Pumping Tank • Irrigation/Distribution System • Willow Bed
  25. 25. Household Sanitary Installations • Optimizing Sanitary Household Installations • Kitchen – dishwasher • Bathroom – shower/bathtub • Toilet – Flush >6l – 6/3 – 4/2 • Vacuum toilet • NoMix With/Without flush
  26. 26. Standard Construction Willow Bed and Distribution System • Soil Barrier 30 cm High • Distribution system and layer • LDPE/HDPE Lining • Geotextiles • Reused soil in bed • Willow •
  27. 27. Distribution System • Distribution Pipe Ø32-63mm in the middle • Holes Ø8-10mm – 1m between holes from 4 m • Distribution layer 16-32mm stones or plastic • Inspection/Emptying Tank at the end • Drainage Pipe Inner Ø90-110mm
  28. 28. Application in Denmark • Wastewater with or without WC • Calculated water consumption not as a gven standard but known or expected from the household • Dimensioning m2/m3 • Willow Bed Dimensions
  29. 29. Running Manual in Denmark • Settlement Tank • Pump and Pumping tank • No heavy weight on surface • Flush Distribution Pipe ever 2-3 years • Total Weeding first year • Planting if necessary • After 1st season cut 50% down to 15cm in Jan/Febr. The last 50% following year • Then one half, third or fourth every year
  30. 30. Running Manual • If Water Level on surface more than 20 cm in December – Remove • Check Concentration of Chloride every 5th. year
  31. 31. Running & Maintenance • Empty Settlement Tank • Flush Distribution Pipes • Service of Mechanical Parts • Control and taking care of Willow • Control of Water Level • Chloride Concentration
  32. 32. Hydralic Load - Dimension • Expected or Actual Wastewater Load from existing persons in household/households • Not due to 1 household 5PE = 5 x 150/180l • Accepted loads 80 – 120 l/p/d • Minimum load 100m3/year • Minimum willow bed surface 100 m2 • Also for Greywater load alone
  33. 33. Willow Evapotranspiration Beds WILLOW EVAPOTRANSPIRATION BED AT MARJATTA Tappernøje
  34. 34. Marjatta Evapotranspiration Bed
  35. 35. Technical Data • Plants on 556 m2 surface, 50.5 m2/p • Willow clones 78-195 + 78-082, 2400 Sticks • Total surface, 707 m2, 64 m2/p • 690 m3 over fibre textile, 150 m3 under • Estimated water storage volume, 35 % • 520 mm wastewater/a,11 p, 80-90 l/p/a • 512 kg N/a, 95 kg P/a and 188 kg K/a
  36. 36. Wastewater Load • Average 1 m3/11p/d 365m3/a • If to sewer 365 x 4 Euro = Euro 1460
  37. 37. Precipitation and Evaporation • Average 30-years precipitation 562 mm • Average 1992-96 + 1999 769 mm • 1993 910 mm • 1994 970 mm • 1999 907 mm • Penman evaporation 572 mm • Potential evaporation 610 mm • Evapotranspiration 1310 - 1370 mm
  38. 38. Biomass Growth and Evapotranspiration Biomass growth • 1992 3 t DM/ha/a • 1992-1994 14.4 t DM/ha/a • 1996-1999 8.5 t DM/ha/a • 2003 17.1 t DM/ha/a Evapotranspiration • 1992-1996 1301 mm/a • 1999 1366 mm/a
  39. 39. Results • Good running stability • Good evapotranspiration, 1310 – 1370 mm/a • Up to 60 % capacity used for precipitation • 30 – 40 % storage volume in bed • No indications of heavy metals as limiting factor for future handling of soil • Sodium-cloride a limiting factor but can be pumped out during low water levels
  40. 40. Further Developement • Potential use of source controle sanitation to reduce the amount of sodium chloride and surplus of nutrient directed to the bed. • Use of optimal willow clones with a even bigger evapotranspiration potential in order to minimise the surface and cost of the bed. • Discharge of rainwater from the surface before contact with the wastewater to minimise volume, surface and cost of the bed. • Raising the pore volume in the beds from 35 % up to 80 %. • Easy access to pump out sodium chloride
  41. 41. Premises – Dimensioning Model • Willow Evapotranspiration Wastewater System Without Discharge • 8 m WIDE – with a DEPTH of 1.5m and 45° GRADIENT on the sides and ends of the system • Useable PORE VOLUME in the bed is expected to be 40 %
  42. 42. Premises – Dimensioning Model • EVAPOTRANSPIRATION from the system s expected to be 2.5 TIMES LARGER than the calculated Potential Evaporation from the local area • Calculations are made with 30-years average figures of MONTHLY PRECIPITATION and POTENTIAL EVAPORATION in 20 x 20 km grid cels
  43. 43. Premises – Dimensioning Model • SURFACE AREA dimension to avoid water storing on the surface in a year with normal precipitation and with a maximum of 10 cm of surface water with a precipitation which statisticly occurs in one out of 10 years • Same LOAD of wastewater every month
  44. 44. Dimensioning due to Grid Cels • Average Precipitation 524 to 903 mm/y • EVAPOTRANSPIRATION 1343 to 1470 mm/y • Potential Capacity to Evapotranspirate wastewater from 452 to 936 mm/y • Calculated load after reduction due to lacking storage capacity 357-894 mm/y
  45. 45. Dimensioning due to Grid Cels • Surface Willow Bed Area from 124 to 292 m2/100m3 WW (Average 173 m2/100 m3) due to Grid Cell
  46. 46. Surface Area – m2/100m3 WW
  47. 47. Tappernøje - Pilehuset • POTENTIAL EVAPORATION 572mm/y • Calculated EVAPOTRANSPIRATION from WILLOW SYSTEM 2.5 x 572mm/y = 1430mm/y
  48. 48. Tappernøje – Pilehuset (from 1992) • Grid cell calculated surface area 141m2/100m3 • Wastewater load to system 365 m3/y • Calculated specific surface area 514.65 m2
  49. 49. r
  50. 50. Wexford Ireland • Potential Evapotranspiration Johnstown Castle, Co. Wexford 543mm/year • Estimated Willow Evapotranspiration 2.5 x 543mm = 1357.5mm/year • Precipitation 1000 mm/year • Wastewater Evapotranspiration Capacity 357.5mm/m2/year
  51. 51. Dimensioning Wexford Ireland • Without source controll (eg. Without dual flush toilets) • 2 – 5 P 150l/p/d = 306m2-766m2 • 2 – 5 P 180l/p/d = 368m2-919m2 • 6 P 180l/p/d = 3021 m2
  52. 52. Dimensioning Wexford Ireland • Going from single flush 6x9l to dual flush 4x2l + 2X4l could save 38/l/p/d • Surface Willow Bed Area (SWBA) 279.72m2/100m3 • SWBA 1P (120l/P/d) = 122.51 m2 • SWBA 3P = 367.53 m2 • SWBA 6P = 735.06 m2
  53. 53. Irish Modell? • Reduced Wastewater Production/Inlet • Precipitation Cover • Higher Pore Volume • Deeper Bed • Longer with less width
  54. 54. Conclusion • After 25 years in Denmark • Considered best practice by Authorities for highest demands • Good experiences from performance •

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