Soil for groundwater protection and wastewater treatment

Transcription

1 THT 281/05 Soil for groundwater protection and wastewater treatment Petter D. Jenssen Department of Mathematical Sciences and Technology Norwegian University of Life Sciences

2 Ecological engineering Ecotechnology The development of human society with nature for the benefit of both. (Mitsch and Jørgensen 1989)

3 The water cycle

4 (Eritrea) Rainwater harvesting Foto: Kjell Esser, Noragric

5 Rainwater Harvesting: Surface collection of water and infiltration/storage Water collection area Water infiltration /storage The Agricultural University of Norway

6 Rainwater Harvesting: Surface collection of water and infiltration/groundwater recharge Well The Agricultural University of Norway

7 Rainwater Harvesting: Surface collection of water and infiltration/groundwater recharge Well The Agricultural University of Norway

8 Constructed wetland flow direction/purification The Agricultural University of Norway High quality effluent

9 Constructed wetland at Dal primary school Average influent (STE) and efluent concentrations (mg/l) Parameter Influent Effluent Total - P 2,9 0,2 Total - N 29,0 12,0 COD SS < 5 T. coli. /100ml < 2

10 Rainwater Harvesting: Surface collection of water and groundwater recharge

11 Foto: H.P. Mang Kabul 2002

12 Pathogens NO 3 Foto: H.P. Mangx Uncontrolled/random infiltration Well Groundwater

13 Decentralized solution? Controlled infiltration Foto: H.P. Mang Well Groundwater

14 Decentralized solution? Local recycling? Controlled infiltration Foto: H.P. Mang Well Groundwater

15 Kabul 2002 Greywater and urine Faecal matter Foto: H.P. Mang

16 Composted faecal matter Foto: H.P. Mang Foto: H.P. Mang

17 Kabul 2002 Greywater and urine Faecal matter Foto: H.P. Mang

18 Pathogens NO 3 Foto: H.P. Mangx Uncontrolled/random infiltration Well Groundwater

19 Foto: H.P. Mangx Uncontrolled/random infiltration Well NO 3 Groundwater

20 Foto: H.P. Mangx Uncontrolled/random infiltration Well Groundwater

21 Greywater treatment options Infiltration Package treeatment 2m Biofilters 0,6m Ponds Biofilters/ constructed wetland

22 Small buried infiltration systems (Siegrist et al. 2000)

23 Small buried infiltration systems (Siegrist et al. 2000)

24 Water treatment by filtration through sand

25 Treatment efficiency Mounds and small infiltration systems Infiltrasjon Jordhaug 20 0 Org. materiale Fosfor Nitrogen (Køhler 1998)

26 Reduction of organic matter biofilm media in activated sludge conventional systems K1 K2 Natrix O d= 9 mm d= 15 mm d= 60 mm Biofilm media surface area m 2 /m 3 Kaldnes TM

27 Reduction of organic matter Expanded clay aggregates (FiltraliteHC TM ) as biofilm carrier Particle size 2-5mm Surface area Bacteria on Filtralite > 5000m 2 /m 3 surface

28 Reduction of organic matter Porous media as biofilm carrier Filtralite Particle size 2-5mm Sand Particle size mm Surface area > 5000m 2 /m Surface area >> 5000m 2 /m

29 Phosphorus removal in soils depth of infiltration trenches Organic layer, O horizon Oxidized layer, B horizon Subsoil, C horizon

30 Phosphorus removal in soils Organic layer, O horizon Oxidized layer, B horizon Subsoil, C horizon

31 Phosphorus removal in soils Fe 3 (PO 4 ) 2 AlPO 4 Ca 3 (PO 4 ) 2

32 Phosphorus forms in soil dependent on ph Brady

33 Water treatment by filtration through sand

34 Small buried infiltration systems (Siegrist et al. 2000)

35 Infiltration systems bacteria removal Depth cm Soil surface Infiltration trench Bacteria/100ml or 100g of soil E coli Total coli Total bacteria Clogged zone (McCoy and Ziebell 1975)

