ONSITE AND DECENTRALISED SEWERAGE CONFERENCE AWA, October 2008

Transcription

1 ONSITE AND DECENTRALISED SEWERAGE CONFERENCE AWA, October TOWARDS WASTEWATER NUTRIENT CYCLING ASSESSMENT OF DECENTRALISED SYSTEMS IN URBAN VILLAGES L.N.Thu, Maya Radin, Stewart Dallas, Martin Anda, Goen Ho

2 Contents Introduction Methodology Results Conclusion

3 Perth-Western Australia Expanding population & geographical size Climate change (rainfall fluctuation & decrease) Great pressure on water resource Question: HOW TO MANAGE WATER RESOURCE EFFICIENTLY? A centralised or decentralised approach to wastewater sanitation? Drainage, Nutrient and Irrigation Management Plans

4 Water Resource Management State Water Strategy (Western Australia Government, 2003) Premiers Water Foundation (PWF) Demonstration of Decentralised Water Recycling in Urban Villages (Environmental Technology Centre, Murdoch University)

5 Project Aim Complete a waste water recycling trial by June 2009 at 3 sites within the Metropolitan and Peel Regions to demonstrate and evaluate the performance, reliability, attributes and feasibility of decentralised wastewater recycling.

6 Zero Emission Nutrients (ZEN) Monitoring protocols: Nutrient levels in relative components have to be sampled and analysed

7 Objectives Provide an overview of the progress and early findings focusing on ZERO EMISSION NUTRIENTS model for urban land developments in 3 studied sites

8 Banksia Tourist Park Bridgewater Village Timbers Edge Village

9 Studied sites Bridgewater Lifestyle Village - household greywater; Timbers Edge Residential Resort - village greywater; Banksia Village - village wastewater;

10 Monitoring protocols Sampling and analysing nutrient levels in greywater, groundwater, soil Managing sampling bores (location, depth) by GPS, maps, aerial photos The practical results will be compared with model outputs of contaminant flows at Ellenbrook, a suburb of Perth (predicted by Gray and Becker, 2002)

11 Case study 1 Bridgewater Village No. of houses 389 Development area 14ha Wastewater streams (flows/volumes) Treatment systems Soil types/water bodies/groundwater Reuse systems Application rates Blackwater + kitchen to sewer. Greywater onsite 25,550m 3 /year. Each house has direct to subsurface irrigation primary filter only. 88 with reedbeds for nutrient removal Sand PRI = 1-2, category A, high groundwater area. Close proximity to Peel-Harvey estuary Subsurface drip irrigation to 301 lots. 88 lots with reedbeds followed by leach drain disposal 10mm of greywater per m 2 as per (DoH 2005 )

12 Bridgewater village Village layout Bridgewater village ETT constructed wetland for nutrient removal Clubhouse with rainwater collection tanks Pump and control room

13 NOTE Irrigation tank Balance line Main irrigation tank WM10 Irrigation of public open spaces WM Water meter Bore Water Treated Greywater Scheme Water Irrigation tank Clubhouse Irrigation Bore Water Untreated greywater Rainwater Water to main sewer Condensate Irrigation tank Rainwater WM9 WM8 WM7 WM6 WM5 WM4 Water meters Sampling bores Bore 4 Bore 3 Bore 2 Bore 1 Swimming pool WM3 Tube lysimeters To Water Corp. public Sewer Family Centre WM13 Clubhouse WM12 WM14 Clubhouse Irrigation Treated Greywater Tube lysimeters WM2 Greywater Pit Spin Klin WM Village Dwellings Greyflow Dwelling Irrigation Treated Greywater Mains Scheme water Supply WM1 Evapotranspiration trench Bridgewater Greywater System Schematic Flow Diagram Version 3, last updated 16th May 2008 Bridgewater Integrated Water System Flow Schematic

14 Case Study 2 Timbers Edge (City of Mandurah) No. of houses 260 Development area Wastewater streams (flows/volumes) Treatment systems Soil types/water bodies/groundwater Reuse systems Application rates 18ha Blackwater + kitchen to sewer. Greywater onsite. All greywater collected at central point followed by constructed wetlands Fine-medium grained loamy sands-sandy loams. PRI = medium ( ), category A. High groundwater area ( m below ground level). Close (<1km) proximity to Peel-Harvey estuary Subsurface drip irrigation on public open space (2.1ha) and road verges Max. rates: <140kg/ha/yr inorganic nitrogen; <10kg/ha/yr1 reactive phosphorus Est d volumes: x10 3 m 3 /yr.

