Sewer servicing and integrated resource management

Transcription

1 Sewer servicing and integrated resource management Gabriola Village Center Ian Ralston Eng.L. 1 Outline Sewage systems, servicing Regulatory context Decentralized concept Management Treatment techniques Dispersal techniques 2 1

2 Traditional sewer servicing RESOURCES IN Community WASTE OUT ANY RECYCLING IS UNINTENTIONAL E.G. WATER CYCLE 3 Collection to central treatment and discharge Discharge to ground or ocean 4 2

3 Alternative: Custom servicing A toolbox with a range of options Includes decentralized options Integrated water resource management Sewage, greywater, storm water Resource recovery options 5 Waste to Resource Integrated resource management WATER IN Community WASTE OUT MAXIMUM REUSE MAXIMUM RESOURCE RECOVERY 3

4 Triple bottom line 7 Integrated water management REGULATORY CONTEXT 8 4

5 Regulations Up to 5000 I gal/day, Sewerage System Regulation Over 5000 I gal/day, Municipal Wastewater Regulation Re use may also need Island Health approval 9 MWR Allows ocean discharge Allows for re use of reclaimed water No discharge limit Prescriptive Difficult to meet ground discharge req. Monitoring requirements very onerous Special approvals unlikely, slow 10 5

6 SSR Performance based Professional reliance Flexible, options for all sites Rapid process Ground discharge only Re use limited to landscape or aquifer recharge Discharge limit 11 Greywater In building re use systems CSA standards Monitoring and maintenance management needed Modified sewage systems Landscape re use Purple pipe systems under MWR 12 6

7 Integrated water management DECENTRALIZED SEWER (AND STORM) SERVICING 13 Wastewater treatment scale 14 7

8 Scale, treatment and discharge Decentralized Centralized Mix of onsite, clusters is practical Management is critical Integrated planning is preferable 15 Ownership of decentralized Individual Utility Local Gov. Central planning with mix of ownership models is practical. 16 8

9 Management of decentralized Individual No oversight Individual Central oversight Central utility Local Gov. oversight Local Gov. Central oversight or management improves reliability and performance. 17 EPA example 18 9

10 Benefits of decentralized Flexibility Appropriate servicing Greatly reduced Inflow and Infiltration Reduced leakage Community capacity building Lower capital and operating costs Lower capital risk 19 Decentralized flexibility Flexible to demand Flexible to future development Fault tolerant Match system to neighborhood Flexible to re-use opportunities May avoid inflexibility of MWR 20 10

11 Cost and flexibility DECENTRALIZED = LOWER RISK 21 Village center context Roughly 15,000 to 20,000 IG/day Small for centralized MWR system No advantages to MWR cluster systems Potential SSR mix 22 11

12 SSR decentralized mix Existing or upgraded onsite systems New or upgraded cluster systems New cluster systems for new development Central management and monitoring Central planning for integrated water and resource management 23 Decentralized discharge and re-use EXAMPLE TECHNIQUES 24 12

13 Collection options Sewers Septic tanks with gravity or pumped effluent discharge (STEP) Vacuum sewers 25 Treatment options Conventional, extended aeration Wetland systems Intensive wetland systems (e.g Living Machine ) Sand media and soil based treatment 26 13

14 Integrated system examples Combine park and treatment/discharge Aquifer recharge and discharge Riparian area enhancements Water features Combined management with storm water 27 Treatment & Recharge Wetlands Green Cay Groundwater Recharge Wetland Palm Beach County 3 MGD, 70 Acres 28 14

15 Ponds, water features 29 Dockside Green Courtesy: Dockside Green and Aqua-Tex Scientific 30 15

16 Urbanization and aquifers Shallow GW = riparian enhancement Aquifer recharge and indirect water reuse Infiltration system 16

17 Public area dispersal and sub irrigation 33 Boulevard dispersal 34 17

18 Questions? Ian Ralston Eng.L