36 Infiltration systems bacteria removal Clogged zone Depth cm Soil surface Infiltration trench Bacteria/100ml or 100g of soil E coli Total coli Total bacteria Cloggede zone (McCoy and Ziebell 1975)

37 The fate of microorganisms in soil

38 The fate of microorganisms in soil

39 Size of soil pores vs. size of microorganisms

40 The fate of microorganisms in soil

41 The fate of microorganisms in soil

42 The fate of microorganisms in soil

43 Rapid infiltration Open rapid inf. Dam, 69 o north Setermoen 5000 pe Foto: P.D. Jenssen

44 Treatment results Rapid infiltration - phosphorus Bardu Lesja 20 0 Organisk stoff Fosfor Nitrogen (Kraft 1998)

45 Groundwater level

46 Treatment results Rapid infiltration - nitrogen Bardu Lesja 20 0 Organisk stoff Fosfor Nitrogen (Kraft 1998)

47 Nitrogen transformations in soils (Lance 1978)

48 Rapid infiltration Anaerobic zones Oksidized zone Photo: P.D. Jenssen

49 Loading rate assessment Wastewater infiltration system Natural groundwater level Groundwater level with infiltration Critical cross-section 1. Hydraulic capacity 2. Infiltration rate 3. Purification ability

50 Site investigations Office preparations Topographic maps Soil or geological maps Groundwater interests/wells

51 Site investigations Hand auger Surface observations Vegetation type Land formations Soil observations from roadsides/or other open surfaces Groundwater observations from wells/vegetation

52 Site investigations Hand auger Subface observations Hand auger Motor hammer Backhoe

53 Site investigations Hand auger Subface observations Hand auger Motor hammer Backhoe

54 * Indirect assessment of vertical texture profiles Site investigations The use of a motor-hammer

55 Site investigations - the use of a motor hammer

56 Site investigations Excavations - the use of a backhoe

57 Hydraulic capacity Wastewater infiltration system Groundwater level with infiltration Impermeable Natural groundwater level Q = K* M*L*i Q= Hydraulic capacity (m3/d) K = Hydraulic conductivity (m/d) M = Acceptable rize in groundwater level (m) L = Length of the infiltration trench (m) i = The slope of the groundwater surface (h/l)

58 Manual infiltrometer Electronic infiltrometer

59 Infiltration rate for wastewater How much water can be infiltrated per unit area?

60 Loading rate assessment diagram Md/So (Meso) diagram Sorting ( d 60 /d 10 ) Mean grain size (d 50 )

61 Design of wastewater infiltration systems Loading rate (cm/d) Sorting ( d 60 /d 10 ) K (m/d) 1,3 L.R. (cm/d) 2-2, > ,0 4,0 Mean grain size (d 50 )

62 Design of wastewater infiltration systems Wastewater infiltration system Natural groundwater level Groundwater level with infiltration Well 1. Hydraulic capacity 2. Infiltration rate 3. Purification ability

63 Darcy s law: q=k*i Q = K* M*L*i q = Q/(M*L) = K*i Q= Hydraulic capacity (m3/d) q = Darcy flow (m/d) K = Hydraulic conductivity (m/d) M = Acceptable rize in groundwater level (m) L = Length of the infiltration trench (m) i = The slope of the groundwater surface (h/l) Wastewater infiltration system Impermeable Groundwater level with infiltration Natural groundwater level

64 Average velocity in the soil pores (v) Impermeable Wastewater infiltration system Groundwater level with infiltration Natural groundwater level q=k*i, q = Darcy flow (m/d) K = Hydraulic conductivity (m/d) i = The slope of the groundwater surface (h/l) v=q/n e v = average velocity in the soil pores (m/d) n e = porosity available for flow (0-1,0)

65 Average flow velocity (v) Darcy s law: q=k* i v = q/n e v = average flow velocity in the soil pores (m/d) n e = available porosity (dimensionless) Clay Gravel Stones