Innovation in Sechelt
- By Jenni Green, P.Eng
The District of Sechelt Water Resource Centre has created an opportunity for communities around BC and beyond to transform how we think about wastewater treatment. The LEED-Gold certified; tertiary treatment plant created a transparent space in the residential heart of residential Sechelt that engages the public in meaningful ways. The Centre encourages the public to witness their role in the hydrological cycle.
The facility rethinks traditional municipal wastewater treatment by revealing and highlighting the mechanical and biological systems instead of sequestering them behind a locked chain-link fence. The system is disguised as a greenhouse and botanical garden between residential areas and the Sechelt Marsh nature reserve. The site surrounding the plant has been transformed into a public park where residents are free to observe the bioreactors. The building includes a public meeting room that supports educational tours and community events.
Wastewater travels by gravity and force main to the treatment plant. Larger solids are removed by mesh screens. Wastewater is aerated to mix contents and prevent odours, while organic waste is broken down by trillions of microbes. Larger solids are allowed to settle to the bottom and smaller solids are filtered out by membrane filters. All effluent is disinfected with UV light before release to the environment
|Treatment Capacities:||Treatment Specifics:|
|Average day flow: 4000m3/d
Peak flow: 6000m3/d
Future expansion capability to 8000m3/d
Influent Holding: 907m3
Batch Reactors: 4 x 1000m3
Secondary Equalization: 400m3
Sludge Holding: 400m3
|Primary: 6mm fine screens with cyclonic grit separation
Secondary: Organica Fed Batch Reactor
Tertiary: Membrane Filtration to 20nm
Biosolids: Centrifuge dewatering to 20% and composting to Class A compost
The process design includes plants suspended over treatment tanks enclosed in a greenhouse. The plant roots enhance the biological treatment process, making it more efficient, reducing energy and space requirements. The greenhouse also helps meet the aesthetic objectives for building the facility in a residential area, as well as controlling fugitive odours and noise. Although the plant was created with a small footprint, the plans allow for future expansion.
Upon commissioning, the plant achieved biochemical oxygen demand (BOD) less than 2, total suspended solids (TSS) less than 1, and no detectible fecal coliforms. This plant is in the top tier of treated water quality compared to similarly sized plants throughout Canada.
The plant design also effectively limits operational costs, which was an important consideration in selecting the treatment technology. While meeting indirect recycling water quality and Class A biosolids standards, the plant can operate using roughly 40 percent less electrical energy than the previous two plants.
The facility has received numerous awards over the last five years:
- Architectural Innovation from Architectural Institute of British Columbia – 2018
- Southern Interior Construction Association (SICA) – 2016 Innovation Award
- Federation of Canadian Municipalities (FCM) – 2016 Sustainable Communities Award
- Canadian Design Build Institute (CDBI) – 2016 – Grand Winner – Awards of Excellence
- Association of Consulting Engineering Companies (ACEC-BC) – 2016 Award of Excellence
- Association of Professional Engineers and Geoscientists of BC – 2016 Environmental Award
- Canadian Construction Association (CCA) – 2015 Environmental Achievement Award
Funding for this $24.9 million project was provided from a variety of sources.
- Contribution from the Shíshálh Nation – $1,680,250
- Senior Government Grants – $12,200,000
- District reserves – $1,219,500
- Debt – $7,400,000
- Development Cost Charges – $1,488,000
The facility is classified by the EOCP as WWT Level IV.