15 Timbers Edge Layout of village Timbers Edge Greywater collection tanks Greywater Sand filter, Constructed irrigated area with chlorination wetland signage

16 260 HOUSEHOLDS GREYWATER INPUT/SOURCE WM 1 Scheme water into village Biofilter 1 Greywater Pump Station Overflow Sewer Pump Station WM 2 WM 9 Water Corp. Public Sewer Biofilter 2 Biofilter 3 WM 3 Greywater prefilter lint & hair Overflow Gravity fed Overflow WM 8 WM 7 Bore Water Tank 22kL WM 4 WM 5 Lysimeters Bore 1 Bore 2 Untreated greywater Biofilter 4 WM 10 Greywater Balance Tank 15kL Irrigation Tanks 22kL WM 6 Irrigation of Public Open Spaces Biofilter 5 Biofilter 6 Gravity Fed Water Meter Returned Treated Greywater Tank 27kL WM 11 Envirophos Tank 12kL Envirophos Tank 12kL TIMBERS EDGE GREY WATER SYSTEM SCHEMATIC FLOW DIAGRAM NOTE VALVE WM WATER METER PUMP Sampling bores Bore water Scheme Water Untreated greywater Treated greywater To main water corp sewer TIMBERS EDGE GREYWATER FLOW SCHEMATIC Version 3, last updated 16th May 2008

17 Case Study 3 Banksia Tourist & Caravan Village (City of Swan) No. of houses Development area Wastewater streams (flows/volumes) Treatment systems Soil types/water bodies/groundwater Reuse systems Application rates 76 park homes, 95 caravans 7ha Combined Moving bed bioreactor (MBBR) for all wastewater Sand, no nearby water bodies A percentage directed to subsurface drip irrigation on 40m 2 of public open space. Remainder to existing oxidation ditch To be determined subject to PRI analysis

18 Banksia Banksia s layout Dripline Moving irrigation Bed Bio system Reactor Current sewage lagoon

19 Scheme Water into the village WM All wastewater, 50kL/day, from village to sump 76 Park Hones, 95 Caravan sites Sump Sampling bores Water meter Moving bed Bioreactor Note WM Water Meter Gravity fed to oxidation pond. WM Trial site Irrigation through dripline with treated wastewater Lysimeter Pump Scheme water Oxidation pond Tube lysimeters Untreated wastewater Treated wastewater Banksia Tourist Park Wastewater System Schematic Flow Diagram Banksia Wastewater System Flow Schematic Version 3, last updated 16 th May 2008

20 Initial results Bridgewater Village Groundwater: low background concentration of nutrients N-NH 3 lighly increase after one year commenced greywater reuse. Total N: stable and low ( mg/L) Total P: low before and after reusing greywater ( mgp/l) New lysimeters will be installed soon.

21 Initial results Timbers Edge Groundwater has low nutrients Total N: mg/l Total P: mg/l Some bores no water due to water levels drop down. New lysimeters will be installed soon Low phosphorous detergents and cleaning products are encouraged

22 Intitial results- Banksia Groundwater sampling protocols are on-going Dripline system has been installed New lysimeters are installed

23 Conclusion Two possible future development scenarios for urban water system infrastructure (Eiwirth et al. 2000) a continuation of the present high tech end of pipe approach with further refinement = centralised; or low cost, low energy solutions based upon maximising source control procedures and the application of alternative decentralised biological systems

24 Conclusion Three case studies represent the applications of latter model in Western Australia conditions. More accurate equipment will be used for sampling protocols Establish the nutrient balance Answer the feasibility of ZEN

25 THANK YOU Any questions?